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Cracked chainstay on Michael’s bling build 29er – repair update!

You might remember I featured Michael’s bling build short stay 29er earlier this year in April (over here in case you missed it:

Michael was back in touch recently to let me know that he had to send the frame back under warranty when he found the drive side chainstay had cracked:

Not what you want to see - the chainstay cracked all the way through just behind the bottom bracket.

Quick update for you. I have broken the frame! It took me a while to figure out what was wrong at first, all I knew was the chain kept coming off the single chainring on the front. I’d put it down to the chain guide not working properly but now I know that the rear end was flexing due to the crack and unshipping the chain!

It cracked on the chainstay just by the large chain ring. Porter thinks it was due to chain damage but I think it might have been related to lack of chainstay bridge… who knows?

Looking at where it broke I’d say it was potentially due to the chainstays being heavily manipulated to curve around the wheel and meet the bottom bracket. Given Michael’s short chainstays the amount of bending needed would have been greater than on most other frames.

It’s also in the heat affected area coming from welding it to the bottom bracket which could have contributed to making the tubing more brittle.

You can see here the heavy manipulation needed to give decent tyre and chainring clearance.

Anyway, XACD repaired it for free and paid the cost of postage back (but not out) it took about 1 month. The only problem was that they didn’t return the rear mech hanger! Porter said that it wasn’t on the frame when I sent it to them but I am 99% certain it was. I really can’t remember taking it off and its not in my workshop… anyway long story short I had to buy a new one but the price was pretty steep! I have bought two just to be on the safe side.

I think pretty steep is an understatement! The bill was:

Ti replaceable hanger for breeze dropout FOB XI’AN USD 39.00/pcs   2pcs  USD 78.00
Shipping costs(EMS express): USD 32.00
Handling charge: USD 11.00
Total: USD 121.00

Holy crud – $121 just to get hold of two replacement hangers! I’d have been tempted to just order one and then look for a pattern hanger somewhere else but I can appreciate Michael’s dilemma about what to do. I decided to be a cheapskate and not go for a replaceable hanger on my frames and have managed to get away with it so far. I’ve trashed a couple of derailleurs but the hanger itself has stayed straight, as they should do if they’re 6/4 Titanium! There is always the risk though…

Michael got XACD to reinforce the area with a chainstay bridge that he didn’t put in the first design due to concerns over mud clearance. I’ve got a steel frame that Greg Fuquay (ask your dad) built for me and that’s managed without one for many years. Greg told me that the chainstay bridge was mainly for the benefit of keeping the real triangle aligned, as the builder made the frame, rather than to contribute to the overall strength.

They replaced the whole of the chainstay, it looks like a very neat job, you would never know it had been changed. I hope the new bridge gives it a bit of strength as I didn’t really do that many miles on it before it broke, and it cost about £90 to send it back to China!

If it breaks again I am not sure if it is worth getting it repaired a second time, the only problem would be finding a frame that fits the forks/headset, seat pin and BB I have.

I’ve asked Michael to keep us updated on progress and let us know if it happens again. The new bridge should help to reinforce the area (or will the additional heat make the tube even more brittle?).

Perhaps the best solution would be to go with a chainstay bridge made of titanium plate like Ragley and Lynskey do. It’s not particularly light or pretty but it is a good solution where chainstays are short and clearance is tight.

At least on the positive side we can say that XACD will honour frame repairs under warranty even if you do have to be careful to strip the frame right down before you send it back…

Have you had experience of working with XACD? If so I’d love to hear about it so drop me a line via the contacts page.