Darren Baum - How Bikes Behave

Episode 161 - show transcript:

Hottie (00:04)
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at SILCA.cc. I'm Michael Hotten, aka Hottie. Marginal Gains is also supported by Shimano. You know, gravel racers have an interesting balance going on. They need the grip and gears of a mountain bike and the position and power of a road bike. When it comes to pedals and shoes, they love that connected feel of road pedals. They may have to get off and walk. Enter Shimano's Pontoon System. Pontoon is a specially designed cleat and tread that works with two models of shoes in the Shimano lineup. Both the cleat and the tread are replaceable, so no matter which wears out, they can be updated, ensuring that the rider always has that planted feel that they get from road shoes and cleats. Check out the pontoon system at bike.shimano.com. We've never claimed on this show or otherwise that looks are a marginal gain. But if you think about it, having something that looks good does produce a level of inspiration or motivation.

I play guitar. Poorly, but I play. I keep my guitars out where I can see them. They look great and they do inspire me to play. Same thing with a bike. Having a great-looking bike can inspire us to ride, which is one reason we like Baum bikes. They are possibly some of the best-looking bikes made. Universally, they are loved by cycling photogs who shoot them at various bike shows. The man behind these bikes is Darren Baum.

He and his company hail from Geelong, Victoria, Australia, home to 2011 tour winner Cadel Evans and Phil Anderson, the first non-European to wear the yellow jersey. Darren Baum's home helped inspire his mission to build properly fitted custom bikes with most of the models in titanium. Josh and Darren go back a couple of decades. In this interview, the two of them share interesting thoughts on bike handling and trends. And we really nerd out on chainstay length.

It's a bike builder's look at marginal gains and the geometry chart.

All Marginal Gainers, Darren Baum is our guest. Baum Cycles is the company. They're out of Australia. This is a great opportunity, Josh, to talk to the future. Like it's tomorrow there, right? So if you want to know what's gonna happen in the bike industry, you should just ask Darren right now. He could probably tell you. It's tomorrow where he is. We're here and what is this, Thursday and he's on Friday. So great. We gotta we're we're speaking to the future.

Josh (03:35)
Quite literally, I love it. Four for anything new fourteen hours from now that we need to know about, Darren?

Darren Baum (03:41)
Uh the beers come in earlier?

Josh (03:44)
Yeah.

Hottie (03:47)
Awesome. Awesome. Well, Darren, it's great that that you joined us. morning time there in Australia, evening here for for us two, for Josh and I. so thanks for being on the show and and sharing your story about about Baum cycles. Josh always likes to hear this question asked first and I've kind of taken it over, Josh. I'm sorry I've wrestled this away from you, but I think it's it's a brilliant one. And that is, Darren, how did the bike enter your life?

Darren Baum (04:12)
Very early on, as an actual fan of the sport, I lived six to eight miles out of town. And the longest, biggest one-day race in the world went across our front driveway. So I used to stand out there as a little kid and watch the Melbourne to Warrnambool go by. So that was the very first thing, just being a little kid fan of the side of the road. as I sort of entered high school.

was looking for independence, was riding a good old sort of 10 speed bike to school. And there was the local bunch that was going by that I was, you know, getting onto the back end of the bunch. And they'd do a little sprint at the first street sign. And I had the school bag on. I was sprinting against them. So they would kind of like, hey, maybe you should come and join this at the start of the ride. So from there, that definitely got me into the bunch, the riding, which

very quickly got me into, hey, I need some new com you know, new new components, more speed, more free speed. So I could afford a new bottom bracket and stuff, but I couldn't afford for them to do the shop mechanics to actually fit it. So I talked them into allowing me to do my own mechanics in the shop. And they saw that I was pretty handy with the tools.

And they after I put my own bottom bracket in that I just purchased from them, they offered me a job straight away. That's where my story starts get getting murky. Cause to get the job I was underage, so I lied about my age. So I I started my working career off a lie. So I definitely have too many years of working in the bike industry that doesn't quite add up. the very next big significant thing that got me

Into the industry, we did a a careers day and we traveled to Melbourne, which is like 40 miles away on the bus to work out what careers you're gonna do at the exhibition buildings. As I turned up there, the old Australian bike show was on, which was just purely trade, no public. And as any good, ambitious kid would do, he broke into it, jumped the fence.

Got in, I found a company that was British International, and they were the distributor for Reynolds Tubing. Somehow, I don't know what my pitch was, that I convinced them that I was an up-and-coming athlete and was going to be a frame builder. So they sponsored me a tube set. With that, I ran around and I found a frame builder, Brian Cross.

And I convinced him that I should be allowed to do work experience with him to build up this tube set. Which I stated that I wasn't going to put his brand in on it. I had to put Baum on it because I was going to start my own brand. So I I wish I could have been a fly on the wall and seen those two pictures. Came out, I remember a teacher just screaming at me, thinking, you really think you're going to do this as a career?

