Trials bike problem, any users in here

hyperst · 31 May 2011 at 14:24

Hi, my son has a Onza trials bike, the bearings in the crank was making a bad noise and so took it to a local bike shop who said it needs a new bottom bracket which he ordered in and we took in the bike shop and had him replace it, thing is the next day the bottom bracket is loose and if holding each crank it can move up and down

, now I got my son to take it back to the shop who now says we need a new frame :eek:

, so is there any experts in here that can shed any light on this as I don't know where to start to diagnose what is actually wrong

hyperst · 31 May 2011 at 16:42

yeah I will go to the bike shop myself tomorrow and see what he says, and ask him why he replaced the bottom bracket and yet a day later it is all wobbling as when it went in originally it only made a rough sounding noise from the bearings.

here's a video of it so you can see what I mean, it's still proccesssing but should not take too long

hyperst · 31 May 2011 at 20:32

Saytan said:
that's the axle moving in the BB, not the BB moving in the frame.

Now that is what I was thinking, the bearings have gone, but the bloke at the bike shop says it needs a new frame

hyperst · 31 May 2011 at 20:44

Not really possible to go else where with it, and only a small town where i live so will go back to him and tell him to show me what he did, I got a feeling he didn't change the BB at all and just greased the bearings up and pocketed £23, I did actually just order the BB, when he said it would be in stock I went back to the shop and he got shifty about selling it to me and said he would need to fit it as it required special tools so took his word for it and had to take the bike to him and leave it with him, do you think he's just after me splashing out on a frame so he can make some money?

hyperst · 31 May 2011 at 22:47

Saytan said:
where do you live? i know a few guys in lincs who ride

Alford mate, I will be in the shop tomorrow with it for sure as I am not happy what has been done, there was no mention of the frame needed replacing, I am going to get him to strip it and show me what is wrong as a new frame to replace what was originally rough sounding bearings does not sound right

hyperst · 2 Jul 2011 at 04:24

just reviving this thread as I think I might have found what is wrong, after some googling and looking at pictures of bottom brackets it seems the bike shop have installed a Raleigh bottom bracket, now I'm no expert but surely it should have been an onza bottom bracket

hyperst · 2 Jul 2011 at 12:29

Here's the Raleigh one that the bike shop used

and here's the Onza one, I'm wondering if there is a slight difference in threads, I don't have the old one as the bike shop said they threw it away

The actual part that came loose on the Raleigh one is the thread side on the left of the picture which looks different to the thread on the left of the Onza, it has a raised part on the raleigh and on the Onza it doesn't, could that be the cause of it?

hyperst · 2 Jul 2011 at 12:57

Andelusion said:
Why not email Onza and ask if the Raleigh one is compatible (give them the part number).

Are you also sure the crank isn't loose on the axle?

I will try that, I'm not totally sure how to check the crank if it's loose on the axle?

hyperst · 2 Jul 2011 at 15:06

At the time of the video I knew nothing about how they work and it moves like that because I later found out on the other side the retainer? had worked loose and that's why it wobbled, the side that is loose is the side the bike shop says the frame threads have gone

, it's looking more like a new frame is needed, as the thread is quite loose and can wiggle about if not fully up to the frame

hyperst · 4 Jul 2011 at 02:19

Thanks for the advice guys, it's appreciated

What I am going to do is order the correct onza BB, at least that way I can compare the threads on both and then if there is a difference I will be back to the shop with both BB and ask them to explain what they are going to do.

Failing that and if it is not the shops fault the only thing I can think of is plastering the new BB shell with JB Weld or similar around the threads and put it in and hope it will hold it firm enough, in my mind it seems like it should fix it but won't know until I try