Custom carbon?

[woodworker]

Originally Posted by prototoast

Where did this come from? Do you have some knowledge of chronic speed wobble on custom carbon frames?

Leonard Zinn, who is pretty tall and makes bikes for taller cyclists (and also writes the Technical FAQ column at Velonews), talks about this during the podcast below on frame geometry. It's a problem for taller riders, apparently (I'm not one), so he reinforces the headtube and takes certain other measures to account for it. The podcast is a good listen in terms of frame geometry issues.

https://www.velonews.com/2018/10/bik...rd-zinn_480109

Greg.

[prototoast]

Originally Posted by woodworker

Leonard Zinn, who is pretty tall and makes bikes for taller cyclists (and also writes the Technical FAQ column at Velonews), talks about this during the podcast below on frame geometry. It's a problem for taller riders, apparently (I'm not one), so he reinforces the headtube and takes certain other measures to account for it. The podcast is a good listen in terms of frame geometry issues.

https://www.velonews.com/2018/10/bik...rd-zinn_480109

Greg.

Yeah, I've listened to that already, and have read lots of other articles on speed wobble after having my own issues about 10 years ago. What I can't figure out is why rnhood chose that as a particular issue to raise. Obviously no one wants speed wobble, but that certainly isn't a problem specific, or even more common, with custom carbon bikes compared to any other bike. And I've never heard of any company offering a "speed wobble guarantee".

I just found it a strange comment, and one that seemed designed to drum up fear more than anything else. There aren't that many custom carbon builders, but folks such as Mr Crumpton seem to get overwhelmingly positive reviews. In choosing any custom builder, it is important to go with somebody you trust to do a good job, and to single out the one issue of speed wobble, un-prompted, seemed to imply that was a common concern he should have with a custom carbon build, and I wanted to know if he had any evidence to support his concern.

[rnhood]

Originally Posted by prototoast

Yeah, I've listened to that already, and have read lots of other articles on speed wobble after having my own issues about 10 years ago. What I can't figure out is why rnhood chose that as a particular issue to raise. Obviously no one wants speed wobble, but that certainly isn't a problem specific, or even more common, with custom carbon bikes compared to any other bike. And I've never heard of any company offering a "speed wobble guarantee".

I just found it a strange comment, and one that seemed designed to drum up fear more than anything else. There aren't that many custom carbon builders, but folks such as Mr Crumpton seem to get overwhelmingly positive reviews. In choosing any custom builder, it is important to go with somebody you trust to do a good job, and to single out the one issue of speed wobble, un-prompted, seemed to imply that was a common concern he should have with a custom carbon build, and I wanted to know if he had any evidence to support his concern.

No, I am no aware of custom carbon builders having a speed wobble issue other than Calfee (and he promptly resolved it) so, there should be no problem getting a guarantee (or some type assurance) from them. I do know that larger frames in general, have been more susceptible to this unsafe handling phenomena. I have experienced it, I know other people that have experienced it, and it seems steel bikes are far more susceptible - larger ones in particular. If I was spending big bucks on a custom frame - carbon or metal - I would want assurance that it is not going to happen. The next person may not have any issue with slowing down and/or clamping the top tube with his knees. But that is not my preference. I want a bike that does not do it, and fortunately I have one - an S-works Tarmac.

If I only rode flat terrain, Florida for instance, I may not care. But that is not the case with my riding.

The point here, is that I believe or would want some type assurance that speed wobble on a fast descent isn't going to happen. In other words, if I am to pay thousands of dollars for a high zoot bike, it better damn well behave like a high zoot bike otherwise, I want my money back.

Your mileage may vary.

[cgolvin]

Originally Posted by m4rk540

You're in MASH SF?

I'm sure there's a very funny joke there that I'm not getting

Originally Posted by m4rk540

Didn't Hern start at Predator? They were building interesting yet rough CF bikes a few years back.

Very possible but I only met him down here, someone recommended him to repair the BB shell on my Pina, he did a nice job.


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[m4rk540]

Originally Posted by cgolvin

I'm sure there's a very funny joke there that I'm not getting





Very possible but I only met him down here, someone recommended him to repair the BB shell on my Pina, he did a nice job.


Sent from my iPhone using Tapatalk

If we're talking about Hernando Montenegro, I'm only aware of what's been related by my former elite BMX and MTB associates. There's a great video out there where he does a ride on a track bike with his BMX bike strapped to his back. He proceeds to rip some rad BMX freestyle at a park. At that time I think he was the only non-SF member of MASH.

https://www.youtube.com/watch?v=aNCPEzdZs5s

https://www.youtube.com/watch?v=VTEWIiFPDN4

https://www.benscycle.com/cinelli-ma...lt_163/product

I guess Predator moved from Santa Monica to Nashville.

[cgolvin]

Originally Posted by m4rk540

If we're talking about Hernando Montenegro,

That's him. I have seen a video of him doing a fixie race around Griffith Park with some quality braking skills. Good descender in my experience as well


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[Kirk007]

I too find this comment a bit contrary to my experience.

I ride big bikes and I have experienced speed wobble in the past with a couple bikes - particularly if I loaded up the bars with a bag or unbalanced weight on some bikes. But I'm betting most speed wooble has as much or more to do with rider conduct or other factors.

If everything else was ruled out I can't imagine a responsible custom builder not addressing it. For the record, I can ride my Hampsten carbon, Kirk Steel, Sachs steel, Spectrum ti, 333Fab steel - all 60+ frames, all custom - downhill no handed on a bumpy road at 35+ mph without even a hint of wobble or instability.

