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Discussion Starter · #1 ·
Hi guys, I've been crunching numbers and found out that my stock tire size is causing my speedometer (and odo) to be 3.8666% off and to fix it I will need 215/50R17 (stock is 215/45R17), will the 215/50 fit in my wheel well with no rub? It is at stock height and i don't plan on lowering it or anything. its not that big of a difference but i just wanna be safe

Thanks in advance,
Treyb0
 

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How are you calculating that and against what tire size are you comparing?

I don't think you can get closer than the stock sizes on the car...
 

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Check out my list of mods your answer is there
 

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Discussion Starter · #5 ·
To calculate i found a nice stretch of flat highway and set my cruise to 60(according to the speedometer) then i time myself (multiple times for acuracy) on how long i travel from mile marker to mile marker (if you watch your ODO it won't work because it'll be just as off as your speedo).
for me i traveled a mile in 1:02.32 (when it should be exactly 1:00min)
so that is 3.866% slower than actual speedo reading, so to compensate i need a tire with approx 3.866% larger circumferance (215/50/17s are 3.4% larger in circumferance)
 

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Anyone know what the legal tolerances are for speedos being off? For some reason I remember 5% over is okay? I believe anything under is not legal.

Not to say that wanting to fix it is wrong, but my impression was the majority of vehicles have some fluctuation in the speedo readings.
 
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