New Pegoretti and Italian BB woes

[sjbraun]

I just picked up my new Marcelo on Friday afternoon. I had hoped to post a ride report and some pics, but instead, I need some help.
After two rides and 90 miles, I feel a skip in my right pedal. I figure its just time to replace mt Speedplay cleats, they've been worn for a while. I pedal on another 1/4 to 1/2 mile when I look down to see the drivetrain side of my BB has almost completely unscrewed. A quick stop shows that the BB has pretty much dis-assembled itself. I call a friend and get a ride to the bike shop. None too pleased with how my new frame was built, we reached some agreement on how I wanted the situation remedied. My questions for you mechanical types :
Does this happen with Italian BBs? (I should mention that the BB is the new Campy Centaur model.)

Is there a solution, Loctite maybe?

Do I need to worry that my BB threads have been stripped by what happened? (Because if that's the case, I think I'll be asking for a new frame.)

I should mention briefly, that before today's unfortunate turn of events, I was really enjoying the ride of the Marcelo. I had some concerns about the posibility of its stout rear end causing a harsh ride, but I found the ride to be ridiculously plush. At the same time, the bike accelerates like my last OS aluminum frame. I'm thinking that once this BB porblem gets sorted out, I'll find the Marcelo is everything I had hoped it would be.

Thanks for your assitance.

Steve-trying to stay calm in Tucson, but I will have plenty to say to the LBS's owners tomorrow. :confused: :confused: :confused:

[ShockTreatment]

Yes, Italian BBs can loosen if they are not installed tight enough. I use plumbers teflon tape on the threads of the bb cups to eliminate noises in aluminum frames. If you tighten the cups with the proper torque, they should stay in place. I doubt that your threads are stripped, since the cups are also aluminum. If the cups easily thread back in but are not loose, they are probably OK. It would be good to have a knowledgeable person inspect them.

[dbrk]

Your Italian bb coming loose is not at all uncommon, though it is unfortunate. This almost never causes the threads to be spoiled nor is it more than an inconvenience. Certain bb's work poorly with Italian threading, others very well indeed. For example, I have had terrible luck using the otherwise excellent TA Axxis bb: the rings are too soft to be really torqued down. I've had far better luck with perfectly fine, cheap Shimano bb's (which I warmly recommend over most everything else that costs a fortune and performs no better). Phil Wood is the best of all worlds and is the only expensive bb that I think is worth the price. If you are using a new-fangled Shimano then I'm not so keen on the mechanicals of that but standard Campagnolos have not caused too much trouble.

As was wisely suggested, a little effort and maybe, maybe some teflon tape, but generally you need to just put them on extra tight (or with a torque wrench) and -carefully-!!!

There is no good reason why bikes should have Italian threading except that they are Italian (though the old Merckx Belgium-made bikes do as well).

dbrk

[Andreu]

to me with my Marcelo and a PMP bottom bracket after about 30 miles in April.

They need a bit of extra help to stay in that's for sure (tape, loctite) as they tend to unscrew with the natural direction of pedalling. Unfortunately, my BB melted completely (not sure how) and I have not heard from the supplier after an e-mail about 5 weeks ago (but that is another story). I have a Campy BB in now - no damage to the frame. I have done about 10 000 Km on it everything is working fine.

you´ll be fine but it is annoying.
A

[Dave]

In my experience, with a Tommasini, two Colango C-40's and a Fondriest, all using Campy BBs, I've never had one come loose.

There is a chance that the BB shell needs facing, but I never faced any of the frames mentioned above.

Just be sure that your mechanic is smart enough to torque the right hand cup to the maximum torque. I never used anything but grease on the threads of my BBs.

The common misconception is that the RH thread causes the right cup to come loose. That's not the case. The cause is something else, but the result is that the cup will unscrew itself after it's loose whereas a LH threaded english BB will just stay loose and not unthread itself to any large extent.

Some mentioned the Phil Wood BB. Although it's well made, the lack of a fixed cup on the right side requires the use of two tools (one on each cup) to properly tighten an Italian thread. Without two tools, tightening either side can cause the opposite side to screw out. Two tools aren't mandatory with an English thread.

[Bill Bove]

Hear! Hear! Doug-O, there is no good reason for Italian bottom brackets and far less for French threads, on anything other than lingerie. French lingerie, ooh la la :banana: :banana: :banana:

[CNote]

The common misconception is that the RH thread causes the right cup to come loose. That's not the case. The cause is something else, but the result is that the cup will unscrew itself after it's loose whereas a LH threaded english BB will just stay loose and not unthread itself to any large extent.

If it's not the right-hand threading, then what other unique aspect of the Italian BB could it be?

Use blue (non-permanent) loctite and forget about it.

