Does anyone know what the stock bottom bracket would be on a 1987 Cannondale Black Lightning?
On a related note, what would I need to do to install newer (10/11 speed compatible) Shimano cranks on this bike—do I need to swap out bottom brackets (assuming this is even possible)? Thinking about doing a winter project with this bike, so any advice/insight would be appreciated.
I’ve got a 1987 Cannondale SR600 that I’m 99% sure has the same frame. It’s a regular English threaded bottom bracket. A modern Shimano BB will screw right in. Your bigger issues will be: 1) the rear triangle is 126mm. A modern bike is 130mm. You shouldn’t try to force it on an aluminum frame.
http://www.sheldonbrown.com/frame-spacing.html
And 2, you’d need to get an adapter to convert the down tube shift lever mounts to a cable stop for modern brake/shift levers.
The bigger problem is the frame spacing. I converted mine to single speed. Or just leave as is. But I wouldn’t try to squeeze a 130mm rear wheel in there.
Thanks for the reply. I suspected it was regular english threaded, but thought I’d ask.
And yes, I already know about 126mm vs 130mm spacing, but I can fit a 130mm wheel in the rear easily, and after searching online, I know a lot of people across the web have done it with zero issues on these older aluminum C-dale frames as well. I know some people still disagree with doing it, though, and that’s fine. Thanks for your help and the sheldon link.
Just to chime in on the axle width, my brother and I both had aluminium Kleins with 126 dropouts. We both used 130 hubs in them with no problems. I checked this with my LBS (owners are both retired pro road racers so I respect their opinion) and they told me the 4mm difference on an alloy/aluminium frame was fine, but under no circumstances do it on a carbon frame.
Conversion will be no problem. Standard English BSA threaded BB, still in wide use (and a far better system). For the rear triangle, it’s only 2mm per side. Any decently strong rider will put it through more flex while riding.
I’ve got a 1987 Cannondale SR600 that I’m 99% sure has the same frame. It’s a regular English threaded bottom bracket. A modern Shimano BB will screw right in. Your bigger issues will be: 1) the rear triangle is 126mm. A modern bike is 130mm. You shouldn’t try to force it on an aluminum frame.
http://www.sheldonbrown.com/frame-spacing.html
And 2, you’d need to get an adapter to convert the down tube shift lever mounts to a cable stop for modern brake/shift levers.
The bigger problem is the frame spacing. I converted mine to single speed. Or just leave as is. But I wouldn’t try to squeeze a 130mm rear wheel in there.
I’m inclined to agree on the 126 vs 130mm. Aluminum is not as elastic and has a lower fatigue limit than steel. Sounds like you are determined, though, but just be careful and check your frame for signs of fatigue occasionally. The point where the chainstays meet the bottom bracket, and rear brake bridge are going to be the most likely points of failure.
Your current bottom bracket might work, but if you want to optimize your chain line you might need one with a slightly longer spindle. If you are spreading by 4mm, you might get away with splitting the difference and going with a spindle that is 2mm longer, but a new crankset would probably negate that measurement. Research chain line on Sheldon Brown’s site as mentioned by kcb203 above. Also, I wrote an article on chain line that you might find helpful, one of only a few good articles on by site: http://homebicyclemechanic.com/perfect-bicycle-chain-line/
Good luck.