And so from that was 89. that was my first bike. From that point on, I have built bikes from that. 96, we started doing commercial work, and 2004 was full-time. So that means commercial work, we've been doing it for 30 years. 92, where I got most of my experience, was I entered the aircraft industry, and so I did a

decade alongside an aircraft. So that's started racing in that eighty eight kind of era and you know you still pin a number on today.

Josh (08:11)
I love it. What a what a great way to I mean, cut your teeth. I would like to be a fly on the wall in that room as well. Like the things we did as kids, you're like, I can't believe I did that. Like I'm I'm proud of myself. I th that's amazing.

Darren Baum (08:24)
Yeah, I just wish I could go back and see what the pitch actually was, if you know what I mean. It's like, yeah, I'm I'm a good enough athlete and a frame builder. Like let's just let's just send it. Nothing's like confidence.

Josh (08:36)
That's right. Fake it till you make it. And and you've made it, right? So and then you cut your teeth in aircraft. I know you and I so we've we first met four, I think, give or take? Yeah. Yeah. And so

Darren Baum (08:46)
Yeah, O four. At

that s that stage I was supplementing the frame building with bringing an American Classic and at that s we were using zip rims and we had a strong discussion on where they were maybe had some issues at that stage.

Josh (09:04)
Yeah. Yeah, those were early, early carbon wheel days. But yeah, and then we catch up at I mean, I l really enjoy I feel like we're always the two at the end of the Australian handmade show who are standing there like sharing a beer and chatting as they're like trying to close the show down and like, everybody it's time to leave. Like, no, but we're still going. Which I I I really enjoy. So But yeah, talk talk to me about your your time in aircraft. I mean I'd have a deep

love of aircraft and aerospace engineering and and that's something you and I both enjoy talking, but what a what a great world to cut your teeth in to do what you do now. Yeah.

Darren Baum (09:45)
Yeah,

so the aircraft rungs runs extremely strong in the family. So my father has a private airport, so I I like bikes, so I build bikes. He likes airplanes, so he has an airfield. And so our emergency fire and services for our state are run out of here when things are out of his place when it goes wrong. So Alva's the big air.

Helicopter that does all the fireBauming that runs out of his place. So he has quite a thing. But I was in heavy maintenance. So 747, doing section 41s, where we took the frames from being 7075 T6 to 2024 T3, which was a huge project. Then we also were doing pylon mods. So my true background is, you know, doing engine runs on seven four sevens and that type of stuff.

I did a lot of machining of titanium in that. I probably nearly felt like I found my spot. I was kinda up in the machine shop, making all the tooling, doing all the special projects from a very early age, you know, from I started that at seventeen.

Josh (10:59)
amazing. So do you you ever get to do any of the five engine seven four seven runs with moving engines around on that fifth pylon or I There's some of my favorite photos of just it looks so wrong, but so

Darren Baum (11:12)
I was responsible for stopping that, so

I I I remember being a a third year apprentice being very, very arrogant. inspection panel was taken off to the hot section and to do a probe to have a look, and when they're doing the bolt back up, they broke it off and they got me in to remove the the the broken bolt and all the rest. And if it fell into the hot engine, the hot part of the engine, they were gonna have to fly.

A fifth engine out on a extra pylon, which is, you know, not a commercial flight. It's like it was gonna actually shut the company. So it was like I had all the white suits down there inside the engine, sort of telling me, you get this wrong. The company literally goes broke. We can't afford to fly an engine out on the fifth, on the fifth pile.

Josh (12:09)
Aaron That's amazing. For for the listeners who aren't playing people in a 747 has four engines, the engines were so big they were really expensive and almost impossible to transport otherwise. And so there's a fifth hidden fifth pylon that you could bolt an extra engine on one and it could fly its own engine to be a spare for another aircraft somewhere. So if you Google it, the photos are amazing. You get three engines on one side and two on the other. It it it's really cool in a in a very w wonky, wrong looking sort of way.

Darren Baum (12:39)
Yeah. But I I I just see dollar signs like it's big like flying an extra engine to Australia is yeah, that's twenty four hours of that huge thing just hanging out there. It's not marginal, that's for sure. Yeah.

Hottie (12:55)
I sense a balance issue there, or no? I mean, wow, that seems wild.

Josh (12:59)
In a plane that already just drinks gas.

Fantastic. Okay, so you're you're machining titanium and you're finding your y are you thinking like this is my thing? Like this this is were you seeing bicycles in in as you're

Darren Baum (13:17)
I I thought I I saw bicycles from day one. So my original graphics at high school was all about bikes and logos. So I started working on that logo from day one. I when I entered aircraft, I let everyone know that I was going I wasn't gonna hang around, I was gonna now go off and build bikes. So it was the only thing that I've been absolutely consistent with. Now the aim was to be to win races on my own bike.

I did manage to do that a few times, but I definitely be was more renowned for an actual frame builder than a bike rider.

Hottie (13:54)
What kind of races were you in?

Darren Baum (13:56)
I was a a very good young young rider, but in '92 I was ran over by a car that was doing 70 miles an hour on on on on on the highway. So that sent me down. That was the worst thing from an athletic point of view.

