255/45/18 tire size

[rsoto80]

Would it be a good idea to run 255/45/18 compared to the factory 235/55/18 my car came with? I notice there are a few selections in this tire size. I did the tire calculator on the Discount tire website and it showed that it would be about an 1" smaller in diameter. My car has the srt8 suspension so it sits slightly lower so the fender gap shouldn't be bad. thanks!

[BigBlackRT08]

I've seen alot of people with 255/55/18 with no problems...I don't think it would be much different. There are many threads on the 55's.

[FuelMJ]

No, you want the diameter difference to be with within 3% of the original tire. The tire you want would be 4.05%. Running that tire would run the risk of brake failure.

[rsoto80]

I've seen alot of people with 255/55/18 with no problems...I don't think it would be much different. There are many threads on the 55's.


I know, I seen pics of that set-up but I think its a little too much sidewall for my taste.

[Discount Tire Direct]

Would it be a good idea to run 255/45/18 compared to the factory 235/55/18 my car came with? I notice there are a few selections in this tire size. I did the tire calculator on the Discount tire website and it showed that it would be about an 1" smaller in diameter. My car has the srt8 suspension so it sits slightly lower so the fender gap shouldn't be bad. thanks!

The approved rim width range for size 255/45-18 is 8" to 9.5" with 8.5" being the most ideal. Your factory wheels are 7.5" wide so we do not recommend you run this size based on that. To shadow what FuelMJ said, you want to keep the tire diameter within 3% of the original equipment size as well. If you want to decrease sidewall height, the best way to do this is by increasing your wheel diameter. A 20" wheel and tire combination would be a good option to consider.

If you want to stick with your factory wheels, a good size to consider would be 245/50-18. This size is approved for your factory wheels and you will be decreasing the sidewall height by .25" when compared to the OE size.

If we can help further, let us know.

[carchitect]

No, you want the diameter difference to be with within 3% of the original tire. The tire you want would be 4.05%. Running that tire would run the risk of brake failure.

wait... what?

care to explain that statement a little more?

I can see the argument that tire in those sizes aren't designed for heavy vehicles such as the LX's, or that the speedo will be off if not correct by a Predator or Superchips. But brake failure from lowering unsprung weight? Unlikely.

[rsoto80]

The approved rim width range for size 255/45-18 is 8" to 9.5" with 8.5" being the most ideal. Your factory wheels are 7.5" wide so we do not recommend you run this size based on that. To shadow what FuelMJ said, you want to keep the tire diameter within 3% of the original equipment size as well. If you want to decrease sidewall height, the best way to do this is by increasing your wheel diameter. A 20" wheel and tire combination would be a good option to consider.

If you want to stick with your factory wheels, a good size to consider would be 245/50-18. This size is approved for your factory wheels and you will be decreasing the sidewall height by .25" when compared to the OE size.

If we can help further, let us know.


thanks! i'll check out the selections you guys have in 245/50-18

[rsoto80]

wait... what?

care to explain that statement a little more?

I can see the argument that tire in those sizes aren't designed for heavy vehicles such as the LX's, or that the speedo will be off if not correct by a Predator or Superchips. But brake failure from lowering unsprung weight? Unlikely.

Yeah i was wondering that myself. The only way i can see brake failure would be if i had uneven tire sizes on both sides of the vehicle. That would cause a difference in revolutions and mess up the ABS.

[FuelMJ]

wait... what?

care to explain that statement a little more?

I can see the argument that tire in those sizes aren't designed for heavy vehicles such as the LX's, or that the speedo will be off if not correct by a Predator or Superchips. But brake failure from lowering unsprung weight? Unlikely.

Yeah i was wondering that myself. The only way i can see brake failure would be if i had uneven tire sizes on both sides of the vehicle. That would cause a difference in revolutions and mess up the ABS.

Was using the Tire Calculator on the 1010tires website, and that's what they said, so that's where I got that info.