A little bottom bracket help please....

Hi all ,

I need to replace my bottom bracket, which I thought would be very straight forward. I may have been wrong! Just pulled the old Octalink unit out of the Zaskar frame and it says BB-M952 116mm, brilliant I think, I'll get another one......I can't it turns out. So now I am confused!

This is what I have:



Everything that looks to similar has slight differences mostly it is the width but also against the BC1 37 x 24 (truth be told I don't actually know what these numbers are!). The Shimano ES51 comes in 113, 118 & 121mm and the picture shows 36 x 24. I am assuming I can do something with the width as mine has a little spacer as you can see in the picture, approx 3mm.

Any help and guidance would be greatly appreciated!

Mark

Re:

That's the xtr / dura ace / ultegra spline, known as Octalink v1 I think. Most have longer splines, these are still fairly easy to source. The shorter ones a bit harder.

Getting one the right length, well, you might get lucky but it could take some digging

Re: Re:

RickTheUncivil":2vgd7hhy said:

That's the xtr / dura ace / ultegra spline, known as Octalink v1 I think. Most have longer splines, these are still fairly easy to source. The shorter ones a bit harder.

Getting one the right length, well, you might get lucky but it could take some digging

Click to expand...

Hi Mr Uncivil,

Do I have to get the same or is there something else that will work, I am not precious about the spline length to be honest. Would a 113mm BB work given the 3mm spacer I have?

Mark

Re:

The challenge you'll have is you need a v1 splined bb assuming you are using xtr m95x cranks. The mtb versions came in 112.5 and 116mm, road versions were shorter at 109.5 and 118 iirc. You can get away with using the road versions (105, ultegra or dura-ace) if you are happy with the resulting chain line and frame clearance). It must be the v1 spline for xtr cranks though! Mtb ones are hard to come by, well expensive at least.

Is your current one shot then? I've always fancied trying to take one apart to see how they are put together and to see if it is possible to replace the bearings somehow. If you fancy donating it for my experiments, let me know.

118mm 105 68mm shell V1?

https://www.ebay.co.uk/itm/Shimano-BB-5 ... SwCDZa8wYm

Re: Re:

ishaw":15y7ap4o said:

The challenge you'll have is you need a v1 splined bb assuming you are using xtr m95x cranks. The mtb versions came in 112.5 and 116mm, road versions were shorter at 109.5 and 118 iirc. You can get away with using the road versions (105, ultegra or dura-ace) if you are happy with the resulting chain line and frame clearance). It must be the v1 spline for xtr cranks though! Mtb ones are hard to come by, well expensive at least.

Is your current one shot then? I've always fancied trying to take one apart to see how they are put together and to see if it is possible to replace the bearings somehow. If you fancy donating it for my experiments, let me know.

Click to expand...

I have S-works strong arm cranks, they are 2001 I think. So this in 113/118mm is no good then https://www.chainreactioncycles.com/shi ... rp-prod908

More than happy for you to have a play with the old one if you want to, it feels rough, it was at least 5 years old when I stopped using it and it had a hard life! Are you local or does it need posting? I'm in Bristol but travel about a fair bit so our paths could cross at some point in the near future.

What does the 37 x 24 signify then?

legrandefromage":15y7ap4o said:

118mm 105 68mm shell V1?

https://www.ebay.co.uk/itm/Shimano-BB-5 ... SwCDZa8wYm

Click to expand...

If this will work I'll buy it! If not is it going to more simple to buy a new set of cranks and a bottom bracket perhaps?

Re:

I thought strong arm cranks were square taper?

Happy to pay postage if that's easier for you, I'm in Epsom so not local sadly.

Re: Re:

ishaw":1duk0nbx said:

I thought strong arm cranks were square taper?

Happy to pay postage if that's easier for you, I'm in Epsom so not local sadly.

Click to expand...

Mine are identical to these....I thought they were strongarm but possibly not! It was 17 years ago that I bought them!

http://www.retrobike.co.uk/forum/viewto ... p;t=247232

My sister lives in Camberley, not quite on your doorstep but closer than Bristol if that helps, otherwise happy to sort out getting them posted.

I have a set of Sugino triple road cranks that use the V1 spline system too.

Re: Re:

Hovis_loaf":2b6fbc0x said:

What does the (1.)37 x 24 signify then?

Click to expand...

Cup type/size: English threaded...1.37" cups x 24 threads per inch.

With regards to your link to Chain Reaction; Shimano ES51 Octalink Bottom Bracket is the V2 version - here is a list of some models, and more importantly, the difference in the Spline dimensions, which are not interchangeable:

• Octalink ® V1 Spline: BB-M952 (XTR), BB-7700 (Dura-Ace), BB-6500 (Ultegra), BB5500 (105)
V1 BB spline grooves 5 mm long, ridges 2.2 mm wide.

• Octalink ® V2 Spline: ES70/71, ES50/51 (Deore XT M571/572, Deore LX M751/751, M510-8, M440-8, also 2005 Tiagra FC4401 & 4404, 2005 Sora FC-3001 & 3004)
V2 BB spline grooves 9 mm long, ridges 2.8 mm wide.

Edit: BTW 36x24 is Italian thread 36 mm x 24 TPI

Pip