jonzer12 Posted November 17, 2003 Share Posted November 17, 2003 For those of you who have added flairs and larger tires, ie >= 245mm how is the handling of your z? My project will be strictly for the street and handling is really important to me, I am used to small, light, great handling cars and want to my setup to feel accordingly. Does larger tires on a Z ruin the "feel" of the car? I was planning on 225 in the front and 245 - 275 in the rear. Keeping in mind that I already have a new rear drivetrain and the car will have new bushings, springs and struts. I only want to know what large tires themselves do to a z. The car will have ~335 bhp so I do need a goodsize footprint. Anyone have any opinions? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 17, 2003 Share Posted November 17, 2003 I run 250/45/15 slicks at low pressure and it's not easy to turn at low speeds. My Z is not flared. I've been looking to see what's going to happen with that WRX power stering rack upgrade. Tread and higher pressure will help you steer at low speeds, and the my car definitely handles much better with the bigger tires than with the street meats, 195/60/14's. Jon Quote Link to comment Share on other sites More sharing options...
RPMS Posted November 18, 2003 Share Posted November 18, 2003 It sounds like what you're talking about is handling feel, not ultimate grip. I was watching an episode of Top Gear, and they mentioned that the engineers made the new Lotus Elise understeer (plow) like crazy to keep it tractable for the masses, and in doing so they pretty much neutered the car. When the driver asked the suspension engineer how they would have to do to restore neutral handling, the engineer said to put on larger front tires. It makes sense, for both the front and the rear. If you're looking to have a car that's steerable with the accelerator, I guess you'd need to be able to exceed the traction limits of your rear wheels by limiting your rear wheel grip. And I think the wider the tires you have on the car, the more suddenly it will break loose. I've driven Z's with tires skinny (stock 170 width) and wide (current 220). The skinny tires gave much more notice about when they were going to break loose, and were much easier to get into a 4 wheel drift. Wide tires hold the road better, but as a rule are noisier. don't do as well in the rain, and aren't as predictable when they finally let go. Just my observations - I could be wrong. Quote Link to comment Share on other sites More sharing options...
fl327 Posted November 18, 2003 Share Posted November 18, 2003 My buddy had 14x10 rear wheels with 245/60/14 (old) tires on them he said in the rain he was basically a hover craft, he HATED driving it in the rain. It was his only car at the time and he said that it just plain sucked. In the dry it was incredible. a stiff suspension teamed up with big wide tires and a stock 6, made for some fun four wheel drifts thats for sure, except that it was hard to get enough speed to do it!!! I know a guy also with 15x13 rears with 315/50/15 or something ludicrous like that, and also said it was hovercraft season in the rain. Shoot, rwd sportscars dont do well in the rain as a whole, especially an older one. Right now I have car parked in drydock but i do take it out at least once a week to get the feel back, driving isnt so hard, its the stopping distance and the inability to hit the go pedal that bums me out about it! Quote Link to comment Share on other sites More sharing options...
majik16106 Posted November 18, 2003 Share Posted November 18, 2003 ya, i had worried about that too, i wouldnt think it would matter so much what was on the back as what is on the front... running 245s up front like some of these guys do... i was planning on doing it but im afraid ill need to do some more working out before i can take slow turns.I often wonder what its like to pull into a parking spot with no power steering on a wide bodied early z.... Quote Link to comment Share on other sites More sharing options...
fl327 Posted November 18, 2003 Share Posted November 18, 2003 ive done the parking lot thing with the 14x10 wheeled car, had 14x8 fronts, flared car of course. sucked, but not too bad if you can keep the car rolling a little bit and steer in, but if you have to stop and cut the wheels alot, its definitely forearm excersize. too small of a front tire and tall profile is bad in rain too i think, 205/60/15 on turbo swastikas on my car and the thing just washes out on me in the wet, but at least it does it at equal rates. Ok fine, that was me doing the 4 wheel drift in the rain Quote Link to comment Share on other sites More sharing options...
