265/50-18 Revs Per Mile

[ctrlraven]

For those that use this size rear tire only, what do you set your Revs Per Mile at in your tune?

I've been using 730 and yesterday I turned on my gps speedometer on my phone and used 2 different programs and both were saying my speedometer was reading a whole lot faster than I was going. So at 60 mph I am actually going 55-56 mph. I'm not sure if it has something to do with the revs per mile which I will double check in the tune or is my speedometer needle just off that much since when I did my white gauge cluster mod and removed the needles.

[Blk Mamba]

By a calculator it is 709.68.

[ctrlraven]

By a calculator it is 709.68.
Nitto even says the Revs are 731 for their NT555 265/50-18

[Blackened300a]

According to this calculator. 708.9 revs for a 265/50/18 tire.
http://www.rimsntires.com/specs.jsp

[Mercguy04]

Does the 265/50/18 require a 9 to 9 1/2 rim widening?

[MOTOWN]

Does the 265/50/18 require a 9 to 9 1/2 rim widening?

No it does not

[babbage]

afaik Nitto is the only tire in this 265-50-18 size.

I will soon have 265-50-18's on all corners! Fronts are mounted today (RoadForce Balance!) Is this what you are doing Birdman?

[ctrlraven]

I guess I'll give the 709 revs per mile a try and see how it matches up to my gps speedometer on my way home.

[Krytin]

I use the recomended Revs/Mile for the 255/45-18's and my speedo & GPS are dead on. You should be able to achieve this.

[ctrlraven]

I use the recomended Revs/Mile for the 255/45-18's and my speedo & GPS are dead on. You should be able to achieve this.
Recommended by the manufacturer?

[Krytin]

Recommended by the manufacturer?


Yes - Original Nitto spec was 731 and the speedo/GPS matched then in '07 and when I replaced the Nittos w/Coopers I still had the match.

I hope you get yours sorted out!

[ctrlraven]

Yes - Original Nitto spec was 731 and the speedo/GPS matched then in '07 and when I replaced the Nittos w/Coopers I still had the match.

I hope you get yours sorted out!
If your 255/45 spec was 731 then my 265/50 is def not 730, I'm reprogramming to 709 right now and going to test out that rev per mile.

[Black Terror]

I have used this calculator for Revs Per Mile and set into XCal 2. Speedometer is very accurate.
http://www.miata.net/garage/tirecalc.html

[Krytin]

If your 255/45 spec was 731 then my 265/50 is def not 730, I'm reprogramming to 709 right now and going to test out that rev per mile.

That sounds better - Good Luck!

[ctrlraven]

So 709 is coming up about 1.5-1.7 mph faster than what my gps is read so that's close enough for me.

[ctrlraven]

afaik Nitto is the only tire in this 265-50-18 size.

I will soon have 265-50-18's on all corners! Fronts are mounted today (RoadForce Balance!) Is this what you are doing Birdman?

No I have 255/45-18 front and 265/50-18 on the rear since I have traction control.

[CobraSVT657]

My 265/50's and GPS were pretty dead on.

[BirchMarauder]

discounttire.com says 265/50-18 is only half mph slower @ 65-70-75. very close

[babbage]

No I have 255/45-18 front and 265/50-18 on the rear since I have traction control.

Ah, forgot you have 04. I now have all 4 now that size. I figure It will be nice to be able to rotate them.

[babbage]

I have used this calculator for Revs Per Mile and set into XCal 2. Speedometer is very accurate.
http://www.miata.net/garage/tirecalc.html

ditto ^^^ this is vey good plus gives you side by side comparison.