It's the worst trait a performance tire can have....it makes the turn in crap. I love hard as a rock sidewalls, like Bridgestone Potenza S-03's, and even the stock Potenzas on my 07 18's had great initial turn in. Tires known for soft sidewalls? All Toyos I've driven....a lot of Sumitomos, some Michelins, those crap *** General Exclaim's, and all Kumhos except the MX's. Best known for hard sidewalls are Bridgestones and BFG's. Problem is a stiffer sidewall=more weight. But that's how the T1R's are light, they dont use enough support in the sidewall area.

 

they are cheap so many vendors supply them.

they are nice, but IMO it's not super nice..

only if you are looking for silky smooth ride and don't care about pushing your car to the limit @ the corners.

 

+1 I have Kumho MXs and compare to stock 040, it's softer. however, I had coilovers and ride was too stiff with stock 040s.. feeling every single bumps and rocks. MX are softer, but stiff enough to holds at the limit. I love my MX!!
I heard many autocross people run them!

and yeah, brigestones and BFGs have stiff side wall. especially Bridgestone!!

 

He was referring to sidewall rigidity or stiffness. I’m not sure if there is any industry rating on sidewall stiffness, but I do know there are instruments that will measure this. The benefits and handling characteristics of varying sidewall rigidity are certainly arguable.

A couple of sidewall characteristic I think everyone agrees with:
1) Softer sidewalls provide a more comfortable (i.e., softer) ride with all other factors being the same (e.g., suspension, tire pressure, etc.).
2) Tires with more rigid sidewall feel more secure when cornering hard since the wheel remains more over the center of the tires main axis. In other words, softer sidewalls feel a little more wiggly. Note: Whether or not the grip is better is debatable since that involves all sorts of things (e.g., tread design, the tire’s compound/material-makeup, etc.).
3) You can notice a handling difference between stiff and soft sidewalls when driving a car with a sophisticated suspension (the Z being a good example).

Characteristics you could argue about for hours or with many messages:
1) Softer sidewalls allow better tread adaptation.
2) Tires with stiff sidewalls corner better because they inherently maintain tread adaptation.
3) Stiff side-walled tires won’t grip as well on wet roadways.
4) Soft side-walled tires run more quietly.
5) And the list can go on and on…

--Spike

 

I just replaced my tires all around on my '07 Enthusiast,and went 245-40x18 on the front and 245-45x18 on the rear based on a post stating that steering response would be a little sharper with less understeer.My wheel size is the stock 18x8 & 18x8.5,and I am running the ProjectKics spacers all around(15mm front/20mm rear to widen the track.I have Hotchkis adjustable sways on my car with the middle hole used in the rear and the third hole from the end used in the front.On the stock Bridgestone RE050A tire my car would enter a corner with slight understeer and with a little throttle, snap to oversteer.With TC off,I would get sideways in a hurry so was facing a little dilemma.I am happy to say that the slightly wider tire on front has really helped! Turn in is much sharper without the unsettling transition I previously felt.I needed an all season ultra performance tire,so went with Bridgestone RE960AS and so far am very pleased with how quiet and comfortable they are to ride with and no apparent loss in performance over the OE 050A Bridgestones.Also no significant increase in weight,so straight line performance remains the same. Since the 245-40x18 is very close in diameter to the 225-45x18(only .2" shorter),no problems with the TC engaging prematurely.I hope this may be helpful to any looking to replace their tires and having a hard time deciding which way to go.

 

Blackjack???

Do you have any pic's of your ride, i'm in the same boat as you and am thinking of that size wheel in the BFG for my ride.

cheers

kevin

 

with stock sized wheels, you could also run 245/40 18 front and 255/40 18 rear

 

255/40/18 front & 275/40/18 rear

 

Not on 18x8 18x8.5. No way.

 

Hey newb, I've mounted 275/40/17 tires on 17x8 stock rims on all four corners for autocross.

