Mixing Tyres (and why you really shouldn't!)

[andlid]

Thanks Dan, I thought it will be the R888 and you have confirmed it. I have only used MPS cups with 3.5mm left on the zed and was disapointed. Was crap to start with, then once the old sheen had come off and was up to temp it gripped for about a lap and then just gave up suddenly But it will be unfair to rate it since i did not try them from new

 

If for any reason you need tyres when you are there i will pm you a contact to help out. He actually runs the Nissan in Adenau and can get you the ultra performance MPS, Continentals road/track at trade price He quoted full 245/35/19 and 275/35/19 for Eu800- including fitting. Can also rent lightweight wheels FOC if you by his tyres and has a facility where you can store your wheels/tyres ad lib and use them on subsequent visits.

 

Cheap service and geo too. He ran a GT4 spec 350z on the ring for a while so has good advice on settings but porche is his first love like all germans.

Sounds like your tyres got to hot... 'melting' dont think thread matters really but you've got them cooking from the sounds of things, driving a bit to hard for them

[GT4 Zed]

Sounds like your tyres got to hot... 'melting' dont think thread matters really but you've got them cooking from the sounds of things, driving a bit to hard for them

 

You maybe right though as overheating can have this effect

 

But may have been pushing on especially in the corners towards the mid-end of the first lap but nothing extraordinary as compared with MPS2 on. As they inspired confidence I braked later and put on power earlier as i could feel the rear hook up each time but I never powerslid or did any lairy stuff

I came into the carpark for a quick tyre check and it looked perfect with nice heat tranformation of the surface compound. I checked my pressures which were fine then went for the next lap and by Hocheichen corner which is one of my favs it was squealing like a pig and broke grip at the rear into progressive slide but a few miles later it just understeer into a 4 wheels in drift then the rear would follow and i had hold with opposite lock but my confidence had gone. I took it easier from then on but it seemed to grip and be planted on corner entry but as you got tighter midcorner it just squealed/understeered and so i was having to put power down later and later and just damn slow in the end.

As i said the tyre may have been old or had seen a hard life before and little left of its performance window

 

Some of the Porsche guys said that this was not uncommon behaviour to experience sudden drop in performance with this tyre and it was irrespective of whether you were running low thread or not. When the grip goes it just went and thats the end. They also said it was optimal at around 4mm so some guys shaved them to get almost the best performance straight away in

[andlid]

what colour did the wheels have? Like blueish? any photos?

 

 

above is a tyre that has done to many heat cycles. Reason why bikers use tyre warmers after each session on the track is ALSO that it keeps the tyre in the same heatcycle...

[GT4 Zed]

what colour did the wheels have? Like blueish? any photos?

 

My wheels are gloss black

nope!

No photos of the tyres and wheel on this occasion.

 

You always see some guys especially the Porsche crowd(p---ks) @ the Ring with their temperature probes and other gizmos and are forever altering stuff and i feel they are posing too much or showing off They drive and act like they own the place and it give me great pleasure when i manage outbrake one or stay in touch with them in the technical sections or genuinely overtake

 

But i guess it makes sense to keep the tyres optimal.

[andlid]

I didnt care much for tyrewarmes until I lowsided due to cold tyres...

[Husky]

annnnyway. dont mismatch tyres kids

[Roo]

I changed all 4 for re50's even though the front has at least 4-5mm on them. Not worth the risk of saying "well I saved 200 quid" as the ambulance crew cut me out...

[Ebized]

Thanks for the work you put into the post Dan and given the subject of mixing tyres is a regular issue hopefully that will help newbies who may be wondering about tyre choice.

 

A vital aspect of maintaining a ZED and getting the best from it that you simply do not skimp on, IMHO.

