New tires - size up!

[mcrews]

I went into to RADIAL TIRES of SACRAMENTO this morning after researching sizes this past weekend.

Background:
THe 02 Q45 Sport came from the factory w/245/45/18 (26.5 inch diameter)on 18x7.5 alloy rims.
At 60k miles I went to a 255/45/18 (27.0" diameter)

The base of the Strut tower on the front is the limiting factor to how tall a tire can be without using 30mm spacers( BAD)


We tried a 245/50/18 and there is an 1/8 inch gap!!!

THe diameter is 27.7 inches.
The tire weighs 31lb and the current size weighs 30 lbs.

They ordered them today and will install tomorrow.

[320touring]

You could cut off the spring platform and fit threaded sleeves so you can fit 2.5" diameter springs

[mcrews]

Got the tires on today.
new 245/50/18 27.7" dia. at 55mph 1625rpms
old 255/45/18 27.0 dia at 55 mph 1725rpms

will do mpg runs in a day or so.

[mcrews]

as you can see there is no more room!!!

talk about cutting it close!!!

[gone-ot]

...do you think there's "contact" when driving at high speeds and centrifugal forces are attempting to "enlarge" the wheel diameter?

[Vekke]

If you install coilover suspension you dont need so big spacers to get more room. Or change you ET on your wheels.

[mcrews]

Originally Posted by Old Tele man

...do you think there's "contact" when driving at high speeds and centrifugal forces are attempting to "enlarge" the wheel diameter?

Well, it's been a month. Had a round trip from Sacramento to LA.....450 miles each way.
No problem with any rubbing.

I had some obdII codes that I had to resolve. And am still addressing some ecu issues pior to my TTT (trip to texas) on Oct 12.

But I just ran a brief highway run.

At 63mph 1775rpms got 30.9mpg (didnot have the grill block or the front underbelly panel in place)

epa is 22mpg highway.

[gone-ot]

...cars need an "electronic" wheel diameter compensation "box" to allow for use of different diameter wheels & tires!

[mcrews]

somebody was posting that in europe it's illegal to go up or down in size........
I run a garmin gps on the dash right above the scangauge, so it gives the correct speed.
That way I don't tie up one of the 4 displays on the scangauge.

[mcrews]

Originally Posted by Vekke

If you install coilover suspension you dont need so big spacers to get more room. Or change you ET on your wheels.

Why would I want to ruin the electronic suspenion........