Ron,
If you can hang in there and wait for just a bit yet, the answer may be here in spring/summer 2014. The last I talked to Bill at Diamond Back (8/23/13) that is when he was projecting they would have certification testing done on a new 235/75R14 radial. That's the size many of us need to "fill the wheel wells" with a similar diameter tire to original - I think they will be 27.5". I don't want to bug him too often, but I should check up on it again in a month or two.
I'm running the same size make-do tire you are and my speedo tells me nothing more than that I'm moving. It's at least 10% high all across the scale. I use a Garmin on the windshield, and the only time the speedo and Garmin agree is at zero.
Keith Boonstra
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