maichor Posted November 18, 2003 Share Posted November 18, 2003 Great posts there about personal experiences with wider tires. But . . . I would like to know how PS changes that. My car now has PS, but I haven't driven it yet, so I can't comment. I bet Terry (blueovalz) could offer some great insight here! I am running 275's up front and 335's in the rear, same as a Viper. Terry I think has 315's all around which would be a much better setup. photos.yahoo.com/maichor75104 Quote Link to comment Share on other sites More sharing options...
majik16106 Posted November 18, 2003 Share Posted November 18, 2003 because its assisted steering... less manual effort required by the driver. i was talking about the effect on the turning radius, rather how hard it would be to physically turn the wheel, with bigger tires it would be harder to turn the wheel Quote Link to comment Share on other sites More sharing options...
maichor Posted November 18, 2003 Share Posted November 18, 2003 I hear ya. My bro has an 70's Bronco with No PS no PB and running 35/12.50's. It is scary to drive since everyone if front of you has antilock brakes and PS. Still, I throw my question out to anyone who has PS AND wide tires. Parking aside, is overall handling hurt at all by large tires, assuming fair weather? Quote Link to comment Share on other sites More sharing options...
Guest Perry Posted November 18, 2003 Share Posted November 18, 2003 for what it's worth my car stayed very nuetral and good handling when I switched from stock wheels/tires to 215/60/14's on 14x7's with 0 offset. Handling is very effected by your offset too, I had some wheels on it for a while with too small of a backspacing and the car drove terrible, followed grooves in road etc.. the bigger tires just increased the speeds it took to slide around. breakaway was just as predictable as with the smaller tires, but I still had some sidewall. we'll see how it handles with my 17x8 wheels and lower profile tires. I like same size tires all around for a decent sportscar. Z's are nearly 50/50 front rear weight distribution so I would thing same size tires all around would be best for handling. But I also don't mind lots of wheel spin and oversteer. Perry Quote Link to comment Share on other sites More sharing options...
johnc Posted November 18, 2003 Share Posted November 18, 2003 Parking aside, is overall handling hurt at all by large tires, assuming fair weather? Larger tires bolted onto an otherwise stock chassis will make the handling worse. As with any modification, changes are required to take full advantage of larger tires. Wider tires increase steering kickback (some folks call it bumpsteer) which it more a comfort issue then a handling problem. Bumpsteer spacers reduce this kickback. A bigger issue is the handling problems caused by lower profile tires (45 aspect ratio and below). The Z chassis needs a certain amount of compliance to grip properly. If the suspension is not supple enough the tires tend to skate over bumps and the suspension isn't given enough lateral load to bite. Normally this compliance comes from the tire sidewall (50 aspect ratio and above) but when you go to a lower aspect ratio tire the sidewalls are stiffer. Now the compliance that once existed in the tire has to be moved somewhere else. It can be moved to the suspension bushings and/or the shocks. If you stick with spring rates around 200 lb. in. the Tokico Illuminas set at no higher then 3 will work with lower aspect ratio tires. With spring rates over 200 lb. in. the Illuminas set at 4 or 5 (to get proper rebound damping) have too much compresison damping which causes the tires to skate over bumps. The car feels like it wants to take a set but then unloads and moves a bit and then tries to take a set again. So, as you can see, you have to make a number of changes (springs and shocks) to get the larger tires to work. Without those changes, a smaller tired car will be able to get around the track faster. FYI... ITS prepared 240Zs run on 225/50-14 tires and are very fast around racetracks (1:34s at Willow Springs, 2:03s at Thunderhill, etc.) If I was building a street 240Z I would run 225/50-15 tires regardless of the horsepower. Remember, tread compound has much more to do with traction then tread width. Quote Link to comment Share on other sites More sharing options...
majik16106 Posted November 19, 2003 Share Posted November 19, 2003 gotta remember though too, a lot of the big wheel thing, i think has to do with style, I know a 15 would be cool, or a 16 with good tires, but it looks just plain badass to have 17x11's with 7inches of lip on the back under big flares and having big wheels up front. I guess you'd just have to be more careful with whats up front, i may drop to an 8 in the front and run a 235 or something. Quote Link to comment Share on other sites More sharing options...
