Audi RS3 Reverse Staggered Tire option

[flipflp]

I just saw on the Audi RS3 build page that in their "Dynamic Package" you get a set of 255/30-19 Front and 235/35-19 Rear staggered tires.

Just based on the two tire sizes, a 255/30 is 25.1" diameter and a 235/35 is a 25.5" diameter. Admitting ignorance here, but will the haldex system be okay with two different tire diameters or is something done in the car's setup with that package to make it work? I'm guessing because it's clutched and not a direct drive like the Longitudinally mounted Audi quattro that it doesn't cause an issue, but I wanted to see what others thought.

And yes, I know that reverse staggered tires sounds weird but this isn't a new idea. And yes, I know you can't rotate your tires then. And yes, it will likely help very little for most people in regards to traction, handling or feel over a matched F/R setup. But it's different!

 

[MrConflicted]

Definitely. Remember in normal operation, the haldex is either not loaded, or only partially loaded. This slipping generated by different tire sizes causes no downside under normal duration.

The real question here imo, is if this bigger front tire diameter will cause an increase in understeer when the haldex is coupled AND could you instead swap in a bigger rear tire to bias more oversteer?

Obviously with a reverse stagger, I highly doubt understeer will be an issue. Running even 225/215 with an RSB on my GTI netted substantial oversteer bias.

 

[flipflp]

Definitely. Remember in normal operation, the haldex is either not loaded, or only partially loaded. This slipping generated by different tire sizes causes no downside under normal duration.

The real question here imo, is if this bigger front tire diameter will cause an increase in understeer when the haldex is coupled AND could you instead swap in a bigger rear tire to bias more oversteer?

Obviously with a reverse stagger, I highly doubt understeer will be an issue. Running even 225/215 with an RSB on my GTI netted substantial oversteer bias.

That is what I thought about the haldex clutches. Thanks for confirming.

Actually the front tire is a smaller diameter, 25.1" vs 25.5". It's wider but is a lower aspect ratio (30 vs 35 series) so yes, if what you're saying with the haldex coupled is true this setup would have ever more rear bias.

400hp and 354 ftlbs of torque is damn good power, and the less time traction control has to step in, or if your TC is off, the less time you're potentially spinning a front wheel is great. Combine that with less mechanical grip in the back (and possibly higher AWD bias) and you've got a car that's planted in the front and rotates better in the rear. Win win.

 

[MrConflicted]

That is what I thought about the haldex clutches. Thanks for confirming.

Actually the front tire is a smaller diameter, 25.1" vs 25.5". It's wider but is a lower aspect ratio (30 vs 35 series) so yes, if what you're saying with the haldex coupled is true this setup would have ever more rear bias.

400hp and 354 ftlbs of torque is damn good power, and the less time traction control has to step in, or if your TC is off, the less time you're potentially spinning a front wheel is great. Combine that with less mechanical grip in the back (and possibly higher AWD bias) and you've got a car that's planted in the front and rotates better in the rear. Win win.

Oh heck yeah! Sorry read it wrong the first time (back vs. front). That's gotta be an absolute riot to drive.

 

[breaking badly]

Tire diameters/circumferences don't necessarily need to differ. Remember the RS3 comes
with dedicated R01 or R02 rated tires, which most certainly are designed with a specific
circumference in mind.
Regarding the Golf R, run the same size both front and rear. If you want to decrease rear
end grip, increase rear tire pressure. There's no advantage in using staggered wheels and
tires. You want to keep the ability to swap your tires front and rear frequently, in particular
when you use to drive your car hard.

 

[madface1]

Tire diameters/circumferences don't necessarily need to differ. Remember the RS3 comes
with dedicated R01 or R02 rated tires, which most certainly are designed with a specific circumference in mind.

That one. R8s come factory with a pretty large difference in tire size, I believe almost 1.5" difference in overall diameter in some cases (245/30 and 305/30 for factory 20" wheels). Most of the R8 guys who run aftermarket wheels even run staggered diameter so that the sidewall of the tire is closer to the same but still have the larger overall diameter as to not affect the quattro, it just looks better on those cars.

It comes down to how the car is designed to work, so going to an aftermarket wheel/tire setup is when you would have to keep that in mind.

 

[scrapin240]

i find it most interesting that the wider tire is on the front. don't think I've seen that before.

EDIT: The circumference difference has been in use in AWD for some time now. Before it was a no-no, but our 335xi has staggered tires as an option on the AWD.

 

[flipflp]

Tire diameters/circumferences don't necessarily need to differ. Remember the RS3 comes
with dedicated R01 or R02 rated tires, which most certainly are designed with a specific
circumference in mind.
Regarding the Golf R, run the same size both front and rear. If you want to decrease rear
end grip, increase rear tire pressure. There's no advantage in using staggered wheels and
tires. You want to keep the ability to swap your tires front and rear frequently, in particular
when you use to drive your car hard.

From my reading of what an R01 or R02 Audi spec tire is, it's references a spec compound and in some cases a different sidewall profile for applications where the tire will come closer to the fender (RS3 reverse staggered, R8s, etc.).

I'm happy to be corrected but the tire size itself is what dictates tire diameter, that's static. If Audi wanted a different diameter tire, they'd just spec a different size. Doesn't make sense at all for a tire to be spec'd at a size and then made the diameter/spec of a totally different size.

If you have empirical evidence, and not just personal theories, about the benefits or lack there of in using staggered tires in these applications you better get on the horn to Audi ASAP! I'm sure they'd love to know they are wasting their time and their customer's money

 

[flipflp]

That one. R8s come factory with a pretty large difference in tire size, I believe almost 1.5" difference in overall diameter in some cases (245/30 and 305/30 for factory 20" wheels). Most of the R8 guys who run aftermarket wheels even run staggered diameter so that the sidewall of the tire is closer to the same but still have the larger overall diameter as to not affect the quattro, it just looks better on those cars.

It comes down to how the car is designed to work, so going to an aftermarket wheel/tire setup is when you would have to keep that in mind.

Using the R8 as an example for when staggered wheels and tires are used is sort of opposite to the RS3 example because of the cars layout and design. FR vs MR, the type of AWD, where the weights in the car are located, etc. But I get what you're saying. R8s by design use different wheels front and rear, where the R/S3/RS3/TTRS setups until recently are all square setups.

I think some of my confusion with AWD like our Haldex or the Audi Quattro is the concern of using different tires left to right, which I believe is a major problem/concern and why tires are always replaced in pairs.

 

[flipflp]

i find it most interesting that the wider tire is on the front. don't think I've seen that before.

EDIT: The circumference difference has been in use in AWD for some time now. Before it was a no-no, but our 335xi has staggered tires as an option on the AWD.

Wider tires in the front or a reverse staggered setup is definitely not common, because for the most part it only benefits big power FWD or transverse mount cars. I've seen this used on Honda/Acura/etc track cars before as well.

I found this article and it pointed out the last time a manufacturer did this was Pontiac in the Grand Prix GXP. I KNOW, I know...not exactly a shining example for the merits of this setup BUT if you read the article they talk about how it changed the driving experience, a more direct and planted front end, and the car was more willing to drift and much more exciting to drive than other Audi models.

http://www.autoguide.com/auto-news/...and-a-pontiac-grand-prix-have-in-common-.html

This setup is probably not going to set Nuremberg Ring records like a set of bespoke 20 tread wear "streetable track tires", but the comparison to the FRS/BRZ/86 that uses a tire that has a lower grip to allow for low speed shenanigans is what I like to hear. AWD can be very safe and lifeless, so a tire setup that adds some flare is good in my book.