[blake6551]

So in the continual search for 21" All seasons, has anyone considered going to 285/40-21 on the front?

There are a few all season options in this size combo using the stock rear staggered size. The current model Porsche Cayenne also uses this same combo, 285/40-21 and 315/35-21.

The overall difference in circumference is less than 1", overall tire height increases 0.3" and speedo error comparing front to rear is about 0.5mph.

Any thoughts?

[parkstr8]

I'm having a dilemma as well on AS tires...

[Auricom]

Originally Posted by blake6551

So in the continual search for 21" All seasons, has anyone considered going to 285/40-21 on the front?

There are a few all season options in this size combo using the stock rear staggered size. The current model Porsche Cayenne also uses this same combo, 285/40-21 and 315/35-21.

The overall difference in circumference is less than 1", overall tire height increases 0.3" and speedo error comparing front to rear is about 0.5mph.

Any thoughts?

Rears will be -1% difference in diameter compared to the front which should be fine for xDrive - guidance is that you want to be within 1%.

It's unfortunate that 21" tire options are horrible.

[blake6551]

Originally Posted by Auricom

Rears will be -1% difference in diameter compared to the front which should be fine for xDrive - guidance is that you want to be within 1%.

It's unfortunate that 21" tire options are horrible.

Thanks! Continuing to look at the Porsche Cayenne specs, they have a lot more variation in their wheelsets. Their stock 20" staggered setup matches the Euro spec X5, with about a 0.3% diff in diameter, the 21" setup with 285 front is 1% difference front to back and their 22" setup is 1.7% difference front to back!

I think I'll try the 285 up front, I can't imagine it'll affect the X-Drive or any other components and I doubt Porsche is changing anything in the driveline per car based on fitting 20-22".

[parkstr8]

I'm headed this morning to put on Pirelli AS Verdes - in spite of the mixed reviews. Since I'm in Seattle now, I will need AS tires...

I don't drive too much (its 1 year old last month with only 4200 miles on the clock), so those who said they wear quickly - doesn't apply to me. And if I don't buy my car off lease, I'll put my stock RF's back on and call it a day.

I contemplated a whole wheel swap with a 22 set..but 5k for wheels and 2k for tires just didnt make sense, and i didnt want a full set sitting around for 2 years.

I'll report back. Good thing is if i don't like them- Discount Tire has a guarantee for that. I can always just put Michelin Pilot sport summers on and only drive my new Q7 - which has all seasons - during the worst weather here.

[blake6551]

Originally Posted by parkstr8

I'm headed this morning to put on Pirelli AS Verdes - in spite of the mixed reviews. Since I'm in Seattle now, I will need AS tires...

I don't drive too much (its 1 year old last month with only 4200 miles on the clock), so those who said they wear quickly - doesn't apply to me. And if I don't buy my car off lease, I'll put my stock RF's back on and call it a day.

I contemplated a whole wheel swap with a 22 set..but 5k for wheels and 2k for tires just didnt make sense, and i didnt want a full set sitting around for 2 years.

I'll report back. Good thing is if i don't like them- Discount Tire has a guarantee for that. I can always just put Michelin Pilot sport summers on and only drive my new Q7 - which has all seasons - during the worst weather here.

What size Pirellis are you putting on?

[parkstr8]

Running the stock sizes. Keeping the spacers - 12mm front 15mm rear.

Funny thing...and it could just be me...but they seem different from stock when on. I verified the exact measurements of stock RFT tires compared to the new ones...and only one dimension was like .1 mm different.

And the driver-side rear seems more inset, while the front seems more poked.

I checked the spacers to make sure they didn't remove them and then get confused on put the front on the rear, or vice versa...but they are correct. Thank goodness H&R puts the part number on the outside edge of the spacer so its easily legible.

Ride is def much improved in all aspects so far. Especially on the Seattle roads...its all cement here...

I'll do updates as i drive on them more.

