da_guitarist

Since I put my 19s and springs/shocks on, my cruise control will engage, but shut off within a minute or two. Anybody had this problem? I don't know if it's because something is wrong or if it's the new wheel size that throws it off.

CLKCLK

I don't think the new wheels do anything with cruise control

TresX

Probably have a bad cruise control stalk. Mine went bad too. The part is < $100 online. You just need a breaker bar to get the wheel off (not as hard as some here have mentioned in the past). Other than that...just remember to replace the clock spring exactly in the position you took it off (or else you're gonna have issues with your blinkers). Good luck

MarcusF

Are the rear tires taller than the fronts? If so, that's it.

The OEM rear 245/40-17 Conti Sport Contacts rev 828 times per mile. The OEM front 225/45-17 Conti Sport Contacts rev 831 times per mile. They are almost an exact match. When there's a large enough difference, the ESP is programmed to log that as a error and to shut the cruise down. That's also the reason why some people have trouble dyno'g their cars. The front wheels aren't moving so the car acts "different". "Different" like the dyno sheet indicates less HP than my quarter mile trap speed would indicate.

da_guitarist

Hmmm...that might actually be it. I believe it's the other way around though...the fronts are taller than the rears (235 35 and 255 30). I'll just wait until the tires wear down and put on the 265's and see what happens.

I did some calculations and got 816 rev/mile rear and 808 rev/mile front for stock, and 806 vs 792 for my combo. so 8 rpm difference for stock, and 14 rpm difference for my setup. maybe that would make the difference?

i used: radius= .5*wheel_diameter+(tire_ratio/100*tire_width) for the radius (should change a little once the tire is on the wheel and depending on the amount of air)

and then i used: 5280 ft /(2*pi*radius/12) for 1 mile and inches to feet to get total rev/mile

MarcusF

Tirerack lists the revs per mile specs for most of the tires they sell. Many tire manufacturers will list the spec on their website. When I bought my tires, I went with a 225/45-17 and a 255/40-17 because Yokohama specifically said those two both turned 828 revs per mile.

The Tirerack guys said it would make the car push a little more, but I've got a cure for that

da_guitarist

Yea, I checked Toyo's website. Looks like they're 14 rev/mile apart. I'll find out when these tires wear out if that's the problem. Thanks Marcus!