FSA Square Taper BB J.I.S or ISO ?
 

I have a Seal BB Square with a FSA 34/50T crank set. Are all the square taper "tapers" interchangeable ? I have a choice between a FSA Tempo Adventure 30/46T or a FSA Vero Compact crank set. The Vero says J.I.S, but the Tempo doesn't list the type of square taper.

Also, how can I determine what square taper is of my FSA BB.

Thnaks for the assistance.

The taper angles are the same between JIS and ISO. But the length and small end size are different. The vast majority of cranks and BBs are JIS these days. Not saying that your possible cranks are both JIS, BUT I would be surprised if two cranks from the same brand would not be the same taper (the cost of the tooling to make a taper accurately is not small). Andy.

all FSA cranks and bottom brackets are going to be JIS. The only ISO square-taper is Campy and Stronglight (and a couple other small european makers). I'm not sure who amongst this group still makes square-taper cranks.
A few Asian-made *track* cranks also use JIS, but only for single-chainring track cranks with 144mm bolt-center.

Thank you guys. As Andrew states, different standards from the same mfg, wouldn't make since. The FSA BB and crank set were installed by my LBS in 2011. No model is printed on the crank, but I'm thinking it might be Vero, as it is an older crank set, as the 30/46T is no longer listed. Tempo 30/46T being shown on FSA's current Website.

Edit: The part number of the Vero is 602SS (according to FSA) and I see "602" stamped on the crank arm of my FSA crank, so this might be an early model. Looks like the Vero 30/46T will work.

All of FSA's square taper cranksets will be JIS, but they may not be designed to use the same bottom bracket spindle length as one another.

Thanks, help me determine that length . I'm using a double at now. I would like to go from a FSA Compact 34/50T to a 30/46T compact. Leaving the BB alone.

Yup FSA is made in Asia, so natrally JIS..

look for places with sales of the exact same crank, those shops will suggest the spindle length..


want to leave the BB ? try the crank and see if you can , that will answer if for you..

You could just buy a new 46 tooth ring for your current crank and call it a day. That is of course if anything else isn't worn out.

If you do go the new crank route, as Fietsbob says, it is a trial and error method of obtaining the right bottom bracket length. My guess is no change is needed.

Glancing at FSA's web site, I didn't see a recommended spindle length for either crankset. If you contact FSA, they could probably tell you. Then you'd have to measure your current spindle to see if it matches either of the cranksets you're considering.

In a worst case scenario, it's not a match and you need a new bottom bracket, so you pick up a new Shimano UN-55 in the appropriate length for $15-20. Plus a bottom bracket tool like a Park Tool BBT-22 or BBT-32 if you don't have one for another $10-15.

Thanks, it's not the 46T I'm after, it's the 30T. The 30T chain ring has a BCD of 80mm. So I would need the whole crank set. BB is sealed and in good shape, as is the chain rings. At 70, I'm trying to get into the 29-27 gear inch range. I'm at 32 inch now.

Another option I'm considering, a medium cage (I prefer 105 RD), and Shimano 14-32T cassette, will get me to 27.9 inches, at about $60. The crank set will cost me about $90, so I'll get with FSA for some details. Also, the Tempo crank set 30/46T is 9 speed, I have 7 speed in the rear. So I don't know if that will cause more issues than I need. The RD and cassette seems less costly and will work.

Got a reply from FSA, I need to have a 110.5 spindle for the tempo crankset to work. I'll have to pull off the cranks someday and measure before buying.