isthrizzy

So I am rubbing due to my tires and I need to get narrower tires. At the same time I want to get something that has a more rounded sidewall too to gain even more clearance... If I'm going to get new tires, might as well get more rounded sidewalls while I'm at it.

I read on the TR website that treadwidth doesn't necessarily tell you info about how rounded the sidewalls are. So, how do I figure this out?

I'm currently looking at the following tire sizes:
Front: 215/35-19
Rear: 255/30-20

My current set up is:
Front: 235/35-19 Hankook V12
Rear: 275/30-20 Hankook V12

I can live with the rear tires I have, but if I change brands then I'll change all 4.

Since there's not a ton of options for the 215s, I'm wondering how much the sidewall differs in terms of roundness between Hankook V12s and Yokohama S drives.

Anyone know?

zig@tr

What is the Year/Make/Model and what is the width of the wheels you are running?

scoobystev

I understand what you are wanting to do here. But you do realize that you are taking close to an inch off the width of the tread patch. no matter if the side wall is rounded or not you will be gaining a lot of clearance. And if your fenders are not rolled, get them rolled. Im seems a lot of people are hesitant about it. Get a professional or learn how and it clears up alot of room. That is if you havn't already done this

isthrizzy

Zig,
2006 IS350
Rear wheels are 20x40, +40
Front wheels are 19x8.5 +35

Stev,
Gotcha on that. My fenders both front and rear are heavily modified with lots of shaving...in fact, in the front they shaved too much and I'm not happy about that.

I realize that I will lose about .78" of tread width, which I know is more than sufficient for the rear. For the fronts, I'm pretty sure I want as much "help" from my tires as possible.

My fronts are only a problem when turning, going up an incline. During normal driving I am not scraping on bumps. So I tried to check this out to see what I shall do. So I drove the rear driver side up on a ramp that was roughly 3.5 inches high. this forces the front passenger side wheel to move up closer to the fender. At this point I cut the wheel to right so I can see where it hits. It seems to me that if I gained 0.25" or so of clearance on the tire, I'd be all set.

But, as you can tell I only tested this in one condition, and I'm not sure how it mimicks real driving behavior. So while I think going down to a 215 would work, I figured if I'm dropping $$ on new tires I might as well get as much clearance as possible.

With that said, I also realize that my current tires are in decent shape and not ready for replacement...so if I could get away with only replacing the fronts, that would be great. However I don't like having mixed tires front and rear, it looks odd.

So scenario #1 is I just buy Hankooks in 215 size just to replace fronts (~$350 or so)
OR
Scenario #2 is I get all new tires which puts me at closer to $800 (and I can change brands to get a more rounded shoulder)

What I want to avoid is getting the 215 Hankooks, but then wish I had got something with a more rounded sidewall.

What I don't know is whether the sidewall on the Yokohama S Drives is dramatically rounder than the Hankook V12s.

zig@tr

I would refer to the Lexus ISF fitment data 225/40R19 Front and 265/30R20 Rear. The rear size you are requesting may be ok but the front would look kind of narrow with a 215 and would make the car even more prone to under steer. The IS already has a bit of under steer built in but making the tires even more narrow would just make the problem worse.

isthrizzy

Thanks Zig. That's something to consider, but I don't track the car so I'm not sure I care too much about a change in the amount of understeer. I am not sure if the 225 will give me the clearance I'm looking for.

How about a comparison of the roundness of the sidewall? How do the Hankook V12s compare with the Yokohama S-drives?

mitsuguy

iTrader: (2)

Yokohama tires run wide size for size, so, if you had the V12's and the S-drives sitting side by side in the same size, the Yokohama's would look wider... somewhat squarer shoulder as well...

isthrizzy

Thank you, that's what I needed to know.