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Old 06-28-2015, 10:21 PM   #1 (permalink)
ScottOmatic
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Location: Madison, WI
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Default Picking New Tires, Trying To Get More Front Grip

Hey,

I have been laboring looking through hundreds of posts trying to gain the necessary information needed for when I buy new tires a little later this summer (Still on the stock sport package RE050's at 22,500 miles).

There has been a lot of great information given out and I thank you all for that, it is really helping me hone in on my choices.

As the title states though, I am thinking about taking some of the grip away from the rears and bringing it up towards the front. Not that the Z understeers all that much but I think I would like to free it up a little more by getting more contact with the road with the front tires.

Maybe this is not the smartest way of going about it, maybe it is a dumb idea, maybe it isn't even possible to make much of a difference with out the VDC light coming on all the time (which I don't really want to see) but I figure that if it's possible to loosen the car up by changing the tire size at the front, this is going to be cheaper than upgrading the suspension (currently I am stock everything besides exhaust) and I got to get new tires anyways.

Below I have attached an image from a tire size calculator, comparing the stock tires to common options I found on tirerack.com (I think I was primarily looking at sizes in the Bridgestone S-04 Pole Position simply because there are a lot of choices, for the sake of punching in numbers into the calculator).

If I am doing and processing everything correctly, the only way to get more surface area and thus more grip to the front tires would be going with something like 245/45R 19 or 275/40R 19, everything else that is wider (that is available) is in 35 or 30 sidewall percentage and that actually comes up short compared to the stock size and thus, less surface area and less grip (in theory).

If I were to think that the 245/45's seem like a nice bump up.. if we then look at the rears, the stock 275/35 is 675.10mm OD, 3.5mm smaller than the stock fronts (245/40).. they are now 18mm smaller than the fronts if the updated 245/45s. I am guessing thats a pretty big difference and will cause the VDC light to go on constantly.

The other issue is I don't think I want a lot more front sidewall than rear sidewall, if aesthetics mean anything to me, I would much prefer the rear tires having a fatter sidewall.

I could bump the rears up to 285/35 19's for a 1.04% increase but that still might trigger the VDC and the sidewall will be noticeably smaller than with 245/45s at the front, or even 270/40s on the front (if those even fit).

I could leave the fronts at the stock 245/40 and try to thin out the rears a little with a 305/30 (665.60mm OD) or a 295/30 (659.60mm OD) but I am not sure that is the right way to go.

I may just end up going with the default sizes if this idea doesn't pan out.

If anyone has any insight on what I am trying to do here, please feel free to share your thoughts. Thanks!
Attached Images
File Type: jpg tire_sizes.jpg (215.2 KB, 31 views)
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