GrainBrain

Hello all, if this isn't the place for this question I could have it moved.

I have a 2019 Cannondale Topstone Carbon. Carbon fiber frame, and the bottom bracket is the BB30A-83. It uses a one piece Aluminum shell that's molded into the carbon frame where the bearings are pressed into. Apparently it's developed a crack, I've included a photo.

Any ideas on how to repair, or solutions for this? I've seen an option for a sleeve like this one from BBinfinite

https://www.bbinfinite.com/products/...32294189629573

I was also thinking about trying to drill a little hole at the end of the crack, then maybe epoxy and hope it stops?

Thank you all for your time and input!

unterhausen

I take it that the bike isn't covered by warranty? I am not sure what that sleeve would do other than hide the problem. The real question is if the crack is continuing to grow.

Cynikal 

Cannondale will warrantee that if you are the original owner. Check with your shop.

GrainBrain

Yup I am the original owner and the shop is in process of doing that. Just paranoid from all the bad experiences I've heard over the years. I bought this back in the spring of 2020. Cannondale has promo pictures of the bike carving up mountains and such with pro riders - I'm like 175lbs and riding in the flat lands! You'd think it would stand up to what I put it through.

The original sleeve was supposed to be the solution to stiffen the bottom bracket compared to other press fit systems that go directly into the carbon frame, as I understand it. So the sleeve isn't super structurally important - the bottom bracket area has a ton of carbon fiber, it looks beefy.

Thanks for the replys! I'll post back with an update from the shop.

Canaboo

It's hard to visualize what stresses could have started this crack.

It would be very easy to patch it though.

msu2001la

If I were you, I'd park the bike and wait for Cannondale to fix or replace it.

GrainBrain

Yes it's at the shop and infact I've gotten information today that it will be warrantied!

Still, I posted this to frame builders because it is an odd failure and I wondered if there was much work being done with carbon fiber now that it's become really mainstream. Don't worry, I love steel too!

GrainBrain

I imagine it was from pedaling - the crankset bearings are pressed into either side of this sleeve. Contrast with some designs that used separate cups or were pressed directly into the carbon frame.