[acronymous]

I'm considering buying a second set of off-road tyres and wheels for occasional use in my home area when mud and poor road conditions can happen.

If I use off-road tyres with a 50mm increase in diameter it will give me another 25mm of extra clearance on top of that provided by PASM, on top of the grip advantages of off road tyres.

Increased diameter will also change the gearing somewhat, though I don't know how this might work with the Porsche transmission given shift points are related to load as well as speed [or semi-manual of course]

What do you think? [I'm essentially talking about low speed work here]

 

[SomeGuy]

Would you swap them on only for the times you're going to use them off road? Or is this an all around tire?

If anything, size down to the smallest wheel you can fit to get more sidewall, along with a more aggressive tire should make a pretty good difference off road. Unless it's really rough, I doubt an extra 25mm ground clearance will make much difference.

 

[[email protected]>@W]

25mm = 0.984 inch

FWIW...

 

[Beardy]

Do you really need the extra clearance? Apart from mucking up the gearing do you think you will get the necessary guard clearance to run the bigger tyres?

 

[acronymous]

Thanks for the feedback

Would you swap them on only for the times you're going to use them off road?

Yes, only for times when wet weather creates extreme conditions.

Do you really need the extra clearance?

Max clearance would be up from 230 mm [~9"] to 255 [~10"]. It's not much I agree but from driving cars with marginal clearance over bad tracks I can say that extra clearance adds to peace of mind and makes picking the best path easier.

Apart from mucking up the gearing do you think you will get the necessary guard clearance to run the bigger tyres?

The gearing remains an open question to me ... With 7 to choose from and the normal tendency of the Macan being to lope along at less than 1500 rpm, I'd guess it wouldn't make a noticeable difference but I could be wrong. The clearance looks generous though I'd have to talk to a tyre fitter first.

Looks like I might have to try this to see

 

[FAST]

I had this exact conversation with my Porsche Service Advisor (PSA) when I was looking at snows. He stated that changing the total height by more than 1 inch would have a meaningful negative impact on the performance of the anti-lock brakes and vehicle stability calibration, potentially even leading to damage which would not be covered by the warranty. He stated anything above .5 inch or weights 5-10+ pounds above stock weight would noticeably impact handling. <-- I've not tried to verify this with a Porsche expert, but by Audi manual for the SQ5 does state this.

Bit off topic: My friend went 295/35 all around on his Turbo in order to improve handling and his 0-60 times were poorer by .2 second and he gets about 40-50 less miles per tankful (about 7% less).

 

[muncie]

Never can understand why someone thinks they can outsmart a car manufacturer--Porsche no less--and re-engineer tire sizes for "better handling."

 

[FAST]

Never can understand why someone thinks they can outsmart a car manufacturer--Porsche no less--and re-engineer tire sizes for "better handling."

Not really outsmart, but tuned for that individuals unique requirements. Porsche is forced to make compromises when they set-up the suspension and select tires. Almost all manufactures design their cars to understeer as you approach the limits because it's considered easier and safer for most drivers as the car is less likely to spin or flip if the driver loses control (thank the Corvair).

The Macan also understeers, if you install larger or grippier tires on the front, the Macan will move to more neutral performance, but give up a little acceleration and mileage. Unfortunately all the ABS and vehicle stability technology limits what you can do as noted in post 6.

Porsche has to offer a balance between performance, price, tire life, noise, comfort, load rating, etc. based on their target demographics and the fact whatever tire they select must work anywhere in North America (thus the all season Vedres or Latitude). None of the tires offered on the current Macan are considered maximum performance tires. Throw on a pair of Michelin Sport Pilots and the handling, rain and grip improvement is significant, but they wear faster and you can't use them if the temperatures are much below 40F. Quite a few threads here talking about high performance tires.

Many people on this forum have gone with stiffer and lower springs and/or shocks and noted the improvement. I believe the Macan would also benefit from a stiffer sway bar (hard to find) and stiffer bushings.

 

[muncie]

Much of what you say is true and I know people love to modify their rides. I think if Porsche wanted to compromise as you say, they would have installed a square setup because it would be a lot cheaper. Most all-wheel drive vehicles have way more grip than power and I don't think the Macan in any form up to 500 hp is going to have major issues with oversteer. There was one guy on the forum that flipped his Macan, but I don't think it was from his staggered tire setup.
Confused on what you said about only having all seasons available. I mean the Pirelli P zero is offered stock from factory and I think a Michelin maybe Conti summer high performance rubber too. They aren't race slicks or 60 treadwear tires, but they are pretty high performance.
Only track times would tell if your buddy's square setup was better than stock.

