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A friend's Race Face Next carbon crank pedal insert and axle insert have come unbonded.
What is the best epoxy to use to attempt to fix before he chucks them?
Sorry to tell you that I tried it with a few epoxies, including araldite (can't remember the other grades/names as it was a few years ago), and it didn't last. Binned them and will never buy them again.
I did a bit of reading on this when mine failed out of warranty and general consensus seemed to be it's not simple.
A few folks suggested they'd drilled a small diameter hole in at 45 degrees each at 12, 3 6 and 9 o'clock, pushed carbon repair in until it backed out then tided up after it dried. The difficulty was there was no way of knowing if you'd filled the void or otherwise, some lasted hours, one poster reckoned they managed a few months so far...
The agreement seemed to be the insert needed taking out completely, a bigger hole drilling in the crank then pinned, filled and bonded back in. I'll be honest what to use at that point didn't interest me as I wasn't in the mood for drilling my cranks.
(what spindle etc, and drive or non? Mine are still in the garage somewhere, 24mm spindle think it's the nds on mine that are shot, next sl triple but can't remember the length...)
Dunno what spindle, but it's the NDS on his that's knacked.
Epoxy won’t work for any length of time, a methacrylate adhesive would be much better.
https://www.techsil.co.uk/plexus-ma300-50ml
Got a receipt or bought with a bike*? Contact silverfish/raceface, sorry to say that raceface carbon cranks are shit, every single pair in our riding group has failed.
*IMO, they should have issued a recall given how dangerous it is.
Mine failed at the axle so I backed off the big Allen bolt. 16mm I think and made a washer to fit, then tightened the 16mm on to it, Acted likes a pressure plate. Worked until I dropped on an arm on eBay. So far that one is holding up.
The agreement seemed to be the insert needed taking out completely, a bigger hole drilling in the crank then pinned, filled and bonded back in.
This is what I would do (and what I did do while repairing my frame).
I have an open tube of Araldite 2031 that I chose for the job. If I can find it again I can put it in the post but you'll need your own applicator gun.
Araldite 2031
If you're brave enough to try, this is the stuff it's used for all sorts of motorsports and sailing construction, it's dead cheap - but a word of warning, make sure you use it in a very well ventilated room or even better outside as it's severely smelly and you get high as a kite 😀
SirHC
Got a receipt or bought with a bike*? Contact silverfish/raceface, sorry to say that raceface carbon cranks are shit, every single pair in our riding group has failed.
*IMO, they should have issued a recall given how dangerous it is.
Same here, and the last time this came up, I think 95%+ of the cranks that folks on this forum had either owned or were aware of had failed.
Yep, they're shit, the words 'not fit for purpose' have never been more right. I'm not heavy or particularly rad and I went through 3 sets of Next and 2 Next R before opting for some Turbines (which are still going strong).
RaceFace are just fine and dandy if there's only one material and no moving parts.
Alu bars - fine.
Carbon bars - fine.
Alu cranks - fine.
Bottom bracket - no.
Dropper post - no.
Carbon crank with metal insets - no.
The agreement seemed to be the insert needed taking out completely, a bigger hole drilling in the crank then pinned, filled and bonded back in.
What would the pinning of the insert look like? I get the rest of it (remove insert, drill big hole, fill with that fancy adhesive, replace insert) but I don't understand what pinning it would involve. (I've got a set with a wobbly driveside pedal insert)
actually, if this is what the insert looks like then I would definitely getting something in there without fully removing it. Maybe drilling multiple holes to inject a suitable epoxy...
https://www.mtbr.com/threads/fix-for-play-in-race-face-carbon-cranks.1123865/
sorry to say that raceface carbon cranks are shit, every single pair in our riding group has failed. *IMO, they should have issued a recall given how dangerous it is.
K's lasted 4 years on her Canyon (but she's only c65kg). Both the axle and the pedal insert went at the same time (fine when we left home, both gone after 3 days in the lakes). Really not fit for purpose - the bike has done a lot of miles but that was the first part to actually fail.
Replaced with SLX.
