Originally Posted by
TugaDude
This might be a shot in the dark, but here is Sheldon Brown's page which shows various makers cranks and their respective BB sizes.
What I'm thinking is perhaps you might be able to compare the Suntour crank to a similar Shimano and start there.
In any case, it seems for the triples, except for one that I noticed, the length doesn't exceed 122.5mm, so based on that, you might consider that the top end. And your estimate of 117mm might be good, but it might be a tad high.
Hopefully someone has more/better info to help you. Good luck!
P.S. I tried velobase.com with little luck. Here is the appropriate page. The page on the crank itself was of no help on spindle length.
https://velobase.com/ListComponents....7-e8e9d9083a63
Thanks. I actually checked both of those sources before finding the mid-1980s SunTour catalog with earlier SunTour BB spindle length info on Disraeli.
Unfortunately, neither those nor the 1990 and 1991 SunTour catalogs at Disraeli had the info I needed. Sheldon Brown's bottom bracket database doesn' t list the XCM crank at all. As you noted, the Velobase link for the crank doesn't have the spindle length required for either the XCM 2x or 3x config.
The info in the mid-1980s SunTour catalog may or may not be applicable, since the XCM triple crank seems to date from around 1990. The later catalogs do specify the SunTour BB model for the XCM, and it isn't the same one; it may or may not have used the same spindle length. Plus, the XCM is from after SunTour released Accushift; their mid-1980s catalog listing spindle lengths is pre-Accushift. That might be a factor too; dunno.
Again, thanks. I do hope someone out there has/can point me at the info I'm looking for. I realy don't want to go the "trial and error" route if I don't have to.