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Originally posted by markemark:

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Originally posted by irf3:

I still stand by my original comment to Steve. The Sun ain’t shining yesterday, today, tonight or tomorrow (this is true in 53056 right now). What do I do with this mismatched rollout set of tires to get to within 1/2” of each other?


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I guess go buy a few heat lamps from Home Depot then

So here is my story. As I said earlier in the thread my new MT 3183s came in marked 105 1/4 and 105 3/4. We mounted them and the smaller one measured right at 103" and the larger one was 104 3/4 at 6 psi. This was after following MTs directions: it took 20 psi to seat the bead, I removed the cores, drained them down and filled to 6. I called MT and they said don't even bother trying to stretch as it was too far out. Since I'm a dumb racer I figured I'd try it anyway.

I put 20 psi in the smaller one and about 1# in the larger one and set them in the sun. After about 20 mins I drained the smaller one and refilled to 6. It had gained 1/2". So I pumped back up to like 25 and set it out for another 20 min. It gained another 1/4" so it was at 103.75. I pumped it back up for another 20 min and it didn't grow anymore.

I then pumped the larger tire that I was trying to shrink to 6 psi and it measured 104 so it shrank 3/4. I then put it on the car in the trailer. I put 8 in the smaller one since it was now only 1/4 out and put it on the car as well.

The next morning I lowered the pressure to 6 and the smaller tire was a bit larger actually. I put 3 hits on the car (at 6.5#, a little higher than I had been measuring them at) and at the end of the day the smaller one was 105 and the larger one was 105 1/4. Likely they were bigger because they were in the sun all day and at 6.5 instead of 6.

So it seems like I had some huge variation in the rollout that I was able to get them closer by trying to stretch one and shrink the other. Didn't think it would work but it did, much better than dealing with sending tires back.

Great information 183N.

If the sun is not shining, I’m wondering now if one could use a cardboard box to put the tire into and use a piece of plumbing pvc attached to a car exhaust and box to provide the heat. Make an opening on the opposite side of the box to let the exhaust out and monitor tire temp with an IR gun.