Sponsored by The Tire Rack

[perry1]

HI everyone. I need to replace my rear tyres!. Have been told that if I replace rear cups with PS 2's I will have to change fronts as well. Not too keen to do this as they have a lot of wear left on them. Is the tyre dealer trying it on or what?

[Lemans_Blue_M]

Originally Posted by perry1

HI everyone. I need to replace my rear tyres!. Have been told that if I replace rear cups with PS 2's I will have to change fronts as well. Not too keen to do this as they have a lot of wear left on them. Is the tyre dealer trying it on or what?

Not a good idea to use two different tire compounds on the front and rear axles of the same car.

And even more important...

Pilot Sport Cups should really only be used on the race track. They are NOT a suitable substitute for Pilot Sport 2 street tires.

The PS2 street tires will last longer than the Pilot Sport Cups (treadwear rating is 2.5x higher), and they are MUCH safer to drive on in wet conditions.

[SenorFunkyPants]

Originally Posted by perry1

HI everyone. I need to replace my rear tyres!. Have been told that if I replace rear cups with PS 2's I will have to change fronts as well. Not too keen to do this as they have a lot of wear left on them. Is the tyre dealer trying it on or what?

You could always try it and see...it might be OK (but likely to be quite oversteery)...or it might be a dog, you won't know for sure until you try.

[lucid]

That would reduce understeer and might alter the braking performance depending on what you are doing. Those most likely won't kill you. But getting caught in the rain with used tread on the cups might kill you.

[SenorFunkyPants]

Originally Posted by lucid

But getting caught in the rain with used tread on the cups might kill you.

Quite a lot of Euro M3s came new on Cup+ tyres, AIUI as long as you have > legal tread depth they are not too bad in the rain.

[Lemans_Blue_M]

Originally Posted by SenorFunkyPants

Quite a lot of Euro M3s came new on Cup+ tyres, AIUI as long as you have > legal tread depth they are not too bad in the rain.

Keep in mind that the Pilot Sport cups come in two different flavors and even the latest version barely has enough tread to grip in damp or wet conditions.

Cup tires are borderline for the street when they are brand new. With a treadwear rating of only 80, it doesn't take very long to run that soft R-compound tire down to the cords.

Lucid is correct. One mistake with these tires and the consequences could be devastating.

I have used Pilot Sport Cups myself both on the track and the street, and I almost crashed my car several times by spinning out or fish tailing in wet weather conditions. The last time this happened, I nearly hit a concrete retaining wall by getting caught in a rain shower coming home one night on the the interstate.

These tires can break loose completely if you hit a patch of standing water at even modest speeds. They are dangerous to drive on the street for you and other driver immediately around you.

These tires should only be used on the track IMO. They barely meet the requirements nessesary to be considered a street tire anyway.

Please do not downplay this the fact to the other m3post members here. Thank You.

[lucid]

Originally Posted by SenorFunkyPants

Quite a lot of Euro M3s came new on Cup+ tyres, AIUI as long as you have > legal tread depth they are not too bad in the rain.

They will do OK with fresh tread (6/32"), and that's because those are PSC+s (not regular PSCs) and have wider grooves for evacuation. They hydroplane significantly at ~3/32" just simply driving straight at 65mph on the highway in standing water. If you need to really get on the brakes at that point, anything can happen. On a wet track, braking at 130mph with ~4/32" thread on these tires was neither fun nor stable. I won't attempt that again. Also, don't they make you sign some kind of waiver about driving in the rain if you take delivery of the car with cups on it, or am I not remembering correctly?

[Lemans_Blue_M]

Originally Posted by lucid

They will do OK with fresh tread (6/32"), and that's because those are PSC+s (not regular PSCs) and have wider grooves for evacuation. They hydroplane significantly at ~3/32" just simply driving straight at 65mph on the highway in standing water. If you need to really get on the brakes at that point, anything can happen. On the track, braking at 130mph with ~4/32" thread on these tires was neither fun nor stable. I won't attempt that again. Also, don't they make you sign some kind of waiver about driving in the rain if you take delivery of the car with cups on it, or am I not remembering correctly?

+1

The tread depth on the Cups is already pretty shallow when new. Just a small amount of wear can really make them very squirelly on damp pavement.

As for the waiver, I was just thinking the same thing.

I know the E46 M3 CSL guys who took delivery of their cars, had to sign a wavier.

That legal document essentially absolved BMW of any liability, due to the Pilot Sport Cup tires that were installed at the factory.

[URBAN LEGEND]

Originally Posted by SenorFunkyPants

but likely to be quite oversteery

Why would it be oversteery with a grippier tire out back?