Originally Posted by rnhood

No, I am no aware of custom carbon builders having a speed wobble issue other than Calfee (and he promptly resolved it) so, there should be no problem getting a guarantee (or some type assurance) from them. I do know that larger frames in general, have been more susceptible to this unsafe handling phenomena. I have experienced it, I know other people that have experienced it, and it seems steel bikes are far more susceptible - larger ones in particular. If I was spending big bucks on a custom frame - carbon or metal - I would want assurance that it is not going to happen. The next person may not have any issue with slowing down and/or clamping the top tube with his knees. But that is not my preference. I want a bike that does not do it, and fortunately I have one - an S-works Tarmac.

If I only rode flat terrain, Florida for instance, I may not care. But that is not the case with my riding.

The point here, is that I believe or would want some type assurance that speed wobble on a fast descent isn't going to happen. In other words, if I am to pay thousands of dollars for a high zoot bike, it better damn well behave like a high zoot bike otherwise, I want my money back.

Your mileage may vary.

[doomridesout]

I have no idea how much they cost but I'd look hard at McGovern Cycles. And when you send him an email and find out what they cost, post it here!

[sfo1]

Semi close is nice considering I drive to Tahoe often. Like this bike but really question the rear brake mount and routing. There must be a reason.

Originally Posted by doomridesout

I have no idea how much they cost but I'd look hard at McGovern Cycles. And when you send him an email and find out what they cost, post it here!

[woodworker]

Originally Posted by prototoast

Yeah, I've listened to that already, and have read lots of other articles on speed wobble after having my own issues about 10 years ago. What I can't figure out is why rnhood chose that as a particular issue to raise. Obviously no one wants speed wobble, but that certainly isn't a problem specific, or even more common, with custom carbon bikes compared to any other bike. And I've never heard of any company offering a "speed wobble guarantee".

I just found it a strange comment, and one that seemed designed to drum up fear more than anything else. There aren't that many custom carbon builders, but folks such as Mr Crumpton seem to get overwhelmingly positive reviews. In choosing any custom builder, it is important to go with somebody you trust to do a good job, and to single out the one issue of speed wobble, un-prompted, seemed to imply that was a common concern he should have with a custom carbon build, and I wanted to know if he had any evidence to support his concern.

I can't offer any insight to this question that you've posed, as to motivation.

Also, I haven't run across any comments or articles addressing whether some materials are more prone to this type of problem, especially in larger geometries. I'm guessing that any custom frame builder worth his salt and would be aware of the potential issue on larger bikes and would modify accordingly.

At a personal level, I'm 5'10 inches and ride a 54-55 effective top tube. I never had the problem on a titanium frame from Seven or a mixed carbon ti frame until a few years ago. It was on the titanium frame on a really steep descent, and my chain came off, and I shifted forward on the bike and was trying to catch it by multiple shifts. For me, it was all about my odd forward position on the bike and the speed. It never happened before or after. Just kind of dumb on my part.

I'm sure that you'll be fine. BTW, you might check out Craig Gaulzetti's bikes (all carbon Aerotack). I've seen them at his shop, and they look really nice but haven't had a chance to take one of them out for a test ride. That would be full carbon.

Good luck,

Greg.

[ergott]

Originally Posted by sfo1

Thanks for the tip.

Roubaix is likely the ugliest bike on the road (IMO, of course); snack box, kooky seatpost and obsolete Cannondale head shock gizmo. I rode the hi mod Synapse and it will fit my gangly needs but it just didn't have much road feedback or get up & go. I am comparing to a TCR Advanced SL so maybe not fair.

What about Trek Emonda in H2 geo? Should tick a lot of boxes too. I love custom carbon, but trying to be realistic with your budget.

[prototoast]

Originally Posted by sfo1

Semi close is nice considering I drive to Tahoe often. Like this bike but really question the rear brake mount and routing. There must be a reason

I believe at the time he didn't have a mold for flat mount dropouts so he used plate style, which necessitated ISO mounts. For a small builder, molds are in short supply so you do what you can. I don't think he uses those dropouts anymore, and now does flat mount brakes.

If you're ever in the East Bay and want to see more about the carbon frame building process, PM me and is be happy to show you some of what I've got.

[David Kirk]

I don't know what Mr. Crumpton charges for a bike but if I were in the market he'd be the first guy I call.

dave

[sfo1]

Originally Posted by ergott

What about Trek Emonda in H2 geo? Should tick a lot of boxes too. I love custom carbon, but trying to be realistic with your budget.

The Trek is on the list but in my size I gotta say its 'visually challenged.'

Originally Posted by prototoast

I believe at the time he didn't have a mold for flat mount dropouts so he used plate style, which necessitated ISO mounts. For a small builder, molds are in short supply so you do what you can. I don't think he uses those dropouts anymore, and now does flat mount brakes.

If you're ever in the East Bay and want to see more about the carbon frame building process, PM me and is be happy to show you some of what I've got.

I am in SF. I will drop him a phone call today to get some info.

Originally Posted by David Kirk

I don't know what Mr. Crumpton charges for a bike but if I were in the market he'd be the first guy I call.

dave

A lot. I recall it being in the Argonaut zip code. But, in reading about the suggested Hampsten line, (Crumpton) is advising on the carbon bikes.

I am test riding an Altum today. We'll see if it ticks the boxes.

[Mzilliox]

Originally Posted by David Kirk

I don't know what Mr. Crumpton charges for a bike but if I were in the market he'd be the first guy I call.

dave

yup, no brainer, but he's about 1k over budget if i'm not mistaken. I need to put in a call to Mr Crumpton soon