Zipp tubular rim repair at brake track

Everything about building wheels, glueing tubs, etc.
joejack951
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Joined: Fri Feb 18, 2005 6:50 pm
Location: Wilmington, DE

by joejack951

I picked up a pair of 60mm Zipp wheels with nearly new Corsa G+ tires locally for quite a steal (roughly the cost of the tires). Best I can tell they are from the mid-2000s but the ticked the boxes for my not-well-used TT bike: cheap, cheap, cheap, tubular, rim brake. One reason I got them so cheap is that the rear has some damage at the brake track apparently from a pothole strike. It's really only bad on one side as far as I can tell. I just got a chance to ride them for a short while tonight with some new brake pads (Shimano carbon fiber pads to replace the original pads in the Dura Ace 7800 calipers) and while serviceable, the rear brake is definitely compromised. I'd like to make an attempt at smoothing things out even just a little bit, but obviously am not looking to invest any significant money into this rim. I have some Loctite Hysol epoxy from a Stronglight crankset repair which I'm thinking could use to fill the voids but I wanted to picked the collective Weight Weenie brain before trying anything.

Here's the damaged spot:

Image

Thoughts, concerns? I appreciate any guidance or been there, done that type of advice.

by Weenie


spdntrxi
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Joined: Sat Jul 20, 2013 6:11 pm

by spdntrxi

I would use them on a trainer... maybe

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TwiggyTN
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by TwiggyTN

I'm sorry, but no, that wheel is trash man. Strip the freehub body and hub internals that aren't destroyed and bin it. It's gone....

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joejack951
Posts: 668
Joined: Fri Feb 18, 2005 6:50 pm
Location: Wilmington, DE

by joejack951

Ok, so one vote to rebuild with a new rim :D

[edit] Make that two!

But seriously, what is your concern with the rim if I can find a way to make braking tolerable or even if I decide to leave it as-is?

DarkerxHalf
Posts: 30
Joined: Sat Jul 14, 2018 9:23 am

by DarkerxHalf

What is the concern?! The strcture of that rim is toast, meaning it's an almost definite that your face also may end up toast when this thing implodes on itself.
2002 Moots Vamoots
2018 Cannondale CAAD12 Custom (RIP)
2018 Cannondale Supersix Hi Mod (SOLD)

joejack951
Posts: 668
Joined: Fri Feb 18, 2005 6:50 pm
Location: Wilmington, DE

by joejack951

DarkerxHalf wrote:
Sat Aug 24, 2019 9:43 am
What is the concern?! The strcture of that rim is toast, meaning it's an almost definite that your face also may end up toast when this thing implodes on itself.
I can assure you that the structure of the rim is not toast. The wheel is true, there is no ‘hop’ at that point indicating out of roundness, and the damage is nowhere near a spoke hole. On top of that, it is a tubular tire that isn’t going to suddenly deflate if the rim were to give a little. There are already 24 holes under the base tape of that tire that aren’t affecting it negatively. Finally, it’s rear wheel on a bike that sees almost all flat roads so if something did go wrong chances of significant bodily harm are greatly diminished, and I’m obviously willing to accept that small risk.

So let’s set aside images of this wheel ‘imploding’ and focus on what can be done about improving the brake track, shall we?

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LouisN
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Location: Canada

by LouisN

A few thin layers of carbon cloth and industrial epoxy resin. wrap in plastic, tape it tightly and put that on some decent press, wait 1-2 days, sand, and go !!
It should cost less than $35. on parts to repair.
Personnally, I would keep it for flat TT terrain.
Of course you'll get a better view of the damage when the tub is removed.

Louis :)

joejack951
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Location: Wilmington, DE

by joejack951

LouisN wrote:
Sat Aug 24, 2019 3:40 pm
A few thin layers of carbon cloth and industrial epoxy resin. wrap in plastic, tape it tightly and put that on some decent press, wait 1-2 days, sand, and go !!
It should cost less than $35. on parts to repair.
Personnally, I would keep it for flat TT terrain.
Of course you'll get a better view of the damage when the tub is removed.
Thanks for entertaining my slightly-questionable idea!

I plan to at least partially remove the tire to do the repair. Do you have any suggestions on which cloth and epoxy to use? There are a whole lot of options out there which I guess I'm going to have to dig through to find a good fit for my purpose. On the plus, whatever I do buy I can hopefully also use to repair the slight crack in the top tube of my old LOOK KG386 frame.

The bike stops well enough with just the front brake so I plan on putting some miles on the wheels this week pre-repair including a least one longer ride. Wish me luck! ;)

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LouisN
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by LouisN

You can't expect to do any kind of decent repair work on such a dirty surface. You will have to remove the tubular completely first. That will help evaluate the damage.
Look at some Youtube videos, ( use "carbon bike repair" as key words) lots of info there.... happy search !!

