Correct Tire Size For New Wheels?

[Zoso]

Hey everyone, I just purchased a set of 2004 LS430 wheels for my 1st gen 1992 LS400 (17inch X 7.5 inch). I am trying to figure out what the correct tire size I need to match the wheel/tire combo diameter of my original 15inch wheels and standard tires for the 92 model? I would like to have the speedo stay as close to standard as possible. What tire size are you guys running on 17inch rims to keep the speedo in line? Any advice would be most helpful. Thanks!

[dcfish]

Hey everyone, I just purchased a set of 2004 LS430 wheels for my 1st gen 1992 LS400 (17inch X 7.5 inch). I am trying to figure out what the correct tire size I need to match the wheel/tire combo diameter of my original 15inch wheels and standard tires for the 92 model? I would like to have the speedo stay as close to standard as possible. What tire size are you guys running on 17inch rims to keep the speedo in line? Any advice would be most helpful. Thanks!

I thought the 04 sc's had 18"x 8" wheels ??? I could be wrong though

[Zoso]

I think they are 04's but I could be wrong. I do know they are 17X7.5's though.

[Arkansawyer]

Give this calculator a try. Has helped me many times in the past.

http://www.dakota-truck.net/TIRECALC/tirecalc.html

[Zoso]

Thanks! That is just what i was looking for. Now one more question....how much is the ride affected by going from a 60 series aspect ratio tire to a 50 series aspect ratio? I assume the ride is a little stiffer, but is it a major change?

[nc211]

Yes, it will be quite a bit harsher and louder. The lower the sidewall, the stiffer it is. You'll feel every imperfection in the road. Went through this with my old Maxima SE. Had 17 inch wheels, 55 profile...rode like crap. I bet Mad Max would agree as well. He has(d) a 2002 maxima.

[Arkansawyer]

But the Maxima is a different machine. More sport oriented.

IMO it will obviously be harsher but not so much that you would want to get rid of the wheels.

It shouldn't be a major change, again IMO.

[nc211]

Great point! Yeah, the Maxima is much more stiffer, and not as well built for insulating sounds...

But the Maxima is a different machine. More sport oriented.

IMO it will obviously be harsher but not so much that you would want to get rid of the wheels.

It shouldn't be a major change, again IMO.

[1990LS400]

Based on my experimenting in the early 90's on a 1990 LS400, I suspect that the 17's are going to be an "interesting" experiment. Are there many potholes in Texas?

By the way, the standard 15 inch wheels on 90-92 LS400 came with 65 series tires - not 60 series. IMO, going from a 65 series tire to a 50 series is a huge step.

On my 90 LS, going down from 205/65-15's to only 225/60-15's kept the speedo accurate but made the ride much harsher and the car noisier. The wider tires certainly improved the braking but my wife complained A LOT.

I can't imagine going from 205/65-15's to 225/50-17's on a 92 LS. Ouch! To avoid pain, I suggest you keep the inflation at the absolute minimum recommended - probably 30 psi if like my 90 LS - and drive very slowly.

[Zoso]

Thanks for the advice guys.....I may rethink this wheel combo? Could be a set of 17's for sale soon.