Problems with my bottom bracket.

mikeysickalrigh

I was riding my bike yesterday, (slow climb) when I heard a crack, followed by the crank arms completely locking up. I looked down and saw that the crank arm was about 5mm or so away from the frame.

On further inspection it appeared that the bottom bracket was coming out of the frame, and the plastic cup(?) had a crack down the middle. This bike is only 5/6 months old.

I took it into my lbs today to be fixed and later got a phone call saying that they had just screwed it back in, saying that when they tighten the bottom bracket, the cups often crack due to the tension. Could someone with the knowledge tell me if this is correct? Shimano have made a product that has to be broken when fitted?! Is it likely to happen again?

I am now nervous to ride the bike, as prior to this incident I was riding at 25mph+ on a single track through trees. If the pedals suddenly stopped moving through there then I would have been in BIG trouble! I surely now have a bottom bracket/crankset that is likely to lock up?

Any advice or comments would be greatly appreciated!! :?:

nicklouse

err sounds like bollocks.

what is the BB? or make/model/year of bike?

mikeysickalrigh

http://www.evanscycles.com/products/spe ... e-ec025034

Camber Comp 2011.

Need to check that it is crap before I go in and make demands!

MrChuck

Wouldn't have thought that would stop the cranks turning. Are you sure it wasn't always like that and the jamming up wasn't caused by a momentary bit of chainsuck or something?

I've cracked the plastic bit before, duno if I'd go as far as saying that it often happens though. But anyway, this

saying that when they tighten the bottom bracket, the cups often crack due to the tension.

Is not the same as saying this

Shimano have made a product that has to be broken when fitted?!

mikeysickalrigh

No the crank arms weren't moving at all up until I took them into the shop.

Bad workmanship? Anyway I have never been confident in their ability to put a bike together...

nicklouse

so what had come lose?

which crank had moved?

nothing in that set up should break.

Evan will not have fitted the BB so nothing to do with them so dont start slagging them off.

mikeysickalrigh

Not slagging evans off didnt buy from them , it's from another local shop without a website.

The left crank. The crank itself had jammed, it looked like the bottom bracket was unscrewing itself. I was told what I could see was the cup. The cup was also split. I would guess that as it was unscrewing itself, the jamming was a result of it cross threading? As the cup I could see had thread on it

cooldad

Your LBS without a website would not have fitted the BB neither, would have been done in the factory.
If it's a fault, should be sorted under warranty, they shouldn't screw themselves out.

lemoncurd

Could someone with the knowledge tell me if this is correct?

Why would you ask a London black cab driver about a bottom bracket?

mikeysickalrigh

I didn't ask a black cab driver, just anyone with knowlede.

I guess I'll go in and ask them to contact specialized.

cooldad

Your warranty is with the dealer, so they should sort everything out.

nicklouse

mikeysickalrigh wrote:

Not slagging evans off didnt buy from them , it's from another local shop without a website.

The left crank. The crank itself had jammed, it looked like the bottom bracket was unscrewing itself. I was told what I could see was the cup. The cup was also split. I would guess that as it was unscrewing itself, the jamming was a result of it cross threading? As the cup I could see had thread on it

the left arm could not move. the cup splitting would not effect operation. the cup touching the arm would.

so it they have refitted it and it works it will be fine. are you sure it was split or was it a molding line. It would be very hard to fit if it was split.

mikeysickalrigh

so it they have refitted it and it works it will be fine. are you sure it was split or was it a molding line. It would be very hard to fit if it was split.

Yeah had a 1mm or so gap between the split, they even admitted it was a split, said that they often split.

wordnumb

Buy an es51, making sure you get the same shell & spindle lengths as you have on the current BB. Use the cup from the new BB with the es25. Keep the es51 for when you need to replace the es25 - they don't last forever.

I use octalink BBs on several bikes and have never cracked one of the plastic cups despite not using a torque wrench.

gilesjuk

Those plastic cups are stupid. I have an old metal cup from a Shimano which I keep reusing for obvious reasons. The plastic ones crack.

mikeysickalrigh

Buy an es51, making sure you get the same shell & spindle lengths as you have on the current BB. Use the cup from the new BB with the es25. Keep the es51 for when you need to replace the es25 - they don't last forever.

The thing is that it is within warranty so I don't want to spend money for the moment.

Might ask them to sell me a es51 at a discount, save us both money

supersonic

The bottom bracket itself should be fine - it sounds like it just needs a new support cup. This is all that cup does.

nicklouse

mikeysickalrigh wrote:

so it they have refitted it and it works it will be fine. are you sure it was split or was it a molding line. It would be very hard to fit if it was split.

Yeah had a 1mm or so gap between the split, they even admitted it was a split, said that they often split.

never had one split on me other than when removing old one.

the metal ones are not really any better as Sonic says all they do is support the bb body.