Speeding with bigger tires
07-28-2018, 03:25 PM
#1
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Year: 1999
Model: Cherokee
Engine: Straight 6 4.0
Speeding with bigger tires
Hey guys I have a question. When I had a 3inch lift with 30s on my 99 XJ it seemed like I was going slower than all the other cars. Now I have a 5 inch lift and 32s (mud terrain) I’ve been told by friends that I’m going 5 over the speed limit when my speedometer says I’m going the speed limit. Shouldn’t it be the other way around? Is it possible it’s been regeared? The problem is it was completely stock before I got it.
07-28-2018, 04:04 PM
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Year: 1990
Model: Cherokee
Engine: 4.0
The larger diameter tire travels further per revolution. The jeep will be going faster than the speedo shows. You have GPS on your phone? It will show your actual speed.
07-30-2018, 09:06 PM
#5
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I'm on 31*10.5's, 10% over speedlimit constant. Soapy, that indicates you have regeared or your Speedo gear has been changed. Regearing can adjust speedometer errors, but more common, and FAR cheaper, is getting a correct speedometer gear.
08-01-2018, 03:35 PM
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Year: 96 & 88 4 dr Cherokees
My 96 still has the stock speedo gear, and running 31's w/ stock gears, my speedo is off my just under 2 mph @ 60 by GPS. So 60 mph is really 62.
But in the stated case, if you are 10% over your speedo speed....then you have the normal stock speedo gear, as 31's should put you ~10% high (actual speed 10% more than speedo speed).
.
Last edited by TRCM; 08-01-2018 at 03:48 PM.
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