tire height question

225/60R15, 235/55R16, 245/50R16, 245/45R17, 275/40R17, 315/35R17 are all 25.7" tall tires, give or take .1-.2 due to tread hight. So any 26" tall tire is about the same. If your running out of gear, maby a 27-28" would help the gear issue as well as increase traction.

When getting different rims, go ahead and get some welds in 15" and get some slicks. ET's arn't really a street tire. If your going to get another couple of pony's then get the same width in DR's, because any wider and the footprint will be distorted, reversing the desired effect.

Here's how you can calculate the height of any tire if you know the size.

So we'll use your 245/50/16 as an example. The 245 means the section width (sidewall to sidewall) is 245 mm. The '50' means that the height of the sidewall is 50% of the section width. And of course the 16 means it fits on a 16" diameter wheel. So, if you convert the section width to inches - 245mm divided by 25.4 mm/inch = 9.65" section width. The sidewall is 50% of that - 9.65 X .5 = 4.82". To calculate height of the tire just add up the pieces -- sidewall at the bottom and a sidewall at the top plus the diameter of the wheel. 4.82" + 4.82" + 16" = 25.6". Stock size - 225/55/16 = 25.7".

To calculate the change in gear ratio by changing tire height, it's simple ratios. So, let's say you move from a 25.6" tall tire to a 28" tall tire. 25.6/28= .914. If you're running a 4.10 gear --- then when you put the taller tires on -- the 4.10 gear acts like 4.10 X .914=3.75 - about like 3.73's. The same ratio applies to your rpm change. If you go through the traps at the same speed you did before, with a 28" tire vs. 25.6" tire, you'd be turning only about 91% of the rpm you were with the shorter tire.

It's actually 225/55/R16 that's the 25.7", not 235/55/R16