[helloelectro]

My car is a staggered setup. My rears are creeping into the yellow on tire depth gauges, but my fronts have some play left.

The car currently has MPSS but I am thinking about moving to the Continental extreme contact to save a little money against the MPS4.

Is it silly of me to just do the rear for now and run the fronts down some more before doing them as well?

Continental doesn't appear to do any deals when buying all 4.

[bmtespar]

Originally Posted by helloelectro

My car is a staggered setup. My rears are creeping into the yellow on tire depth gauges, but my fronts have some play left.

The car currently has MPSS but I am thinking about moving to the Continental extreme contact to save a little money against the MPS4.

Is it silly of me to just do the rear for now and run the fronts down some more before doing them as well?

Continental doesn't appear to do any deals when buying all 4.

I don't see anything wrong with doing this. As long as the tread pattern on each axle is the same, you should be fine. It does some what depend on exactly what you with your car. (ie: tracking the car). You'll probably never notice the difference.

[BEM-S4]

xDrive is RWD?

[helloelectro]

Originally Posted by BEM-S4

xDrive is RWD?

I don't have xdrive. I have RWD

[BEM-S4]

Originally Posted by helloelectro

I don't have xdrive. I have RWD

Then you're fine with single axle. But if the fronts are close-ish I'd do all 4 just so I had the tire insurance all around (assuming you don't have it).

[ralawren]

Originally Posted by helloelectro

My car is a staggered setup. My rears are creeping into the yellow on tire depth gauges, but my fronts have some play left.

The car currently has MPSS but I am thinking about moving to the Continental extreme contact to save a little money against the MPS4.

Is it silly of me to just do the rear for now and run the fronts down some more before doing them as well?

Continental doesn't appear to do any deals when buying all 4.

I purchased used MPSS off of ebay for the rears until the fronts were ready. Then changed all 4. They were $75 a piece plus $25 for installation.

[delvec03]

your rear tires should ALWAYS have the better traction. this helps in either scenario when the front or rear wheels break free.

Google it.

[helloelectro]

Originally Posted by delvec03

your rear tires should ALWAYS have the better traction. this helps in either scenario when the front or rear wheels break free.

Google it.

Yeah that's what I'm looking to replace first if
I do one axle at a time.

[amw896]

on rwd that is no problem.

[RoundelM3]

I would recommend having the same brand/tread pattern on front and rear. Either replace the rear MPSS or get a full set of the Contis. If you get the full set, I'd also recommend an alignment.

[p912guy]

I had about 18K miles on the original MPSS when I picked up a sharp piece of metal in one of the rear tires just before I switch to my winter shoes back in November. It was right along the edge near the sidewall, so no one would offer to repair it. Since the front tires had quite a bit of tread depth and looked pretty good still, I opted to just replace the rears and stuck with MPSS to match the fronts. I rack up a lot of interstate hwy. miles along with my day to day commute and don't stress my tires much so I often get near or beyond the mileage from my tires. I like the MPSS, but I'll probably look at other options when it's time to replace all four tires. My winter set has about 18K miles also and they look good for at least another couple seasons.

[Sportstick]

I've found that my car has a 2:1 ratio of life expectancy for rear tires versus front (must be something other than the driver, I'm sure.). I have replaced just the rear with new tires, but kept them identical, as I have a square set-up...same brand/model/size with Michelin Pliot AS3. No issues.

[helloelectro]

I may just do all 4 as the more I think about it I'd prefer one trip to the dealer. lol.

I'm also thinking of just spending the extra hundred or so dollars and going mps4s. The MPSS are being phased out and tread wear is notoriously terrible. I had MPS4S on my previous car and loved them.

Sportstick LOL!! Totally due to the road conditions I'm sure.

[helloelectro]

RoundelM3 I had an alignment done 3 weeks ago when i had the lowering spring added. Think I can hold off?

[Sportstick]

Originally Posted by helloelectro

Sportstick LOL!! Totally due to the road conditions I'm sure.

Eureka! That's it! The road conditions under the rear of my car are wearing out my tires. I must go tell my wife to explain the extra tire purchases! Thanks!

[dradernh]

Originally Posted by delvec03

your rear tires should ALWAYS have the better traction. this helps in either scenario when the front or rear wheels break free.

Google it.

When I have to put two fresh tires on a car at the track, they go on the front. That's so the car keeps going where I point it. The rear goes where the front goes, unless there's a driver malfunction.

[p912guy]

Originally Posted by dradernh

When I have to put two fresh tires on a car at the track, they go on the front. That's so the car keeps going where I point it. The rear goes where the front goes, unless there's a driver malfunction.

Oh really? Ask the long-hood 911 driver about trailing throttle over steer and the P car's tendency to not follow the front tires. I don't do track events so I can't speak to what's the protocol at the track, but I think in everyday driving I'd rather not have a loose rear end, especially in the wet, but that's just me.

