ferris11

wow, I should have read this, first. I just dropped off my car at the dealer, yesterday. I'm sure he's gonna just say that I need new tires. It was so loud, I figured something had to be wrong with the car.
I had these BS tires on my old MR2. Pieces of s***. They wear down way too quickly.

Not sure what I'm gonna get, but it definitely will be cheaper, and better than the potenzas.

th1rd3y3

My comment wasn't meant to tell anyone what to do, however, when people complain about not getting 30k miles on a set of Z rated summer tires they are obviously either ill informed or not looking at the real issue. These tires aren't meant to go that long. Period. This cost is part of owning the car, and by buying the car you're accepting responsibility for the cost of the tires, whether they last 100k miles or 10 miles.

My comment basically states that if you can't keep up with this cost don't buy the car, very simple. You can put whatever tires you want on your car, but don't complain that the car sucks in the rain/snow/dry because of your choice. The car is great in EVERY element with the right set of shoes.

RX8-TX

Agreed on this.

S-AIR

I use to have that wow wow wow sound too....thats just the design of the rims...however if u feel any vibrations...thats when the trouble start....i had tumors on the inside wall which i couldn't see....if u get a chance make sure air pressure is good....and try to feel the walls at the back....

RX8-TX

I would also pay attention to brake pedal feel.
1. Does it vibrate under braking?
2. If Yes, from what speeds?
3. Does the car seem to jump under braking as well?

Those are signs of an alignment or serious tire problems.

Here is some info about brakes: http://home.att.net/~m.prendergast-a...l/BRAKCHRT.htm

ferris11

nope brakes are fine. I know what you're referring to, as far as uneven rotors that need to be machined due to being warped. They're fine, though.

pressures were good in the tires and I check them regularly.

Generally speaking, a softer tire that provides more grip will not last as long as a harder tire that provides less grip. But at the same time, just because tires are high performance, doesn't mean that they go to s*** when they get worn down a little.

My tires are far from bald, but the noise that they're making makes me think that I'm riding on the steel belts

RX8-TX

I know what you are saying. And someone else made mention to it here, the compound of the tire as it wears becomes much harder than the outter layer. Now, riding on all seasons, I can't believe that I can actually hear every noise the engine makes.

RX8_Buckeye

Yes, as a fellow automotive engineer, I also found Mazda's selection of the OEM tires very strange. I'm not speaking only about the poor NVH performance and treadwear, but also the decision to go with an ultra high performance summer tire instead of a high performance all-season tire. When you look at the RX-8 and what Mazda was trying to achieve with the car, the tires seem counterintuitive to what it's all about--a "practical" sports car. The car has so many features that contribute to its practicality: 4 doors, usable back seats, adequate trunk volume, easily manageable engine output (yes, there is one benefit of an engine with low torque ), etc. Then you come to the tires that last at most 20-25k miles, are extremely noisy, and most importantly they CANNOT BE USED DURING WINTER IF YOU LIVE NORTH OF XX DEGREES LATITUDE! The notion that one has to buy a second set of tires and swap them twice a year completely destroys any practicality advantage that the RX-8 has over other sports cars. The new Mustang, with its Pirelli PZeroNero All-Seasons is much more practical than a stock RX-8 in the dead of a northern winter.

I just don't get it... those that have replaced the OEM tires with the PZeroNero all-seasons have reported fantastic results. Subjectively, they handle just as well as the stock Bridgestones, they are significantly cheaper, and can manage okay in the the snow. The Mustang program realized this and chose Pirelli as its supplier. There are only 2 reasons that I can think of that explain Mazda's choice of the Bridgestone Potenzas. 1) The purchasing people at Mazda are in bed with their Japanese buddies at Bridgestone, or 2) Mazda couldn't achieve the performance targets for the RX-8 program using anything but an ultra high performance summer tire. I'm half-kidding about reason #1, but reason #2 troubles me somewhat. We all praise the RX-8 for its outstanding handling characteristics... how it can outpace so many vehicles on a road course, etc. Well, how much of that is due to the tires? For instance, what if the Potenzas were to be installed on a Mustang GT? If there is any truth to reason #2, the gap in the handling characteristics between the Mustang and the RX-8 is not nearly as big as some on this forum would like to think.

myfuncar

I can't believe this - 14,000 miles? That's not a whole lot of mileage. Geez.
I have put 6800 on my original Brigestones. They do handle razor sharp, but they're loud. I had Blizzak's on for four months this winter and they were way quieter, smoother, and the handling was definintely a step away from formula one and a stop towards Buick, but not such a big deal.
I'm wondering if I should just junk the Bridgestones now and have a quiet, smooth summer?

MrWigggles

Okay guys,

Before blamming the tire. You might want to blame the allignment for causing what a lot of people call "cupping".

For anyone that has the wOw, wOw, wOw, sound, check the interior tire wear especially on your tires that have been on the rear of you vehicle. You might be surprised to see (or feel) little waves at the interior edge of the tread. This comes from bad camber which my RX-8 has. And my rear suspension is stock and my trunk mostly empty (lowering your car pitches the wheels in at an even great angle).

Once your tires start "cupping" getting the allignment fixed will help slow down the rate but won't fix the problem with the noise (i.e. the damage is done)

Anyway, my stock tires were rotated every oil change and I got cupping problems on my stock tires after about 15K miles. However, I didn't know what the problem was at the time so when I got my new tires and the noise went away, I made the assumption - bad tires.

