MACHINING 16.5" DOWN TO 16"?

[SquareRoot]

It took 2.1 seconds for Google to populate my que with company websites that will design and make ANY wheel your heart desires. Here's the first one:

Custom Rims

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thewheeldepot.com

 

[wanderinthru]

This CANNOT be done for 16 / 16.5 applications, there is not enough material on the wheel.

There are stories on the net about machining semi truck wheels, my understanding is that there is a LOT more material on the wheel to work with.

To machine a 1/2" off the wheel you'd have to turn 1/4" off of the circumference, if you look at the overall thickness you'll see there wouldn't be much material left. In addition, the angle of the lip of a 16.5 wheel is about 45 degrees whereas a 16 is 90 degrees, again you'd have to trim almost all of the material off to change the angle.

As for the heat gun theory, rubber can be heated and stretched, the steel cable bundle inside the tire bead cannot. Hackery, dangerous and a good way to ruin a tire.

The angle of the bead lip is what the old tire guy told me. Though if I recall the diameter of the wheels are the same. The tires were givin the .5 so to know they had the odd ball bead, 16.5, 22.5,

 

[nvrenuf]

I heat and stretch steel with my torch all the time.

Context sir, context....

How will you heat the steel cable inside the tire bead enough to stretch WITHOUT melting off the rubber it is encased in?

 

[DoubleDingo]

Curious, aren't the wheels in question of the OP made of magnesium? Or was that only rally wheels?

 

[SquareRoot]

Context sir, context....

How will you heat the steel cable inside the tire bead enough to stretch WITHOUT melting off the rubber it is encased in?

You don't have to heat the steel wire only the rubber bead. That's the secret to why this process is possible. The composition of 99% of all steel wire in modern tires is ASTM A228. Often used for music wire, it's tough, has a high tensile strength, and can withstand high stresses under repeated loading. In round form (used in tires) it's diameters range from 0.005 to 0.125. Also used in spring steel. It can be stretched (to a degree/percentage) and return to its normal size.

 

[SquareRoot]

Curious, aren't the wheels in question of the OP made of magnesium? Or was that only rally wheels?

I can't tell you how many hundreds of magnesium wheels and VW Engine blocks I have witnessed tossed into bonfires at the sand dunes over the years. Better than any 4th of July

 

[85K304SPD]

I think the OP was trying to save some money by not buying the correct stuff. Even if it could be done, imagine how much a machine shop would charge to do something like that... There ain't no free lunches out there...

 

[CalSgt]

I have 16.5" slots and was told it can't be done because the 16.5" wheel doesn't have the safety "lip" that keeps the bead seated on the rim (also why they so easily throw the tire off the bead when they get aired down too much or are run in a low pressure situation) and there isn't enough meat on the bone to machine them down. They said it had been done before but it compromises the wheel integrity. Since there's only a handful of manufacturers making tires for 16.5" rims and I don't really like the look of most all terrain tires available for them that when the time comes i'm going to bite the bullet and replace them with a modern 17" slot wheel made by US Wheel.

This CANNOT be done for 16 / 16.5 applications, there is not enough material on the wheel.

There are stories on the net about machining semi truck wheels, my understanding is that there is a LOT more material on the wheel to work with.

To machine a 1/2" off the wheel you'd have to turn 1/4" off of the circumference, if you look at the overall thickness you'll see there wouldn't be much material left. In addition, the angle of the lip of a 16.5 wheel is about 45 degrees whereas a 16 is 90 degrees, again you'd have to trim almost all of the material off to change the angle.

As for the heat gun theory, rubber can be heated and stretched, the steel cable bundle inside the tire bead cannot. Hackery, dangerous and a good way to ruin a tire.

^^^ Valid points here

You may not have asked for my opinion but I'll share it anyway, WHY WOULD YOU RISK YOUR SAFETY AND THE SAFETY OF OTHERS TO SAVE A DIME.

Tires are the only thing connecting you to the ground in a 4000+ pound vehicle, choose tires designed for the wheel and rated for your application or get different wheels.

 

[bucket]

It doesn't matter how close the actual rim diameter is, the .5 size rims and tires all have a much different bead profile than a standard rim and tire.

There's not enough meat on the rims to machine the proper bead profile into them. Guys do it all the time with 22.5's (in aluminum, not steel) for use with a passenger car type 22" tire... but those are heavy duty big rig wheels with a lot more meat. There's enough material left over that it's "ok" for use on a lighter duty pickup.

 

[bucket]

And don't get me started on safety beads, lol. True, the 16.5's generally don't have them, especially aftermarket. However, GM produced many of them with a safety bead and Dodge actually made 16" truck rims WITHOUT a safety bead.

 

[SquareRoot]

This thread was fun. I was trying too see how many folks I could take down the rabbit hole with me. lol. I'm out!

 

[Ricko1966]

@SquareRoot throwing magnesium was always part of having a bonfire here. My front pasture would be lit up like daylight.

 

[Bennyt]

@SquareRoot throwing magnesium was always part of having a bonfire here. My front pasture would be lit up like daylight.

late to the thread...I worked part time in HS at a socal VW shop and we seemed to have a never-ending supply of junk 1300-1500 Type 1 cases. The later 1600 cases had a lot less mag. I think we used to sell the case halves for $5 each for bonfires. I know I used to always grab a couple for parties. Only one guy in shop would do the welding on the cases to reinforce the rear main and even then, occasionally one would burn up in the process.

 

[peats]

This is an experiment i would not try. Do you really want the possibility of failure at speed?

 

[oldretiredafguy]

I went out in the barn to look at some 16.5 factory GM rims (steel, 8 lug). It is stamped on the wheel plain as day "Do not mount 16" tires on this wheel".
The bead seat design is totally different for 1/2" size wheels.

1/2" tire sizes are for commercial applications (heavy duty).
14.5-Mobile home axles.
16.5-3/4 & 1 Ton trucks
17.5-HD trailer applications
19.5-Medium duty trucks.
22.5-Class 7 & 8 trucks
24.5-Class 8 heavy haul.

Of course, you'll always find a mix of wheel/tire sizes on different trucks. If a human can do it, he will.