midnightsaint

I put my 19" wheels on and now my cruise does not work above 70 mpg.
Has anyone had this happen and how do a fix it?

illest

are they staggered?

giuseppesalvato

cruise control is speed related, it is fixed to the rotanional speed of your wheels, the bigger your wheels, the greater the circumferance, hence the greater distance covered in one rotation, which puts it out of sinc with your cruise control. you need to put the original wheels back on for your cruise control to work properly.

raymond g-

i dont think this is entirely the case. you can have larger wheels, larger tires,
but the deal breaker will be rotational difference of more than 2% between front
and rear and it will throw the computer off, thus disengaging the cc.

after all, folks have successfully moved up from 16" rims to 17, to 18, to 19 and
the cruise function has remained intact.

giuseppesalvato

thanks for that, that's something else i have learn'nt today.

raymond g-

95% of what I learned came from the forums. the rest came from first
hand knowledge and through testing items myself.

midnightsaint

Raymond, that what we thought. But I switched to the same size wheel and tire(no more stagger) last week. It did not correct it.

Wheels are 19x9 with 225/35/19 tires front to rear. The cruise works until 70 Mph and then stops.

giuseppesalvato

I wonder if the ECU has to be reset to account for wheel size ???.

renault12ts

No.

Are all your tyres the same age...or is there a difference between front and rear.
When my rear tyres were badly worn the CC would kick at about 70mph.

raymond g-

what was the exact sizing before and after?

aside from that, the peachparts tech section comes this info

i'll measure mine this weekend

renault12ts

225/35 19 tyres are 2mm smaller in diameter than the standard 215/55 16 tyres. This difference is absolutely insignificant.

Tyre size is not the problem here.

Plutoe

I am coming late to this discussion, however another factor to consider is tire inflation. See what happens to your CC when you take about ten percent of the air out of a single tire!! The system is very sensitive for safety reasons!!

midnightsaint

I think you guys cleared it up and one of the guys at worked help. My front tires have been on for a year now. The rear(the new tires to match the front) are also a different brand. After taking a measurement the fronts are smaller than the rear. By 1/2 of and inch!! So this is the reason. After the first of the year ill match the front and rear.

Thanks for the help guys.

renault12ts

I was glad to help.

Will Hart

I have the same problem. I have 255/40/18 fronts and 255/45/18 on the rear. Of course for that reason, CC doesn't work. Is there anything I can do or bypass to get it to work? I'm not afraid of ripping out a sensor or something, but I'm not where I can just buy new tires.

scorp_za

Hi Will,
Cruise Control uses your ABS wheel speed sensors, disconnecting these will render your ABS and ESP inoperable. The only fix really would be to match the tyres.