[docwra]

Great post, and Im not arguing for a second with the logic, but shouldnt you be driving to the conditions anyway? You dont drive flat out in the wet, and I struggle to see how this is different from driving on mismatched tyres (not on the same axle mind you). yoiu drive to your level of grip

 

Road conditions play a much greater part in grip than any tyre combination will. If you run rubbish tyres then you are going to get less grip, thats a given, if you use lower quality brake pads then you are going to stop slower as well ........ the only instance I can think where mismatched tyres might cause an issue is in heavy standing water, where the front may start to aquaplane faster than the rear due to differing water displacement, but then if you are aquaplaning you are already going too fast

 

Maybe Ive missed something here, but my car handles better now than it ever has (on Re050 fronts and Vredestein rears), it was fine with Toyo T1's front and FK452 rears and vice versa, and the worst it ever handled, gripped or gave any feedback was on Nankang NS-2's, the only set of matched tyres its ever had on it.

 

Is it not the case that different tyres work better for different applications too? Tyres that are good on FWD arent always the same on RWD, so does it not stand to reason that certain tyres and patterns will give better grip on the driven wheels and others on the non driven/steering wheels?

 

As I say, Im not arguing, just saying that in my experience there are a number of other areas that I consider to be more improtant than matching your tyres fore and aft

[Husky]

i would say its pot luck if a mismatched set works well, maybe they will work out well or they will be bad.

 

The problem of mismatch is in the unpredictable nature of them

[docwra]

Im speaking from track and road experience in a variety of cars though, both FWD and RWD - the simple fact is that the tyres do not all work in harmony, as you could argue the dampers do for instance. You will have a finite amount of grip at the front, and a finite amount of grip at the rear, and thats what you drive to.

 

I cant accept that the behaviour of the front tyres in some way affects the performance of the rears - they are two seperate entities. Of course if you run an RE050 on the front and a Linglong Ditchfinder on the rear the car is going to be a bit tailhappy, but thats not the mismatch, thats just crap rubber on the back.

 

Id add again that mixing across axles is somewhat suicidal though

[Ekona]

I cant accept that the behaviour of the front tyres in some way affects the performance of the rears - they are two separate entities.

But they're all part of the same car... The setup you've got will be very prone to oversteer, and as such is the worst possible combination out of the three options. For the most part a good tyre is a good tyre, but weight distribution does play a part as well.

 

Of course you should always drive to the conditions, but it's the unpredictable nature and a billion and one variables that also affect your car in ways you can't prepare for. If someone pulls out on you and you have to swerve to avoid them, a driver on matching tyres will be better placed to avoid the danger than you will on mixed tyres. In an emergency situation, or where you catch a bit of oil on one side of the car, you're going to find out just why mismatched tyres are a bad idea. Like I said in the main post, those who think it's fine have just been very lucky so far.

 

 

Great post, and Im not arguing for a second with the logic

If you can't argue with the logic, then you know you're in the wrong on an 050/VUS split.

[magic84]

so heres were i need your help do i.....

 

buy new rears for £288 and so on untill the fronts are dead.

buy 4 new falken 452's for £401.16 and sell the fronts.

How much do you hate the RE040s? If you really hate them then yes I'd change, but if money is a big issue then no harm in getting a fresh set of rears which should hopefully die by the time you need new fronts

 

not enough to throw away to perfectly good tyres . sounds like a good idea just replace the rears and then all 4 next time round

[Demolition49]

Well said

 

That is what i will foward anybody who ever questions me about spending 500 on tyres

[H5]

I think it's more about getting the handling as the manufacturer intended rather than anything else. For example, if a car was known to understeer massively in the wet in 'standard' guise, then you might try some better performing wet weather tyres on the front to 'dial in' you own front end grip. But the point is unless you really know what you're doing it is a dangerous game to play!

 

For example, if you owned a Vectra you would put Conti Eco Contact Sports on the front and run the rears on the wheel rims in the vague hope it might turn a corner.

 

I think the post explains itself.

[Zedman08]

A very well written article as to the whys-and-wherefores of spending a liitle more to keep you on the tarmac and out of the ditch.

On collection of my Zed, I was truly satisfied with their RE050 tyre choice as I've been running my 250bhp turbo-charged Saab beast on Bridgestone S02s and S03s for years now (the former has a fantastic tread pattern but is now only recommended for Porsches!).