Originally Posted by blake6551

What size Pirellis are you putting on?

[blake6551]

Originally Posted by parkstr8

Running the stock sizes. Keeping the spacers - 12mm front 15mm rear.

Funny thing...and it could just be me...but they seem different from stock when on. I verified the exact measurements of stock RFT tires compared to the new ones...and only one dimension was like .1 mm different.

And the driver-side rear seems more inset, while the front seems more poked.

I checked the spacers to make sure they didn't remove them and then get confused on put the front on the rear, or vice versa...but they are correct. Thank goodness H&R puts the part number on the outside edge of the spacer so its easily legible.

Ride is def much improved in all aspects so far. Especially on the Seattle roads...its all cement here...

I'll do updates as i drive on them more.

So is that the mixed Pirelli set with the Volvo front and Porsche rear?

[parkstr8]

Its not a mixed set...same tire different sizes - both stock sizes.

Originally Posted by blake6551

So is that the mixed Pirelli set with the Volvo front and Porsche rear?

[blake6551]

Originally Posted by parkstr8

Its not a mixed set...same tire different sizes - both stock sizes.

Huh, I haven't seen those available anywhere. How did you find them?

[GrussGott]

Originally Posted by parkstr8

Its not a mixed set...same tire different sizes - both stock sizes.

Isn't the problem with those that they have different speed ratings for front & rear? That's why Tire Rack won't sell the Vreds: the sizes / load ratings are right, but the speed ratings are different which means you have different handling characteristics front and rear (i.e., grip in cornering becomes mismatched in the front vs the rear) ...

without an exact match of rubber compound, speed rating and tread design you can be risking unpredictable handling and braking performance, especially in wet conditions

honestly I think if we have the 21s we're screwed (assuming you want matched speed ratings) - there are no tires sizes that work as even if you get the size/load, you the speed ratings are different.

[parkstr8]

I will try to be as complete as possible...as there is not a perfect solution to our 21 AS tire dilemma.

I do in fact have two "different" tires...in that one has one spec that varies slightly.

Front: 275/40r/21 XL (VOL) 107V - Volvo (VOL)
Rear: 315/35R/21 XL (NO) 111V - Porsche (NO)

The tires share the same construction, tread pattern, speed rating, temp rating, traction rating, etc. Both have XL ratings.

I did not check the age of the tires.

The only variances other than size are:

- Treadwear - 500 vs 600
- Load Rating - 107V vs 111V. I believe this is due to the size difference between the two.

It is not an issue as I will never load my car other than my Dobermans, and I will never drive above 100 (even tho speed rating is the same at XL) - if that.

I spoke to my dealer service manager and he acknowledged the 21 issue, and said this combo is fine. I will put my summers back on during the summer.

Is it 100% perfect? No. Will it do for me for now...yes.

[GrussGott]

Originally Posted by parkstr8

Front: 275/40r/21 XL (VOL) 107V - Volvo (VOL)
Rear: 315/35R/21 XL (NO) 111V - Porsche (NO)


I will never drive above 100 (even tho speed rating is the same at XL) - if that.

I spoke to my dealer service manager and he acknowledged the 21 issue, and said this combo is fine.

good find! that's prolly ok, though I ain't no tire expert, but here's the thing ...

The speed rating is kind of a misnomer AFAIK: it's not so much for the max speed (100 mph or whatever), it's more for the handling characteristics of the tires in corners. The reason you don't want to mix speed ratings is you don't want, say, rear wheels with less cornering ability than fronts or vice-versa. In those scenarios under a hard corner or emergency maneuver it can cause instability, though granted it's edge-case stuff. I've never tested mixing on dry conditions.

In your case, though, they're both "V" rated so, yeah.

[nZtiZia]

Originally Posted by parkstr8

Front: 275/40r/21 XL (VOL) 107V - Volvo (VOL)
Rear: 315/35R/21 XL (NO) 111V - Porsche (NO)

The tires share the same construction, tread pattern, speed rating, temp rating, traction rating, etc. Both have XL ratings.

