How to taper a lug hole?

[bobs409]

I just got some wheels/tires for my wrecker project to replace the split rims. These are the 1 ton style wheel that use flat back lugs however the holes are the 9/16" and my lugs are 1/2" so I need to taper the lug holes and switch to tapered lugs. (got all the new tapered lugs from Summit)

Any idea on how best to go about this? Any special degree of taper?

I sure hope there is an easy way, there are 32 of them!

[onebadbowtie]

What if you just used a bigger drill bit? and only drilled to the end of the taper of the bit?

[Beat68CST]

I think I'd get a reaming bit for that.

They come in different angles, I think like a 60* would be ideal, somewhere around there.

[GCncsuHD]

Not such a good idea.

The wheels were designed to center on the hub, not the lug. While centering on the lug is fine, it will reduce your load capacity.

Your biggest issue will come on the rear duals. So what if you taper the outer wheel? Your inner wheel will still have nothing to center it on the hub or stud.

Personally I don't feel there is enough material there to taper there anyway and get a good contact patch with the 60* tapered lug nuts, especially with the larger opening creating less material to work with.

Your best, and safest bet would be to machine a hub adapter to make the wheel opening fit the hub snugly. This may require machining the wheel opening out even larger to get enough material to machine an adapter. If you perhaps have the 2001+ GM wheels, then you could get by with welding a little extra material in and machining it out to the correct 4.56" opening. Any of the pre 2001 GM 8lug dually wheels should have the correct hub diameter and you would be able to just bolt them on and go.

[john]

Originally Posted by GCncsuHD

Not such a good idea.

The wheels were designed to center on the hub, not the lug. While centering on the lug is fine, it will reduce your load capacity.

Your biggest issue will come on the rear duals. So what if you taper the outer wheel? Your inner wheel will still have nothing to center it on the hub or stud.

Personally I don't feel there is enough material there to taper there anyway and get a good contact patch with the 60* tapered lug nuts, especially with the larger opening creating less material to work with.

Your best, and safest bet would be to machine a hub adapter to make the wheel opening fit the hub snugly. This may require machining the wheel opening out even larger to get enough material to machine an adapter. If you perhaps have the 2001+ GM wheels, then you could get by with welding a little extra material in and machining it out to the correct 4.56" opening. Any of the pre 2001 GM 8lug dually wheels should have the correct hub diameter and you would be able to just bolt them on and go.

I think that would be a big problem with flat wheels not designed for tapered lugs.

[bobs409]

REALLY good point on the inner dual wheel GCncsuHD. I never thought of that.

I checked the hub hole on these and they are the same as my split rims so should have no problems there thankfully.

Since the hub hole is the same, I probably could just use my old lugs which are flat on the back but it might be safer to use the new tapered lugs I bought.

I'll wait to see if anyone else has some ideas before deciding. There's no rush, it ain't going down the road anytime soon! (but hopefully in about a year or so...)

[ChevLoRay]

IF it is the thing that you decide to do, a chamfering bit is what you want.

I worked in a machine shop several years ago. We made valves for the Alaskan oil pipeline and the bolt holes in the flanges had to have a chamfer. We had a "bit" that fit the bore that also had a cutting edge that was spring-loaded. As the bit fed into the bore (using a drill motor) the chamfer cut the leading edge of the hole. We'd pass it through the flange and chamfer both sides of the hole.

But, I'm no engineer and I wouldn't ever encourage anyone to do something that would weaken their wheels and risk the safety of anyone on the roads.

[GCncsuHD]

Originally Posted by bobs409

REALLY good point on the inner dual wheel GCncsuHD. I never thought of that.

I checked the hub hole on these and they are the same as my split rims so should have no problems there thankfully.

Since the hub hole is the same, I probably could just use my old lugs which are flat on the back but it might be safer to use the new tapered lugs I bought.

I'll wait to see if anyone else has some ideas before deciding. There's no rush, it ain't going down the road anytime soon! (but hopefully in about a year or so...)

If you have the correct hub diameter that fits snug on the trucks hubs, put them on and run them with your old flat lugs.

Contrary to popular belief, the lug nuts do not carry the weight of the vehicle on lug centric wheels, and neither does the hub on hub centric wheels. The purpose of hub centric and lug centric is just what it infers: centering the wheel on the hub. The friction from the clamping force of the lug nuts holding the wheel onto the mounting surface is what actually carries most of the load, although hub centric does carry an extra dose of insurance if the lugs are not torqued down enough and any slippage does occur by transmitting the load to the hub rather than the studs which would shear easily.

So if you throw the wheels on there, the hub centric design will center your wheels correctly to kill any vibrations and irregular wear, while the clamping force of the lug nuts holding the wheel on the mounting surface will carry the load. No need for the tapered lug nuts.

[bobs409]

I just might do that. I'll have to do a test fit tomorrow to be sure. Now...what to do with 32 new lug nuts.