But from actually trying to work out how to put the South back together, that was the drive for me for all the fitting knowledge I have. It was very personal as about trying to solve personal problems. But I I'd certainly raced against guys that had ended up winning, you know, grand tours and grand jerseys and so I I I raced against the best and I made look very good.

Hottie (14:40)
That's very nice of you to say.

Josh (14:44)
well and and similarly your your your story you just told I mean, you're essentially Eddie Merck's, right? Hit by a car that forced you into an obsession with bike fitting. So that, you know. So that that tracks that tracks also.

Darren Baum (14:57)
Yeah, and bike fitting has just changed so much along the way. And that is sort of the basis of the ethos of the company still. It's like that's why I was so keen to become a frame builder, because I worked out very quickly that I was a very odd, odd shape. So back when I was probably, you know, 20 plus kilos lighter, sorry for the metric, I used to ride like a fifty-four

Tall frame by sixty long with a one fifty stem. So like and looked normal on it, so that was the first drive. No, I wasn't that un unusual it was very aware that I needed a you know a tailored frame. six foot one.

Hottie (15:44)
Yeah, and how tall are you? Okay,

you're my height. But a sixty you're saying a sixty top tube? Is that what you said?

Darren Baum (15:51)
That's what I used to when I was racing used to be sixty top tube with a one fifty stem and looked right along looking looking normal. That that that was it was just really quite freakish. So the the lower part of my leg's very, very short. My upper thigh is very long. Okay.

Hottie (16:11)
And so how did the injury or injuries inform your knowledge of fit and what you did with fitting?

Darren Baum (16:23)
it I had problems with the left leg going numb and mainly the interaction with seats and feet was very num the other unusual thing is I've got very short toes for the size foot I have, which makes it very easy to drop drop your heel and your hip will chase your heel down.

So there was that underlying problem and then being hit by a car and you know very become quiet wonky didn't matter how many car I practiced and that I went to or different kind of physios, with that added of dropping the heel as well. So there there's nothing like the motivation of just trying to fix yourself to just keep digging. It was very personal.

Hottie (17:20)
And then through that process you learned a lot about some of what was accepted about some common knowledge about fitting and learned what was wrong with that process. Is am I correct in making that leap?

Darren Baum (17:34)
I was working in aircraft, so that got me cheap flights. So anyone that thought they were a good bike fitter, I was willing to go and visit. So the first thing I did was try to solve it by, you know, just going to if someone thought they were good at fitting, I'd turn up there and be fitted by them. So I got all that learnt learnt experience. so bat that was huge. Then there was a renowned

bike fitter that was Steve Hogg in Australia, which is probably I still classify him as one of the greatest fits. he when he went to be when he got his learnings, I was the Grom on the bike for those four days. Peddle and Wayne as he was being teached. So I got all those learnings as as well. So this has just been a pursuit of mind since

eighty nine, you know, when I went to Brian Cross as the frame builder, he the first thing he identified was like, hey, you you're definitely long, you're right, you definitely need a, you know, he called her a custom frame back there. He measured me up straight away, made it long. So as soon as if you're told you're outside the box very early on, you're quite happy to stay outside the box.

Josh (18:59)
Well, and and that I mean has all come full circle for you. I mean, I you're I think one of the things you're extra famous for is I mean people from all over the world fly all the way to Australia to be fit by you, right? So that that what an awesome full circle moment. But yeah, I guess talk talk to us about some of that or as as much as you can tell us.

Darren Baum (19:20)
We've

been a very open way. all the way through we've learnt all the different methodologies. and knowing how that also makes the bike handle. It's about making a complete bike that is the most important thing. the big topic now is cranklenth, and we're lucky to have the bikefitting.com or the Shimano Fitbike.

That we work our crank length by vectors. So we can see where the vectors are actually happening. And that tells us what muscle you send off that. We can decide what is the right crank length for it. And it just pops out. Yeah, if you get a red one at 12 o'clock vector, you know the crank is too long, the hip is being jammed. we can also see if the gym's that the hip's being jammed by a Q factor.

At the same time, we fit by a balance method. So, you know, seat going forward and aft changes how much weight is on there on the hand. And then changing the cleat position changes where those vectors actually go. So we use a lot of technology and a lot of eye. the thing that probably does interest your

listeners now is in recent times we've put low sales on each corner of the fit bike. And so we're also using the center of gravity. We can measure center of gravity in real time. and we use that both in the fitting part first up and then we use that for the actual handling of the bike from there. some of the most surprising things we found recently as much as putting

Increasing the Q factor by as little as four mil can open up the hips and we can get a like a fifteen mil shift of C or G forward. Which is just kind of you wouldn't you y it's just one of those things you just don't kind of accept. You know what I mean? And it's

Josh (21:33)
Right, right.

