jimn

Hi,

I have a bike with the Ultrgra 10-speed from 2005 or 2006. It has about 700 miles on it. It features the cranks described in this document - Hollowtech II.

I'd noticed that the crank bearings seemed a little stiff. Took the chain off and spun the cranks. If I push them hard, they will spin maybe twice and then stop. Contrast this with a bearing on another bike that's 20 years old and just spins indefinitely.

Now, because of the design, it does not seem that one can lubricate the botton bracket at all. I hesitate to even try to get in there, because you need a g-- d--- torque wrench to put the crank arm back on!

Is this something that will just wear in? Can I adjust or lube this myself without a torque wrench?

Should I just ignore it and develop massive thighs from all the extra work I am doing on my rides?

Thanks in advance for your help.

Jim

greyghost_6

When you spin it is is smoothe? If its gritty and chunky then I would take it someplace that has the tool dis assemble and re assemble. If it is nice and smoothe, then the extra resistance is probably just the seals and such that keep grit out of your bottom bracket. I overhauled the same years bottom bracket in the dura ace style, If I remember correctly when i spun it it didn't spin and spin and spin either. So I think you are ok. I know that Ultegra is known for its superior seals, so I think you are good for thousands upon thousands of more miles, might even loosen up too.

HillRider

If the bearings are stiff on a Hollowtech II crank (i.e. external bearing bb cups), I expect it's because the frame's bottom bracket shell faces aren't parallel and the bearings are binding. The first thing to do is have the frame faced which should solve the problem.

Also, was the crank preload done properly when the crank was installed? This could also be a contributor.

Give up, it won't make your thighs the envy of your riding buddies no matter how tight the bearings are.

supcom

The stiffness you feel is negligible drag and there's no adjustment to make. External bearings are known to have a bit more drag than internal BBs. It's OK.

No-load drag has little to do with drag under load anyway.

Peek the Geek

I noticed the same thing back when I got an Ultegra-equipped bike. In fact I asked the same question here on BF, and I've seen several others ask it since then. I'm assuming it's pretty normal, and no, my thighs have seen no significant growth.

jimn

Thanks, I see this has been mentioned before though I didn't find it.

I suppose I can ignore it, though as others have said, it just feels wrong.

As mentioned in another thread, the cranks spin with the same resistance all teh way around, so it's probably not the BB faces (though I would not doubt that this frame is not assembled terribly precisely - Bianchi Virata from Taiwan).

Any engineers here want to expand upon no-load drag, etc?

I suppose overall this bike's a lot better than the one I was riding before it - a swapmeet amalgam of 20-year-old parts, weighing about 10 pounds more than this one. I think I had the cheapest bike of anyone in my club.

DMF 

That doesn't make sense. The bearings and the axle are symmetrical. Cock a bearing off perpendicular (as a un-square face would) and it will bind evenly all the way around.

operator

This is normal. Replace with ceramic bearings and/or loose ball/bb + crankset if you want lower drag.

kenhill3

If he INSISTED, yes. Otherwise it would be plain silly.

Reface and/or a new BB.

ginsoakedboy

This is common and typical with all the Shimano (and other makes too) outboard bearing bb's. I have two bikes set up with the XT M760 bb and one with the Ultegra 6603, and this is the way they come straight from the box. Nothing to be done, adjusted, faced or replaced -- because there isn't any problem. I've replaced the bearings in one of my XT sets with Phil Wood ceramic bearings, and the drag difference is negligible. The one thing you should make sure is that you don't tighten in the crank arm too tight with the star nut before you secure it with the hex bolts.

operator

This is not going to solve his "problem".

jimn

OK, the consensus seems to be that this is par for the course with the bearings in newer BBs.

I still don't get why this is not considered a problem, though. I mean, sure it's probably OK in the short term, but over the course of a 60-mile ride this has got to make a difference. Not that I am at this level, but it's hard for me to believe that people who pay $6k for a bike because it weighs 10 grams less are putting up with mechanical resistance of this kind without complaint.

ginsoakedboy, are you saying that the Phil ceramic bearings have this same tight feeling?

Ingleside

What you are experiencing is normal with most external bb systems. If you have a newer bike chances are that bb shell is pretty close to being fine and there is nothing to be done with it. facing may or may not make the bb smother but at the end of the day a traditional bb will have less drag than the external systems that are common today.
although all external bb systems do exhibit more drag than a traditional bb, i have noticed that campy does apprear to have the least amount of drag in their bb. their system uses a different seal system that has lower drag than the shimano/fsa style bb.

one last thing, you may want to check how much preload there is on the bb. the end cap that threads into the left side of the bb axle is responsible for preloading the bb and there if there is too much pressure it will cause the bb to be tighter.

Al1943

The one that spins indefinitely probably needs grease, I don't think that is normal.

ginsoakedboy

Yes - a little smoother, a minor improvement in terms of the drag, but not a night-and-day difference. I don't think I would invest in another set unless they show a dramatic improvement in durability over time. BTW - contrary to Shimano's instructions, the bearing cassettes can be replaced - you don't have to buy entirely new assemblies. But the cassettes are press-fit into the cups, so removing them takes some doing. I see that Phil Wood sells a kit for removing the cassettes, but I just had the LBS do it.

I mentioned it, and Ingleside talks about it in more succint terms -- if you overtighten that end cap, you will cause the arms to press inward on the plastic seals/covers, which in turn will interfere with the free rotation of the bearings. I think the spec for tightening that cap is like 5 nanometers -- which is like nothing. It's easy to overtighten, especially if you use the Park Tool that puts the nylon star-shaped bit at the end of a 10" metal bar.

ginsoakedboy

You won't lube them yourself because the bearing cassettes are sealed. You will just replace them. But they should last quite a while.

Peek the Geek

Perhaps "indefinitely" is a bit of an exaggeration. On the other hand, my older square-taper cranks (which are greased properly) spin for a good 8 revolutions or so before stopping. Just sayin'.

NoRacer

Check the preload first. There's a cap on the non-drive side that must be adjusted properly or it will cause the crank to bind if too tight. You can get the proper tool to adjust this at your LBS.

It is NOT NORMAL for a Shimano external bearing BB to only spin 2 times and stop.

If you find that after loosening the cap a little (there should be no side-to-side play) that the crank still seems to be binding, then have your LBS replace the BB bearings or you could do it yourself--reference www.parktool.com for directions.

tellyho

If by old, you're referring to cup and spindle, then I think it's totally normal to expect a cartridge BB to spin much less freely than an older one. I don't know about outboard bearing BB's; I still have square taper.

ScrubJ

By their nature, any sealed bearing is going to have some drag. Go to a bearing house, ask to see a new sealed bearing, hold the inner race and give the outer race a spin. Feel the drag? It's a combination of the grease and the friction of the sealing lip on the inner race.