SKF BB binding slightly on installation

[njh...@gmail.com]

Looking for feedback from any other users of SKF bottom brackets. I just installed a 107mm SKF bottom bracket in a new frame. Before installation, when turning the axle in the BB housing, I could feel some drag from the seals on the BB but the bearings felt perfectly smooth. After installation, the drag was noticeably greater and, when turning the axle by hand before fitting the cranks, the bearings felt slightly rough. With a pair of cranks fitted but no chain, if I give the cranks a good shove with my hand hand, they will only rotate about two turns before stopping.

I'm pretty sure the problem is not the BB shell, as a) before installation I chased the BB shell threads and faced the BB shell with the piloted taps and cutters from my Campag toolchest, and b) after feeling the change in the BB bearings, I remove the SKF BB and installed a Shimano UN55 BB, and the bearings in that did not suffer the same change after the BB was installed.

Any suggestions on possible cause/remedy?

Nick Payne

[bikerbob]

I put one in my bike about 2 years and 12K miles back and it has been fine.  I would contact the dealer/seller (Compass? - that's where I bought mine) and explain the issue.  They should make it right (replace or repair).  I did have a similar problem years ago with a Phil BB and the company was very helpful and replaced the bearings.

Bob Bingham

[Igor Belopolsky]

I'd ask Compass as I am assuming that is where you bought...

(If anyone knows another source for SKF then I'd love to know)

[Philip Kim]

from jans' comment about the drag:

What feels like a lot of drag when you spin the BB in your hand in fact is only a couple of Watts. Once you are riding, you don’t notice it, and it won’t slow you down. The waterproof seals need some pressure on the spindle, otherwise, water and grit would force their way past the seals.

Longer ISO spindles: There are no plans right now, but in most cases, you can use a slightly shorter JIS spindle. The taper is the same angle, just a little thicker. For example, a number of customers have replaced their worn Campagnolo Nuovo Record bottom brackets (114.5 mm ISO) with 113 mm JIS SKF BBs, and found that they fit very well. Basically, the JIS and ISO tapers are so similar that the tolerances overlap.

On Tuesday, January 10, 2017 at 10:01:46 PM UTC-5, njh...@gmail.com wrote:

[Alex Wetmore]

Shimano square taper cartridge BB's aren't at all sensitive to BB thread alignment, so I don't think that is a good way to verify that your BB shell is true.  Shimano's design was done in a way that allows the BB shell to be extremely rough and poorly faced and still offer good BB service and life.

I don't have any personal experience with SKF BB's despite being friends with everyone involved at Compass.  I'd give them a call or email and ask.

alex

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From: 65...@googlegroups.com <65...@googlegroups.com> on behalf of njh...@gmail.com <njh...@gmail.com>
Sent: Tuesday, January 10, 2017 7:01:45 PM
To: 650b
Subject: [650B] SKF BB binding slightly on installation

 

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[somervillebikes]

This is interesting. I had the identical experience with an SKF BB. I installed the BB as part of a complete build for a friend with a new custom Mike Flanigan ANT.  Mike is a very experienced builder and I have no doubt that the BB shell had been properly cut, chased and faced, even though I did not have the tools to verify this. A short conversation with him after experiencing the problem solidified my confidence it had been done right. The SKF remained smooth up until the point of torquing it. As soon as a small amount of torque was applied (less than 10 lb-ft, less than adequate for permanent installation) it started to bind and spin rough. The more I torqued, the more binding I felt.

At the end of the day, after a conversation with Compass (who had supplied the SKF), we decided to torque it to spec and just live with the added drag. As far as I know, the owner has not had any issues with it since then. I should followup and ask whether the binding resistance has subsided over time.

Anton

velolumino.com

On Tuesday, January 10, 2017 at 10:01:46 PM UTC-5, njh...@gmail.com wrote:

[somervillebikes]

It makes me wonder, in this N=2 observation, whether their was a bad lot of SKFs in which the DS flange was out of perpendicular plane to the thread axis, causing the BB cartridge to distort when torqued.

Anton

On Tuesday, January 10, 2017 at 10:01:46 PM UTC-5, njh...@gmail.com wrote:

[Alex Wetmore]

I strongly doubt it.  It is much harder to control BB facing than it is to control bearing alignment in a CNC'd bottom bracket.  The pilots on BB facing and tapping tools normally do it, but since they use crude alignment systems the facing can be crude as well (especially if done in a rush).  In comparison a CNC lathe of the size that SKF likely uses is extremely stiff and has incredible alignment.  If the bike is painted after facing it is also easy to have the paint build up more on one side than the other.  