Feels like the wrong axis. Like we went wider and and that we shifted

Darren Baum (21:39)
Forward. Yeah. It's just like where you open up that hips and just allows them to bend forward. And it's we can you see it same with all these different seat shapes as well. There can be a seat that is comfortable, and then we can have a seat that you can see actually rotates the pelvis and you can measure it by angles and stuff. But now we can also measure that what it does with the C or G.

So that that's been really it's be it's given us a lot of insight.

Hottie (22:15)
So when you're measuring for center of gravity, are you doing this dynamically? In other words, you have the rider stand, sit, corner. Can you do it in in all types of positions?

Darren Baum (22:25)
Yes. so my other great passion is mountain bike. So we've got load sales on each corner of the fit bike. So we've got l live C of G. so the first the main part of fitting, we use the seated position for the seated position for the bulk of the COG fitting. And then we look at in

the drops for all the handling side of stuff for road bike. And then we also look at sitting no pants up, no hands and what that actually is. and we don't really use the XY that the height, we don't calculate that. We use that by just measuring the belly button. If we're doing more extreme gravel fit or a mountain bike fit,

We also look at the alpha and beta angles of that C or G of weight going over front axle or the ability to pull the front wheel up for manually at the same time. So if we take that C or G measurement from the fitting and once we've got it where we're happy with, we then can put that into a program that we look at the weight.

of fore and aft. And so it's like scaling a car, like so we know how much weight is on the front wheel, how much weight's on the rear wheel. At the same time, since we've got the weight, we're doing the tire pressure calculation, like recommending what tire it is. those calculations we're looking at as a percentage and a raw kilo weight as well.

Josh (24:14)
Yeah, this is something that you you and I actually had an amazing discussion about a month ago when I was in Australia on d in in discussions around the 32-inch wheel. You know, I had I think a year ago when we talked in 32-inch wheels were like the brand new thing, and you had one of the first bikes I'd ever seen with 32s. I mean, I think as is typical that that started to happen and people are like, let's talk to Darren.

But you know, I had made the comment of like, God, it's going to be 29er all over again. And for those of you who weren't here when 29ers happened, the first two generations were like absolute rubbish to ride. And you s you quickly said, I think we got it on like what the first or second try because of this because we're looking at C of G and I went, shit. So so I guess talk us through the 32-inch progression, because it sounds like you've got that geometry pretty much dialed.

Darren Baum (25:07)
Yeah, we'll we'll go back in history and look at where I feel geometry really came about all ties had the same amount of grip. And so anything that we're doing a lot with geometry was about just trying to get weight, as much weight on the front wheel to create as much grip as possible. When we sort of jumped forward 30 plus years now and we're starting to talk 32, we

naturally have a lot of grip on the front wheel because just by the pure size of the wheel we have a long chain stay. So long chain stays transfer a lot of weight to the front wheel. We've got a a a big tire and actually width and longitudinally with the contact patch. So it's the first time in life that we just have lots of grip. So if we think back traditional design and of handling of bikes is all around grip and all of a sudden we've got

So much grip, we don't have to as much look at that trail and head angle. Yes, it's still very important, but it isn't the biggest driver of grip now. And 32 has been a lot easier transition than the 29. And there's there's a lot of reasons for it. we've already got through axles. So the stiffness of the forks and all the rest is there. We already have carbon rims, we already have.

tubeless. We already have all the new compounds and the tyres are grippier and just way better constructed. we already have the gear ratios to actually run it in small chain rings. So that was it's already been no invented. We already got the you know headset standards and steering and tapered steering. So all those original incremental steps that we had with the 29er

most of those are already been sold for thirty two.

Hottie (27:09)
Yeah, the grip seems to be the increase in grip, and I've heard you seen you talk about this before, seems to be one of the big things that you believe should drive a rethinking of geometry. Did I understand that that correctly?

Darren Baum (27:25)
Geometry is a i it's a very complicated thing to go around. And probably it's easier if you go what type of bike we're actually talking about, if we're talking about a 32 or a road bike. but even in the road bike category now, even from what used to be, you know, 23s, 25s, they were very grip limited. And so we used to have to have

650C tires for small females because we just didn't have enough grip. So the easiest way to get more grip there was bring that front contact patch as close as we could get. All the females that have come back in that I had as 650C bikes from 15 years ago, I've managed to emit onto 700C bikes. Because if we put them on a modern 32 mil road tire.

It's just got so much grip, we can push that front wheel out, and it's can create the same amount of grip with less kilos actually on it. And so we can push it out there. It it it kind of hurts. it hurts your head thinking about it because we thought the drum the geometry did work. Okay. But why it worked, it was because that geometry gave a certain amount of grip. And that was because we're always in a

Ooh, grip limited situation.

Hottie (28:54)
Well quite obviously folks, Darren is a is a deep thinker on how the human body interacts with the bicycle, how they're set up, how they're set up for each and individual rider. and I think y you illustrated that pretty clearly, Darren, in twenty nineteen when you created what you called the Darren bike.

and this was during the rise of of the gravel bike. Tell us about the Darren bike and and the evolution of it.

