Tires

2

20ducks

Elite
Here is the scenario:

Z4 with 18" staggered tire set up
all tires are all the same manufacturer Max Performance Summer Tires
Front tires have 2/32" tread
Rear tires have only 3000 miles on them, ie very little wear

Front tires need to be replaced now.

Are there any con's to replacing the fronts with a set of similar Max Performance Summer Tires BUT from a different manufacturer? If so, what are they?
 
Mine runs different brands front/rear - and that's what the dealer did! I've always thought you can have different manufacturers front/rear, but same axle should always be the same.
 
I'm of the same opinion as Mattt -same on each axle. Can sort of see an argument for having all the same - different handling characteristics/grip with different makes etc - but guess youd have to be pushing on a bit for this to be much of an issue...
 
I'd add the caution flag that the traction characteristics from different manufacturer's rubber compounds could be problematic in a dicey situation.

I have attended some talks by engineers who worked in the tire industry and found it a little surprising (at least to me) that the composition of the rubber compounds used by each of the major manufacturers was somewhat of a black art and based on something more akin to a kitchen experiment than a rigorous science like metallurgy. As often as not new rubber compounds have been the result of someone deciding to see "what happens if we toss a little of this into our basic compound". The primary rubber compound for each of the major manufacturers (Michelin, Goodyear, Firestone, etc.) is basically the same one each has been using for decades and the manufacturing process in use to make the base compounds makes it very difficult for each to change. Most of the differentiation of the product lines for each of them is in the additives, treatments, and treads that come after the basic compound has been made.

The base compounds are quite different between the manufacturers, so I would expect that you will definitely end up with traction differences front to rear if you mix the tires on your car. I can't think of a way this would be a Good Thing(TM) in an emergency car handling situation.
 
That being said Alan, wouldn't each batch lot even by the same manufacturer be different, therefore, handling characteristics different?

Sidebar: staggered set ups add to "differences", no?
 
From personal experience on my Z4 I would say mixing tyres does have an effect on how the car drives. Mine was all over the shop. Not too bad if I kept the speed down, i.e. 50/60mph but anything over it was as if the back end was all loose.

J.
 
AlanL said:
I would expect that you will definitely end up with traction differences front to rear if you mix the tires on your car. I can't think of a way this would be a Good Thing(TM) in an emergency car handling situation.
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People can run different tyre pressures front & rear (or even side to side if really fine tuning on a track for instance), all to give different handling characteristics. As long as you know what you're doing, different traction characteristics front/rear can, in theory, help you.
 
20ducks said:
That being said Alan, wouldn't each batch lot even by the same manufacturer be different, therefore, handling characteristics different?

Sidebar: staggered set ups add to "differences", no?
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While there are most likely some degree of differences between batches I don't those would be quite as much of a variance as what you would get between the various manufacturer's base rubber compounds. Tire manufacturers have written articles suggesting that it is not a good practice to replace the rubber on only one axle because of the potential for unequal front/rear traction as you get into driving conditions approaching hydroplaning. Their take is that the older (less tread) tires will hydroplane before the new ones which could lead to a spin.

But then again - they are in the business of selling you new tires and they make less when you don't buy all four at once. :smart:

Sidebar comment - if the car weight distribution/suspension is designed for it staggered setups with match tread compounds add a degree of tunability to the car's handling. Adding a staggered set of wheel sizes to a car whose weight/suspension doesn't call for it can lead to some less than useful outcomes. Audis are a great example here - Audi's are by definition nose heavy cars that have suspensions tuned to act like they are better balanced than they really are. They can still understeer like pigs under the wrong conditions (like an off camber turn) and Audi is very adamant about having 4 tires of identical size. This is for both steering and the drivetrain. That doesn't stop the younger folks from still wanting the "look" of the wide rear wheels so they go out and buy staggered setups with the same outside tread diameter to keep the drivetrain happy. I'll bet you can guess how badly that would suck in a turn on a car that wants to understeer anyway :)

That's an admittedly extreme example but unless you do a lot of suspension/steering tuning to make up for it adding a staggered wheel setup to a car that wasn't originally designed for it can often have unintended consequences.
 
AlanL said:
20ducks said:
That being said Alan, wouldn't each batch lot even by the same manufacturer be different, therefore, handling characteristics different?

Sidebar: staggered set ups add to "differences", no?
Click to expand...

While there are most likely some degree of differences between batches I don't those would be quite as much of a variance as what you would get between the various manufacturer's base rubber compounds.
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There was quite a large 'scandal' (if you can call it that) over here recently whereby online tyre suppliers (e.g. www.mytyres.co.uk) were allegedly selling grey imported tyres that didn't carry the 'E' marking and weren't approved for use in the UK - the excuse given was that they wouldn't perform as well in our colder climate. So, if true, there can be quite a significant difference between two tyres that are named, appear and are marketed the same.
 
The latest notion over on our side of the pond is that we need to be having the mfg. date on the tire so we can make sure we are getting equally fresh ones too. I can see it now - "Best if used by xx-xx-xxxx" :roll:
 
woo i finally have some input!!!

Firstly, if they are VERY similar, then it should be ok. in my situation, i ran Dunlop SP3000 in the front and Kumho Ecsta Sport Ku31 in the rear. The fronts are alright in the wet and the rears are top of the range kumhos and does not grip if its cold or has moisture. My experience is that when i start some spirited driving, the rear is twitchy but as i get into it, the kumhos (rear) take over and cause me to understeer a lot making the experience worse
 
Umm - that doesn't exactly sound like a traction scenario I would go out of my way to induce but your testimony certainly does reinforce the idea that mixing different tire manufacturer's products front to rear can lead to somewhat unpredictable outcomes depending on the traction conditions at hand when you are in desperate need of grip.

:popcorn:
 
20ducks said:
AlanL, sidebar...will your chapter allow z4 roadsters in your DE's this year?
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BMW ACA in the Portland area yes. BMW CCA based out of Seattle no. Our regional CCA chapter closed the door for rag tops last track season.
 
Bummer, here too. Looks like numb nutz Wade doesn't feel like individual chapters are smart enough to know what safety is. I'm unimpressed to far with this higher-than-thou iron fisted leadership.
 
PhilDZ4 said:
20ducks said:
PhilDZ4 said:
Are these the tires you're on the track with? Or, just daily driving?
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Daily driving.
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No problem then...
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Not really. Track conditions are actually far more predictable in terms of traction challenges because you have a very good idea of how and when you are pushing the limits of your car.

Daily driving on public roadways is where you really don't know what is going to get tossed your way next in terms of emergency handling situations and you have far less control over the hazards you need to avoid in order to recover without some form of accident.
 
Simple question of Why would mix tires?

AlanL has some very good points and tires are the only thing keeping you on the road, so I bet there are better places to save money. And just to have the peace of mind that if a situation occures, you have the best ability to keep the car under control... No-brainer to me.
 
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