One way to test would be to take the same SKF BB and put it into another frame known to have a well faced bottom bracket.  You could also use a freshly machined BB shell that hasn't been welded into a bike yet (but you'd have to figure out how to get it in there tightly without distorting the shell).

I use a lot of Shimano Pro headsets (they were being closed out cheaply about 5 years ago) and they are also extremely sensitive to headtube facing.  They will bind in most frames that were faced before painting (which is almost all production frames).  They are great headsets and give a long service life, weigh little, look nice, but I think this is probably what these first design models from being very successful.

Most modern external bearing BBs also require well faced bottom bracket shells.

alex

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From: 65...@googlegroups.com <65...@googlegroups.com> on behalf of somervillebikes <atu...@gmail.com>
Sent: Wednesday, January 11, 2017 10:02:34 AM
To: 650b
Subject: [650B] Re: SKF BB binding slightly on installation

 

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[somervillebikes]

That makes sense. FWIW, the BB was faced after painting to avoid any paint issue.

Anton

[Jack Fortune]

Alex,

The SKF mounts like the Shimano cartridges - the entire cartridge threads into the fixed cup threads and the locking ring wedges between the bb shell and the cartridge on the left side.

I don't believe that anything puts any force against the end of the bearings (like Phil Wood bb's).

It doesn't seem that end facing accuracy would affect anything. Even if the left and right bb threads were axially misaligned, it doesn't seem like the locking aluminum locking ring could exert enough force on the cartridge to distort it.

In any event, they should contact Compass.

all the best,

Jack Fortune

Eugene, Oregon 

[Alex Wetmore]

Cool, I must have been confusing it with another unit that I've played with.  Sorry about the confusion.

alex

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From: 65...@googlegroups.com <65...@googlegroups.com> on behalf of Jack Fortune <jfort...@gmail.com>
Sent: Thursday, January 12, 2017 10:32:54 AM
To: 650b
Cc: njh...@gmail.com
Subject: Re: [650B] SKF BB binding slightly on installation

 

[Hahn Rossman]

The fit between the non drive side cup and the cartridge in the SKF is a lot tighter than most other BB. Can you thread the non drive side cup in easily until it bottoms? If you need the tool to get it in your shell is distorted or machined wrong (or both). The shimano design is a lot looser and lets the driveside cup establish the alignment and then the non driveside has quite a bit more slop. This is probably a better design in terms of letting suboptimal shells and machining (or paint) not cause the cartridge to bind. It also may be why they don't last as long a sthe SKF. 

Hahn Rossman 

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[njh...@gmail.com]

Yes, I can thread the non-drive side cup in by hand until it bottoms. As I stated in my original message, I used the bottom bracket taps and facing cutter from the Campagnolo toolchest to chase and face the BB shell before installing the bottom bracket. I'm pretty sure the problem is not due to any distortion or misalignment in the BB shell.

[somervillebikes]

And when I installed the SKF BB that was binding, it threaded right in smoothly, as did the NDS ring. It was only after torquing that the binding could be felt.

Anton

[Hahn Rossman]

Anton and Nick

Does your tool also face the shell square to the threads? 

Is it only when you torque the drive side that it binds? 

Hahn Rossman

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[njh...@gmail.com]

Yes, both the taps and facing cutter are piloted. See http://www.os2.dhs.org/~john/campy-bb-tap-set.jpg - the taps share a common shaft, to ensure that they remain aligned and co-axial while in use.

Once the threads have been chased with the taps, the pilot for the facing cutter threads into the left and right sides of the shell and the shaft of the facing cutter slides through the pilot to ensure that the cutter remains square to the threads while in use - see http://www.os2.dhs.org/~john/campy-bb-facer.jpg.

Nick

[Hahn Rossman]

Nick

Can you loosen or remove the non drive side cup and tell me if there is still the binding?

Hahn Rossman

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[njh...@gmail.com]

The non-drive side cup doesn't affect it at all. And the drive side cup doesn't cause it to bind with only a small amount of torque applied. But as soon as I torque the drive side cup to somewhere around the recommended 35-40Nm, it binds slightly, with a feeling similar to a cup and cone hub where the cones are slightly too tight.

[Clayton]

all the skf bbs I have used bind. perfectly machined she'll or not. always a little crunchy. none of this mattered when riding and after thousands of miles they spin freely when out of the frame.

these days only one bike has one the rest all run happily on shimano hollow-techs. cheap, easy to adjust, inferior from an engineering perspective but awesome in real life.

cheers,
Clayton Scott
SF, CA