From Tire Rack's website:
"Regardless of where the worn tires were removed from, when replacing a pair of tires, the new pair should always be installed on the rear axle. Installing the new tires (with full tread depth) on the rear axle will ensure that any differences in traction between the two pairs of tires will not lead to a dangerous oversteer situation. In an oversteer situation, the rear tires will begin to slide and can be very difficult to correct. However, if the front tires have significantly less tread depth than the rear tires, the front tires will begin to hydroplane and lose traction on wet roads before the rear tires. While this will cause the vehicle to understeer, you can correct this by releasing the gas pedal, staying off the brake and allowing the vehicle's weight to shift forward and load on the front tires to improve grip while you regain control."

[XutvJet]

Originally Posted by dradernh

When I have to put two fresh tires on a car at the track, they go on the front. That's so the car keeps going where I point it. The rear goes where the front goes, unless there's a driver malfunction.

^This.

Also, you should always match your tires and not run different brands/models on separate axles.

[msej449]

Re tread depth - remember that a lot of tyres have a non-linear tread depth vs stopping distance curve (below) This is a real dry surface test example from a government transportation Agency, designed to illustrate the point: as the tread wears and the depth reduces, the stopping distance increases. But not necessarily consistently, which can catch people out.



For this tyre, the manufacturers have biased it to maintain stopping distance well from new down to 4mm (5/32"), then really, it's bad news as the tyre wears from 4mm onwards. So really, the minimum legal indicator isn't where you want to be - on this tyre, you'd probably start thinking about replacement some time between the 4mm->3mm (1/8") mark, well before the (UK) legal minimum of 1.6mm (1/16").

So at new to 5/32" the stopping distance is about 79ft, but at the UK 1/16" legal minimum it's extended 28ft to 107ft. And that's on dry tarmac.

[albertw]

Interesting discussion. I have assumed that reduced traction with tire wear was related to ageing and hardening of the rubber. The idea that tread depth is also important is new to me.

This seems to me to be easy to turn into an argument for putting the new tires on the front. During hard braking some weight transfers to the front tires, so that's where the most effective braking will be done. That suggests that the shortest stop will come when the best tires are on the front, assuming ABS does its job and keeps all wheels at the right amount of slip.

Regarding hydroplaning, the front tires remove some of the water, even when hydroplaning, so the rears have less water to disperse. That seems to me to be an argument for putting the newest tires on the front.

Regarding the balance of traction front to rear, I ordered my RWD with allseasons to get a square setup for a better balance, and that's what I got. I like to slide the rear around and don't like to have to work too hard to get it. The staggered setup is reported to give a bit of understeer. Putting new tires on the rear likely will accentuate understeer. Putting them on the front might reduce it a bit.

[dradernh]

Originally Posted by p912guy

Oh really? Ask the long-hood 911 driver about trailing throttle over steer and the P car's tendency to not follow the front tires. I don't do track events so I can't speak to what's the protocol at the track, but I think in everyday driving I'd rather not have a loose rear end, especially in the wet, but that's just me.

From Tire Rack's website:
"Regardless of where the worn tires were removed from, when replacing a pair of tires, the new pair should always be installed on the rear axle. Installing the new tires (with full tread depth) on the rear axle will ensure that any differences in traction between the two pairs of tires will not lead to a dangerous oversteer situation. In an oversteer situation, the rear tires will begin to slide and can be very difficult to correct. However, if the front tires have significantly less tread depth than the rear tires, the front tires will begin to hydroplane and lose traction on wet roads before the rear tires. While this will cause the vehicle to understeer, you can correct this by releasing the gas pedal, staying off the brake and allowing the vehicle's weight to shift forward and load on the front tires to improve grip while you regain control."

I'm afraid so. That's why if you're going to the track the driver mod needs to come before the making-the-car-go-faster mod. Those skills translate fairly well to the street, too, which is an added bonus.

The willingness of 911s to rotate is a desirable trait at the track. I imagine before electronic safety control systems came along street drivers would get caught out by that from time-to-time. IIRC, C&D reported not too long after the whale-tail P-cars came out that some 80+% of them were going back to the dealer with major rear-end damage. That was back in the day of when-in-doubt-give-it-more-gas being a common way to drive the typical performance car, which had modest power.

I think the text from the Rack is fine, although I know few drivers I want to be sitting next to when their front-end starts hydroplaning. That's especially true if getting it right is the difference between just sliding around and a major smash-up.

[RoundelM3]

Originally Posted by helloelectro

RoundelM3 I had an alignment done 3 weeks ago when i had the lowering spring added. Think I can hold off?

Probably so, but if you had a 4-wheel alignment done on worn rear tires, there might be some slight variance with the new rear tires mounted - but maybe not enough to require any adjustment.