Problems replacing a bottom bracket on a Trax TR1

Trojan Hussar

I've owned this bike for about six years, it spent most of this rotting gently under a tarp but about a year ago I rediscovered cycling and have gradually been upgrading it bit by bit.

The bottom bracket was probably never tightened properly and I always recall the pedals having a bit of 'play'. I recently decided to fit a new cartridge, measured the spindle length (126mm) and ordered a new cartridge from eBay which was stated as 127mm (I figured 1mm was well within tolerance). It arrived and I fitted it but the crank side appears to be so far from the frame the derailleur can only move the chain to the middle crank even with the adjuster set to maximum.

Having looked up other cartridges the sole measurements usually listed are the shell size and spindle length. Nobody mentioned asymetrical spindle lengths.

Any suggestions?

Regards,
Jason.

jimothy78

What crankset is it (there's usually a model number on the inside of the crank arms somewhere)? That's what determines the spindle length needed.

Also, when you talk about "the adjuster set to maximum" do you mean the barrel adjuster (that sets cable tension) or the high limit screw (that sets the physical limit of the derailleur movement) - you will need to adjust both to get the derailleur cage to move further out from the frame...

The Rookie

The axle shouldn't ever be asymmetrical.....if the new one is the same length as the old the crankset will be in about the same position but the slight differences will mean the front needs indexing, see Parktools.com for an excellent guide.

jimothy78

The Rookie wrote:

The axle shouldn't ever be asymmetrical.

But it can end up that way if you try to fit a BB designed for an e-type mech when not using one (or vice-versa) as the spindle is effectively shifted a little to one side. Also guessing you might end up with a similar problem if you tried to fit a 68mm BB into a 73mm shell...

montyburns56b

The BB is too wide for that bike, you need something closer to 118mm.

nicklouse

So what are the cranks?

And what length does the old BB actually say on it?

nicklouse

montyburns56b wrote:

The BB is too wide for that bike, you need something closer to 118mm.

How can you say that if you don't know what the cranks are?

bikaholic

First, take a quick gander at the crank fastening.

Is it an Allen socket bolt (requires an 8mm Allen key to remove) or a hex nut (requires a 15mm socket tool to remove).

Next, ID the cranks by the model number stamped somewhere on the crank arms and then google the specs for the corresponding BB.

If the BB has a square taper spindle, then verify if it has a JIS or ISO taper.

If no data is available, then extract the BB and read its label for the model number. If no label is available them take measurements and compare them to a known BB type.

The Rookie

This is a Trax, will be a 15mm hex bolt or nut, JIS taper, BB is probably cup and cone. Crankset may not even have a name on it!

montyburns56b

nicklouse wrote:

montyburns56b wrote:

The BB is too wide for that bike, you need something closer to 118mm.

How can you say that if you don't know what the cranks are?

I used to work at Halfords and if he is still using the original chainset then it will be 118mm.

nicklouse

montyburns56b wrote:

nicklouse wrote:

montyburns56b wrote:

The BB is too wide for that bike, you need something closer to 118mm.

How can you say that if you don't know what the cranks are?

I used to work at Halfords and if he is still using the original chainset then it will be 118mm.

And that is a very big IF.

IF THIS IF THAT IF SOMETHING ELSE. You should use this!

And as it is a Halfords supplied bike are we sure it even was supplied with the original crankset?

Other bike shops are also know to swap parts off one bike to fix a customer bike.

Until the spec is known WD are only guessing. You might be guessing right but then it seems the BB was not original. Which makes me thing that there is just a little chance the cranks might have also been changed.

So let's see.

jimothy78

I think we've all wasted our time anyway - OP looks like a classic one-post-wonder....

Trojan Hussar

Crank arms have FC-GSP312 / EN-14766 on them and the pedals are badged 'Union'. Beyond that there's nothing on it, they are the originals that came on the bike. BB was cup and cone and the old spindle was 126mm.

I've managed to get it working with the front derailleur at full stretch, it was slightly bent which meant it didn't *quite* reach when I first tried. Apologies for not checking the thread earlier but I've just finished replacing the rear hub and rebuilding the wheel. Took it out last night for a little 10 mile test and nothing dropped off.

So much smoother than it's ever been before, the BB has always been loose and I've just put up with it. The rear axle appears to have been bent since new and the cup in the rear hub was split when I pulled out the old bearings. Needless to say it all runs very smoothly now compared to how it did before. Not too bad for a dirt cheap (£79.99) bike that's done over 2,000 miles according to my Mapmyride stats.

Thanks,
Jason.

JBA

You are replying to a 4 year old post and the OP hasn't been back since May 2014.

cooldad

How to turn a BSO into a shit ebike.