Ride not as smooth after putting on new wheels
 

I recently put on a set of new wheels\tires (XXR 527 w\ Michelin Pilot Super Sports). When driving at highway speeds, the car doesnt feel as smooth. There's not quite a vibration but it feels like minor rapid bumps almost, it's hard to explain, it's just not as smooth as when I had my stock setup. I started to think that maybe the balance was wrong. I checked each wheel and no weights have fallen off, but I did notice that one of the rear wheels has no weights on the inside surface while all of the other 3 wheels do. Is there a chance that one of the tires was perfectly balanced from the factory? Should I go back to the shop and ask them to re-check the balance on all wheels. I went to a GoodYear tire shop that has great reviews on the web and my family has gone to them for years. I don't want to be that a-hole customer going back and doubting their work but I just want to be sure it's done right. I also need an alignment since I recently installed springs so I thought about going back and asking them to double check the balance and give me an alignment.

Is this normal for these tires or is there likely a balance\alignment issue? I expected to see no difference in ride quality since I didn't go cheap with tires, but if it's the price to pay for better performance then thats ok with me.

You went from a 215/45 to a what size tire?

Anytime you decrease tire sidewall ratio, you potentially harshen the ride to some degree.

Edit: re-reading, it does sound like balancing.

Get your wheels balanced again.

225/40/18

Sounds like a balancing issue. Get them balanced.

Yeah I agree with the other posts , you should probably get your wheels balanced again !

And there's the reason, bigger wheel and tire setup with less sidewall.

I'd expect to feel more bumps as a result of that. Not an imperfect ride on a smooth surface.

I'll just leave this here. I had a set of adjustable coils and was showing my cousin what "adjustable" meant. I set it to full stiff and drove on a fairly flat road. His response? I didn't know there were bumps on this road.

That is the kind of thing that happens when you increase your wheel size, decrease your aspect ratio, AND get a tire with a stiffer sidewall. All those variables at the same time and BOOM, something you never noticed is there.

If your steering wheel isn't vibrating I doubt you have a tire balance issue and it is just you went further than you thought with your wheel and tire mod.

From what I've read, a shakiness in the steering wheel would indicate front wheel(s) are off-balanced, while shakiness in the seat would be rear wheel(s).

Idk, on my first highway stretch this morning I didn't experience it at all and I though all was well, then on the 2nd highway I started to feel it (after driving for about 20 minutes). Maybe it's the surface of the 2nd highway? I'll see what happens on my way home today. Maybe I'll rotate my wheels tonight and see how my drive is tomorrow.

This probably won't offer you much help as like others have said - it sounds like it may be a balancing issue, but I'm someone that likes to start at the bottom with the most basic (do we really need to check this?) issues.

Two or three times I've experienced a ride-doesn't-feel-as-smooth issue, and even felt (like you mentioned) sort of like I was rolling over something super small, but definitely noticeable on a flat road like the freeway.

It turns out each of these times I had a good-sized pebble wedged firmly between one of the grooves of a tire, and it was poking out a bit. After removing it, it was clearly the source of the problem.

Again - might not be the case with your issue, but figured I'd mention it.

Have you re-torqued the lug nuts?

I plan to remove all wheels tonight and rotate them. In the process I will inspect for anything in the treads.

Yes, I re-torqued them with a torque wrench about 3 days after putting them on.

Another consideration is Radial Force Variance:

[ame="http://en.wikipedia.org/wiki/Radial_Force_Variation"]Radial Force Variation - Wikipedia, the free encyclopedia[/ame]

Anytime you change wheels and tires they could have their own variation of out-of-roundness and you could risk stacking the asymmetries if you don't balance them out. Assuming their is an asymetry at all. You have to measure on the machine to know for sure. Michelins should usually be pretty decent, XXR, no idea.

Most techs, tire/wheel shops and dealerships have no idea what this is or have the equipment to balance for RFV. Usually only racers, engineers and specialty shops deal with it. I know a proper Lexus dealership should have the equipment and be able to offer this as part of balancing, whether their tech will know what to do is something else.

Some tires cause more vibration than others, thats why i went with the Nitto Invos. I do not know the specs with the super sports, but /shrug.

Did the balance work? If you added springs with no alignment than get one. :P

I recently got new wheels/tires mounted with an alignment and after it felt smooth like butter.

could be either wheels or tires, that are out of balance. given that the setup is michelin pss and xxr, my bet is on the xxr's being bad. lol

I didn't cheap out on tires, I dont think, the few reviews I read on tires prior to my purchase used the Super Sports as the benchmark so I figured they would be a nice set; they got great reviews all over the net. I'll do the rotation and see how it drives, if the problem is still there I'll have them check the balancing and at the same time I'll get an alignment.

PSS are the best performance street tire on the planet.. Of course you did not cheap out... It is not the tires.

Stiffer springs, stiffer sidewalls, and smaller sidewalls all at once will DEFINITELY make a very noticeable difference in bumps.

The difference between my summer tires (225/45/17 ZII's) and snows is huge!

Yup. This. I had the same thing happen when I switched to 18's. Normal

Wait...WHAT?

If you have adjustable coils and you adjust them, that does nothing to the ride harshness, just the ride height (unless you had it sitting so low it was against the bump stops).

Do you mean you had adjustable shocks?

But I'm not saying bumps are more harsh, I do expect that, but not a bumpier ride while on a smooth surface.

I'm sure he means coilovers...

Adjustable coilovers still do not change ride firmness when you adjust them up & down.

Changing from one coil over to another can change ride stiffness, but the adjustable perches only change height.

Electric steering. Your wheel wouldn't vibrate due to that b/c steering column has no physical connection to the steering rack.

I'm able to compensate adjusting the dampers for my coilovers, maybe that zion meant.

I had an out-of-round tire that was doing that kind of thing. Tire had to be completely replaced.

On a side note, I think I want to start a "How NOT to ruin your car" thread... :popcorn:

There is most definitely a physical connection to the steering rack, want proof... turn the wheel with the car not running.

The electric power steering is just a geared motor that adds assist to the steering column before the rack.

Nope, there's not. Not in our cars. That's not resistance you feel. That's a total lockout, and even if you got the wheel to turn, the wheels wouldn't.

Unless we're electric assist steering (which I'm pretty certain we're not).

Edit: In my STI, with the car OFF I could still get the wheels to turn with the steering wheel, though it was very hard. With the BRZ it's impossible.

That sounds right, the steering is locked until you turn on ignition/accessory. I never realized why until now.

"Power steering" means "assisted steering". There is a physical linkage between the steering wheel and the steering rack. The effort at the steering wheel is reduced by either a hydraulic pump or electric motor.

Steer by wire on the other hand has no physical linkage between the steering wheel and steering rack when it is enabled.

86s use "Electric Power Steering". Not "steer by wire".

Edmund's details the steering system in 86s here.

http://www.edmunds.com/car-reviews/t...alkaround.html

Lol..there are usually dampening adjustments as well. It's not just height adjustments

ermahgerd

Have you ever looked at your steering rack before? It has a physical linkage that goes straight to... drum roll please... your steering wheel!

Look at this picture looking up from underneath the driver side of the car. You can see the end of the rack (with boot) and shooting up towards the firewall is the steering linkage. Which goes to the steering wheel.

http://www.tune86.com/sites/default/...uspension1.jpg

Whodathunk?

http://www.tune86.com/sites/default/...PSAssembly.jpg

Just going by what he said.
The quote was:
As far as I know there is no such thing.
My ground controls on my racecar have adjustable perches for the coils (does not adjust ride stiffness) and adjustable shocks (dampeners) that DO adjust stiffness.

It's all just terminology used improperly.

I just love it when people say "I'm going to upgrade my BRZ and get coil-overs!".
Ummm.. yeah, the car already HAS coilovers....

Now if I said I was going to upgrade my Porsche front end to have coil-overs, then that would mean something.

may already have coilovers but I don't see how they are adjustable.

I dont see your point. You can upgrade the stock non-adjustable coilovers to aftermarket non-adjustable coilovers too.

My point was everyone want to "upgrade my car to have coilovers" when the car HAS coilovers stock.

I think what people really mean is "I want to upgrade my car to have coilovers with adjustable spring perches and variable dampening shocks".

But just saying I want coilovers is like me saying "I want to upgrade my BRZ limited to have push to start".

And my first post was questioning you when you said "I had a set of adjustable coils ....":bonk:

If you meant "I adjusted the height of my coils" then it would not have made the ride any stiffer unless you lower the car onto the bump stops.

What you probably menat was "I adjusted my shocks to be stiffer".

I can say that little changes will make big differences. I got stock size Michelin Sport A/S 3 tires on 17x7.5 with +45 offset and the steering is much lighter on the new setup, almost too easy to turn the wheel now. Not sure if that is just the new tires or if something with the offset or sidewall shape is also playing a factor. Don't discount the smaller tire height or larger diameter wheels causing the change in ride quality.

I didn't seem bad today so it might be my mind overlooking things now. I'm still going to rotate the wheels and see of there's a change. I'm going to swap fronts with rears and see what happens.

Is it possible for 1 wheels to have no inside-wheel weights while the other 3 have at least 4+? I just want to be sure the guy didn't accidentally forget to put then on. The one without inside weights does have a weight on the inside lip so it was definitely on the balancing machine.