11 replies to this topic

[blazex01]

Greetings. I'm looking at increasing the overall height of my wheel / tire combination on my '01 Blazer extreme from 27" height to 28". I'm told this may affect my vehicle speed sensor in a negative way, i.e. ABS system, etc. Has anyone done this successfully without problems? Stock tire is 235/60-16, want to go to 255/55-18, with new rims, of course!

[y2kz71yukon]

Unless my math is bad, 255/55/18's are closer to 29" tall.

Edited by y2kz71yukon, 18 January 2005 - 09:16 PM.

[blazex01]

You're right, Yukon. I looked at the wrong line on my chart - meant to write 255/50-18 which should come in at 28.1".

[Envoy Fan]

This chart will tell you the size difference and speedo changes

http://www.eunos.com/tirecalc/

If you go to a larger diameter tire you will also notice a loss of performance on take off.

[oohyeah4]

I can tell you this from experience, if the over all height on the tire ends up being taller than original, then your speedo will be off ,indicating your going slower than you really are. on the other hand, if the tire is shorter ,than it will indicate your going faster, if you go with the taller ones, I would imagine you would gain better gas mileage on the highway and vice versa, if you go smaller. good luck

[blazex01]

Thanks for the response, guys. I heard something about the ABS going crazy because the vehicle speed sensor doesn't agree with the slower rotation of the wheel, therefore causing problems..........?? Has anyone successfully increased the height of their tires without any problems?

[Envoy Fan]

When I have my 20's on my tires are 1" taller. Have not noticed any computer problems yet after over a year with them. I do notice that I must not follow as close as the heavier wheel/tire combination requires longer braking time to stop.

[blazex01]

Now that's something I didn't consider. It does make sense with more mass, inertia etc. Obviously the speedometer will be off as well. I think the difference in rollout over 1 mile traveled was something like 30 wheel revolutions.

Do you notice any sluggishness when you pull away from a light?

[Envoy Fan]

Do you notice any sluggishness when you pull away from a light?

<{POST_SNAPBACK}>

Yes, my axle is a 4.10 ratio, but with the bigger tires, it is more like a 3.73 ratio. My speedometer is 3% slow, when shows 60 actual more like 63 mph.

[blazex01]

Thanks EnvoyFan. Your ride looks great with the 20s, but if you had it to do over again, would you increase the tire height or not?

[Envoy Fan]

Thanks EnvoyFan.  Your ride looks great with the 20s, but if you had it to do over again, would you increase the tire height or not?

<{POST_SNAPBACK}>

Good question. I wanted a tad taller sidewall to help protect the chrome rims. Current is 265/50, would look at 265/45's.

[blazex01]

My reasoning exactly. I hit a small pipe lid in the street and taco'd a wheel on a '92 Corvette I had right after I had the wheels chromed. And that was with the original factory tire size. A little more sidewall would have given the wheel some cushion.