Darren Baum (29:18)
Yeah, it's one thing to have all these theories floating around and getting good results, but then when there's a step change of going to gravel, we made we made a bike that had a adjustable head angle, changed stay length, a centric bottom bracket. We also had a seat post that was flippable. So what we could do is very quickly for my size bike have it nearly through the whole

size range. We also had a angle adjust headset in it and adjustable fork rake. So I could go out and ride and make intermedical changes very quickly on the same day in the same conditions and just go and go and play and worked out what actually worked and what didn't work. the findings that came from that was

bottom very quickly that you could actually have a bottom bracket too low. And that was a kind of a scary moment. If you just keep dropping the bottom bracket and you get it onto asphalt road going fast, lower bottom bracket makes the longitudinal axis spin quicker and re-re-correct itself. So if you lent the bike over and then let it come

Back up, it'll come back quicker than the organic piece could actually do it. So the bike would stay upright and you'd actually could fall off the bike. So and that's certainly something with a 32-er that you can actually drop the bottom bracket too low and the bike will read correct and the human will just keep going, can't change the direction, can't change the direction as quick.

The other very interesting thing that was the chainstay length. short chainstays will push the bike through the corner. So it'll bike all under steer. And you'll you'll feel it in it's cut sometimes it's easier to feel on a mountain bike. So if you ride into a berm, your front wheel goes up around the berm and the back will try to push down into the bottom.

o of the the corner. If you lengthen that that stay, the back wheel will run closer to where the front wheel tracks.

And the big difference I found in a gravel bike, and especially when from the Durham, the next big step was when we got into putting mountain bike tires onto our gravel bikes. That also lengthened the rear end even again, just by necessity, you ended up with the wonderful situation of you had more grip on the front, so it'll stay. The chain stay being longer.

It would naturally want to fall into a speedway slide. So instead of trying to understeer and push you through the corner and make the wheel flop away, it would fall into a Broadway slide. So the back wheel would go wider than the front wheel and sit there and just be stable. And you know.

It was frightening the first couple of times that it just naturally fell into that situation. I'm just at kind of the fifty mile an hour mark, I was descending on gravel and it just went into a beautiful two-way slide. And you're just like, Okay, this is this is frightening that this works so well and feels so comfortable. And

those scenarios is like, okay, I've got this to work extremely well for myself. How are we going to put these numbers to to our customer base? And that's what actually drove us into looking at more of the COG of what's happening where the weight is actually falling.

Josh (33:37)
Yeah, that's fascinating. It it it's kind of reminiscent to be. I mean, you're talking about like like modern aircraft stability or you commercial aircraft stability, right? It's a very similar like you know, C of G relative I mean, obviously there they're aerodynamic forces, but yeah, you're talking grip forces relative to your C of G having sort of a self-stabilizing effect, right, right, right as opposed to understeer is not stable, oversteer is not stable. but you're better to be a little bit

in that longer chain stay to have it almost self stabilizing.

Darren Baum (34:12)
If the back wheel pushes to the inside of the corner, the wheel will that's kind of the fall you end up with breaking the collarbone. Where if it goes to the outside, you fall down and you just get grazed. So it's a actually a lot safer slide. The the big fear is that you if it does slide too far, you will may find grip in the high side, which is nasty. But we don't seem to have that problem.

With bicycles of a higher side, we just don't have the the bike itself doesn't have enough weight to catch there. So the the our aim now is for the bike to have that speed weight fall on on gravel and it's just a lot more cut it feels controllable is the easiest thing and can go into a slide and it just feels natural.

All the same things happen back on on to a road bike. It's it's mountain bike road, they all follow the same same theory. the downside sometimes to it is you do end up with longer front centres and maybe shorter stems. So the weight falls behind the front axle. So out of the saddle, climbing can feel a little bit different.

So that that's that's a that that's the downside. Yeah. The longer stems climbing out of the saddle definitely always feel better. Like the the the closer you get those hands to that front axle line or in front, it definitely feels better. So with this geometry or that that's the downside of things.

Josh (35:55)
Interesting. So what I guess in terms of length, where where do you find your kind of what's your most common chainstay length gotten to these days?

Darren Baum (36:03)
Myself, if we talk about road, I'm we're around the four twenty. And that's with me with a C a G being about sixty-five mil in front of the bottom bracket. And with a front and centre of six hundred. And with that and my weight, that ends up being fifty-two percent on the back wheel and forty-eight on the front wheel. With riding

in FLAT, so the the numbers end up where basically where you want to be. that's where flat sort of train going is where we find that there's where it gets tricky for us is it's quite easy to get someone C or G only being fifteen mil behind the fifteen mil behind the bottom bracket or so. Sorry, C or G being fifteen mil in front of the bottom bracket.

Yeah, so it then it's sort of discussion of hey, you know, I think we should try to get to four thirty, four forty in the chainstays. cosmetically on a road bike that can look a bit different. So we'll play with, you know, an offset C post and or non offset to sort of so we can hide how it actually looks. Or on gravel, I think even ourselves were not long enough.

