making setup bearings

Gonna be doing gears in my D30 this weekend and am wondering if I can use my old bearings for setup bearings or if I actually need to go out and purchase new ones for this task. I'm getting some conflicting info from other sources and thought I would ask here. TIA

you usually mess up your old bearings getting them off so you pretty much have to go get new bearings to do this.

I used the old bearings out of my 44 as setup bearings. I read later that you shouldn't do that due to them being worn. I haven't noticed any whine or excess heat so everything seems fine to me.

When I did my D60, I used the old bearings.

You don't need a whole set, either...pretty much the inner pinion race and the two carrier bearings are all you'll need to mess with.

I use a setup bearing for the outer pinion to set the preload. It's alot easier to get the pinion out if the outer bearing slides off easily.

Thanks for the replies. I guess I'll go ahead and try pressing them off and go from there.

You can get new low grade bearings from the parts store for about $8 a piece that aren't worn. That's what I did anyways.

What are you guys using to hone out the bearings so you can slide it on and off?

A wheel cylinder hone works good,I just use a dremel tool with a drum sander!

RCP Phx said:

A wheel cylinder hone works good,I just use a dremel tool with a drum sander!

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I used the same thing. Worked great... Ya know, the thought never crossed my mind to do the same thing with the pinion bearing race...

lowrange2 said:

I used the same thing. Worked great... Ya know, the thought never crossed my mind to do the same thing with the pinion bearing race...

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I bet that made setting up the gears more of a PITA.
I used a dremel with the drum sander too.

lowrange2 said:

You can get new low grade bearings from the parts store for about $8 a piece that aren't worn. That's what I did anyways.

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That will work but for me I always use TIMKEN so I use "new" TIMKEN bearings for set-up. The reason being that the same manufacturer/same part number bearing should hold a tolerance and be very close in size, other manufacturers may not set the same limits of tolerance in their manufacturing process.

I'm not saying that you must use TIMKEN but you should use the same bearing brand for the set-up bearings and for the final set of bearings.


I have set-up bearings for a few different rears now, they are handy.

My $.02

xjtrailrider said:

That will work but for me I always use TIMKEN so I use "new" TIMKEN bearings for set-up. The reason being that the same manufacturer/same part number bearing should hold a tolerance and be very close in size, other manufacturers may not set the same limits of tolerance in their manufacturing process.

I'm not saying that you must use TIMKEN but you should use the same bearing brand for the set-up bearings and for the final set of bearings.


I have set-up bearings for a few different rears now, they are handy.

My $.02

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Dude, you have gotta get out of my head. That was exactly the question I was planning on asking when I got on here. That for the input.

Meh, that ain't all it's cracked up to be. I wouldn't worry about it. You really think Timken can control tolerances across the globe better than anyone else can?

If it's an HM88649 bearing, it is what it is. You won't be guaranteed a country of origin no matter who you buy it from. Any of the reputable manufacturers will be within tolerance; they can't afford not to be.

Longevity after setup might be a different story, and if you want to use Timken, that's your prerogative. I don't think there's a Timken bearing on the shelf in my warehouse, and I work with more bearings every day than most folks will change on their rig in an entire lifetime.

Set 'em up and go wheelin.

vetteboy said:

Meh, that ain't all it's cracked up to be. I wouldn't worry about it. You really think Timken can control tolerances across the globe better than anyone else can?

If it's an HM88649 bearing, it is what it is. You won't be guaranteed a country of origin no matter who you buy it from. Any of the reputable manufacturers will be within tolerance; they can't afford not to be.

Longevity after setup might be a different story, and if you want to use Timken, that's your prerogative. I don't think there's a Timken bearing on the shelf in my warehouse, and I work with more bearings every day than most folks will change on their rig in an entire lifetime.

Set 'em up and go wheelin.

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Nope, I didn't say that Timken was better or worse than any other bearing manufacturer. I have had good luck out of them though.

The purpose of my post was to give the advice to the OP to use same "brand" bearings for set-up and final set-up for a more consistent final result.

xjtrailrider said:

I'm not saying that you must use TIMKEN but you should use the same bearing brand for the set-up bearings and for the final set of bearings.

Click to expand...

xjtrailrider said:

That will work but for me I always use TIMKEN so I use "new" TIMKEN bearings for set-up. The reason being that the same manufacturer/same part number bearing should hold a tolerance and be very close in size, other manufacturers may not set the same limits of tolerance in their manufacturing process.

I'm not saying that you must use TIMKEN but you should use the same bearing brand for the set-up bearings and for the final set of bearings.


I have set-up bearings for a few different rears now, they are handy.

My $.02

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I certainly see your point. It makes sense. The last set-up I did I used the O'Reilly generic brand for set-up and Timken for final and I haven't had a problem. It ran the same pattern, backlash and preload after final assy. as it did with the cheap bearings. But your logic does make sense.

Just because the manufacturer is the same does not mean that you will have two tapered rollers close in width and/or cone stand.

Axial registration tolerances on two piece tapered rollers are not that tight. For example, the tolerance class that automotive bearings are made under, allows the overall width of a tapered roller assembly to be +0.008"/-0.000".

Setup bearings cut that down to a possible +0.004" in assembled width variation because cup/cone stand tolerance is half the max assembled width. You use the final assembly cup on carrier bearings with setup cones & the opposite for pinion depth.

So even with setup bearings, your final assembled bearing stack might vary by up to 0.004" compared to the setup bearing stack.

On carrier bearings, you might get bit more backlash or a bit less. Same for pinion bearings, variation between the setup cup & the final cup, on the inner bearing, will change the pinion depth.

Exactly, why you double check the backlash & pattern after final assembly.

In our tapered bearing stock at work, for each size we have 'measured' and 'standard'.

The measured ones we pay extra for, and they exactly match the 'nominal' specs shown on the blueprints. If I build something with those, it will be right on the first try 99% of the time.

I can also measure individual bearings from the standard box, build up a shim stack, test backlash a few times, etc. For something with a normal lead time we'll use these. For something that needs to get out the door fast, we'll use the measured ones, and the increased cost is built into a rush delivery fee.

I don't do automotive stuff - like Goat said, the sizing and general usage for automotive components is pretty lame compared to true industrial equipment. Our midsize bevel gearsets are roughly the size of a Dana 30, and I think the input power limit for those boxes is somewhere around 20 HP. However it's not uncommon that some of our gearboxes will run non-stop 24/7/365 for upwards of 10 years at full rated output.

Not that it has any bearing on this discussion (ha ha ha), but as an example here's one of our older large gearboxes:



That one runs a pretty critical pinch roller for Nucor Steel in Decatur, AL.