i noticed you guys are saying 255/40/20 or 255/35/20

but the website says 245/40/20 for 1992 s10 blazer

 

It's only 10mm wider and barely any taller. Either should work.

 

The 255/40/20 are 4 mm taller than the 245/40/20 and the 255/35/20 is 8.75 mm SHORTER than the 245/40/20.

 

ok that cleared it up a little bit. but still some what confused. will these work.

wheel = 20 x 8.5
tires = 245/35/20

I made my decision on the rims, I just dont want to place the order on the net and then they dont fit right, cause local rim shops around my area are way to expensive.

I'm getting a good combo deal on here is why I'm so worried

 

Someone tell me if my math is wrong here:

245/35/20

The tires will be 245 mm * 35% = 85.75 mm
A 20 inch rim is 508 mm
Total is 593.75 mm tall

235/70/15
The tires will be 235 * 70% = 164.5
A 15 inch rim is 281 mm
Total is 445.5

The difference being the 20 will be 148.25 taller which equals out to be 5.836614173234651 inches taller.

From what I know about tire sizing I am thinking this is correct. Please let me know if I am wrong.

 

Ok, you asked for it! Your math is WRONG!

You need to double the side wall to come up with the diameter of the tire.

245/35/20 => 245*.35/25.4 = 3.38" per sidewall => 3.38*2+20 = 26.75" OD
235/70/15 => 235*.70/25.4 = 6.48" per sidewall => 6.48*2+15 = 27.95" OD

To better match the stock tires, I would go with a 245/40/20 (OD of 27.7").

 

With a stock 205/75/R15 tire I would go with a 255/35/20. OD is 27.0 compared to stock 27.1. Closest your going to get to stock.

 

DOH!! Thanks for the fix there.

 

lol wow ive only had one to really honestly answer my question. If possible I would like more than one opinion please if its not to much to ask

 

Wow...what more do you want? They will fit. Buy them.