I've been reading many threads on this board about how people have managed to fit 255 width direzza's onto the stock Evo8 wheel. I'm considering upgrading to that size as well, but would like to know of any drawbacks this setup will pose? This will be used for autocrossing.

 

Not that you care with your mods, but it puts you into a different class (if you'd not touched the engine). 245 max width in STU.

Otherwise, you lose a bit of acceleration because you have to move more tire. If the overall height of the tire + wheel is different than stock, you'll change the effective gearing. Taller = more top speed, less low end. Shorter = rev faster, more low end grunt, less top speed.

On an 8 you might have rubbing issues as well. The StarSpec run a bit wide vs. what they say they are.

 

why would an 8 have rubbing issues and not a 9? 255's fit 8's and 9's fine so I hear

 

I run the * Specs in 255 and honestly haven't noticed any change in spirited street driving.

Edit: 17x9 +35 Advans. Zero rubbing.

 

I said might... and it will depend on your tires, wheels (offset), spacers, alignment and suspension mods whether they rub or not.

 

wouldn't 255 width tire makes the side wall softer than running on a 8.5 or 9" wheel?

 

yeah i wouldn't run a 255 size on a 8" width wheel.. bulging side wall = softer side wall FTL

 

1. Costlier to maintain

2. More likely to hydroplane

3. Added weight given that you use the same model of tire (and eventually widened wheels as well)

Just slapping on a 1" wider tires to replace worn out ones is not really a good idea. You need to look into the type of the tire, your wheels, and power mods. Also if a suspension tuner helped you with a set up with old tires, you may need to get a re-tune after getting wider tires.

 

1-3 are right.

But suspension is setup at the hub (camber, caster, tow), not the width of the tire.

Unless you really want to run SM, stick with a 245 or OE sized tire. Even in a street tire indexed class, going to SM doesn't help your indexing. I run a 245/45 for my AX/track runs. Z1s do run wide. And I like the slightly taller dia for getting some extra room out of 2nd gear on the course.

 

Thanks for your help guys.

SmikeEvo, do you have any rubbing issues using the taller 245/45? I'm about to get a full KW coilover suspension setup with Robi. I'm not sure how low I'll getting set up at.

Does running 255 make the side walls softer? Is that detrimental in autocross? I'm not concerned about classing at the moment. I just compete locally for now and am in a SM class.

 

Go with the 255's. I ran the 255/40/17 Star Specs this past spring/summer and there was only 1 car that ran street tires (star specs (265's) on a 350z) that could keep up with me. I only have minor mods (mbc, intake, exhaust, tune and BC coilovers).

I used every single inch of these tires during autox. Anyone who says 255's are overkill for the stock wheels is lying to you. I did have a bit of rubbing at FULL turn on the inner linings, but nothing detrimental to the tires/car.

Here's a couple pics of my tires after this season, vs a 225 width tire that I'm using for the winter.

 

A bit wider would help increase steering response and dry handing. However, you will take away from wet traction and add a bit of weight.

 

We tried both 255 and 245 on stock wheels for autox and never had rub issues with the 255s. 245-40s have always been faster for us. We use a lot of third gear on course!

Rick

 

+1

A 255 sits better on a 9" rim.

 

Only thing i can add, and this might not be noticed by some, is that the ride comfort decreased with the wider tire. Not alot, mind you, but i noticed it.