[JAJ]

Originally Posted by perry1

HI everyone. I need to replace my rear tyres!. Have been told that if I replace rear cups with PS 2's I will have to change fronts as well. Not too keen to do this as they have a lot of wear left on them. Is the tyre dealer trying it on or what?

It's hard to tell where you are (UK?) but I'm guessing that you are in Europe and your new car was delivered with the 19" wheel option and Pilot Sport Cup+ tires. In North America, the 19" option only comes with PS2's.

The PSC+ tires are designed for street use and the regular PSC's are not.

I wouldn't take the risk of running a mixed set of PSC+ tires on the front and PS2's on the rear. There will be an imbalance and the handling can be quite unpredictable depending on the temperature and whether the road is wet or dry. Keep the same tires at both ends. You might get a decent set of four tires (say, Bridgestone RE-11's) in the right size for less than the cost of two PSC+ rears.

[Lemans_Blue_M]

Originally Posted by JAJ

It's hard to tell where you are (UK?) but I'm guessing that you are in Europe and your new car was delivered with the 19" wheel option and Pilot Sport Cup+ tires. In North America, the 19" option only comes with PS2's.

The PSC+ tires are designed for street use and the regular PSC's are not.

I wouldn't take the risk of running a mixed set of PSC+ tires on the front and PS2's on the rear. There will be an imbalance and the handling can be quite unpredictable depending on the temperature and whether the road is wet or dry. Keep the same tires at both ends. You might get a decent set of four tires (say, Bridgestone RE-11's) in the right size for less than the cost of two PSC+ rears.

+1

Do not mix R-compound/street hybrid tires and street radials on the same car.

[TLud]

Originally Posted by URBAN LEGEND

Why would it be oversteery with a grippier tire out back?

Read the OP again. He'll have Cups up front and PS2s in back.

Having different rubber front and back is generally a bad idea anyway, but the cups in front and PS2s in back is especially bad -- much worse than the other way around IMO.

[KonigsTiger]

Noooooo!!!!

[SenorFunkyPants]

Originally Posted by Lemans_Blue_M

These tires should only be used on the track IMO. They barely meet the requirements nessesary to be considered a street tire anyway.
Please do not downplay this the fact to the other m3post members here. Thank You.

The CUP+ (NOTE THE +) tyre was supplied as OEM fitment to many Euro cars...no waiver needed to be signed AFAIK.
Other euro users that I know who have these tyres as OEM fitment use their car as a daily driver.

[SenorFunkyPants]

Originally Posted by TLud

Read the OP again. He'll have Cups up front and PS2s in back.

Thanks, saved me the trouble.

Originally Posted by TLud

Having different rubber front and back is generally a bad idea anyway, but the cups in front and PS2s in back is especially bad -- much worse than the other way around IMO.

Why would Cup+ on the front and PS2s on the rear be any worse than the other way around?
For me I would always prefer a pointy car to one that understeered.

I have to admit to mixing front to rear tyre makes mostly on the 911 turbos I owned as I tried out different tyre makes (with differing tyre wear rates front to back you ended up changing the rears well before the fronts).
Sometimes mixed tyre makes front to rear worked fine but other mixes would make the car almost undriveable...you can't predict how the car will drive until you try it out.
Having said that, the safe option would always be to have all four tyres the same.

[lucid]

Originally Posted by SenorFunkyPants

Other euro users that I know who have these tyres as OEM fitment use their car as a daily driver.

They can, but that doesn't mean that they are safe in standing water. They simply aren't because they hydroplane with semi-worn tread. As I've said, I've tried these tires myself in several different conditions and they DO hydroplane in standing water on the highway with semi-worn tread--especially if you get on the brakes. I don't understand why folks continue to imply they are fine. Normally, I'd say to each his own, and would stop commenting, but this is a safety issue and I would like potential buyers to be informed, so I will keep on stating this fact. Saying that PSC+ tires are fine in wet conditions--especially standing water--is like saying PS2s are fine in -10C weather. If it is just damp pavement, they might be fine, but anytime there is a significant need to evacuate water from the contact areas, you will be in serious trouble with these tires if they are slightly worn--and it doesn't take very long to take tread off these tires.

[SenorFunkyPants]

I'm not going to argue with you despite the fact that for several months of 2008 Euro M3 production the car came with the cup+ tyres as OEM fitment for markets that are renown for bad weather (the UK frinstance). Not that the cup+ tyres won't aquaplane on standing water, I'm sure they do but then the PS2s do as well.

[lucid]

Originally Posted by SenorFunkyPants

I'm not going to argue with you despite the fact that for several months of 2008 Euro M3 production the car came with the cup+ tyres as OEM fitment for markets that are renown for bad weather (the UK frinstance). Not that the cup+ tyres won't aquaplane on standing water, I'm sure they do but then the PS2s do as well.

