Hey,
Can I get some advice on changing the rear tires only?
My rear tires, stock pzeros, are not completely worn out, but I can justify changing them early. The front tires look like they've never been used, so I'm gonna have to keep them. Is it ok to upgrade the rear tires only, or are there negative side effects to that? Will I get the benefits of the PSS if I'm just changing the rear?
Do I just get the same tire size I have now?

 

absolutely no problem just changing the rear tires. you can get the same size or do the 305s in the rear. from what i've read they are stickier so you should get some better traction, but honestly I have no personal experience so no idea if you can tell the diff in "normal" driving.

 

If I remember correctly how this works, the 305 will be about a centimeter thicker. Is that for better traction?

 

Each tire is made of a different compound. Some are stickier than others, but might sacrifice road noise, ride quality, longevity, wet handling, etc. Even within Michelin brand you can get stickier tires like the Sport Cup tires that are on GT3, 918s, etc.

Sizing is just to make sure it fits the wheel/car. Stock size is a good starting point, and as long as you are reasonably close to those dimensions than it won't mess with things like the speedometer. But heck, if you really wanted to you can run all kinds of crazy tires/wheel sizes. The car will then become crap (ride height too high/low, etc.), but it can be done. People mention the 305s because it doesn't really differ from the stock dimension that much. It's marginally wider so that helps a little, but it's more about the compound.

 

A taller tire will help reduce wheel spin. But that's not why its thicker... its just due to the way tires are sized.

 

I have the 20 inch Gyrodynes with the OEM Pirellis. I'm near the wear bars on the rears. I'm considering downgrading to 285 in the rear from the 295. There are SOOO many more options in a 285 size. Some actually measure the same or a bit more than the Pirelli 295

 

Ok. Thank you!

 

Generally, on dry pavement, the same tread/compound will offer more grip the wider it is. if you go with a wider (305) PSS you will definitely enhance your traction. (compound and width enhancement). Leaving the P-zeros on the front, you will experience more understeer (or less oversteer) than you are currently. Not a problem...you just need to adjust your driving accordingly

 

Looks like Costco is helping me with my decision. They only have 295 on the pss. Although tbh, I'm not sure I should be doing this at Costco...

 

If ur worried about wheels getting scratched just buy the tires and take them to trusted installer.

 

+1. A good installer (at least here on the East Coast) charges only $20-25 per wheel for mnt. & bal.

 

Tire change completed. Rear tires only replaced with PSS.

A few immediate thoughts:
- Grip seems a little better. Not as much as I thought it would be after all I've heard.
- Pzeros actually looked better on the car. They have a better shape, but I think they are also a tad thinner on the outer edge. It makes them blend perfectly with the rims, and the pattern looks better as well, but that last part is subjective.
- It turns out one of my rear tires, right side, was almost bald, especially on the inside. I had only taken a close look at the left tire before, and that one must have been at 50% when they removed it. Anyone have any idea as to how the discrepancy could be so huge?

 

I'd take the car in for a laser alignment. Improper toe/camber can cause premature tire wear.

 

1. Alignment for the rear has a negative camber so the inside will alway wear just a bit faster than the outside.
2. If you are a bit aggressive with your driving the right rear wheel will wear much faster than the left since you generally are taking far sharper right hand turns on the street than left and the inside wheel will be trying to spin faster than the car is moving unless the LSD is fully engaged.

 

Hello,


From a safety perspective I would recommend finding out whether either your front tyres or rear tyres are designed to work in a system of 4 tyres. Most high spec tyres these days are designed to work in harmony, i.e. same compounds.. same water disperse rates.. anti aqua-planing.. grip levels..

 

Not saying you can't be right, and I am no expert, but I am sceptical about this concept, although I wouldn't put it past a tyre company to make the claim. In a 2WD car there is no connection in the drivetrain between front and rear and on modern cars with ABS, DSC, EBD etc each wheel is monitored separately and the cars electronics are more than capable of making hundreds of changes a second to make sure that any differences in traction for whatever reason can be dealt with.

 

Get the tracking checked (and have a look at the full width of the front tyres).

-ve camber will cause the inner shoulder of the tyre to round off, but you would have to be running lots of -ve to wear the inner edge to the point where it's bald.

Even small amounts of toe out on the rear relative to the thrust axis will wear the inner edge off in a couple of thousand miles.

For reference, Alfa Romeo used to deliver cars with so much toe-out on the front that the inner edges of the tyres were shot in less than 5000 miles of road use.