Louis

spdntrxi
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Joined: Sat Jul 20, 2013 6:11 pm

by spdntrxi

joejack951 wrote:
Sat Aug 24, 2019 1:59 pm
DarkerxHalf wrote:
Sat Aug 24, 2019 9:43 am
What is the concern?! The strcture of that rim is toast, meaning it's an almost definite that your face also may end up toast when this thing implodes on itself.
I can assure you that the structure of the rim is not toast. The wheel is true, there is no ‘hop’ at that point indicating out of roundness, and the damage is nowhere near a spoke hole. On top of that, it is a tubular tire that isn’t going to suddenly deflate if the rim were to give a little. There are already 24 holes under the base tape of that tire that aren’t affecting it negatively. Finally, it’s rear wheel on a bike that sees almost all flat roads so if something did go wrong chances of significant bodily harm are greatly diminished, and I’m obviously willing to accept that small risk.

So let’s set aside images of this wheel ‘imploding’ and focus on what can be done about improving the brake track, shall we?
why ask then.... you obviously had it x-ray'd already right. You do know how fibers work.. ok have fun with it. Up your life insurance. :noidea:

TurboTommy
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Joined: Sat Feb 20, 2016 12:32 pm

by TurboTommy

Op I get the feeling you came here to try and reinforce the decision you’d already made rather than actually listen to other opinions. You have no real idea what damage has been done to that rim, and you’re talking about trying to repair it with no experience. Without even taking the tub off. I think that alone shows a level of laziness that could get you into real trouble. Get someone who knows what they’re doing to take a proper look at it. Or don’t....

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JKolmo
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by JKolmo

Oohh I would bin it for sure!

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wheelsONfire
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by wheelsONfire

I don't get how you even can consider doing a DIY repair on this?
What would you think if you survived a severe crash and your bike wash damaged really bad (for sure cost you even more than a new rim/wheel)?
Bikes:

Ax Lightness Vial EVO Race (2018.12.21)
viewtopic.php?f=10&t=156137
Paduano Racing Fidia (kind of shelved)
Open *UP* (2016.04.14)


Ex bike; Vial EVO D

DarkerxHalf
Posts: 30
Joined: Sat Jul 14, 2018 9:23 am

by DarkerxHalf

joejack951 wrote:
Sat Aug 24, 2019 1:59 pm
DarkerxHalf wrote:
Sat Aug 24, 2019 9:43 am
What is the concern?! The strcture of that rim is toast, meaning it's an almost definite that your face also may end up toast when this thing implodes on itself.
I can assure you that the structure of the rim is not toast. The wheel is true, there is no ‘hop’ at that point indicating out of roundness, and the damage is nowhere near a spoke hole. On top of that, it is a tubular tire that isn’t going to suddenly deflate if the rim were to give a little. There are already 24 holes under the base tape of that tire that aren’t affecting it negatively. Finally, it’s rear wheel on a bike that sees almost all flat roads so if something did go wrong chances of significant bodily harm are greatly diminished, and I’m obviously willing to accept that small risk.

So let’s set aside images of this wheel ‘imploding’ and focus on what can be done about improving the brake track, shall we?
Whys there no face palm emoji?
Good luck to you, you obviously don't want real oppinions from people that may have experience with damged carbon, again, good luck.
2002 Moots Vamoots
2018 Cannondale CAAD12 Custom (RIP)
2018 Cannondale Supersix Hi Mod (SOLD)

joejack951
Posts: 668
Joined: Fri Feb 18, 2005 6:50 pm
Location: Wilmington, DE

by joejack951

spdntrxi wrote:
Mon Aug 26, 2019 2:45 am
why ask then.... you obviously had it x-ray'd already right. You do know how fibers work.. ok have fun with it. Up your life insurance. :noidea:
Perhaps I mislead some posters by even entertaining the idea that there was a reason to be concerned about the rim. The damage is obvious so it is obvious why some people are concerned. Unlike myself, they can’t see the damage or ride the wheel to understand how little it affects the wheel structurally.

I won’t bother responding to everyone but I came here looking for advice on repairing carbon fiber. I’m far from the first to do this and while I have no CF repair experience, I have plenty of experience repairing other things. I’m not stupid or lazy enough to leave the tire on in the area I’ll be working. I also don’t see a need to fully pull off a tire with a 2+ meter circumference when I am working in such a small area. I’ll expose enough rim to do the work I need to do (partially remove the tire). If it turns out the tire gets in the way, I don’t mind fully removing it but I know there is more risk of damaging the base tape.

Of course, I’m willing to scrap the whole plan if someone with actual experience in carbon repair has attempted something similar and failed. No need to repeat past mistakes (unless they learned from their experience and can give advice on how it can possibly work). Posts about bodily harm do no good as they sound like ‘steel is real’ guys hating on carbon fiber in general or the vast majority of the people when I talk about cycling on the roads. We all take some risks based on perception of the risk and experience and I feel like the risk here is minimal otherwise I wouldn’t bother. The biggest risk to me is wasting a bunch of time hence my request for help. If all I’m going to get is fear mongering, I’ll look elsewhere. CF can be repaired, even structurally, so I see no good enough to shy away from this project.

by Weenie


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