Speedo: How off with 33s? (1 Viewer)

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macneill

Rollin’ on 33s
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Jun 2, 2004
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Port Washington, NY / Edgartown, MA
What is difference in mph with 33s?

Not that Grandpa here rarely goes above what I think is 65, but was just wondering how off it is.
 
macneill said:
What is difference in mph with 33s?

Not that Grandpa here rarely goes above what I think is 65, but was just wondering how off it is.

Mac,
With my 285R75 16 GY MT/R's the actual difference (GPS) is 5%. So at 65mph the actual speed is 68mph (actually 68.25).
 
Ahhh... very good. Thanks.
 
I had mine checked a few years back, but I remember that there was a 12-13% difference with my FJ60. I have 33x12.5x15. So when it shows 65mph on my speedometer, I am actually going about 75mph... Hope this helps..
 
If one didn't have a GPS...

33"/31.3"=1.05
A 5% increase given the speedo is accurate in the first place.
 
Remember "31", "33" etc. is nominal dimension...ultimately the actual circumference may differ slightly for each brand/model of tire.
 
mheredia2930 said:
I had mine checked a few years back, but I remember that there was a 12-13% difference with my FJ60. I have 33x12.5x15. So when it shows 65mph on my speedometer, I am actually going about 75mph... Hope this helps..

This would make sense, as I think stock tire size on the 60 was a 235/75/15 The 100 would be seeing a smaller difference because of the taller OEM tire. :)
 
spressomon said:
Mac,
With my 285R75 16 GY MT/R's the actual difference (GPS) is 5%. So at 65mph the actual speed is 68mph (actually 68.25).

Pretty much what I get too when I have the 285/75R16 Revo's on.
 
5.4% difference for 285/75R16 vs the 275/70R16 stock tires. YMMV
 
285's.

60 on the spedo is 64 on the GPS...............I don't do math :D
 

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