TimZ Posted November 20, 2003 Share Posted November 20, 2003 Wider tires increase steering kickback (some folks call it bumpsteer) which it more a comfort issue then a handling problem. Bumpsteer spacers reduce this kickback. Well, not quite... Wider tires can change the scrub radius, which does have an effect on steering kickback. The scrub radius is simply the distance between the center of the contact patch of the steered tire to the point that the contact patch rotates around when steered (they are seldom in the same place). If the center of the contact patch is to the outside of the center of rotation, then you have a positive scrub radius. This, however, is not the same as bumpsteer, and the so-called "bumpsteer spacers" will not have much effect on the scrub radius. Also, wider tires won't have any effect on the bumpsteer characteristics. With bumpsteer, the toe-in changes with suspension travel, and the car's heading can change erratically when you have large amounts of suspension travel. There doesn't have to be much steering kickback in this situation. ...Just trying to keep the terminology straight. Quote Link to comment Share on other sites More sharing options...
jonzer12 Posted November 20, 2003 Author Share Posted November 20, 2003 Wow, lots of interest but let me change my question a bit, how does a z FEEL with larger tires. Every sports car I have every owned has been a high winding 6 cylinder that loves corners, I was with little thought going for big flares and large tires because I love the look of Z's that way but now I am worried that it may kill that sports car feel that I love. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted November 20, 2003 Share Posted November 20, 2003 FYI... ITS prepared 240Zs run on 225/50-14 tires and are very fast around racetracks (1:34s at Willow Springs, 2:03s at Thunderhill, etc.) If I was building a street 240Z I would run 225/50-15 tires regardless of the horsepower. Remember, tread compound has much more to do with traction then tread width. Man, glad to hear that. I have a set of 225/50-15 BFG Auto-X tires on zero offset Riken wheels in the garage. I use to auto cross with them back in California. They were probably the #1 choice among the auto crossers I hung around. That was some years ago, so probably better tires available now. I will second the compound comment. My street tires are 205/60-14 (on stock steel wheels). Going to the auto X tires was absolute night and day. Go into a hard turn with the street tires and I would get a lot of noise and excitement. The first time I took a hard turn with the auto-X tires I practically ended up in the passenger's seat. Compound will also make a huge difference in the rain (as anyone who has ever upgraded tires on a pickup truck can tell you). As for feel? The 225/50's definitely transmit more road feel into the car, but if anything the steering is lighter and more precise. 225’s are definitely not excessive. The auto X tires have about a 1/16 inch tread depth so hopefully I will never experience them in the rain. IMO the #1 mod you can do to ease parking is to replace the rubber steering coupler with a solid one. Replacing the coupler and upgrading to urethane steering rack bushings made an immediate difference in turning effort. I went from needed two arms to crank the wheel while parked to using just the palm of one hand. No BS. Quote Link to comment Share on other sites More sharing options...
majik16106 Posted November 20, 2003 Share Posted November 20, 2003 supdog- you just answered my next question, i was going to buy the urethane coupler but i was gonna ask if anyone else had done it and what difference it had made. Quote Link to comment Share on other sites More sharing options...
