Tire size question affect on AWD system

[uHu]

Your speedo is probably more correct after a 3% increase in circumference, as they normally show 3-6 % too much anyhow.

 

[SWUtah]

I've considered that, since you are in a roundabout way altering the mileage on the odometer. Technically, the warranty could be voided.

Since the speedo also thinks you're going slower than you are, I would guess the tranny would shift slightly later than normal, so maybe that's part of your 1mpg loss. On paper, both the 275/60R18 Bridgestone HT and 275/65R18 revo weigh 40 lbs each. The other part of the loss is the small 1/2" greater diameter. I'm leaning towards going w/ the Yokohama AT/S in the OEM size (to be released in early '07) when the time comes to play it safe on the warranty.

Is there any way to recalibrate the speedo to account for the 3% tire size increase?

I would love to hear your winter driving review on these new Yoko AT/S tires. I still have 7-8/32nd's on my Michelins so I won't need new tires until next winter, enough time that I can learn what is working best on other LC/LX owners rig's. I like Michelin just because I have always had good luck with them, quality/wear/etc.

 

[Jim_Chow]

Your speedo is probably more correct after a 3% increase in circumference, as they normally show 3-6 % too much anyhow.

Yes, I think you're right. I noticed my 4runner tires were 3% off (reading fast on the speedo) with 31x10.5's w/ 4.56 gears. Also, there are manufacturers variations in diameter for the same published size, but this should only account for like 1% difference. Not everyone's 275/65R18's are the same size. I'm probably still 2 yrs off from changing the tires on the LX (waiting for the HT's to wear down), but 4runner tires need changing this year or next year at the worst. Was planning to try what I plan to install on the LX (either revo's or the geolander AT/S). The AT/S is supposed to be available in a LT 275/65R18 while the revo isn't a LT (not sure if it matter that much...sidewalls are thicker on the LT?).

 

[mikesurfs]

FWIW,

I had a fulltime 4wd K-5 Blazer running 33 inch tires, one of which I flatted in the desert near Victorville. I had a 31 inch spare inside and placed it on the front axle. I drove about 100 miles back to L.A. and smoked the front diff. I will never use an 'off' size spare again. You're better off to use some a fix-a-flat and replace later with the proper size. I used fix-a-flat for an entire weekend of prarie dog hunting in Texas. On our two rental Pathfinders we flatted 7 of the 8 tires and fix-a-flat worked great!

Mike.

 

[SWUtah]

FWIW,

I had a fulltime 4wd K-5 Blazer running 33 inch tires, one of which I flatted in the desert near Victorville. I had a 31 inch spare inside and placed it on the front axle. I drove about 100 miles back to L.A. and smoked the front diff. I will never use an 'off' size spare again. You're better off to use some a fix-a-flat and replace later with the proper size. I used fix-a-flat for an entire weekend of prarie dog hunting in Texas. On our two rental Pathfinders we flatted 7 of the 8 tires and fix-a-flat worked great!

Mike.

Good info. thanks

 

[farinvail]

You will be able to fit the large size into the spare location, if that is a concern. I got the tire shop to give me "trade in" on my old spare to encourage me to buy a 5th tire. I believe $50 off the price.