Well my new wheels and tires are staggered so I don't rotate them. After 20K miles on my new AVS dB2 tires, the cupping has returned on the rear. By close examination it is obvious what is causing the problem, the rear suspension has too much camber (good for track use, but not good for tires.) I have not fixed my allignment yet but I have remounted the rear tires to opposite sides of the vehicle so that the internal cupping is now on the outside (and now very obvious to see.)

I will take pictures when I get a chance, but anyway it isn't all of the stock tires fault. On my vehicle (and probably yours) the rear allignment is at least 50% responsible.

-Mr. Wigggles

MrWigggles

Alright here is a picture of my rear allignment. You can clearly see that there is a lot more pressure on the inside of the tire and the payment.

Remember this is AFTER I swapped the passenger side tire to the driver side (and vice-versa) so the visible heavy wear is on the outside of the tire.

MrWigggles

Here's a picture of the cupping. It is fairly subtle but that is all that it takes to make the tire sound horrible.

(And once again all this apparent outside wear came from the time it was on the passenger side so it is actually 20K miles of inside wear)

HeelnToe

Aha! You may have just solved a mystery for me.

I had snow tires swapped onto my stock wheels in december, but didn't think to first mark the OEM's as to which tires were fronts and which were rears.

Come March, and time to swap the summer tires back on, and I noticed that two tires are MUCH more worn than the others. But I now didn't know which tires came from where. So I started a thread and asked everyone which wears quicker: rears or fronts?

The verdict was the rears.

I was suspicious though, as the worn tires are ALSO worn heavily around the edges... leading me to believe, against all advice, that they MUST be the fronts, having been scuffed by hard cornering.

Now you have me wondering... maybe the scuffing on the edges is what you're showing here... and thus my worn tires really were the rears as everyone suggested. Interesting...

c2k4-8

Would the cupping problem be a warranty issue?

RX8_Buckeye

I doubt it, unless you can somehow prove that the cupping was caused by a bad alignment from the factory. Alignment is only covered under warranty for 12 months I believe, so any tire wear due to bad alignment after that period is your responsibility.

ferris11

does anyone know the factory recommended settings for the alignment? front and rear?

From a racing perspective, different rates of camber are configured to increase the tire patch on the ground. If you look at an Indy car, you'll notice that there is a lot of negative camber so that when the cars are on the banking, they have an increased tire patch to provide better grip. but when they are sitting still, a good chunk of tire is not even touching the ground.

It is great for hard cornering, however, for a street car, since most people don't push their cars around turns (most of the time) I'm surprised that Mazda would set the camber like this. As we've seen, it chews up the tires.

If you notice the suspension on Boxsters and 911's, you'll notice that they are set up with a good amount of camber as well.

Dark8

It's done to create understeer for safety reasons. Here is a link where the factory specs are posted: https://www.rx8club.com/showthread.p...8&page=2&pp=10


Last auto-x season I ran -1.5F and -1R and the car had way too much oversteer. It would make a great drifting set up. I'm running -1.3 all around this year and it is much more nuetral with a little bit of oversteer that is very controllable. I buy new tires each season and only put about 5K on my tires so I can't comment on the wear.

But, if I was going to go to something like -0.5 in the rear i would take all of the negative camber out of the front to keep the rear from getting too wild.

ferris11

have you adjusted the toe-in/out on your car?
Also, have you ever put your car on a set of scales to see the balance?

Are you running the stock ride height?

edpare

Me too: only 8K miles on Bridgestone Potenzas and am getting fast, repetitive sound from the rear. In previous cars, that sound meant a split belt/tread. Vibration gets bad at 125. I am now looking for bigger tire for stock rims.

rx8daniel

Does anyone remember about how much tread was left when they deemed their OEM RE-040s as having served their useful life? Regardless of the mileage. But - if you changed got rid of them just to change sizes and / or brands before they were 'worn out' then it doesn't count!
Anyone? thanks!

alnielsen

iTrader: (4)

I'm not quite sure what you are asking here, but mine were almost down to the "wear bar" when I replaced them. I had a bad hydroplane incident where I spun my car on the expressway. I didn't touch anything. 2 1/2 rotations is enought to scare anyone. I now have Falcon ST615's on the car and use Pirelli PZero Nero M/S in the winter.
We will welcome you back to Illinois when that time comes.

RX-GR8

i've got 19k on my bridgestones so far. changed them with dunlop winter M3's for the winter.

Gwoody

rx8daniel: the bridgestone spec is when tire treat reaches 2/10 of an inch they are worn out.

TexasKyle

I put Yoko avs 1000's on mine here a few months ago. 245/40/18's. While cheaper, and readily available ( the Eagle F1 DSG3's I was looking had to be ordered) they are no where near as grippy as the Pots. Of course, they have twice the treadewar rating too. I expected to give up some grip for longer treadlife. The back end will try and step out more than it did before and I can also get a much longer "chirp" when hard shifting into second. Face it, the Pots have a treadwear rating of 140! 140 = Early Death of tire.


(edited for spelling)

MadRonin

My Dunlops are getting extremely loud after 25k miles. I noticed the other day that the center tread on the rears are pretty low. I was hoping to make it to the end of the year on these and worry about new ones after I took my winter tires off; but it looks like these won't make it.