The grip is fantastic and the wear is .......I don't really care as "tyres are the last thing touching the road before you go off".

..........and the Zed? Just reminds me of my karting experiences .

[SwissZ]

 

...............i dont believe however that people would go about replacing half worn tyres just to match them up every time you get unbalanced levels of tread ..........

 

The Germans do ... they have done it for years ..... where do you think the part worn tyres sales places get their tyres from ?

 

Oh and 'cellent explanation Ekona

 

 

Where did that idea come from? I lived in Germany for 15 years and never binned a healthy tyre. Used to be 2 sets of fronts to 1 set of rears (an Astra) and the last time I changed the Zs tyres I was travelling in Germany and just changed the rears as the fronts were fine. Same in Switzerland, and they are strict Don't have an accident here in winter without winter tyres on though..... pretty much the same as having no insurance!

 

Good write up, but it should be common sense, especially on a Z.

[Jotun]

The most comfortable handling my car has ever been was with Falkens not too worn on the front and very worn RE40s on the back. Now obviously the rear grip wasn't great but it was very predictable and I knew exactly what I was getting from the tyres and how to drive because of that. I've found that now I've got RE50s on the back they have a lot more grip but give up in a more sudden fashion. I think the way I drive the car for fun more suited the grip I before.

 

I think my point here is that while it may not be ideal to have different rubber front/back and some extremes may be dangerous, if you drive according to what you have under you, you can't go far wrong.

[docwra]

If someone pulls out on you and you have to swerve to avoid them, a driver on matching tyres will be better placed to avoid the danger than you will on mixed tyres.

 

A driver with Re050's on the front and Vredes on the rear will be in a hell of a lot better position than someone running NS-2's all round. Trust me, Ive been there

 

By definition then, if all of your tyres should be "matched", are you guys suggesting that you should buy them in sets of 4?? Using my example above, Id bet that a car on 2 brand new NS-2's at the front is going to stop quicker in the wet than one on 2 heavily worn Re050's .......

 

Id rather run differing compounds than differing wear levels ........

[Ekona]

They won't be in a better position because they do not know how the car is going to react under any given circumstances. You've introduced a new set of variables that you don't need, and that leads to a certain amount of unpredictability.

 

 

Look, without trying to sound too harsh I've given as much info as I can on this subject without going into ridiculous amounts of detail, and there's enough on here to convince you that running mismatched tyres is a Very Bad Idea Indeed. I'm more than happy to continue with a sensible debate about this if people want to ask specific questions, but I refused to be drawn into an argument with people saying that X combination is great or Y combination part-worns will be better: If you honestly believe that, then that's fine, but please don't come to me for any sympathy when you have an accident and blame everything apart from the nut behind the wheel who makes the tyre choices. This isn't aimed specifically at you Docwra, it's more of a general "Let's leave it there before it gets nasty/boring". I want this to be an informative Sticky that people can reference or ask specific questions on rather than a huge 20 page epic involving all the people on mixed tyres.

 

 

That said, if anyone would like to PM me with anything I'll be happy to correspond with you that way, and then we don't have to bore others with circular arguments.

[docwra]

Cool, like I said, Im not here for an argument.

 

One question though - do you replace all four of your tyres at the same time? Is this what you are recommending?

[Ekona]

Not at all, although in an ideal world with limitless funds I'd love to! It's more about common sense than any strict rule really, personally I don't change my tyres until I have to, but I will be aware of the conditions I'm driving in and how I'm driving to take wear into account. I usually replace them when down to about 3mm on the PS2s, and then kill the old ones off on track.

[Scottie]

Let's think about this logically. Let's picture the Top Gear test track at Dunsfold as it's a place just about everyone is familiar with, and let's say it's bone dry. Our test car is a stock 350Z naturally, and in the first instance is fitted with RE040s all round. Get in, drive, enjoy. No issues at all, car feels just like it should. After a few laps it starts raining, so you adjust your driving and speed to match. Car feels noticeably slower, tyres have nowhere near the grip you're used to, but nothing feels drastically out of place. Car goes back into the pits, time for a spot of lunch, and ZOMG! THE SUN'S OUT! YAY FOR A DRY TRACK IN THE AFTERNOON!