 

Noobie? Cute, I've owned more performance cars than you are old kid. But anyways, any tool that thinks a 275/40 17 on a 17x8 is ideal lives in a quasi dreamworld.

EDIT: And good ole Tire Rack, you know, the guys that know the most about wheels/tires fitment recommend the following for that 275 tire. 9-11"
Meaning, your piddly 8" isn't within that range. Better luck next time.

 

Wow, I'm impressed . . . here's your signature:

2007 Silver Alloy Base 6 spd (current) BBS RE forged 18's, 07 Yaris hatch, 06 GTI 2.0T Revo'd, 06 RSX-S, 05 Civic VP, 00 Civic Si, 00 Sentra, 97 328i, 96 Jeep GC, 95 M3, 95 318is, 92 325is, 92 325i, 91 318is (all past)

A freakin' Yaris & Civics!? High performance cars?

Newb, the word "recommended" is strictly that. Get over it! It's been done before, and you just didn't know it since you probably have never tracked your car. Oh, I forgot, you have a Yaris . . . never mind. I won't argue with you anymore since you own a Yaris, your so called high-performance car.

 

Wow, that's the best comeback you came up with....Mr self proclaimed old timer round here?! Cute, the "recommended" sizes are, well recommended by the manufacturers, not just some random Z dude. Enjoy your mis-sized setup, it suits your personality well.

Yeah, pick out the Civic and Yaris DD's, and completely miss the 6 Bimmers, RSX-S, 2.0T GTI, and not that I'm bragging, but my Dad has had, let's see, a NSX with Arc titanium exhaust, 200+bs weight reduction, TE-37's, 6 M3's, 12+ Porshes, and I've been behind the wheel of a sick amount of fast, performance cars....I'm hardly unqualified to give your noob azz tire advice. Being that I've had 30+ wheel/tire setups over the years.

 

My friend runs 285/30's on all 4 on stock track wheels 8 and 8.5" wide for auto-x. Rest assured it pudges some but he has no issues with them, and the car is driven harder than most Z's on this site. Recommended sizes are not the end all be all for sizing tires. This is him:

 

That's totally feasibly sure, but is that because that is the *best* setup for those sized tires? Or because of cost cutting? My guess is the latter. None of the top autocrossers would run 8" wide wheels with 285's....just those saving money and being cheap. BMW autocrossers run 17x10's with 275's.

 

Thanks, Alberto!

This newb just won't give up! He is obviously clueless and an idiot for assuming that autocrossers are "cheap" for not using wider rims. Most autocrossers probably spend more money on the Zs every month to prep their cars than what you pay on your monthly payment.

Newb, do you actually know why autocrossers are using certain sizes for their rims? Go find out for yourself and make sure you remember the word "class" when searching.

 

STFU with the noob...jeezus. I am a BMWCCA member and have autocrossed a lot in my E36's and a E46 M3. STFU with all your ASSumptions. Why do you think i know so much about sports cars? It's because of my experience. My join date hardly has ANYTHING to do with my knowledge base. ****ing moron. Figures you would have ZULater as a name.....kiddies. Bring that s-l-o-w 06 out and I'll trounce it with my HR. Must suck to spend all that money on a 06 only to have a 07 blow your doors off in any category.

 

I’m curious about problems one might encounter when going past the recommended tire width for a wheel. For example, if you go too wide, what’s the risk?

- Bead breaking loose?
- Poor (wiggly) handling?
- Any other things?

I would guess the aspect ratio would be a factor here. For example, too wide with a higher aspect ratio should be more forgiving.

--Spike

 

Hey Justin, if you are going to bash on someone's character and who they are, bash on that. We are all car enthusiasts here, so no point in bashing the 350z. Be the bigger man and state facts, thats the best way to prove your point.

Back on topic, check this out: http://www.350zmotoring.com/modules....ex&name=Wheels has some very good information on plus sizing.

 

Newb, you've got some anger management issues as well . . .