El Kabong

I'm interested in a set of autocross tires that I can also use as daily drivers. Anyone have any experience running 255/35-18 ?

What would the safety issues be WRT this size?

Thanks,

Kabong

hemmingway_bg

I am curious to. Also 275X35X18 on 18X9.5 wheels.

Ole Spiff

I've never done it but I'd imagine the issues would be darty steering on ridged or grooved road surfaces like they have on California freeways; more road shock transmitted to the car (less tire to cushion it); and greater vulnerability to rim damage from any kind of rut, speed bump, driveway lip, curbing, etc. Maybe you could have a set of rims with these tires for autocross that you put on for that day/event, then switch back to your normal wheels/tires at the end of the day? You could do it at the house so you wouldn't have to lug them to the track; switching for one day wouldn't be a big deal.

Just an idea.

lurch519

my buddy runs 225/35 18 on his ep civic, much lighter car, has bent all 4 rims, so you may have issues.

IZoomZoomI

you won't have any issues with 255/18/35. The wheel diameter is the same, I know of a person that runs this setup, more tread = more traction. I don't know about going above that though.

Moostafa29

I think PURNRG has 255/40/18. That is the route I am thinking about going, so there is a little more tire to work with versus the 255/35/18.

IZoomZoomI

you lose some gearing advantage with 255/40's compare to 35's.

Moostafa29

With turbo, I doubt its a huge deal.

PUR NRG

Bent rims can be from tire profile, sidewall stiffness and/or wheel quality. The key factor is the wheel itself--most cases I've heard of are due to "cheap" wheels that don't have much safety margin.

The RT615s in 255/40-18 have the same outer diameter as stock--or close enough to it to make no difference. A lower profile tire will give you better gearing which is always a benefit in autocross but as a daily driver you throw your speedo and odometer off. Speedo isn't so bad but odo means you're artificially inflating the reported mileage. Not such a good thing when it comes time to sell the car.
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Weed