You don't need to mark the rim because you only break the bead on the front of the tire. The back bead stays on the rim so the tire cannot move.

 

Thanks so much for you help on this topic! I Utubed several clips on this...I have patronised my local Discount tire for 12 years now and have purchased more tires and rims there than I can remember...that may change from here on out...Thanks again!

 

Discount Tire is actually my favorite tire place. I suspect you just talked to someone who did not know any better. If you lived close to St. Louis, I would say you could just come by and we could swap out your sensors. I have a tire machine that I bought because of too many times the tire shops screw things up when they change tires. We don't have a Discount Tire locally, so I buy my tires from their online site and mount and balance them myself. That has worked out great for me with the exception that once your family and friends find out you have a tire machine, everyone comes knocking on your door asking for "favor"!

 

So you did this with run flats? Aren't the sidewalls almost impossible to compress?

 

Yes I did it with the Michelin OEM Run Flats that came on my 2018 Stingray as well as with the RE71Rs I put on the car. Sidewall stiffness of run flats is not much different from the RE71Rs. I used DeWalt woodworking clamps to compress the sidewall away from the rim for access to the sensor. I think tire shops have a special clamp to do the same thing.

 

Thanks for the heads up. I just bought a used Coats 70x ah3 tire changer and a new Beissbarth 550 balancer to go in the shop I'm building. They're working on the wiring today and I should have everything operational in a few weeks. It's really nice to be able to do stuff at home and not be at the "mercy" of anyone else.

 

I suggest buying 4 of the clamps I mentioned. They make changing low profile tires easy. You use them around the tire to keep the bead under the lip of the wheel. They also come in handy when changing TPMS sensors! Without them, you will struggle on your tire changer with Corvette tires and other high performance low profile tires. Make sure you get the "600 lb" heavy duty clamps. Less capable clamps won't get the job done.

Another tip is always use outside clamping. Most tire shops use inside clamping and it tears up your wheels. Every tire machine manual I looked at has instructions that say outside clamp only for aluminum wheels. But it takes more work so the shops ignore those instructions.

Also learn how to line up the tire for 11 and 5 o'clock starting points (referenced to the duck head as 12:00) to avoid sensor damage. 11:00 for dismount and 5:00 for mounting.

 

badhabit - i looked up the manual for your tire changer. On page 5 it says: "Clamp steel wheels from the inside (clamps push outward against wheel). Clamp mag and custom wheels from the outside (clamps push inward against the outside rim edge)."

Thus again my suggestion that you outside clamp is backed up by the manual for your specific changer. I know that it is hard to believe that almost all tire shops do it wrong. Once you try it, you will understand why they do it wrong. Inside clamping just requires you to toss the wheel on the machine and stomp the clamp pedal. Outside clamping can be a pain in the back side. But the whole reason I bought my own machine (and suspect you did also), was so I could do the job right and not risk tearing up my wheels.

Anyone who does not believe the shops do it wrong only need to watch the next time they have tires replaced. If the shop places the wheel on the machine and hits the clamp pedal, they are not following the instructions the manufacturers of tire machines have provided. You can also tell by looking at the barrel of your wheels. Inside clamping on aluminum wheels leaves gouges inside the barrel of wheels near the back of the rim. These gouges are because the clamp jaws have teeth to make them grip the inside of the wheel. The clamps jaws have a wedge shape with protective padding on the side used for outside clamping so no damage will be done to the wheel.

Outside clamping requires closing the clamps part way (open just enough to clear the rim of the wheel), then placing the tire on top, then slowly closing the clamps in on the rim. Usually the tire will get in the way so you have to push down on the wheel while looking under the tire to make sure the clamps don't miss grabbing the wheel rim. This is another time I use the Dewalt clamps. They help me to push the wheel down so the clamps will catch the rim. If you have two people working the machine, one person can push down on the wheel as directed by the other guy looking underneath and operating the clamping pedal. If you are doing the work by yourself, the DeWalt clamps make a nearly impossible task for one person almost easy. This difficulty again is for low profile wide tires like modern Corvettes use. For your typical minivan, SUV or truck tire, outside clamping is usually easy because the tires are not stiff and the weight of the wheel holds it down enough for the clamp jaws to grab the rim.

By the way, I figured all this stuff out by researching tire changers on the web plus about a year and a half of using my machine to change about 100 tires. ( mostly for family, friends and fellow racers.... ) I did make some mistakes along the way - like learning the hard way that inside clamping is no good. Hopefully I can help you avoid learning some mistakes the hard way. Same thing about the 5 and 11 positions to avoid damaging sensors - you can guess how I learned about that...

 

I appreciate your input. I didn't know about the 5 and 11 positions. I got lucky and got the balancer for 900 new. It was one that had been in a warehouse and hadn't been sold. We tested it and everything worked find and it will be fine for what I do.
My local tire guy has Hoffman machines and he is very particular but for some reason the guy that does the tire changes can't air the tires up. The last 3 or 4 sets I've gotten I've had to go to the shop and get the beads to seat. I didn't mind because it saved me a 2 hour round trip, twice, to the shop that could seat the beads. I got a Michelin rep to show me how to seat the beads and then watched the owner at Atlantic tire do it in Raleigh. That's how I found out how. It's really pretty simple once you've done it a time or two. Our local guy still wants to use air from the machine and a Cheetah. That just doesn't work. So the deal has been I go and when Juan gets them on the rim I seat the beads.
It will be so much better being able to do that in my back yard.
They're finishing up my Mohawk lift install today and the electricians should finish the wiring next week. Then I have to pour the front pad to my drive and I should be ready to roll. I can't wait to have it finished. I have 2 sets of cups on the rims now so it may be a while before I change my first set. There's no way a local shop will be as careful and take care of my wheels like I do.