On the flip side, I've two sets of X01 carbon cranks that have had the shit kicked out of them for 6 years each, finally retired them as I'd worn the crank axle running them on hope BB's (they've gone slightly oval). Much better than the 6 months for the Next SL's.
Certainly heard less reports of Sram carbon cranks failing than Raceface - Wondering in what way the bonding process differs? One would have thought Raceface would have sorted this issue out by now or dropped the product line. The amount of times I've heard 'not fit for purpose' is perturbing to say the least..
See, usually I say, the repair needs to be stronger than the original part since it's already proven not to be strong enough, and achieving that DIY is generally impractical.
But I had 2 sets of these and they were apparently stuck together with pritt stick or something so, it's probably more doable. And both of mine failed really soft, I was able to ride for a decent length of time on them with the loose inserts (a whole mad kinlochleven enduro, one time) so if you glue it and they fail again you just get hte same failure back. Do they ever fail catastrophically? Never seen it but maybe it happens.
Considering how many of us must have half a crankset, maybe we should have a STW Swap Shop? Bound to be able to make some complete cranks
We bond our 80m turbine blades with epoxy glue, sure it ain’t strong enough?
Maybe what you have is an insufficient bond area, or non-activated surface, is it possible to remove some material around the insert?
I had Sram XX1 carbon cranks before the Nexts and they didn't last anywhere near as long - they started wobbling on the crank axle.
I have a set of FSA carbon cranks on my full suspension bike for four years and they're fine, the Nexts lasted three and the XX1s lasted 2. I've replaced the Nexts with more FSAs but it'd be nice to get them running again.
Considering how many of us must have half a crankset, maybe we should have a STW Swap Shop? Bound to be able to make some complete cranks
Kill off the ones that havent failed....
One would have thought Raceface would have sorted this issue out by now or dropped the product line. The amount of times I’ve heard ‘not fit for purpose’ is perturbing to say the least..
Poorly engineered, non existent validation/testing, poorly made, non existent QC. Likely to be a mix of all of them.
That's the bb end rather than pedal. You'd not get a bigger hole drilled there, though that said it'd be unlikely to adversely affect the integrity if you did!
Pinning as I understand it was several small pins drilled into the inset perpendicular to the outer surface, extending a few mm into the new larger hole* which means when you back fill it there's an irregular surface rather than the (allegedly) polished smooth one of the insert. In honesty I've not tried. I lost interest at, "cut the old one out (there's a flange on both ends) drill a 22mm hole in your crank."
In my not-very-good-at-these-things head, it seems sensible - I'd have expected they'd be machined "not circular" in the first place though.
*edit having just thought about it between the flanges, parallel to the insert's outer surface might make more sense depending how tall the flanges are.
Easy Composites VM-100 Methyl Methacrylate Adhesive
chrishc777
Free MemberWe bond our 80m turbine blades with epoxy glue, sure it ain’t strong enough?
I'd trust any basic epoxy with the job if I could get the surfaces cleaned up and guarantee good coverage, but these don't come apart when they fail, extracting the insert would be very destructive. So since it's such an imperfect repair I'd want every bit of it to be as strong as I can make it.
Do you actually mean glue two bits of blade together or make an epoxy composite. There's quite a bit of difference!
It's always a bit of a weird question this in any case. "Epoxy" is a generic term and they are by no means equal. Besides, the glues are 2K and the amine or thiol in the other component is often more important. The epoxy group itself forms the cured matrix but isn't all that involved in adhering to a substrate (although the free OH groups can).
When I looked at "tensile" strength in bonding aluminium to painted surfaces this stuff did well, better than the DIY araldite equivalents.
But some of the industrial products above will be better I'd guess. The Methacrylate lap sheer results do indicate it will perform well. They mostly seemed to be metal and plastic so how well they will bond to the composite I don't know. If you can't warranty then that is what I'd go for. Otherwise cleanliness and surface prep is everything. Roughen the surfaces and take time to clean them removing dust and grease, probably with a cleaning solvent.
Cheers for all the suggestions.
Bike and cranks are second hand so warranty is out.
He'll probably try one of the above. If it doesn't work, it's still knackered.