Troublesome triple.

[MikeF]

I have a Spa touring frame with a Stronglight New Impact triple and a 115mm BB as specified. Although it works, I think the BB should be 118mm for a better chainline. I have bought one to try, but haven't got round to trying it!

[Vetus Ossa]

I have a Spa touring frame with a Stronglight New Impact triple and a 115mm BB as specified. Although it works, I think the BB should be 118mm for a better chainline. I have bought one to try, but haven't got round to trying it!

I totally agree Mick. I will try spacing mine as suggested, and if successful will see if I can find an Italian threaded one.

[Vetus Ossa]

The other bike is 9 speed, my problematical one is 10.

I have not found the Stronglight Impact Triple to be 10 speed compatible.

May I as why? I can't honestly see how it would make any difference.

[recordacefromnew]

I have not found the Stronglight Impact Triple to be 10 speed compatible.

Since I don't think there is any difference in chain inner width, but certainly the difference in outer width, which can be up to 1mm narrower (e.g. with the Shimano unidirectional chains) could make a difference, especially like the OP when it seems he is running out of fd inward travel. Also perhaps the slightly wider sprocket cluster (but not the stack at the splines) also makes a tiny difference. I am not sure if I would call those 10 speed compatibility issues though, unless you have something else in mind.

Am I right in thinking that if I fitted a longer axled bottom bracket, say 118mm or longer, it would make a difference? I appreciate it would only increase the clearance by 1 1\2mm minimum on the 118mm one.

First thing is do you know for sure whether your current 115mm bb is a JIS or ISO? Second thing is have you measured the chainline on both bikes, what are they?

Using a thin spacer on the drive side is a good way forward, if you have enough clearance on the non-drive side. Alternatively an even layer of kitchen tin foil on the drive side taper should also do for testing purpose.

[Vetus Ossa]

I'ts jis, and have not measured the chainline, but will.
I have measured both chains and make the 9 speed one .5mm wider. Not sure if that will be a factor.

I’ll try one (or two) of these steel badgers tomorrow, and if successful look for a more permanent solution.

[reohn2]

A couple of ideas that may help before a longer BB axle or spacing it out.
Try twisting the mech slliigghhttllyy,so the trailing edge of the mech is moved inward by say 2mm(?)
Or with pliers,bend the outer part of the cage slliigghhttllyy inward in the middle ring area,whilst keeping the front edge in place with a second pair of pliers.


I find 115mm BB's work well with Spa/Stronglight Impact chainsets with 28.6mm seat tubes(two solos and two tandems,tandems on road STI's solos on friction levers on Kelly's).
With a 31.8mm tube a 118mm was needed as the change to the inner ring was hit and miss no matter what I tried.
But all bikes have Shimano Ulltegra/105/Tiagra or Sora front mechs.

[Vetus Ossa]

Just measured the chainline on both and its 45mm....which is what you would expect as both BB's are the same.

[Vetus Ossa]

Should anyone be following this, I have just fitted a spacer on the drive side, and it appears to have made a big difference, shifting is now perfect. Of course that’s on my work stand, I will have to see what it’s like on the road and will test it out as soon as I can.
I imagine as the washer is steel it will rust in no time so will have to source an aluminium one, or bite the bullet and get a longer bottom bracket.
Thanks for your help everyone.

[reohn2]

Amazing what 2mm(in the right place)can do!