All tires will hydroplane under extreme conditions. It's a matter of how much and which ones will hydroplane more/sooner than others. PS2s absolutely have significantly more resistance to hydroplaning because they come with more tread, different and more open tread pattern, and different compound. I can attest to that after driving both PS2s and PSC+ hard on the track under wet conditions with standing water. It took a series of very wide "creeks" crossing the track and getting hard on the brakes at 120mph for the PS2s to hydroplane and I danced around before I could recover. It took a wet track with no standing water for the PSC+ to hydroplane at the same speeds. If there was standing water and I had braked that hard with PSC+, I wouldn't have been able to recover. I am certain of that. The story on the street/highway in standing water is not that much different once your PSC+ are no longer new, and I posted my experience on that as well.

That is why I brought up the PS2s in -10C example. You won't go off the road while you drive out of your driveway, but if you do anything extereme in below freezing weather with PS2s, you'll see that they won't have much traction. Cops won't pull you off the road for driving with PSC+ in standing water or PS2s in -10C weather, but that doesn't mean that those are particularly smart things to do. And when you buy an M3 in Minnesota in the middle of January, it comes with PS2s.

[SenorFunkyPants]

Originally Posted by lucid

That is why I brought up the PS2s in -10C example. You won't go off the road while you drive out of your driveway, but if you do anything extereme in below freezing weather with PS2s, you'll see that they won't have much traction.

What tyres are we supposed to use in the UK in the winter?
I don't know of anyone who has winter tyres for their M3, there probably are some but the vast majority stick with their PS2s and some even on their cup+ tyres. In freezing temps you have less grip and you drive accordingly, same if its raining.

[lucid]

Originally Posted by SenorFunkyPants

What tyres are we supposed to use in the UK in the winter?

If it does get below freezing where you are, especially if it is -10C, I would not use PS2s, and switch to a winter compound for sure. Winter tires have compound that will offer superior traction as compared to summer performance tires in cold temps (I am not talking about ice or snow). That is what people do in areas where winters are rough.

Originally Posted by SenorFunkyPants

In freezing temps you have less grip and you drive accordingly, same if its raining.

When someone runs a red light, cuts in front of you on the highway, a child jumps in front of you on a side street, or there is an accident in front of you on the highway, you can't drive "accordingly." You get on the brakes and/or try to turn to avoid the problem. You'd have to be driving very slowly and give yourself considerable extra space to brake and turn in an emergency without the proper tires. Do you honestly do that? And, on the highway and in traffic in general, others won't give you the extra space you need even if you tried unless you are in the middle of nowhere.

[JAJ]

Originally Posted by SenorFunkyPants

What tyres are we supposed to use in the UK in the winter?
I don't know of anyone who has winter tyres for their M3, there probably are some but the vast majority stick with their PS2s and some even on their cup+ tyres. In freezing temps you have less grip and you drive accordingly, same if its raining.

I did a little online window shopping today for tires in the UK. The prices are absolutely wild! No wonder nobody has winter tires - just having one set is a major investment.

[SenorFunkyPants]

Originally Posted by lucid

If it does get below freezing where you are, especially if it is -10C, I would not use PS2s, and switch to a winter compound for sure. Winter tires have compound that will offer superior traction as compared to summer performance tires in cold temps (I am not talking about ice or snow). That is what people do in areas where winters are rough.

We do get quite a wide range of temps in the UK (if it wasn't for the gulf stream our weather would be like Moscow!) and in the winter sub zero temps are common. You are certainly right about the PS2s not liking cold temps, I picked up my M3 in January and the car would wheelspin in 3rd gear and it wasn't until the weather warmed up did I realise that it wasn't normal. But its very rare for anyone to have a set of winter tyres for their cars in the UK.

Originally Posted by lucid

When someone runs a red light, cuts in front of you on the highway, a child jumps in front of you on a side street, or there is an accident in front of you on the highway, you can't drive "accordingly." You get on the brakes and/or try to turn to avoid the problem. You'd have to be driving very slowly and give yourself considerable extra space to brake and turn in an emergency without the proper tires. Do you honestly do that? And, on the highway and in traffic in general, others won't give you the extra space you need even if you tried unless you are in the middle of nowhere.

When I was a newbie driver I relied on the invunerability of youth and blind luck to keep me safe when I was driving (usually like a complete tosser). Now as a older driver I work on the principle that if its possible that a child might step out or a car might pull out without seeing me then I prepare for that.
If you saw me on the road I'd be that annoying guy driving past parked cars on the road by a school below the speed limit and then wizzing off the moment the road cleared.