Help understanding modernization needs?
 

I am starting a project to modernize an older steel frame. It has 130 mm dropouts and will take modern wheels, was set up with an Exage 7 speed group. I was original just going to put on some tourney 7 speed brifters with the original drive train.

However, I have just been gifted a nearly full groupset of Shimano 105 5700, shifters, front and rear derailleur, Brakes, cassette, chain, and FSA crankset. The crankset came off a bike with a BB30 bottom bracket, and the bottom bracket is the one thing the set is NOT coming with.

The bike to be worked on, as I mentioned, has an Exage group, 300ex to be exact, including the bottom bracket with I believe a square taper. I have a wheelset that will accept the 10 speed cassette.

I figure the shifters, cabling, brakes, and derailleurs shouldn't be too much of an issue, just replace the DT shifters with some cable stops and put everything else on and tune it up.

BUT... the crankset... that I am concerned about. I haven't done it yet, but I imagine that a BB30 compatable FSA crank will in no way fit with a square taper Exage bottom bracket, but it of course would work with the 10 speed group.

My question is what do I do about the crank?

I see a few possibilities, but I don't know which one is possible, realistic, or worth pursuing.

1. - Use the biopace double crank already attached to the exage BB. (Will this work with 10 speed group?)

2. - Find some way to attach the FSA 10 speed compatable bb30 crankset to square taper exage BB. (Is there a realistic, inexpensive way to do this?)

3. - Buy a modern, new or used crankset that is compatable with exage BB AND with 10 speed group? (is there such a thing?)

4. - Buy a new BB that is compatable with the FSA crank and will fit the frame? (Again, is there such a thing?)

5. - Worst case, buy a new BB and a new Crankset? (What BB fits the standard BSA threading and works with 10 speed without breaking the bank?)

6. - Worst worst case, I'm crazy for trying to put a 10 speed group on a 1990 steel bike, I should just sell the group and go back to my original plan for 7 speed brifters on the exage drivetrain? (or maybe throw the group on a 2004 Raleigh I use as a rain bike that has 8 speed Sora instead?)

Any of you more experienced, wiser wrenches have any insight here as to which is the least stupid and most cost effective route to take here?

#4
Take the old bottom bracket or the complete bike to your favorite bike shop and buy or have them order the correct bottom bracket that will fit the frame and the FSA crankset. Might as well take the FSA crankset with you.

Are you sure your bike doesn't have conventional English BB threading? That would be my bet. Assuming it does have English threading, sourcing a bottom bracket to match the crankset of your choice should be a piece of cake. Honestly, it sounds goofy to me to put on all that nice 105 stuff along with a crappy crank.

Yes, Its standard English threading. I had just read that the exage sport BB was a square taper. Honestly, I'm pretty new to the bottom bracket world, this is my first time ever working on that part of the drivetrain. Intended as a learning experience, and working as intended!

Presumably you have the parts in question, so you could test fit everything and eliminate all the guess-work here. Which do you prefer: guesses or first hand knowledge?

Also, first you might understand the concept of "need." Everything else is easy.

Thanks so much for helping me understand the concept of need. I feel so enlightend now.

And If I was home to check the fit on these parts, I would. But, like many adults, I have a job, at which I procrastinate on the web thinking about my project bike. Also, since it is my first attempt to work on a bottom bracket, and I know that a bb30 crank wont fit an exage bb, I fail to see what checking the fit would do exactly.

Thanks, drive through!

You framed the question, and I have no insight whatsoever into your needs just FYI.


So you prefer guesses. That's progress. Good news: you will see plenty of guesses here.

misleading thread title.

If your frame has a 68mm English threaded BB shell and your crank is BB30, then you need something like this Threaded to 30mm ABEC-3 BB - Black Which is an English threaded external BB with 30mm ID bearings for your BB30 crank. This is a bit kludgy but realtively cheap. The most elegant solution would be to get a 24mm spindle external bearing crankset and bottom bracket like an FSA Gossamer MegaExo, Shimano 105 Hollowtech II or Raceface X-Type. This leaves you buying the crank and BB but you may be able to sell or trade the BB30 part.

As for the sanity of this exercise, it depends on the quality of the frame. If it is a good grade of steel with nice lugwork and dropouts in good shape, go for it. If it's a cheap frame with stamped dropouts, get it working with minimal investment, or put the 105 stuff on your Raleigh and waterfall the Sora group.

You cannot use that crank on your bike. A BSA external BB is too wide for a normal BB30 crank.

That won't work if the crank is actual BB30. BB30 and PF30 use flush press-fit bearings in a standard 68mm width shell with greater than a diameter for the larger bearings that go with the over-sized spindle, and that standard width spindle isn't long enough to accommodate a 68mm BSA shell plus external bearings.

Wider 30mm standards can be made to work - that's the reason behind BB386EVO which pairs with appropriate cups in BSA, BB30, PF30, and other frames. Many newer FSA cranks are BB386EVO and can use the FSA MegaEVO bottom bracket for BSA shells.

Oops, thanks for catching that. My fleet is all threaded BB so I know the stuff exists but haven't had to use it.

So what length is the spindle on your 30mm crankset?

Maybe I'm too quick to throw money at a problem, but an English threaded Shimano bottom bracket and a brand new 105 5700 crankset can be had delivered to your door for about 120 bucks from Merlin Cycles. I recently bought exactly that and the parts arrived quickly and were obviously priced right. This route nets you a nice matched 5700 105 group set on your bike.

No English BB / BB386EVO crank adapter there

You cannot fit a BB30 crankset to a frame with an English-threaded bottom bracket, and there's no adapter that can make it work. English and BB30 bottom bracket shells are both 68 mm wide. You can't fit BB30 bearings inside an English shell. If you mount the bearings outboard, the combined width of the shell and bearings will be too wide for the crankset's spindle.

If your FSA crankset is plain vanilla BB30 and not a wide BB30 variant like BB386EVO, you'll need a different crankset for your 10-speed drivetrain. A quick Google search turns up 10-speed Shimano Tiagra 4600 and 4650 cranksets at around $60 from Chain Reaction Cycles. You'd also need a Shimano Hollowtech II bottom bracket, but that'll only add $10-15 to the cost.