[sjbraun]

Thanks for your prompt and helpful replies. There were a few other build issues that seemed to stem from the fact that the guy building my bike wasn't as experienced as he could have been. I asked the shop to have the bike more or less rebuilt, this time by someone who knew what he was doing. They agreed that would be a wise course. I'll have words with the owners next week.
I don't understand how shops who sell BMW or Lexus quality bikes (and at full price, too) can think that anything less than Lexus service is acceptable. When I drop 3K in a bike shop, I expect everything to be done properly and with a degree of care. Ohterwise, I might as well mail order my frames.

[shaq-d]

I've had far better luck with perfectly fine, cheap Shimano bb's (which I warmly recommend over most everything else that costs a fortune and performs no better).

i concur with dbrk here. i've had very good luck with shimano bb's on 2 bikes, including my commuter which went through hell last winter... (still going strong and has never come loose). but then, i tighten my bb very tight with a wrench that has a handle that's at least 13" long...

sd

[Spicoli]

Thanks for your prompt and helpful replies. There were a few other build issues that seemed to stem from the fact that the guy building my bike wasn't as experienced as he could have been. I asked the shop to have the bike more or less rebuilt, this time by someone who knew what he was doing. They agreed that would be a wise course. I'll have words with the owners next week.
I don't understand how shops who sell BMW or Lexus quality bikes (and at full price, too) can think that anything less than Lexus service is acceptable. When I drop 3K in a bike shop, I expect everything to be done properly and with a degree of care. Ohterwise, I might as well mail order my frames.I would not hammer your local mechanic over this. It is a pain, but as you can see it happens alot. It has happened to me a bunch of times although it always seems like it happens when the frames are new? I have stood on the things and they still have come undone. so take it easy on the guy I doubt he rushed and I even more doubt he flaked it.

POOP happens? Jeff

[Cadence230]

Man. Buzz kill. I'm sure you'll be back to enjoying er' in no time. :)

[SPOKE]

it's not uncommon for the italian threaded BB's to work loose. proper torque on the right hand cup is an absolute. i also use a a small amount of the weakest loctite (#242 i think). this allows the cup to be removed with normal hand tools. it alos guards agains the cup working loose. i think the term that is used to describe this pain in the a** is "epicyclic motion" (spelling is probably wrong).
if the threads are lightly damaged then a very high quality tap may be able to make them serviceable. unfortunately, finding a high quality italian thread tap in many of the bike shops these days may be a bit tough.

[shiftinjon]

There is a reason Phil Wood includes thread locking compound with their BB cups. ;)

[sjbraun]

But, when I brought the bike back the more experienced mech, said "Oh that's happened to me before, we just need to use a little loctite." There were few other things: the new guy greased the high bling WR seatpost. and he clearly didn't know how to install the the fork after he had removed it to trim, and he dropped it while carrying it over to the vise and the rear brake housing was cut too short so that the curve back to the brake occurs before the seat tube. So it wasn't just one little misadjustment. And I still think if I drop 2K for a frame and another $1000 on parts, they should be installed properly. If you sell high end stuff, you should provide an equal level of service. So far, I received what I'd expect from the kids at Supergo.

[shaq-d]

But, when I brought the bike back the more experienced mech, said "Oh that's happened to me before, we just need to use a little loctite." There were few other things: the new guy greased the high bling WR seatpost. and he clearly didn't know how to install the the fork after he had removed it to trim, and he dropped it while carrying it over to the vise and the rear brake housing was cut too short so that the curve back to the brake occurs before the seat tube. So it wasn't just one little misadjustment. And I still think if I drop 2K for a frame and another $1000 on parts, they should be installed properly. If you sell high end stuff, you should provide an equal level of service. So far, I received what I'd expect from the kids at Supergo.

it's unacceptable for a mechanic to screw up. simple as that.. i would never, ever, go back to a bike shop where the mechanics are not consistent and good. (and that nicludes bike shops with one good mechanic and one new one). but i can be picky in toronto which has lots of shops...

hm.. some other notes about your notes though. dropping a fork is no biggie, happens all the time. rear brake housing CAN occur before seat tube. really depends on the size of your bike. the proper guide is it's fairly straight when heading into both ends, not where it is relatively to tubes. which might'ev been what u meant.

anyway, u're right about expectations. i would increase that not just to 2000$ bikes, but also expect it from cheaper bikes. if i'm gonna pay for a mech, it better be as good or better than what i'd do myself.

sd

[Climb01742]

dumb question...so what's the difference between an english BB and an italian one? and if the italian ones are so problematic, why do italian builders continue to use 'em?...is there any advantage other than pride? thanks for answering my dumb question. ;)

[christian]

English bb's have a left-hand thread on the drive side, Italian bb's have a right-hand thread on both sides. The reverse thread on English bb's prevents them unscrewing due to precession.

I think it's tradition more than anything. From an engineering perspective, the English design is clearly better, but it's not like problems are endemic with the Italian design. If all the clearances are right, and you torque it down sufficiently, it holds.