I think the longer you go, the better it feels. Like I I think we haven't got to the ultimate handling bikes yet. I think cosmetically we start getting scared before we really actually

Get there. We w it it still needs to look right to our to our eyes. but on the that first thirty-two I ran, that was a four seventy rear rear end with a eighty-five mil bottom breaker drop, I think.

So it just yeah, makes that front wheel stick.

Hottie (38:03)
Not only the visual, Darren, it's you're trying to get over the rest of the industry too. I mean, there's a lot probably a lot of our listeners out there scratching their head a little bit right now. 'Cause the message they're getting, at least when it comes to chain staying length, is the shorter the better. I mean, that's what the industry tends to profess, like, we kept our stays as short as we could, yet got this size tire in in between them. that message is the prevailing one out there and the one most people buy in it makes sense too when you listen to it, right? But

You're saying not so much.

Darren Baum (38:34)
The the short chain stay is something that I've looked into a lot. So chain stays used to be a lot longer on bikes. Through the forties, fifties, sixties, they were definitely a lot longer. They started becoming shorter, unfortunately, when the dirty word drugs came in and the first drug of choice were the stimulants and steroids. And if you're building a bike for five three one and you had a gorilla on it, the only way you could actually make that rear end

stiffer was shorten it. So very quickly we ended up with the narrative a a racer bike has a short rear end. And the short shortness of the rear end was about the stiffness. It wasn't about the handling. Now we've got such with all materials, we've got such an array of different ways to make the rear end of the bike stiffen us or the figures that we're actually looking for.

we can decouple from that shorthand and just look at it from a handling point of view. So it's a a leftover from bad material technology from the early eighties.

Josh (39:45)
Yeah, so that that's fascinating and and makes total sense. I mean, I think of, you know, the the materials of that era, the five three one and then, you know, we had the my personal favorite, the seven five three, which was even thinner and and and lighter but but not quite as strong and and and stiff. So it I'm gonna take a leap and assume I mean you to me one of your hallmarks is that you have just the most beautifully shaped chainstays.

And seat stays. But your chainstays to me are just like absolute artistic and engineering masterpieces. So I guess just talk us through that. Obviously, you're you're really thinking through the the load transfer, the forces, the stiffness, the strengths, the but wow, it's a lot of manipulating goes into one of those tubes.

Darren Baum (40:37)
Yeah, th there's there's a so if we look at the first design principle that we have got away is having it that we can put any length chainstay in in in the bike. So nearly all our chainstays have this nice little small section that runs parallel to each other. And so we've got this area in design that we can lengthen or shorten the chainstay to our desire.

So that's just that's the first rule that we have, we have to have that flexibility. And we haven't given that up. from that, we're mainly a tie builder. So we're because of the crystallized structure of Thai, we have to have constant diameter. So our rears of our chain stays have to have quite a bit of we turn them into a sort of a square shape to lose some of the height, because I hate that.

chain chain slap. And we're lucky now that we've been 3D printing in Thai for ten or fifteen years. We started with our local university doing it. So to get the chain ring clearance and the tyre clearance we can sort of design and do whatever we've whatever we want there. we match all our yolks to the same stiffness as

a raw 25.4.9 tube. So all our yolks are the exact same stiffness. So that's probably the real tricky bit to design them. Now if you open them up and had a look inside, they some have got one stiffening rib, two stiffening ribs, three ribs. Like so there's quite a lot of play on the in inside. There's probably as as long in building a chain stay now

as what I used to build be able to build a Fire 31 bike. So it's pretty it is is a pretty intense piece of work. We've done it all off you know our own custom tooling. You just can't go out and buy it. So we sort of shaped it and, you know, started from scratch.

Josh (42:54)
Also technically technical masterpieces, but also just absolute artistic perfection. I I just love to and I love that it at the trade shows, Darren always has like a couple of chainstay brake side chainstays laying about to just show off. I mean, the the craftsmanship as well is just it's really stunning. So we'll get us some pictures and we'll we'll put them up on the show. But if for those of you listening who

G just Google it. It th you'll find a ton of it's it's one of the photographers' favorite things to shoot at the handmade shows are Darren's chainstays.

Darren Baum (43:32)
They're a actually a compound bend a as as well, which most people don't realise. So they go out and and up. And so they're asymmetric, so they're not the same both sides. So they certainly got a got a lot going on. Like I'd be happy to talk about chain stays for an hour, but most people get bored before that.

Josh (43:53)
Not me.

Darren Baum (43:55)
Yeah.

Hottie (43:56)
How many bikes are in the Baum lineup now, Darren?

Darren Baum (44:00)
how many models or how many bikes have I got personally?

Hottie (44:03)
you can give us both actually. I would love that. Yeah.

