Bottm Bracket Spindle Length?
 

I have to install a SunTour Cyclone 7000 crankset:

http://www.velobase.com/ViewComponen...m=115&AbsPos=4

The listing doesn't say. I've tried thread searches. In Velobase, the SunTour cyclone bottom bracket sets are all 113mm. Is that the correct spindle length for this crank?

Thanks in advance for your collective wisdom.

Phil G.

That's a JIS square taper - right?

One measurement is worth 1,000 assumptions. If it was my bike I'd test fit the crankset using whatever JIS bottom bracket that I had available. Then I'd measure how far inward or outward I needed to move the crankset and make that spindle length adjustment when ordering your bottom bracket.

According to Sheldon, it's 110MM

http://sheldonbrown.com/harris/bottombrackets.html

"Not sure what size...."

God bless Sheldon Brown. I will also use the "measure with the BB you already have installed" method from above (thanks, Retro Grouch). I was just curious as to whether there was a spec sheet answer.

more like: http://sheldonbrown.com/bbsize.html

Remember that the spec sheet assumes that the rear centerline is also 43.1mm. Is it? If you look up centerline on the Brown site you will find the method for calculating the rear centerline. If it is close to what the 110mm BB will give you then you are good to go. If not then you may need to change the BB length to give you the same chain line front and back. Al

It's a 6-speed freewheel on a 126 OD hub, so I'll measure to between the 3rd and 4th position. I can also mount onto the current spindle, which is a Sugino AS road crank.

I'd use something short.

Potentially-irrelevant example: I'm using a 107mm bottom bracket with a Sugino triple crank on an old Bianchi with a 70mm bottom bracket shell and 126mm rear spacing. It's set up as a double, using only the two biggest rings, and the chainline is still a couple mm outboard of being centered with the 6-speed freewheel.

My point? If the BB shell were 68mm, and I were using a double crank, I imagine the crankset would be perfectly centered with the FW, and that's using the shortest BB I can get from Shimano. You don't want to know how badly-aligned it was with the 123mm BB spindle that came with the bike. :rolleyes: