I just got the SP5000s put on the other day, and I'm noticing now that the car's steering seems pretty loose and almost "floaty". I know that these are wider tires than stock, and yes, they do bulge a little. But when I really start doing some back-and-forth movements in the road (like a racer warming up the tires), I notice the car doesn't really have a tight feel, but sort of glides left and right.

Am I feeling the car moving left to right on the extra tire width before it actually starts turning?

Am I underinflated? (I haven't check the pressure yet).

Just trying to get some feedback from others configured this way. Even Blair said the steering felt almost "too smooth", like power steering in big American cars. The last time I felt steering like this, it was when I was hauling a pickup truck load of sod and the front end was raising up a little because of the load in the back.

Any help or input would be appreciated.

I had SP8000 on my 6.5" rims
 

in 225/50 and it felt much better than the stock RS-A's in terms of stickiness and turn-in. However after changing to the 7.5" 300Z rims, the turn-in feel did improve a good bit.

The most adverse effect of the "bulges" will be turn-in. How bad it is depends on the stiffness of the sidewalls. The SP8000 I think is a higher performance tire than the 5000, and I would bet that the sidewall on the 8000 is a little stiffer and offers better turn-in response.

Re: I had SP8000 on my 6.5
 

Do you think that increasing the pressure would help make it a little more rigid? Feels way to "swayish" at the moment.

What PSI are you at now Jamie?
 

It's worth a shot ya know.... Go pump up the pressure a bit, take it for a short spin. Deflate to the level you're at now, and then run the same roads and see if it feels better.

I dunno, I think it's the "almost too big for the wheel" factor on mine. But then again, I'm used to it now, so I don't even really notice it know that I think about it.

Hey, so you decided on the SP5000's over the 8000's? How much where the 5's, they're like $95ish right? Just wondering. I'd almost gotten those, but went with the 8's instead, figuring if I saw snow or incliment weather in Atlanta, I've got bigger problems anyways because people here get crazy when it snows! :)

I had the SP8000s on my 98 SE, and never felt what you did. They did sense things in the road alot more, but they handled really well. Check your tire pressure, might not be up to par.

I've had the SP5000s in 225/50 16" on my OZ Monte Carlo wheels which I believe are 7" or 7.5" wide for about 9 months now and have experienced no adverse affects with them. My first guess would be that your tires are overinflated, not under. I usually run mine at 38 all around.

I once overinflated a set of front tires on my wife's Tercel (to about 70 or so...no guage) and the car had that skittish, jerky, and floaty feeling you describe, like the front tires weren't completely connected to the road.

If the tire pressure is correct, it could be that you have a defective tire or two, which is doubtful but possible. Easiest way to test would be to rotate one side and then the other and see if the problem persists.

It sounds like your tires are overinflated. Tire shops always overinflate tires for some reason.

I inflated my tires from 32 to 36 the other day and my steering became noticably looser.

Well, I deflated them from 36 to 32....
 

...and it seemed to firm up the steering some for sure. I've still got the kind of drunked slide when I do side-to-side turns of the wheel.

It's almost like if you filled up a balloon with water (i.e "the tire"), put it on a table and put your hand flat on it then moved your hand from side to side (i.e. "the car turning from side to side"). There's some lateral slide that is happening I think as the car's weight shifts from the inner part of the bulge to the outer and back and forth.

I just don't know if this was such a good idea after all. Sticky, yes. Stable, not so sure.

Re: Well, I deflated them from 36 to 32....
 

Well maybe you should have stayed with the stock size 215 instead of 225 since those tires do come in that size. The SP8000s have a much harder sidewall. I am not sure where you got them from, but maybe you can return them? Alot of places have a money back guarantee after so many days. I would like to recommend getting the Bridgestone RE730s for a good highperformance all weather tire...

i think it maybe the 6.5 in rims. i am a firm believer that the width of a rim has major effect on wheel/tire combo's performance.
here is why.
i just put some 300ZX wheels (from my 3rd gen) onto my fathers 4th gen with some 215/55/16 and the turn in is great as well as the overall handling. i can say that it definatly feels better than they would on 6.5 because i was a nissan salesman in florida and i drove plenty of 16/6.5 with 215/55/16 and they definatley didnt feel as good as 16/7.5 with the same tires.

my 2 cents.

i am currently trying to find some 17/7.5 or 8 in rims to go with a set tires i just got. i'v seen/driven 2k maxes with 17/7 with 225's and i think that 7.5 or 8 would have looked and performed way better, they also would fill the wheel wells a little better. either way i think that 7.5 is the way to go on a Maxima.

Also note for new tires -->
 

They take a while to wear away the "cast slick" the manufacturer uses when they mold the tire (so it comes off the cast easier).

Once you wear away this layer (a few hundred miles) the tires should feel much better.

I've got 225/50 SP5000's on stock wheels, I never noticed this after they broke in. If anything, turn in is slightly stiffer, but not much. Overall I didn't notice a whole heck of a lot difference other than more grip... I usually run 32 PSI on street, on race days I pump the fronts up to about 40 and the rears to about 36.

Jambo, yes I actually did notice a little numbness ->
 

in regards to steering feel and turn in when I first installed 225's. That first set of 225s were Pirellis and they weren't the stickiest tires around, but I still think the wider tire had something to do with the increase in numbness. Stiffer struts will help this a bunch, but it's just one of the unfortunate things you get with the skinny stock wheels.

I do, however, feel that the change to 225s was worthwhile for the following reasons:
- at-limit grip has increased, I feel
- wider tread looks better ;)
- many, many more tires available in the 225-5X size

But I agree with Daren that the width of the wheel itself is very important to the handling of the car. When you get down to it, the width of the rim is what ultimately supports the weight of the car in a turn...the tire is just the interface...so ultimately, you really can't get a large increase in grip without wider wheels...and the steering response is better as well.

But everything's a compromise.

Jamie, what ever happened with this? Are the tires still a problem?

Jim