 

[FAST]

Only track times would tell if your buddy's square setup was better than stock.

He did shocks/springs first, took the PCA training courses and then did the tires. It was the PCA instructor that suggested the square set-up and the Sport Pilots. His times improved ~2 seconds IIRC. It's tough to attribute all to the tires, he's pretty serious about improving his driving skills.

Much of what you say is true and I know people love to modify their rides. I think if Porsche wanted to compromise as you say, they would have installed a square setup because it would be a lot cheaper.

Cheaper only if they reduced the backs. Part of the decision may have been the competition and cosmetics (I admit I'm guessing). Most high performance SUVS have a staggered setup with massive tires in the back. I like the look of the staggered set-up, I went to 315s in the back and 275 in the front.

Most all-wheel drive vehicles have way more grip than power and I don't think the Macan in any form up to 500 hp is going to have major issues with oversteer. There was one guy on the forum that flipped his Macan, but I don't think it was from his staggered tire setup.

My comments were more about people braking when they lose control. Most drivers don't have proper training to drive cars approaching the limit, thus the manufacturers design for the safer understeer.

Confused on what you said about only having all seasons available. I mean the Pirelli P zero is offered stock from factory and I think a Michelin maybe Conti summer high performance rubber too. They aren't race slicks or 60 treadwear tires, but they are pretty high performance.

I stand corrected. In my area (Toronto has 5 dealers) dealer ordered cars tend to come with all seasons, however if you factory order you can get summer tires.

 

[Beardy]

Thanks for the feedback



Yes, only for times when wet weather creates extreme conditions.



Max clearance would be up from 230 mm [~9"] to 255 [~10"]. It's not much I agree but from driving cars with marginal clearance over bad tracks I can say that extra clearance adds to peace of mind and makes picking the best path easier.



The gearing remains an open question to me ... With 7 to choose from and the normal tendency of the Macan being to lope along at less than 1500 rpm, I'd guess it wouldn't make a noticeable difference but I could be wrong. The clearance looks generous though I'd have to talk to a tyre fitter first.

Looks like I might have to try this to see

Are you looking to go off-roading or just drive unsealed roads that are muddy and slippery in wet conditions? 9 inches of clearance is decent and will get you most places . Have a look at the tracks Subaru’s and X Trails etc take on
I do a lot of off-roading with a modified Landcruiser so understand the difference

For me I would be reluctant to compromise the fine attributes of a Macan with too many changes like that

 

[acronymous]

Are you looking to go off-roading or just drive unsealed roads that are muddy and slippery in wet conditions? 9 inches of clearance is decent and will get you most places . Have a look at the tracks Subaru’s and X Trails etc take on
I do a lot of off-roading with a modified Landcruiser so understand the difference

For me I would be reluctant to compromise the fine attributes of a Macan with too many changes like that

Not interested in off-roading with the Macan. I regularly commute via tracks that are somewhere on the margin between 4X4 territory and just manageable by something like a Subaru. They're the sort of places where a normal clearance car would occasionally ground on something if not for careful navigation.

I agree about not compromising the handling/road holding. I'm thinking that for road use, with the car raised 25 mm by slightly larger tyres but using the lowered AS setting of -10mm, the difference would effectively be that the car would be 15 mm higher than the normal road setting, which is unlikely to make an earth-shaking difference. Certainly, when you look at the extra clearance/instability on most specialized off road 4X4s that have a foot or more of clearance and teeter round on the road looking quite unstable, my proposal is modest.

For me, it's a question of whether the amount of time and distance I spend on poor roads as against the time/distance I spend on highways, swings the balance for some part of the year.

or weights 5-10+ pounds above stock weight

That could be significant though. Must check potential tyre weight differences.

 

[Fast_Eddie]

What sizes and rims are you looking at getting?
I think that the biggest issue will be getting off road tyres that comply with the vehicle's tyre placard.
Just remember that in Australia you legally need to have tyres that are at least of the speed rating and load capacity of that on the placard. If not the car is unroadworthy and if you have an accident your insurance company do not need to pay out.
Most coppers are well clued up on the tyre regs these days, so it is a risk and issue that you will need to consider in your tyre choices.
Off road tyres will weigh more, but that is not a big issue - far outweighed by the change in type and size of tyres themselves.

