Hi all

I bought a pre assembled MTB bike from a reputable UK dealer.

I'm not a massive bike expert btw.

About 6 months ago I took it into a differant local shop for a general tune up.

The guy looked at it and was like "your bikes knackered mate"

What he reckoned, and he was a welder as well, was when the frame was made the frame wasn't allowed to cool correctly when the bottom brack part of the frame was welded on causing the 'splaying' of the tube.

This caused the bottom bracket to move at the larger end the wrecking the thread on the part show as well as the bottom bracket is done for.

He wasn't prepared to fix it as he couldn't gaurente the work and said without doubt it's a malnufacturing fault with the frame. This was pretty much the same story at another shop I took it to.

I havnt had any problems with the shop I got it from (frames are gaurenteed for 3 years) but just wanted to come here and do my homework

Has anyone seen or heard of this?
What's your oppinions of the situation?

Thanks all and sorry for the long post.

safe.

If you're worried then send these shots to whoever you got it from and see what they say. At least they coudl organise to get the BB faced and the threads chased out.

I've not seen enough frames to know if this in unusual, tbh.

yup, gonna send them across to the shop, just wanted to see what peoples reaction to the problem was.

Are the threads damaged at all?

Is it flared on the top off the BB shell as well as the bottom?

I don't know if facing the BB shell woul be of use, as facing ensures the outer edges of the shell are parralell and the problem here is that the shell itself doesn't have parallel edges.

As a bodge, would a heavy duty thread lock secure the BB? Bottom line though is that the frame shouldn't be like that, and this would be an interesting test of the "three year guarantee" that the shop offers.

The thread on the inside is damaged, I can't tell how but the bike engineer said he wouldn't gaurentee anywork on it as it would just ware out.

I'll email them and if anyones intrested in knowing what the outcome is and if I remember i'll post back here.

Thanks all.

Was it creaking from the BB when you rode it?

Do you have any frame builders anywhere that you could get to? I'd be more influenced by what he had to say than a shop mechanic TBH. Not trying to knock the shop staff. Was he a frame builder for the shop? Or has he "just" done welding at some time in his working life. I would think that someone like Chas Roberts or Dave Yates would give you a definitive answer as to whether the BB can be bought back to a workable condition.

What do you mean by a "pre-assembled" bike from a reputable dealer? A Trek/Spesh type from a shop? Or a focus from Wiggle or some other on-line dealer. How long ago did you buy it? Any chance it is still warranty covered.

If the shop is willing to honour their 3 year warranty I don't see you have any problem. If they replace like for like you obviously know what to look for when you collect the replacement. And I assume that you have a good look at all joints and interfaces (head tube ends, cable stops, drop outs etc).

Get it replaced.