Oh lordy, I think I've stripped my BB thread…

Santa Cruz Superlight (alu), Hope BB stainless steel, hollowtech crank. Been fine for years. Other week the plastic end screw (for getting tension when fitting the crank) snapped and fell off. I checked and the crank bolts were also a bit loose. More worryingly the drive-side BB cup wobbled. I could only get it to tighten by removing one of the plastic spacers. Back home in the jig and it looks like the outermost 2/3 of the BB thread has been worn on both the frame *and* BB cup (I thought the steel cup would wear the alu?)! The non drive-side seems fine.
Any ideas as to how this has happened and what I can do?!
Cheers, Will

Either fit a DH specific nb with a longer thread or send it to goldtech to have an insert put in, it’s not very expensive to do

Found this which seems to be what I need
http://www.mountainbikecomponents.co.uk/items.asp?CategoryID=236&Name=Frame+repairs 🙂

How would this happen though…? If the crank bolts worked loose, and I guess causing a bit of movement that bust the plastic end screw, why would cause the threads to strip if the bearings were tight (they are I think)? Where would the movement come from?

Happened on my Prophet recently. Noticed some play at the drive side crank. Cranks were fitted properly with everything tight. Took the cranks off and the drive side BB cup came out with the axle. BB bearings were good too, spinning freely.

Frame has a lifetime warranty but I’m doubtful Cannondale will help me out.
I’m waiting for the shop I bought from to get back to me.

Betd Heli-coil £61 + P&P

Argos cycle’s in Bristol also do BB shell repairs and sleeving.

Don’t have exact measurements, but swapped out shimano cups for a Raceface DH BB and cups insert much deeper, so a cheap fix may be take a cup down the LBS, compare cup insert depths and buy the deepest one they have.

(raceface bearings where crap, swapped to enduro bearings but kept the cups, still in use several years on )

Don’t panic, same thing happened to me just before Easter. LBS said that they could recut the BB threads or fit a longer Bottom bracket but that this would most likely just creak like mad when pedalling.

Frame is now at BETD being repaired ( new drive side BB sleeve installed) , costs about £70-75 for the work plus the courier costs. Far better than trying to bodge repair it and way cheaper than a new frame.

Frame has a lifetime warranty but I’m doubtful Cannondale will help me out.
I’m waiting for the shop I bought from to get back to me.

you will get a standard email about the “lifetime” of an alloy frame being two years, you will have to rebuild the bike and give to the shop for them to inspect. They will probably say it was a fitting error if the BB isn’t the original

don’t get me started on the worthless Kona warranty

retap to italian? then use gxp cranks, only outboard ita thread bb I know of.

you will get a standard email about the “lifetime” of an alloy frame being two years, you will have to rebuild the bike and give to the shop for them to inspect. They will probably say it was a fitting error if the BB isn’t the original

This is the sort of thing I’m expecting….

I had the same issue with my frame and Hope BB. As said above I got a Race Face DH BB, got the threads cleaned out and used high strength loctite. Its been OK for a year now.

When it happened I searched the web and found lots of people having the same issue with Hope BB.

Old hope bbs had plastic spacers which squished under power and let the bb pull on the threads.

New spacers are metal

I had this exact issue on my Superlight. Sent it to betd with a new bearing cup, and they helicoiled it (or some such) and by fitting the bottom bracket they warranty the fix.

All seems fine 6 months on

Oh… and they fitted metal spacers as mentioned above

Ah…just twigged who the op is… We’ve already had this conversation Will.. just get it sent!! Rob

Exactly the same issue here a few months ago. Neither Giant or Hope were bothered. LBS helped out with building up in resin and a tiny alteration in chain line and using metal spacers rather than plastic.
Everything works fine now and a winters worth of abuse has taken no toll.
Absolutely convinced it’s the plastic spacers compressing slightly and allowing some movement.
To be fair having said Hope weren’t bothered, they did at least listen, and provide one drive side cup, although the major thread damage was, of course , to the alloy frame as opposed to the s/s cup.
Had all the questions from Hope and Giant and LBS about facing the frame first, which I didn’t do. My reasoning being that the original Shimano cheapo bb lasted pretty well although it’s race face original replacement didn’t and so did the Hope one for at least 1000 miles before this issue and there is no detectable bearing wear whatsoever..

I cant see how it would have been a warranty issue myself.
I guess with the crack pinch bolts being loose could have allowed the cup to unwind a little (precession), possibly forcing the crank arm outwards a bit, causing the preload bolt to shear off.
Oh and on a Hope Stainless BB, only the bearings are stainless steel, the cups are still aluminium.

The cranks on mine didnt come loose and I was using metal spacers.
As for warranty I fully expect to get knocked back but if you dont ask you dont get. From another thread I asked on I know this is a common problem with Prophets.
If the BB shell inside diameter was oversize before the thread was cut it could lead to the threads stripping, proving this would be impossible though.

Spending £90 plus postage to repair a well used frame that is probably only worth 200 quid at the most seems pointless.

When did Hope change from plastic to metal spacers for the stainless steel BBs? I have one on my bike but can’t check it until much later

So this is why most manufacturer’s are now keen on press-fit 🙄