Darren Baum (44:06)
I think I've got about twelve personal bikes that are in rotation that get ridden, which is and on in in the brand, we've got we've still got we must have 15 or more. So we we've we we've still got tooling that we can make anything that we've had made in the past. And so if you can name it, we will build it for you. but we've got our

Classic rim brake bike, so we still do rim brake bike. Then we've got our Solaris, which is what I built for myself for my 50th birthday. So that's a very traditional silhouette. We've got our Orbis, which is more when I wear my Aerosocks road bike. We've got our all-road bike 40mm tire bike, our X, which is our 50mm gravel bike, an XTM that is our

modern sort of sixty mil gravel one by gravel bike, DBM, which is kind of our thirty-two inch range or suspension or our DBM's drop bar mountain bike. So it takes mountain bike wheels, mountain bike cranks. Then we have our mountain bikes extenders. I've even built myself a I call it just the apogee because I use the apogee full suspension closed box. And then we still do track bikes and

touring bikes and we have Berks and wheels and all kinds of things. So that 30 years of building kind of builds up a lot of a lot of models. And we still got our old first original Ristretto, which is our steel rim brake bike.

Hottie (45:50)
you still do a steel bike? Okay, cool. And rim brake. Hey, hooray for rim breaks. I'm glad I was glad to see that in the lineup still. What's the most what's the most popular model or models right now?

Darren Baum (46:00)
That is from a company perspective our biggest problem at the moment. It's like we've got too many models. We should get rid of some. And they're all selling evenly. Which is like, yeah, which is causes a bit of a problem that we have to rely on very solid paperwork and procedures because we're not doing it by practice. We're doing it procedurally. Like we are

I would have thought that, you know, the DBM would have disappeared, but it's selling extremely well. And it's nearly identical to the XTM. So the XTM is just gravel crank and the DBM is a mountain bike crank or mountain bike or gravel wheels or 148 compared to 142. And they sell equally as well. No, one's coming from the road scene and hey, I've got spare road wheels that I can put into this, or hey, I've got spare mountain bike wheels. So

The sheer fact that everything is selling is is is the problem.

Josh (47:09)
Makes that makes your life quite challenging.

Darren Baum (47:12)
Yeah. And it's the same as the 32 is selling a as as well. The 32 inch my first 32-inch gravel bike's probably my favorite bike to ride at the moment.

Hottie (47:26)
Why's that?

Darren Baum (47:26)
Where I used to ride my hardtailed mountain bike, I can ride that now, probably with more comfort, more speed. it's probably the most progressive bike I've got. So we detuned a lefty fork, so from a 120 down to 80. runs a dropper post. It's got the big wheels, it's got plenty of grip. It's fast on the road. The scariest bit with that bike is I've got a local descent that's you know less than a mile from

one of my houses and I've gone down that on the Ashevel Road quicker than I've done on a road bike. Which is it it it's really hard to get your head around. Like it's a it's a it's a proper road descent and with the drop of post, you you know, you drop it down, you must become more arrow and you just got so much grip that it it's not a concern. So it's just like it's even faster than the rope. So it's amazing

what you can climb up and what you can can descend on

Josh (48:31)
Yeah, it is impressive. I mean, we've got data, you know, I I get cranky about thirty-two inch wheels being yet another thing that the bike shops have to inventory and and all of that. You know, God knows we don't need any more standards in this industry, but but I mean the the testing they it does. I mean I same tire back to back. I mean you're talking eight to ten percent lower C R. It's it it it it

It works. It's it's the real deal. With improved grip, as you say, right? Which both both of those together are not a are not bad things.

Darren Baum (49:05)
Yeah, the trickiest thing has been trying to work out the tire pressures on Because quite often on my gravel bikes where I've been riding is I nearly set pressures to grip. So on the thirty-two I've been going up with pressures because I've got more grip than I need, so I'm nearly going up to decrease the rolling resistance. Like, so it gets confusing because you've and it feels

that you can actually run more pressure but still compliant. And I don't know if that's just 'cause it's displacing it's got more surface area to displace that air pressure spike. Yeah, so

Josh (49:49)
Yeah, I mean it's a it's a relative like tangency angle thing too, right? It's it's just less energy required to recruit that next square millimeter of casing, which is the lower rolling resistance. But yeah, it it definitely we we've experienced the same thing. We're actually kind of working through that now, trying to build data into the the SILCA Tire Pressure Calculator based on what we're seeing, because it everybody ki kinda comes back with the same thing of like, ooh, yeah, that we really do need need different pressures in these.

Darren Baum (50:19)
Yeah, the the the hard the hardest thing to describe with the thirty two is technical climbing. It seems to just climb better and it feels like you have better days. And I feel like I need to put a pair of scientific SRM track cranks on me gravel bike to see if I can actually it's not as spiky. So when you when you're climbing, you're looking for that traction, you don't seem to have that vertical aspect of being

raised and so you don't get the spike in power. So the power and torque seems to be smoother for the same terrain between the bikes. And I've done plenty of back-to-back riding on the same climb. It's one of those things to hard to try to you know pull out of what's actually happening, but you can climb steeper and smoother and feel like you have less torque coming through the cranks.

Which is gonna be a really hard one to weed out of what's really happening.