- Christian

[christian]

The common misconception is that the RH thread causes the right cup to come loose. That's not the case. The cause is something else, but the result is that the cup will unscrew itself after it's loose whereas a LH threaded english BB will just stay loose and not unthread itself to any large extent.

Nonsense. It's clearly the drive-side RH thread that causes it to come loose. The crank spindle turns forward, the bearings backward, and the force from the bearings unscrews the bottom bracket cup. Google "precession."

What else would it be? Intelligent Design? Elves?

- Christian

[Dave]

Nonsense. It's clearly the drive-side RH thread that causes it to come loose. The crank spindle turns forward, the bearings backward, and the force from the bearings unscrews the bottom bracket cup. Google "precession."

What else would it be? Intelligent Design? Elves?

- Christian

I think you're confusing cause and effect. The BB unscrewing is the effect of precession, AFTER it's worked loose, but it does not mean that the same force caused the BB to loosen in the first place.

I can't see any way for sufficient torque to be applied to loosen the threads until after they have come loose. Then it's relatively easy for the cup to unscrew. The CAUSE of the loosening is most often improper torque and/or a BB face that's not square to the threads. Leaving paint on the face of the shell can also cause poor seating of the RH cup. These causes can also loosen the LH threads of an english BB. The LH threaded cup won't unscrew, but it won't magically tighten itself up either. If the effects of precession are as powerful as you believe, a LH threaded cup should tighten itself. Try leaving the RH cup of an English BB loose sometime and see if tightens up all by itself.

I've never had an Italian BB come loosen on the four Italian frames I've assembled and ridden for many thousands of miles. I never resorted to loctite or teflon tape, but I did properly torque the cups and made sure there was no paint on the face of the shell.

http://en.wikipedia.org/wiki/Precession#Torque-free_precession

[cinelli]

"I've never had an Italian BB come loosen on the four Italian frames I've assembled and ridden for many thousands of miles. I never resorted to loctite or teflon tape, but I did properly torque the cups and made sure there was no paint on the face of the shell."

The key phrase here is "properly torque the cups". I have had at least three Italian bottom brackets back out on me until I learned the proper way to torque an Italian bottom bracket. It takes some serious torque and can sometimes be difficult to remove down the line.

[dbrk]

"I've never had an Italian BB come loosen on the four Italian frames I've assembled and ridden for many thousands of miles. I never resorted to loctite or teflon tape, but I did properly torque the cups and made sure there was no paint on the face of the shell."
The key phrase here is "properly torque the cups"..

Not that it matters too terribly much the aluminum rings that TA uses for their bb cannot be tightened enough or properly on an Italian bb. You will snap them before getting them to hold up.

My point is that there are always exceptions, even when things are done as properly as can be. That's one of the interesting things about bikes and bits: they don't lend themselves well to absolutes. Thank goodness something is still like that.

dbrk

[David Kirk]

One thing to remember too is that the quality of the BB treads in the frame as well and the hardness of the material have a large effect.

Good threads, good torque, hard metal and you are good to go.

Dave

[OldDog]

I have a Mercks MXL. The cup loosens. I have tighened it until I thought I may strip it (I did'nt). Threads are clean, face is faced and square. Chorus BB.

I have resorted to Loctite. Problem solved. As Douglas points out, it's one of the quarky things of beautiful bikes.

[christian]

I think you're confusing cause and effect. The BB unscrewing is the effect of precession, AFTER it's worked loose, but it does not mean that the same force caused the BB to loosen in the first place.


Fair enough. What I should have said is that the bb unscrewing is the effect of precession, with an attendant prerequisite that the bb is too loose to begin with.

The issue, however is this; if you torque an English bb to less-than-ideal spec, neither cup unscrews itself. If you torque an Italian bb to less-than-ideal spec, the RH cup does.

While I haven't had any trouble with unscrewing Italian bottom brackets, either, that doesn't negate that it's a far worse design.

- Christian

[Too Tall]

"Fair enough. What I should have said is that the bb unscrewing is the effect of precession, with an attendant prerequisite that the bb is too loose to begin with."

Why is everyone picking on the fast guy?!? Kidding. Chuckle.

Krikey, I've never had an Italian BB come loose or any for that matter however they all weld themselves in place equally.

Italian design not as good as English???? ITS ITALIAN!!!! Interpretation = Needs to be seen by it's mechanic on a regular basis, requires professional installation. Sexy as all get out. Tch :rolleyes:

[Fixed]

bro I argee with T.T. cheers :beer:

[slowgoing]

Not that it matters too terribly much the aluminum rings that TA uses for their bb cannot be tightened enough or properly on an Italian bb. You will snap them before getting them to hold up.

I had an alternative problem caused by the soft aluminum TA rings. They tightened fine. But when I went to remove one, it deformed from the BB tool and I couldn't get it out. That was fun.

Whoops! It was the aluminum Phil Wood BB cups that I used with a TA crankset that deformed. My apologies to TA for the mistake!