JIS or ISO? and where to find a 117mm BB?

Hi

I have jst stripped down the Martrac track bike i bought off ebay last week for a respray and have found that I need a new bottom bracket for it and need some advice.

The current bottom bracket is an unbranded, loose bearing job in pretty bad condition.

It is english thread, 117mm spindle and fits a 68m shell.

What i need help with is working out if the cranks are ISO or JIS taper - I am assuming they are ISO as they are made by Stronglight. They are an old style with a single fixed chainring that is not removable. Is this a good assumption to make? Have Stronglight ever made cranks with JIS thread?

Assuming ISO is the way to go can anyone advice on who makes an ISO taper 117mm engligh thread BB? I have been all over google and can find nothing in 117mm width at all. Stronglight do the JP400 BB but I think that may be a JIS thread and I cant even find that in 117mm.

Any advice would be appreciated as I don't really want to have to buy a new crankset just because I cant get a BB for the one I have!

Cheers.

Shimano UN54 comes in 115 or 118, one of which should be close enough depending on your rear hub/cog combo.

Edit: cheap at Parkers at the mo:
http://www.parker-international.co.uk/6070/Shimano-UN54-Bottom-Bracket.html?referrer=froogle

well phil wood can do any size (within reason) but expensive
how close is the chainring to the stay? could you get away with something narrower?

Old stronglight is ISO, newer stuff is JIS I beleive.

Should be able to find a campy, miche or FSA ISO taper BB in that length. Sure you need 117, seems long for a track bike?

Old stronglight is ISO, newer stuff is JIS I beleive.

Should be able to find a campy, miche or FSA ISO taper BB in that length. Sure you need 117, seems long for a track bike?

I thought it seemed long too but have had it running with my rear wheel and the chainline was spot on.

well phil wood can do any size (within reason) but expensive
how close is the chainring to the stay? could you get away with something narrower?

Chainring is pretty close - think going down to a 115 may be too tight. Guess i could try with a 118 and see if that works.

i think i've got an old sealed 117mm BB that came with a campag double you can have for free.

possibly a very very quick question!

i have just bought a 48T Stronglight chainring and I need to find out if its JIS or ISO taper??? Im a bit OCD on bike stuff, so i NEED to get this right. I need a definitive answer and also have read that stronglight were usually ISo but may have switched to JIS! so it f's me up.

This is the exact chain ring i bought thanks!!!!

http://www.on-one-shop.co.uk/acatalog/info_CSSTMYG17048B.html

oh and sorry for digging up a thread from the grave lol.

ISO and JIS correspond to the size of the sqare taper in the cranks and the bottom bracket needs to match. Chain rings have nothing to do with ISO and JIS.
The BCD (bolt circle diameter) is what you need to be worrying about if you've bought the chainring to fit to your exsisting cranks. The BCD of that chainring is 130, one of the most common these days.

However, I assume that you've bought the whole chainset and not just the chainring. In this case I suggest google'ing (sorry I cant be arsed to do it for you!) to find out whether its JIS or ISO, but im sure someone here will be able to clarify that.

Hope this helps

i did indeed buy the whole chainset. Iv googled but only come up with similar blogs/forums etc. The crank arms do have a J on them but i have no idea if this refers to JIS or if its just soem random letter. Why have the maufacturers not realised to detail which crank goes with which! its so annoying. thanks anyways

But im still stuck for now, ideas???

finally found an english stronglight website but even they dont detail it!! http://www.stronglight.com/stronglight/page.php?nom=produit&keyProd=zlightTrack

is it worth emailing them directly to find out? or can someone help.

www.sheldonbrown.com

or

www.velobase.com

The BB pictured with that is a 107 JIS

The BB pictured with that is a 107 JIS

i dotn have the BB from that pic just the chainset. But i actually just found out and it is JIS. If anyone needs any stronglight info use this link for their current specs detail etc.

http://www.stronglight.com/stronglight/BASES/NOTICE/document/noticeFacteurQ.an.pdf

hahaha I conquered it! thanks all. now i can actually buy my BB.