Hottie (51:18)
Yeah, the half day I spent on one, I noticed the same thing that the climbing I was prepared to really struggle on climbs. I thought, okay, bigger wheels, bigger bike, more weight, yada yada, right? But I thought it came down to grip, Darren. I thought, man, the grip at the rear wheel was so good that every pedal stroke was just getting paid off. No wheel slip, just straight up the hill right away. And in fact, I mean I see a lot of folks saying, Well, you're gonna need lower gears. Like instead of a thirty-two, you're gonna need a thirty or twenty-eight ring up front. And I thought, nah, I had all the gear I needed, twelve speed Shimano, fifty one

plate in the back, thirty two up front and good rip at the rear wheel and it was a hard tail, but boom, I was like you, I was I found the climbing to be surprisingly good.

Darren Baum (51:58)
It feels like you just have good legs and I've done the same climb and I've gone down and I'm lucky enough to have no nearly the identical bike with the same same tire, but in twenty-nine and go and climb it. He's just like, okay, that just it's hard to describe, but it was easier on the thirty-two. Like, I wasn't originally when I looked at the thirty-two, it wasn't so much from a performance standpoint. Is like we have some six foot eight guys that want bikes.

It just suits them better. So originally it was a back to our first principle being fitting, it made more sense from a fitting perspective for these these guys. so that's why I was willing to jump it on an early, but the performance gang sort of bonus along the way if you can actually fit it.

Josh (52:47)
Yeah. Tal talk about that. What talk about what what are you finding or what what's the lower bound of possibility frame size wise with thirty-two inch?

Darren Baum (52:57)
I I

think we're gonna have three sort of generations of thirty-two. I think we're in the era of the first generation now where we're adapting forks or turning forks upside down or whatever it may be. And to me that's around this sort of fifty-eight size is the limit there comfortably. the next era we're gonna have very quickly is dedicated sort of downward sloping stems and whatever to be able to that'll bring it down certainly quite as significantly smaller.

And there's a lot of different stems that are coming in technology for that. And then I think the third generation will open it up to everyone and we're gonna see some true wacky stuff that, you know, the first thing that I'd do if I was in control of Rock Shock would be I'd I'd do a direct mouth stem to the top of the fork crown. And then and as soon as we get there, that's good there's gonna be no size limitation. So to me, we're still in that first generation.

And so we're doing it for the taller rider and recommending it for that. on on the mountain bike side, with that longer chain stay that you end up with, I think we probably will need to run handlebar height a little bit more. And it just it you can't get away from the long chain stay, which if you're a poppy rider and you want a manual more and all the rest, the best thing you can do to bring that back into the design is

Bringing the handlebars up. That's why we've got so many riser bars in our mountain bike scene now. It just makes that front wheel lifting. So you could build that in. So the mountain bike, if you're willing to get your head around it, hey, I'm I'll have those handlebars up and it's an actual benefit. because arrow is not, you know, the most critical thing in a cross-country World Cup.

still the speeds at I know they're fast, but I think you still get more performance out of the the wheel.

Josh (54:58)
All right. You you heard it here first, people. Darren just mashed up s mountain bike suspension fork with eighties pursuit bike vision in my brain. Yeah. That's right.

Darren Baum (55:11)
That's

Josh (55:13)
The ta Russian tachyon pursuit frame, like, now I've got visions I can't get out of my head, man. I think

Darren Baum (55:19)
It it's gonna be beautiful, isn't it? it's

Josh (55:22)
we should let's start now on a next year's show bike.

I I won't I I think I think I wanna I wanna own the first one of these 'cause I can't I can't now stop thinking about it.

Darren Baum (55:35)
There there's definitely there there's solutions there. And it's gonna just be interesting to who that that comes. You know, it's I think there's plenty of engineers that can think of the solution to it's who's gonna be willing to get the no the backing behind

Josh (55:51)
well this this has been fascinating. Darren, I every time I talk to you I come away with a giant smile. and and I think we should definitely do this again. May maybe we do an a whole episode on chain stays.

Darren Baum (56:06)
I'm I I'm up for the chain stay.

Josh (56:08)
Yeah,
I I know you are. And and I I mean that's one of my favorite topics, topics as well. But Darren Baum, I mean just absolutely a pleasure speaking with you as always and thank you so much for coming on the show and we look forward to talking to you again soon.

Darren Baum (56:21)
Thank you.

Hottie (56:27)
Thanks again to Darren Baum. Baumcycles.com is the website. One thing you will notice there is some pretty big price tags. Darren notes that the price includes his extremely detailed analysis and fit, and they are able to handle the entire process remotely if you can't make it to Australia. 

We are always gathering questions for our Ask Josh Anything episodes, and here's how to submit. Text or call to Marginal Gains Hotline at 317-343-4506. You can also comment on this or any episode at marginalgainspodcast.cc, which is where you'll see all the links to the various platforms for listening to the show. We will be back soon with more questions and answers. Thanks again for listening to Marginal Gains.