Crank bearings - plain radial or angular contact?

[Jordan]

There's a drawing that shows both types, in different views of a widecase 350 engine.
See recent message, "Widecase engine sectioned drawing".
I'd love to have a better quality image of it.

I wonder what the story is behind showing both types of bearing?
Maybe plain radials were standardised to save cost?

Jordan

[LaceyDucati]

Jordan

The load rating of the angular contact bearings is greater than the standard single row type, so in principle they should be better.

The only time I have found them in a single is in the Swiss army Condors, maybe they were specified as the bikes were likely to be slogged a lot more at low speed than the normal bikes. Of course the Bevel twins have them as standard, including tufnol cages and an extra ball for good measure! When shown to a UK bearing manufacturer they just said that's the sort of bearing used in stone crushing machinery, with erratic loads Perhaps if Ducati had spent a bit of time balancing their cranks, they could have got away with lower spec bearings. I'm of course being controversial here and I'm sure I will be set Upon by twin owners. I do have a twin myself and love it, so I should be safe

Personally as I said in another post, after 20 plus years of building engines for others, I haven't had any problems with the cheaper standard single row bearings, and so take the attitude "if it ain't broken, don't fix it" camp.

Regards Nigel

[Dave450]

Personally as I said in another post, after 20 plus years of building engines for others, I haven't had any problems with the cheaper standard single row bearings, and so take the attitude "if it ain't broken, don't fix it" camp.

Regards Nigel

+1 Nigel! After as many years and more of rebuilding my own single, which had led a very hard life since it left the factory, the standard single row bearings are fine for mains and gearbox. IMO, they are one of the least problematic areas of the Duke singles.

Dave

[Jordan]

No complaints about radial bearings on singles' crankshafts - just interesting to see angular contact type in what looks to be a factory drawing.
Common radial ball bearings must have some side load capability, as I've seen them on my Norton Commando steering head (earlier Featherbed frame had angular contact "spindle bearings"). Also my MZ ETZ250 had the same arrangement. In both cases, a spacing tube was used between the inner races.

Jordan