Just put on 255/55/18s on Stock Rims/Suspension
#1
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Just put on 255/55/18s on Stock Rims/Suspension
I went to discount tires and got Conti's DWS 255/55/18s which fit perfectly (I had stock Michelin's 235/55/18) - The tires are great, no problem with fitment, I can feel the car handling way better (no more swings cornering) - I think I lost a few MPGs but too early to tell … I can feel the engine 'grunt' a bit accelerating from start (the tire weighs more ?) … The car looks more like a truck now, more fuller around wheels, I'll post pics (sorry my rear side marker's broken & bumper has scratches)
Any suggestions how to calibrate my speedometer ? at 80 MPH I'm actually doing 82.44
Also, Discount Tires gave me a great deal, $221 per tire - I also bought their lifetime replacement plan for $30 per tire
-Adam
Any suggestions how to calibrate my speedometer ? at 80 MPH I'm actually doing 82.44
Also, Discount Tires gave me a great deal, $221 per tire - I also bought their lifetime replacement plan for $30 per tire
-Adam
Last edited by 007400h; 06-18-12 at 02:11 PM.
#4
55% of 255 ain't the same as 55% of 235 (255 and 235 being millimeters, for the records).
Net result is about 3 inches more of circumference with the 255.
You can try this website to check the math:
http://www.csgnetwork.com/tiresizescalc.html
#6
Being there are so very few tires, perhaps one or two and very much at a price premium, at 255/50-18 you have no real choice but to go with a 255/55-18. However, this tire size is will definitely throw your odometer and speedometer off by significant values.
#7
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tire size calculator comparison
Here is a link that I've used. It allows you to see differences between stock tire size and what you are proposing plus a crude visual to go with the numbers.
http://www.miata.net/garage/tirecalc.html
http://www.miata.net/garage/tirecalc.html
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#8
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Actually it should be opposite, 80 on speedometer but 77-78 actual speed. I had same on my 08 rx350 with 235/55/18 till yesterday, I put 235/60/18 and now 80 is 80. 07,08,09 RXs has two sizes 225/65/17 and 235/55/18 so, I assume 55 on 18 giving slower reading but 60, which is not recommended by dealers, I don't know why, giving actual speed (according to my gps)
Last edited by winwin4all; 10-20-12 at 07:13 AM. Reason: Misstype
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