2009 Lx 570 - Tire Size Increase = Problem???

[TJ96TLC]

2009 Lx 570 - Cooper Zeon LTZ 275 55r20

I am looking to upgrade to a 1" larger diameter tire...will that cause problems with the transmission or other electronic systems?? I know the GPS will need to be re-calibrated. It seems like I found somewhere in the maintenance section on the Nav screen to input tire size but now I can't find it. I know how to fix the GPS part. Any thoughts or advice???

 

[Billfish]

I doubt the GPS system will need to be calibrated. That does not use input from odometer to calculate speed or distance. Its a Gobal Positioning Satelite system and works out where it is at each ping and makes a calculation about how far to go, how far travelled and speed between pings etc. There may be a way to recalibrate OD however and it may be done through the head unit somehow but I'm betting that its a workshop intelli-tester tool job.

I'm assume you have 18" rims or 20" rims? The maximum daimater size tire that will not scrub the inner fender and mudflap is approx 33" and will require a lift. You might get away with a 32" tire without lift. Transmission no issue.

 

[TJ96TLC]

The wheels are 20" and the tires are 31.9" and should fit fine. I was thinking I read somewhere on a tundra forum that larger tires caused problems. Maybe with VSC or something. I do know I need a new spare too.

 

[Surfy]

Since a week i have new tyres and rims: 285/70 17 (Cooper STT) without a lift (i have AHC (Europe Spec LC 200)), together with an ARB Sahare Bar, and Kaymar Rear tyre holder without rearbar, and an strengthen AHC Suspension System (from the armored cars).

The car respond now slightly different to my right foot, the automatic don`t react same.

In normal City traffic my revs are higher than bevore, and the milage has gone up approx. 4l / 100 km/h. But with mud tyres, the ARB bar and tyre holder - you have to calculate this way

I hope that i soon can do an overland travel, to have a look of the milage.

I would not do such changes, when i dont had to fight with a transafrica, and to calculate mit more than serious wheeling, when it`s my dayli driver car. No aftermarket engineer works better than toyota. And toyota gave us a very nice stock setup.

 

[ballsbygm]

I doubt the GPS system will need to be calibrated. That does not use input from odometer to calculate speed or distance. Its a Gobal Positioning Satelite system and works out where it is at each ping and makes a calculation about how far to go, how far travelled and speed between pings etc. There may be a way to recalibrate OD however and it may be done through the head unit somehow but I'm betting that its a workshop intelli-tester tool job.

I'm assume you have 18" rims or 20" rims? The maximum daimater size tire that will not scrub the inner fender and mudflap is approx 33" and will require a lift. You might get away with a 32" tire without lift. Transmission no issue.

Cal is done through the maintenance screen, it does have an input when GPS signal is lost (tunnel, initialisation etc etc). The GPS system uses speed (via wheel speed signal with corrected tyre cal and accelerometers, call it assisted GPS without the wi-fi when no signal available).

 

[TJ96TLC]

Went for it... 275 55r20 cooper Xeon ltz. Ride is good. A bit stiffer than the squishy Michelins. Handling and cornering is better. Small amount of noise increase, 2 decibels on iPhone app at 60mph on same stretch of road. Looks so much better. These tires are about .5" narrower and .6" taller. I recorded a 6.3% fuel mileage increase on the same trip home from the tire store 30 miles one way. That included the 2% increase for bigger diameter. It may be more than that because the avg after fill up is harder to change the more miles u go. It stayed at 13.8 on the way and climbed to 14.4 on the way home. The Michelins were so soft that i think they killed te mileage. Air pressure was 33 on Michelins and 36 on zeons. I will update after a few thousand miles.