1150/1100/etc large bevel box bearing question

[Den]

Has anyone came across,or heard of, a large final drive bearing having rollers instead of the usual balls ?

Some Grinnall guys have had the usual bearing problems, and one of them said that when he had his replaced, the faulty one had rollers, not balls.

 

[scud]

I've just been reading a bearing type thread http://www.ukgser.com/forums/showthread.php?t=159180
and someone in there had his bearings changed in Russia and noticed they were totally different to what he expected.....Comradeski

 

[Steptoe]

Has anyone came across,or heard of, a large final drive bearing having rollers instead of the usual balls ?

Some Grinnall guys have had the usual bearing problems, and one of them said that when he had his replaced, the faulty one had rollers, not balls.

Never seen such a bearing fitted as you describe, and that includes on the K series bikes (which use the same bearing) going back to 1984.
And i've seen a lot.

 

[Ian J Hartley]

Ball bearings can support both radial (perpendicular to the shaft) and axial loads (parallel to the shaft). Ball bearings can operate when the bearing races are misaligned. Precision balls are typically cheaper to produce than shapes such as rollers; combined with high-volume use, ball bearings are often much cheaper than other bearings of similar dimensions. Ball bearings may have high point loads, limiting total load capacity compared to other bearings of similar dimensions.

Roller bearings typically have higher load capacity than ball bearings, but a lower capacity and higher friction under loads perpendicular to the primary supported direction. If the inner and outer races are misaligned, the bearing capacity often drops quickly compared to either a ball bearing or a spherical roller bearing.

I suspect that BMW figured radial loading might be a problem so opted for ball bearings instead of rollers. Or maybe they are just cheeper to manufacture. But I might be wrong.

 

[Stewart H]

ISTR a thread over on ADVrider where someone was fitting a different type of bearing, try searching there, I would imagine that the Grinnall can subject them to sideloads that they may not like.

 

[Tattiebogle]

Drive unit has ball bearing ( I assume for positive location and support) and taper roller bearing for support.

Unit and pre-unit BSA 'A' series engines had a problem with positive crankshaft location (side load on the drive side roller) so, in the dim and distant past SRM engineering provided a solution (may still do) of a combi ball/roller timing side bearing (replacing a Ph/bronze bush) which supplied a roller for radial load and ball for axial load/location thereby relieving the drive side of any axial load (plus the benefit of crank end feed oil supply). I haven't checked any bearing catalogues before posting but space will/may be limited for a combi bearing (if available) in a final drive.