I did not check the age of the tires.

The only variances other than size are:

- Treadwear - 500 vs 600
- Load Rating - 107V vs 111V. I believe this is due to the size difference between the two.

It is not an issue as I will never load my car other than my Dobermans, and I will never drive above 100 (even tho speed rating is the same at XL) - if that.

tire specs are very busy, eh? but in the interest of accuracy so you can properly compare specs, thought i'd clarify a few details.

• 107 and 111 describe the load index or rating (2149 vs 2403 pounds per tire)
• the 'V' describes the speed rating (149 mph) and like GrussGott alluded to with different speed ratings, the limit of the lowest rated tire is the fastest you can drive and stay safely within your tire's handling capability
• XL describes the load range and stands for Extra Load

hope it helps!

[parkstr8]

Yep - exactly. Great further clarification. It's why I mentioned I would never go above 100mph - speed rating variance.

If these were summer performance tires, used at a track or autocross, etc...I would never mix any spec.

But these are for Seattle rain, on mandated 25mph all roads city speed limits (crazy!) and the occasional snow. I probably didnt REALLY need to change them as my stocks did fine when I moved here in February...with the worst snow here in decades.

So for my purpose they work.

And I will say - daily comfort on cement roads is much, much improved.

Originally Posted by nZtiZia

tire specs are very busy, eh? but in the interest of accuracy so you can properly compare specs, thought i'd clarify a few details.

• 107 and 111 describe the load index or rating (2149 vs 2403 pounds per tire)
• the 'V' describes the speed rating (149 mph) and like GrussGott alluded to with different speed ratings, the limit of the lowest rated tire is the fastest you can drive and stay safely within your tire's handling capability
• XL describes the load range and stands for Extra Load

hope it helps!

[blake6551]

Good to know. So I did ask Pirelli about mixing this set a few weeks ago, and they told me "no" as the construction was different. I'm not sure I buy it, as it's probably just a CYA for them. Like you said other than treadwear they basically seem very close.

I think I will try this set as well, I'm not really interested in buying a winter set as we get very little snow in DC and I've done the two sets before and its a PITA.

[5pacey]

Originally Posted by blake6551

Good to know. So I did ask Pirelli about mixing this set a few weeks ago, and they told me "no" as the construction was different. I'm not sure I buy it, as it's probably just a CYA for them. Like you said other than treadwear they basically seem very close.

I think I will try this set as well, I'm not really interested in buying a winter set as we get very little snow in DC and I've done the two sets before and its a PITA.

So what are you planning? I am in VA w/a x45e on order and still debating if I should go w/the 740Ms - nice easy choice and I do like the looks - or go slightly fancier w/the 741s ... but then the pain of not AS/RFTs or even AS tires at all. But we do get enough nasty weather in the winter that running on summer tires sound scary and I am not sure I'll feel good putting my wife in the car w/them...

[nZtiZia]

Originally Posted by 5pacey

I am in VA w/a x45e on order and still debating if I should go w/the 740Ms - nice easy choice and I do like the looks - or go slightly fancier w/the 741s ... but then the pain of not AS/RFTs or even AS tires at all. But we do get enough nasty weather in the winter that running on summer tires sound scary and I am not sure I'll feel good putting my wife in the car w/them...

I'm also in Virginia and encountered this dilemma taking delivery with 21" wheels in December 2020. luckily, I wasn't working much but in late January 2021, temps were dipping towards 40° and the summer tires weren't liking it. so I changed to a 20" all-season RFT (45e) square setup as soon as I could. had them on in about 2 weeks and not even 2 days later, our first snow!

[parkstr8]

Update: haven't been driving that much but so far I really like the outcome. Its been raining and so far so good.

Much more compliant tire over bad roads and much quieter.