Pinarello BB upgrade?
 

Hi All,

I need to replace the BB in the early 90's Pinarello Veneto that I am rebuilding. It has a Campagnolo 36x24 f BB now, and is very sticky. I am putting on a mid-80's Shimano 600 group set, and need a square-taper Italian threaded BB to match. Does anyone know which is best?

I'm thinking of getting a Shimano UN55, but don't know if it will be Italian threaded or not.

https://www.amazon.com/Shimano-Squar...s=shimano+UN55

I want a really light one if possible.

Can anyone can send a link to where I can buy the right BB, or know if the link above is the right one?

Thanks!

The Amazon link has options for English or Italian thread, as well as the length. 70x is Italian, 68x is English.

The length you'll need depends on which 600 model crankset you have.

I wouldn't bet on that. Mountain bikes typically use 70mm English threaded. I'd bet that's what's on offer there.

Edit: No, I'm probably wrong about that. MTB bottom brackets are 73mm. The UN55 ought to be good.

I'm not sure if this is the right one for you, but the Velo Orange unit is a little lighter.

What length?
 

Ok I finally got the bottom bracket off, that was not simple.

The crank I want to put on is a Shimano 600 off of a 1985 Trek 520, can anyone tell me how long the spindals should be on the new BB?

The Campagnolo BB that came off was 70x113. But for whatever reason I feel like I'm supposed to put on a Shimano UN55 70x110.

Thanks for all the advice everyone!

We need the Shimano model number off the crank. It will be on the inside of the crank arm. Or you could Google with that info - There is a Shimano table showing the correct BB width for most cranks by model.

...if you're serious about "best", and price is not a disincentive, one from Phil Wood will usually outlast anything Shimano makes ans sells. They are very expensive, relative to most others, but they are make in USA, and they have pretty good service and reputation. They will also tell you which one of their offerings will work.

You need to buy the unit, the Italian threaded installation rings, and the Phil Wood proprietary installation tool. They do make some lighter weight models.

That length difference is pretty minor. I'd suggest putting the Shimano 600 cranks on the existing BB (if it's not too late) then check chain line:

https://www.sheldonbrown.com/chainline-multi.html

As Sheldon notes, the actual measurement doesn't have to be precise, except that there needs to be at least a millimeter or more clearance between chain rings (and any protruding bolts) and the chainstays/BB lug. If you go much smaller then those dimensions, you could have issues with FD adjustment.

As far as sealed bottom brackets, the expensive Phil Wood and SKF are lovely and will probably last long enough to be included in your will to your grandchildren, but an inexpensive Shimano will probably last plenty long enough for a fraction of the cost. Yes, Phil BB allow very fine adjustments to the chainline (I've used them on several bikes, and the SKF on my "better bike" is quite stiff even in the longest available length), but sufficiently accurate adjustments with Shimano can be accomplished by adding thin spacers between the DS flanges and BB shell.

If you have a bike co-op available, they might have used Shimano sealed BB in several lengths so you could experiment for best fit. Remember that the non-DS crank doesn't have to be exactly symmetrical with the DS as far as crank arm spacing, but you'll probably want at least one centimeter (3/8") clearance between the end of the crank arms and the chainstays.

Thank you everyone, super helpful. I'll post a pic when I get the new BB installed. I went with 70x110 Shimano UN55.