 

[Beardy]

There is likely to be a suitable tyre that the likes of Range Rover use?

 

[acronymous]

Porsche appears not to comply with Australian Law in failing to fix an ADR placard on the vehicle that is in compliance with its obligations under ADR42/4. (I say “appears” because it may have some sort of exemption, but I cannot imagine how, as I am not aware of any OEM that has one). It does not comply with the law because it does not specify on its vehicle placard a speed and load rating for its tyre fitments, as is required.

Just remember that in Australia you legally need to have tyres that are at least of the speed rating and load capacity of that on the placard.

Thanks for your help F E, you clearly know your stuff. The above quotes are from another thread you contributed to which seems to indicate the tyre placard might not be up to par on Macans.

I'll have to look at specific sizes but I'm thinking something like Bridgestone All terrain, 16" or 17" with something between 235 and 255, same front and back.

 

[Fast_Eddie]

Many years as a tyre engineer and test driver.
Range Rover is good thinking, but the only tyre I could find that meets the legal requirements is 21" but it is an all-season highway tyre size 275/45R21. Note that "all-season" is not off road. It is a legal fitment for you and will give you 40-50mm more OD ( depending on manufacturer).
Bridgestone (and all others that I have looked at) do not make a tyre that is legal to do what you want. You may also have an issue with getting a smaller OD rim to fit over your calipers?
The problem you have is that any tyre designed for off road use will have a deeper tread, off road compounds and more robust construction. All these conspire against the ability of the tyres to meet the speed rating that you need to comply with the law in Australia.
I have had a reasonable look around, but have not had time to look at everything. So if you have a search and make sure that you choose tyres with a minimum 103 load rating and Y speed rating I am happy to check them out for you.
It is a stupid situation to have a country with such low speed limits but in this case require tyres to be fitted that can deal with double those limits - but that is the way it is.

 

[acronymous]

Thanks for all the research FE

The 275/45/R21 is an interesting idea but surely it's all season on the highway with only a sniff of off road about it? The low profile might look cool and handle well for highway work but it's not something I'd consider for off-road. I presume its load rating is pretty good though.

Bit off topic: My friend went 295/35 all around on his Turbo in order to improve handling and his 0-60 times were poorer by .2 second and he gets about 40-50 less miles per tankful (about 7% less).

In relation to the "slightly off topic" comment ... I've seen some track test results that indicate that super low profile tyres, like the 35s you mention, aren't necessarily going to give better lap times when compared to otherwise similar but higher profile tyres. I've never seen any comments as to why this might be so but to me the unavoidable stiffness of the walls in super low profile tyres limits flex and ability for the tyre to conform to any lateral changes in the road surface from perfect alignment with the tyre tread. Improved handling yes, road holding ... ? What do you reckon FE?

As to all your other on topic comments. Tricky isn't it? Strictly speaking there seem to be no legal off road tyres for a car that has reasonable if not top of the line, off road capability. I'm still considering my options

 

[Fast_Eddie]

All season does not mean any additional off road capability. In fact it is almost always not a good option in Australia except in the very few alpine regions that we have. We are the second driest continent on earth (next to Antarctica).

Track tests:
Depends on the circuit.
Lower profile does not necessarily give better lateral grip, but often it signifies what an engineer is trying to achieve - as such it often does mean exactly that. (With a performance road car it can simply be aesthetics and packaging).
However if you are on a circuit that for example has a lot of slow corners, then the ability to accelerate out of the corners faster can give a massive advantage - additional speed that you can carry for the length of a straight. It can be more than helpful to give up some lateral grip for the greater straight line grip. Have a look at a dragster tyre - nothing low profile about those! I used to make these changes between circuits on race cars for exactly that reason.
Also needs to be remembered that tyres form part of a whole suspension system (which even also include chassis rigidity). So what you are trying to achieve needs to be considered as exactly that. What works for one setup may be horrific on another.

 

[Beardy]

Strictly speaking there seem to be no legal off road tyres for a car that has reasonable if not top of the line, off road capability. I'm still considering my options

To my eyes of all the strong points of a Macan I would not put off-road ability as one if them. No articulation or lockers, There are much more capable vehicles to be had

 

[acronymous]

To my eyes of all the strong points of a Macan I would not put off-road ability as one if them. No articulation or lockers, There are much more capable vehicles to be had

No argument with that ...