I can't find that size in the tire I want. Just wondering if the offset is critical? Any problem with going with the rear size all around in terms of dynamics?

 

Why?

 

you have to assume the Porsche engineers have a purpose in mind.

 

Agree with Hammer911 above. Adding wider tires up front will change the dynamics of the car, which Porsche designed as a total package.

 

Wider in the rear to get a larger contact patch for better rear wheel traction?

As mentioned above, they engineered and designed the total package for reasons (more than one I am sure.)

Mess with it at your peril

 

the same size all the way around would be great for tire rotation and winter tires..... but alas porsche decided on different sizes...

 

Unless you know WHY Porsche made their decision on the tires sizes, I'm not sure you can say anything about whether or not you should change the sizes.

Perhaps some moran(sic) accountant at VW realized that the ever so slightly smaller tires in the front save $10/vehicle and $10*50,000 is a big number.

If it was strictly a fincancial decision, it doesn't really have any bearing on engineering decisions.

Having a slighly different tire size is not going to break your car or your suspension, it just MIGHT not be as optimal as possible.

 

Many sports or sporty cars have staggered setup for better handling while still providing a wide track and better traction at the rear. Let me see if I can think of one ... hmm ... got it, it is called 911 .

 

If you think that the VW accountants made the decision on the staggered wheel setup for the Macan you should not drive a Porsche then.

 

+1

 

i have read somewhere as to why the tire are sized the way they are.
It is a performance and handling purpose.

 

Ahhhh! You're putting me on the spot. This is like sacrilege. Off road. Way too detail oriented over here. Can't get away with non descript.

 

The Macan is awd with mostly rwd biased so rear traction is of particular importance - hence a staggered set-up like most rwd sports car like boxster, Cayman, 911 etc...

If you decide to use a square set-up for winter, rotation, availability or for whatever reasons, the dynamics of handling would be different - in effect would induce more over-steer if it was neutral in the beginning. In spirited driving, I imagine PTM would kick in earlier to give more traction to the front wheels. Your Macan will then behave like its Q5 cousin, I suppose.

 

Not just the 911 -- many of the properly balanced sports cars have bigger tires at the rear. That's where the power gets to the tarmac.

The reason that most vehicles have the same size tires front and rear is because they are very nose-heavy, requiring relatively bigger tires there. But both the stylists and the bean-counters prefer to have equal size tires in front and back for those cars. In many front-wheel-drive cars, you could even replace the full-size rear tires with skinnier lightweight tires and have little reduction in vehicle performance (because the rear tires don't have to manage any propulsion or significant steering forces).

Long story short: trust Porsche, McLaren, Ferrari, Corvette, et al to get it right. Lesser cars make more compromises.

 

Fine I hear you all. Now someone find me an off road tire that fits. Thank you very much.