ZR8ED Posted November 20, 2003 Share Posted November 20, 2003 I believe I can offer some seat of the pants experience here. I have used stock sized tires 195/70/14.. 225/6014.. 225/50/15... a combo of 225/50/16 front 245/45/16 rear, and now my 235/40/17 front 315/35/17 rears on the same car with very minor changes in the rest of the suspension during those years.... I believe the smaller wheels "feel" lighter..less rotating mass.. much easier to steer, and much easier to spin, and lots of howling protest from them when nearing traction limits. I have heard time and time again over the last 15 years, that the 225/50/15 is about ideal for our z's... they have a nice crisp feel to them (tires were firehawk svx's..and yoko A008's) When i went to 16's, launching the car hard became much more difficult (had plenty of hp at that time..)... it slowed the accel a bit too. I had to change my gear set to get the car to pick up speed again...(I know that part of that is the extra ratio of the larger tires...but I still had to change the gears to gain back what I lost.) The 16's were awsome on the track...I could corner like I was on rails (seat of the pants)... They 16's did not like the uneven pavement.. car got more "darty" on highways, and there was much less warning when the tires were running out of traction... I had to add a wing on the back of the car to get it to be half decent in a heavy rain... with wet roads it was fine... The 17's I run currently are working out great! The rain handling is better than when I ran the 16's... even though i have a smaller wing....(better tire compound I think is doing most of the work) The handling is down right wicked, but some of that is due to the set back nature of my particular engine swap choice. I did have to loosen up some of my front swaybar, cause I picked up more understeer with the new tires... It handles very very neutral... compound is I think the most important...the larger the wheel combo, the more careful and thurough you need to be to get the car set up... My 17's give me plenty of capabilitiy, that actually overshadows my suspension.... It is now time to upgrade the suspension to more effectively use my larger wheel combo. Quote Link to comment Share on other sites More sharing options...
majik16106 Posted November 21, 2003 Share Posted November 21, 2003 someone who runs big tires and wheels told me tha really the bigger you go, the more you are going to need a race type tire to really make ti work, he said he could use a small falken ziex (47 a piece) on his 15's, but now he runs big 17's and says that he moved to kuhmo ecsta v700 and it really helped. but he runs a 335 in the back and a 245 in the front. Quote Link to comment Share on other sites More sharing options...
jeffp Posted November 22, 2003 Share Posted November 22, 2003 First off I have stronger springs, and KYB non adjustables on the front. the rear has stronger springs and tokico adjustables. The tires on the front are 225 15 and the rear are 245 15 The front of the car is setup with -1 degree of camber and +6 degrees of caster. toe is set to 0 or 1/2 degree. The front of the car is rock solid. i have never slipped with it. the rear on the other hand is set to position 5 and they are stiff, but I do strait line racing for the most part, position 3 is better for cornering. I have strut position bars with rod ends, no rubber, the rear is poly bushings as well, so there is no movement of the wheel under hard cornering. The biggest thing is the Quaife diff, when you go into a corner the car is very responsive, but the control is at the gas pedel, it wants to go strait under heavy power and when you letup off the throttle it tries to turn sharper, the tires dont push as much. the car is not loud like say my wifes 300 with wide tires. Driving in the rain has always been not to fun in the car even with stock tires it sucked. So I can get a little more grip with the wider tires just because of more contact area, this is out the window with slicks in the rain tho. So look at the tires you want to use, and select a tread pattern the promotes grip in the rain, and also, the skinner the tire in the rain the better its contact area will be, the wider tire will hydro plane easier. Every tire has its limits so find the happy medimum for you and go with that. Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted November 23, 2003 Share Posted November 23, 2003 How does it feel with large tires... Well i run 17's with 205 up front and 215 in back. when i ran my 14's even with good tires i hated driving in the rain.. made me very nervous. Now with the added weight of the 17's and the better tires it's like i'm suction cupped to the road. Puddles at high speed are no problem... cut's right through them. Also unlike many people have written on here... my car is EASIER to turn with the wider tires than the stock ones. At a dead stop yes it is harder to turn the wheel, but i NEVER turn the wheel when stoped once rolling it's easy as cake. Cornering... oh boy... can it stick anymore? The car can easily take a 90 at 40 without making noise. The handling is wicked. you'll be very happy. Quote Link to comment Share on other sites More sharing options...
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