Pre-load of taper-rollers

Off topic but, ha! Hardly Dangerous (HD) used taper rollers in their wheel hubs till 1999!!

The conditions faced by motorcycle wheel bearings are quite different from those in a pinion for a differential. The wheel loads are almost entirely radial, but the pinion has to stand a serious side-load under all driving conditions except coasting in neutral. So, the pre-load conditions required are not comparable. The 'bike wheel also gets heated by the brake to a much higher temperature than the diff.

The collapsible sleeve idea is not as new as might be thought - they were used in the MGB, for instance. And quite possibly, many others earlier. In my case I am using a fairly thin steel sleeve and removing it to take the merest shaving off one end. If I find it needs less than that I shall rub it down on a sheet of fine wet-&-dry. The problem I have with the shims or wedding-ring ideas are in making the shims and holding the washers - the one-piece sleeve is easy to hold in an ordinary chuck. Fortunately, I found a tube with an accurate round surface to start with - actually a cam-drive tube from a 1974 Ducati which I have been keeping (and moving house 7 times) in case it came in handy. There you are, dear, I knew I was right ...

Thanks, everyone, for an interesting and constructive debate.

Regards, Tim

Yes, of course. The graph I posted however is from a bearing manufacturer referring to tapered rollers in general. So I think it still wise to be sure the bearings are not over-preloaded if you want maximum life.

I am sure there are specialist websites and books on building high performance cars that would cover performance diff building that should cover such specifics. The Yanks in particular are very good at that stuff on their insane V8s. EG **LINK**

Similar website on hotrod diff building here http://www.hotrodders.com/forum/carrier-bearing-preload-73464.html

Edited By Hopper on 02/05/2017 11:35:38

Cost saving. Ball bearings are cheaper but won't last as long and require less set up time at the factory.

My 1947 1 1/2 litre jag front wheel bearing was ruined by an M.O.T tester's insistence that he would not pass it unless I eliminated the recommended bearing clearance on the front wheel. I had to go about ten miles to get home.The taper roller bearing turned blue. So it's not always correct to pre load this type of bearing. Colin

Pre loading taper roller bearings in a wheel hub is recipe for disaster.

The epic example was the fatality caused by a dealership assuming that the new mode, like its predecessor, l still used ball races, where the new model used taper rollers. They tightened the nut to the torque for the ball races and when the hub seized at speed, the car went out of control, killing the driver.

Our Skoda 110R improved when I slackened the front hub bearings to give 0.002 - 004" end float. (The workshop manual called for end float, but initially, there was none!) The steering lightened, and self centred after that adjustment. Another improved in the same way as well, given the same treatment.

Renaults of that time specified 0.002" - 0.004" endfloat. For many years, Leyland had specified end float for taper roller front hub bearings. The vehicles in my fleet covered about 60K miles each year, but we never had a failure.

Pinion bearings are preloaded. The workshop manual advised the practice on Ford Anglias, (and presumably Cortinas as well) post 1959, was to install a new crushable spacer between the bearings and then to tighten the nut until a spring balance, on the end of a string around the diff casing gave the required reading.

This suggests that the preload was pretty small, just enough to produce a small drag torque.

Lathe Headstock bearing are often lightly preloaded, to ensure accuracy of alignment.

Hope that some of this helps

Howard