 

Now we leave the RE040s on the front but put RE050s on the rear. Jump in the car, off you go, giving it full beans. Will you notice any great issues? No, probably not. Remember, both tyres are good in the dry, so you'd expect the car to be fairly balanced. It handles just like it should, but you do notice a bit more traction from the back when coming out of the Hammerhead.

 

Soon the heavens open and the track is soaking wet. Same car, same setup (40s on the front, 50s on the rear), same driver. Once again, you go for a fast lap. First time round is slow as you get used to the wet surface again, then you start picking up the pace as you get used to the conditions again. You come round Chicago and brake hard for the Hammerhead, and start to turn in. The front washes ridiculously wide and you're in the gravel. Why? The RE040s have much less wet grip than the RE050s, and so you get chronic understeer despite the rear feeling very planted.

 

Now we change the tyres around, so that the 40s are on the back and the 50s on the front. Same wet conditions, same driver. Out of Chicago, onto the power, brake hard for Hammerhead, car turns in fantastically well to the left, same to the right, but the second you get onto the power coming out the arse end overtakes you and you're suddenly facing the wrong way. As you've put the grippier tyres on the front the car now wants to oversteer everywhere, and as you carry on round the track and all tyres get hotter the differences become more pronounced.

 

I can't make sense of this.

 

What you're are saying is :

 

Scenario 1 : Car has 4 RE040's and is lapping in the wet.

 

Scenario 2 : Car has front RE040's and rear RE050's lapping in the dry.

 

Scenario 3 : Car has front RE040's and rear RE050's lapping in the wet, as scenario 1.

 

Scenario 4 : Car has front RE050's and rear RE040's lapping in the wet.

 

You seem to suggest that it's better to have a car with the four worst tyres, and somehow uprating the rear tyres will cause the car to crash in scenario 3. How is this? The front tyres are the same and conditions being the same will offer the same leve of lateral grip and braking grip.

 

Just changing the rear tyres won't cause the car to understeer, it will be the driver deciding to take the corner at a higher speed.

 

Again upgrading the front to 050's whilst leaving the back the same 040's will also offer a better scenario from all beign 040's, because the front will have more lateral grip, and better braking in the wet as well, whereas you have no less traction or grip from the rear so should have no less grip unless you choose to accelerate harder than before.

 

I have had a succession of different cars with a mix of 040's and 050's on the front and rear. Two weeks I came back from the Ring which has some very wet days, and upgraded the rear from 040's to 050's with the front still on 040's and all I got was extra traction. I didn't suddenly maek the car understeer or have less grip at the front because I still had the same lateral grip as before.

 

My track car is sending 400bhp to the rear wheels, and upgrading the fronts to 050's before I have just upgraded the backs didn't make it any more unstable in dry or wet. In fact it gave me extra grip on the front in the wet, and the back still had the same as you would expect on the same tyres.

 

Through both theory and many years experience I thoroughly agree with Docwra on this, it's more important to have matched tyres on the same axle and good pairs than it is jsut to match all four.

 

Very interesting topic though :-)

[Zedman08]

I'm very tempted to...but I won't ........ you all drive a Zed, so I won't.

As I commented earlier, this is a very good article by Dan and he's only giving free advice to keep you on the road....and full marks to Dan Thank you.

Don't mix your tyres and try to keep all four the same.

Bridgestone are the best and yes, I do know about Yokees, Falcon, Hancook et al on the road and track ( I was a member of Service Crew for a rally team and have karting experience, together with doing +100mph @ Silverstone whilst Pace Car setting 50mph 20 yrs ago) Blah-blah!!

Don't mix your tyres and try to keep all four the same.

Enjoy the ride

I LOVE the drive in mine.

[Husky]

This thread is now going to be so confusing for a newbie looking for a simple answer to a common question. Can we just move the discussion elsewhere and sticky the original post on its own locked? Maybe with a link to the discussion?

 

Just i see this going on for 10's of pages