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Flip RRs on rims?

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Old 05-30-2017, 03:11 PM
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Default Flip RRs on rims?

Anyone know if it's OK to flip RRs on the rims?

AIUI, the RRs are symmetrical, but have specific mounting instructions in order to avoid separating the tread splice. On a Miata, the front tires want to be mounted with the DOT/date codes facing one direction (don't remember if it's left or right) and the two rears with them facing the other. This leads to two tires mounted with the code facing out and two with it facing in, with the pairs being used on the diagonals.

So, given that, once the tires have worn down to a certain level, is it OK to flip them on the rims and then flip which pair goes on which diagonal? That would still satisfy the date code requierment, but would allow for using up more wear. Googling on the net finds a lot of people saying "you can't flip thsse!", but no one explaining why. I called Tire Rack and they didn't think there was an issue with it.

Yes, the tires have probably heat cycled to the point of losing grip, but let's ignore that for now.

This is my second set of RRs, my first set I corded the inside edge on them with -3.5 degrees of camber up front, -2.75 on the rear. That's a setup I originally evolved for use with Hoosier A6s at autox, which did not show the pronounced inside wear that I'm seeing on the RRs. Grip level on the Hoosiers was higher -- am I running too much camber for this tire? Or is it just a case that to maximize grip you wind up braking on the inside edges and wearing them?



thanks,
--Ian
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Old 05-30-2017, 05:20 PM
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Drive harder, you will use more of the tire
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Old 05-30-2017, 05:50 PM
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Alignment for best lap time will be different than alignment for max tire wear. The latter will vary at each track, which is why most people just do the former. I would not flip the RR given their propensity for tread splice separation.
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Old 05-30-2017, 06:37 PM
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Originally Posted by Savington
Alignment for best lap time will be different than alignment for max tire wear. The latter will vary at each track, which is why most people just do the former.
That makes sense.

I would not flip the RR given their propensity for tread splice separation.
If you flip them on the rim and then flip which diagonal they're on (ie, a FL/RR tire becomes a FR/RL), then the tread splice direction remains correct. Essentially this is taking the tire that was mounted on the front left, moving it to the front right (which would normally be backwards), but then flipping it on the rim (so that it is now the correct orientation).

--Ian
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