Tapered Roller Bearings - Why?

[Guest]

Still putting together that '78 Yamaha DT175 and I've come to replacing things like the steering stem bearings.

What's the advantage to tapered bearings? Should I be looking for similar upgrades for things like the swingarm?

[JEEPRUSTY]

I think tapered rollers are either more stable or have a greater bearing area than balls

[UncleMike]

I think tapered rollers are either more stable or have a greater bearing area than balls

That makes sense.

[Billy Ricks]

I think tapered rollers are either more stable or have a greater bearing area than balls

Yup, longevity from having a load spread out instead of covering one small point on a ball. It was a big deal back in the '50s when Harley went from roller bearing cranks to Timkens.

[UncleMike]

I see, I see.

[Nessism]

If the stock bearings are in good shape I'd regrease them and call it good. Tapered rollers are cool and all, but millions of bikes got along just fine with ball bearings in the steering neck.

[UncleMike]

If the stock bearings are in good shape I'd regrease them and call it good. Tapered rollers are cool and all, but millions of bikes got along just fine with ball bearings in the steering neck.

Ah, good to know. Can always upgrade later.

[Billy Ricks]

My old 305 didn't even have caged ball bearings, just loose balls on the triple.

[Steveb64]

Still putting together that '78 Yamaha DT175 and I've come to replacing things like the steering stem bearings.

What's the advantage to tapered bearings? Should I be looking for similar upgrades for things like the swingarm?

Usually the swingarm gets things like 'needle roller' bearings...

If the steering stem bearings are anything like some (most) of the ones I've seen - esp. from similar vintage bikes - you'll need new ones - not just clean the old... Somewhere I've got a manual (well - had - but I'm sure it's around somewhere) - I just went and had a quick look, but couldn't spot it with the others... If I see it, I'll have a look for what yours is supposed to have. It must be pretty close to when Yamaha changed over from balls in the steering stem to the tapered rollers. I Know my '80 YZ250 had tapered rollers.

Nice to see one of those old DT's getting a resto! I always liked them - had a '79 DT250F brand new - my first 'street-legal' bike!

[kingofvenus]

If the stock bearings are in good shape I'd regrease them and call it good. Tapered rollers are cool and all, but millions of bikes got along just fine with ball bearings in the steering neck.

Like Hayabusas, for one example.

[Nessism]

Like Hayabusas, for one example.

I remember from back in the day taper rollers were all the rage, then some manufacturers went back to balls, claming less friction. Not sure what to believe but it's interesting that Hayabusas's use balls. Didn't know that.

[kirkn]

If the stock bearings are in good shape I'd regrease them and call it good. Tapered rollers are cool and all, but millions of bikes got along just fine with ball bearings in the steering neck.

+1

I was never sophisticated enough to tell the difference between tapered and a properly greased / set ball bearing setup.

I've "upgraded" two different bikes over the years, and couldn't tell any difference at all, within the limits of the vintage suspension itself, but I've cleaned/regreased/reset 10 ~ 20 fixer-uppers over the years. The first one was necessary, though, because the races were dented and you could feel the distinct 'notch'.

So, unless the races themselves are 'dented' from being over-tightened, I'd just go with Nessism's advice.

As for the swingarm, they're likely either a bronze bushing insert or even a kind of 'bakelite' fiber insert. That is, no roller element at all. In either case, new inserts will get you back to where you ought to be, without the struggle of trying to 'upgrade' to a roller element.

Kirk

[UncleMike]

Every time I'm reluctant to ask a question here, you guys remind me why I had the inclination in the first place.

[RichDesmond]

Tapered rollers last longer, but have slightly more friction and are more sensitive to preload than ball bearings are.
I tend to put tapered rollers in high mileage touring bikes and ball bearings in everything else.

[UncleMike]

Tapered rollers last longer, but have slightly more friction and are more sensitive to preload than ball bearings are.
I tend to put tapered rollers in high mileage touring bikes and ball bearings in everything else.

That makes a lot of sense.