Hey there bikey people, so I'm replacing the front VO double cranks on my Trek 613 with a Sugino AT triple. I want to stick with the double concept at first so I'm thinking a 34-46 and keeping the granny gear slot empty. The question though relates to my bottom bracket spindle length. I can look up what is recommended for Sugino AT (sup, google), but if I am leaving the granny gear slot empty, I'm thinking I can use a shorter spindle, i.e. the same bottom bracket that is already installed in the bike.
Is this the proper choo choo train of thought? Am I good to go as long as the rings have proper clearance and chainline is decent? Maybe the more important question is, what determines what length spindle a certain crankset "requires"?
joeball
Posted: Tue Jul 07, 2015 8:38 pm
Joined: 24 Jul 2005Posts: 6037Location: Ether
Yeah, right train. The AT takes near the widest BB at 127mm. Going from triple to double you usually want a 5mm more narrow BB. It's based on chainline. For a triple the center ring typically lines up with center cog. For double the mid space between the two rings lines up with the center cog.
Thanks Andre! I'm pretty sure my existing spindle might be too short...Is there an easy way to check how long the spindle is before I take the cranks off?
joeball
Posted: Wed Jul 08, 2015 7:51 am
Joined: 24 Jul 2005Posts: 6037Location: Ether
Cranks gotta come off (easy on off with a crank puller and wrench)
Measure spindle length with calipers (bb can still be installed in frame)
Andrew_Squirrel
Posted: Wed Jul 08, 2015 9:48 am
Joined: 01 Mar 2010Posts: 2098Location: Greenwood
If you need a crank puller and digital calipers for measuring just give me a holler.
jimmythefly
Posted: Wed Jul 08, 2015 2:07 pm
Joined: 10 Jan 2007Posts: 1491
Which specific VO crankset do you have? They list recommended BB on their site, so with that information and knowing how much room you currently have between chainrings and your chain stays you can make a pretty good educated guess.
archie
Posted: Wed Jul 08, 2015 3:53 pm
Joined: 21 Jul 2011Posts: 149Location: cloud nine
Thanks squirrel...I have a puller and also digi calipers.
Jimmy, I bought this bike from Lee and they were on the bike when I bought it, annnnd they aren't on the website anymore so I actually dunno...
archie
Posted: Sun Jul 12, 2015 7:09 pm
Joined: 21 Jul 2011Posts: 149Location: cloud nine
Ok so the spindle is 113mm. Since I'm running it as a double, my measurements are showing it will work with these cranks IF I can put a 3mm bottom bracket spacer on the drive side. Anybody have any bottom bracket spacers?! Would like to pick up tonight!
jimmythefly
Posted: Sun Jul 12, 2015 8:01 pm
Joined: 10 Jan 2007Posts: 1491
Shimano/SRAM cassette cog spacers (that are not splined, just plain circles) are the exact same size and work as BB spacers.
Also, I would first just try it as-is, unless you know for sure your crank arm or chain rings will hit the stays unless you use that spacer.
I am guessing you will use the 46T chain ring most of the time anyways, so no big harm in having it be lined up chainline-wise as if it were a single ring set up.
PS I have a bunch of spacers that will work but I'm in West Seattle. Will be up late come n get em if you like.
archie
Posted: Sun Jul 12, 2015 8:19 pm
Joined: 21 Jul 2011Posts: 149Location: cloud nine
Cool thanks, Jimmy. Those are good tips, unfortunately it does rub the chain stay. Just barely. Didn't know that about the cassette spacers, but shoot, it looks like the ones I have are all splined :( I might have run out of time.. but if I decide to swing by I'll let you know! Thanks again.
All times are GMT - 8 Hours
The time now is Fri Aug 11, 2023 9:00 am
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
Joined: 21 Jul 2011
Posts: 149
Location: cloud nine
Joined: 24 Jul 2005
Posts: 6037
Location: Ether
Joined: 01 Mar 2010
Posts: 2098
Location: Greenwood
Joined: 10 Jan 2007
Posts: 1491
