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-   -   Sugino Messenger cranks + sugino 75 bb compatibility (https://www.bikeforums.net/singlespeed-fixed-gear/611961-sugino-messenger-cranks-sugino-75-bb-compatibility.html)

Silkworm 12-30-09 08:18 PM

Sugino Messenger cranks + sugino 75 bb compatibility
 
Are these parts compatible? I've heard in some cases that ISO cranks and JIS bb's and vice-versa are compatible. Any know if these two are?

erichsia 12-30-09 08:32 PM

different tapers and different spindle lengths. if you want your chainline to be straight, no.

Scrodzilla 12-30-09 08:53 PM

But if you want your chainline to be totally wonky, yes.

bigvegan 12-30-09 09:18 PM


Originally Posted by Silkworm (Post 10207212)
Are these parts compatible? I've heard in some cases that ISO cranks and JIS bb's and vice-versa are compatible. Any know if these two are?

I CANNOT believe this, but they may be.

http://www.sheldonbrown.com/bbtaper.html - " if you install a J.I.S. crank on an ISO spindle, it will wind up about 4.5 mm farther in than it would on a J.I.S spindle of the same length."

Since your Messenger crank needs a 103mm JIS BB, and your Sugino BB is a 109mm ISO BB, the extra length and the narrower taper may cancel each other out and leave you with a chainline that's within 1-2mm of perfectly straight.

Unbelievable.

I'd still buy a new 103mm JIS bottom bracket for $25, but you just may be in luck.

Scrodzilla 12-30-09 10:35 PM

Holy crap!

tgscordv6 12-30-09 11:37 PM


Originally Posted by bigvegan (Post 10207463)
I CANNOT believe this, but they may be.

http://www.sheldonbrown.com/bbtaper.html - " if you install a J.I.S. crank on an ISO spindle, it will wind up about 4.5 mm farther in than it would on a J.I.S spindle of the same length."

Since your Messenger crank needs a 103mm JIS BB, and your Sugino BB is a 109mm ISO BB, the extra length and the narrower taper may cancel each other out and leave you with a chainline that's within 1-2mm of perfectly straight.

Unbelievable.

I'd still buy a new 103mm JIS bottom bracket for $25, but you just may be in luck.

It might work, but it would messed up the cranks over time.

dropspace 12-31-09 10:02 PM

you need to be really careful of jis cranks bottoming out on an iso taper bb since the iso taper is so much narrower. it just depends on the specific cranks involved. you can try it and it MAY work, or it will bottom out and you will round off the taper on the cranks turning them into nice paperweights.

operator 12-31-09 11:46 PM

Why the OP wants to put a crappy crank on a high end bb is another question.

Scrodzilla 12-31-09 11:58 PM

Most likely to try to correct the chainline issues associated with Sugino RDs.

OP - just use a 103mm JIS BB and you'll end up with a chainline that will be off by only 2 or 3mm (perfectly fine). I put a 1mm cassette spacer beneath the cog when helping a friend with his build and his chainline is pretty damn straight.

Build your own 01-01-10 08:43 AM

Or one could use eai cogs on formula hubs(close to 44 mm cl)wich is close enough.

letsgetsandy 01-01-10 07:29 PM


Originally Posted by Scrodzilla (Post 10212153)
I put a 1mm cassette spacer beneath the cog when helping a friend with his build and his chainline is pretty damn straight.

face palm

Scrodzilla 01-01-10 07:51 PM

Why slap yourself? It's perfectly okay to use a cassette spacer as long as you don't go overboard and try using one that's too thick and eliminating a bunch of threads in the process. My friend's cog + spacer ended being just as thick as my EAI cog.

letsgetsandy 01-01-10 08:10 PM


Originally Posted by Scrodzilla (Post 10214557)
It's perfectly okay to use a cassette spacer .

no its not any mechanic that said that was okay is a dip. no bike shop will let a bike go out the door like that.

ern 01-01-10 08:17 PM

why?

Scrodzilla 01-01-10 08:27 PM

Please explain why an EAI cog and a no name cog + 1mm spacer equaling the same width are so different. Are you afraid of seatpost shims and washers too?

ern 01-01-10 09:39 PM

ok. back on topic. sell the sg75 bb. get the correct one. buy a cup of coffee and a donut. dunk donut in said coffee. eat. repeat. have a merry day. yay.

Scrodzilla 01-01-10 09:46 PM

Agreed. Donuts are good. So is coffee. Together, they are awesome. Happy New Year.


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