gathering info on new tires

[freezer404]

i have a 98 S10 4x4 4.3 5spd, (non zr2). i bought it brand new back in 98 and i'm about to need my second set of rubber. i'd like to put on some 30x9.5" Dayton Timberline M/T's, so i can get a little more ground clearance (and that cool zr2 look). I'm gonna go up about 1 to 1.5"s on the torsion bars and some 1.5"s shackles in the back so i'm almost certian that size tire will clear without any problems. (i have a buddy with a 99 4x4 non zr2 with 31's and he only has minor rubbing problems up front with no lift at all.) My concerns are these, a), i've been a mechanic for 13 years and i know this will affect my bottom end torque, but by how much, will i have to slip the heck out of the clutch to even get moving or will it even be that noticable, and b) how far off is my speedo going to be? (i used to know of a tire size/speedo calculator online, i thougth it was on a site called 4x4s10.com but cant find it now) As far as the engine and clutch go, i just rebuilt the WHOLE engine back in march due to a spun #6 rod bearing at 99,000 miles, so the engine is in peak condition again and i installed a new clutch while i was at it, so no problems with lost hp, torque or clutch slippage.

[Blazer69]

well with my speedo i run 235/75/15's in the winter and 235/70/15's in the summer and that makes for almost 6 mph difference in my speedo....i don't think u'll have too many probems with power ....what gear ratio do u have in the rear?

[1993blazerlt]

out of all your concerns i would only be worried about the speedo, that is pretty easy to correct, i would not be worried about losing any bottom end you are not going that much larger tire to affect all that other stuff, if you were going 35's it would be a different story

[Sparky2263]

what gear ratio do u have in the rear?

That'd be my first question also.