bianchi BB question
 

anyone ever have their BB come out while riding their bianchi? guy at the shop said bianchi was the only one to have the BB threaded so that might happen.

My Pista has conventional bottom bracket threading just like most bikes.

I have had three different crank bearing sets, and presently ride with a Phil titanium spindle and alloy cups.

I white grease the bottom bracket threads and use blue locktite on the cup threads, and my crank bearing set stays where I put it, and comes out easily when I want to service my bike.

last summer while out riding part of the drive side spindle cracked failed and sheared off my friends pista... thankfully we were just screwing around riding in cicles killing time and not hulling it in traffic of going down a hill..

I don't know what that means.

Yea, what did he mean by bianchi having their BB threaded?? 99% of bikes today have threaded bottom bracket shells. I've seen quite a bit of crank arms come off of bianchi pista's but thats because the crank bolts come loose from the factory or a mechanic failed to tighten them.

ok. well this is a 1975 bianchi steel lugged road frame. most threads on a conventional BB are threaded reversed, so that pedaling forward, if there were to be friction on the BB would tighten the threads. this bike, has forward threading, and since I didnt He-Man the bracket in there, after a 30 mile ride it crept out about 1/8 of an inch.

yes, with italian threaded bottom brackets, both cups are 'right-hand' threaded. typically some blue loctite is the way to go with these.

The cranks fell off my Pista as well. The mechanic at my LBS said that a faulty BB was to blame.

this never made sense to me, why you would have to use loctite...

I do not use locktite on Italian bb's. I just clean and grease them like anything else with threads. Then, I get down on them with the wrench. You need a good wrench to be able to apply a lot of torque w/o stripping the lockring.

If I do not service it for a while it may loosen up. When I put a bike away for the winter and then get on it this also happens.

Use white grease in the threads of the bottom bracket shell, and blue locktite on the threads of the cups.

Everything will stay in place, and it will come off easily, without the need to wrench anything down "wicked tight."

Loctite is one option for Italian BB's, you can also use teflon tape or just grease it and honk on it. However, I'm a little unclear on why you mention stripping the lock ring, it's the R side that's a problem, the L is fine and doesn't need any more torque than normal.

Also, once you get it in there good, never take it out unless you have to replace it. If it's a loose ball BB, just clean it out and repack it from the other side. It's a little awkward to do but it beats having it fall out. I may be the only one on earth weird enough to do it, but with cartridge Italian BB's I install them backwards so the main unit goes in on the L side, which is properly threaded. It seems to work fine.

to clarify, italian bb's are right hand threaded on both sides and english are left hand threaded on the drive side and right hand threaded on the nds.

so what's the loctite for on one and not the other?

Bearing precession causes the R side of an Italian BB to unscrew, loctite or other solutions keep it from unscrewing. This is unnecessary for English because the forces from precession tighten rather than loosen the BB on the R side.

It means that Bianchis with Italian BB's tend to unscrew themselves from riding. Poor wording - but I get the meaning. Other BB's with right hand thread on the drive side also suffer this problem. French and Italian are idiotic this way. ISO/BSC, whitworth/swiss are all reverse thread on the drive side.

With italian/french, just grease and reef it on. If it's coming loose then you can use some low grade loctite on it.

That sounds more like faulty crank bolt installation, or crank bolt coming loose to me. The only way the BB would be at fault if the cranks fell off is either manufacturing defect or broken axle. More information please?

I have italian threads on my marinoni. The bb comes out unless I exceed Park's recommended torque spec by ~20 footpounds and use loctite.

That's not the case... Most Bianchis are Italian threaded, if I remember correctly. The difference is between Italian and English threaded BB's. I forget which one is which, but one has both sides threaded the same way (in which case one side may *potentially* work its way loose, but it's highly unlikely), and the other has them threaded in opposite directions.
Sheldon Brown's website probably has plenty of info for you to read.

http://www.bikeforums.net/showpost.p...1&postcount=15

I would not say bianchis are mostly italian threaded. Japanese made bianchis come with BSC/ISO 70mm's.