# Tire Pressures: TTS vs. TT-RS



## 32vSC (Oct 11, 2009)

One thing that's been nagging me for a while is that the TTS' door jam sticker lists tire pressure as 

31f / 29r 

and the RS's sticker lists: 

35f / 32r 

and both have 255/35x19 tires (on the same size wheels AFAIK.) 

Edmunds and Kelly list the weights for both cars as: 3306 for the RS and 3219 for the TTS. 

I can imagine that the RS is a little nose heavy compared to the S, but I doubt all of the extra weight is the engine. And in any case an extra 100-odd pounds for the RS is not enough extra to warrant 3 extra pounds in the rear and four extra pounds in the front. 

I googled the interwebs for distribution data, but got bored. And the wiki page on QW is pretty devoid of data. 

Now, we all know the Toyos suck. Maybe they'll blow-up at Autobahn speeds - due to sidewall heating - if they don't have some extra pounds of pressure. 

But, the extra four pounds in the front seems like a recipe for understeer. 

Audi picked those pressures for a reason. 

Any thoughts? 

I'm going to run 32f/30r in the RS for a little while and see what my butt-o-meter tells me.


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## TTracing (Mar 20, 2008)

I'm gonna try the same thing... 
I'm sure my butt-o-meter will say thank you!


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## LongviewTx (Dec 26, 1999)

I started at the track last weekend with oem recommendation 35f/32r. after lowering 3 psi front and back, subsequent runs were much better. a lot better drift with easier oversteer/rotation and tires lost the side hopping t the higher psi. So, i'd say you are on the mark. 

Why, do we all know the Toyos suck? I just don't have the experience. The tires seem to work great. How much am I leaving on the table running these tires?


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## Stevelev (Mar 4, 2004)

Just did a day at the track this past week and cold temps were 33/30. After the 1st session temps rose to 36/33 and I decided to keep them there for the balance of the day. This was mostly due to the fact that it was freakin' hot and the side of the car facing the sun would end up with "cold pressures" 2 lbs higher than the side in the shade ... I figured if it ain't broke then don't fix it.


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## 32vSC (Oct 11, 2009)

LongviewTx said:


> ... after lowering 3 psi front and back, subsequent runs were much better. a lot better drift with easier oversteer/rotation and tires lost the side hopping


 Interesting observations (that support my budding theory.) 



> Why, do we all know the Toyos suck?


 Well, there've been a number of threads with reports of Toyo suckage. One in particular (IIRC the Order Guide Thread) linked (or copied-inline) tire testing reports that indicated that the Toyos understeered relative to Michelins and Pirellis. 

(Here it is: http://forums.fourtitude.com/showth...rder-Guide&p=72723018&viewfull=1#post72723018) (And there are other posts before and after about tires.) 

That post shows that the tests were for the 245/40x18 tires and don't indicate what pressures were used. This last - not writing about pressures - seems to be par for the course and that's irksome 'cause the right tire pressures are critical to getting the balance you want. 

So, we have some indication that lower pressure is better. 

On the other hand, no anecdotes on why Audi chose these pressures. (I can imagine that the extra stagger front-to-rear was to induce more understeer (Thank You Audi Legal Team) or, perhaps, to slightly hobble performance for Marketing reasons...)


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## - Jeremy - (Feb 23, 2006)

I've been pretty vocal about the suckiness of the Toyos but the truth is they're actually pretty decent on the road. I have no complaints about them on the streets, even with aggressive driving. But they're pretty awful on the track; not enough grip, really bad transitions, reduced performance when hot, etc. I guess, like brakes, if you're not used to running something better, you don't know what you're missing. Absolutely, without a doubt, brake upgrades should be the first thing on the track upgrade list. I still haven't changed my tires because they're really not the worst thing in the world. I'll wait until I wear them out. No sense in wasting money. 

- Jeremy -


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## LongviewTx (Dec 26, 1999)

- Jeremy - said:


> I guess, like brakes, if you're not used to running something better, you don't know what you're missing.
> - Jeremy -


 That's me. No point of reference. 

i wonder then how much more awesome this car can be on the track... 

would u consider a bridgestone re-11 as a good replacement for track and road optimization?


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## GaBoYnFla (Oct 2, 2005)

- Jeremy - said:


> I've been pretty vocal about the suckiness of the Toyos but the truth is they're actually pretty decent on the road. I have no complaints about them on the streets, even with aggressive driving.
> 
> - Jeremy -


 Yes, they are good street tires....they will wear (but all will) if you push your car a bit....I got 8,000 out of the fronts and 10,000 out of the rears before replacing them....with same except no curb protectors....and price wasn't too bad....Discount Tire.


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## TTracing (Mar 20, 2008)

Hey,those Toyos are not bad at all.I have 21,000 miles on them and will go another 5 or 8k on them. 
They wear very even.Switched back to front at 5K and again at 15k. 

Went once at the track and they were decent ,but again, all I have to compare with, are Michelin Pilot Sport Cup and Hoosier R6 on my old racekor TT.No comparison... 

35/32 for everyday might be a bit high.It's very rough for sure.I'll try 32/29. 

Story: At Sebring,3 weeks ago,I started at 35 up front,and was at 45 at the end of the first session. Immediately reduce to 40.(40 is what you try to keep with the slick Hoosier).At the end of the second session,I'm back at 43. Again,I reduce to 40. Third session,I totally finished destroying the brakes,fluid boiling,pads burned,rotors blue..After going straight at the hairpin,I directly drive home. 
Next morning,I check my pressures,expecting 27 up front...No,it's at 33 ...


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## mageus (Sep 1, 2004)

Regarding temps: 
I use a thermometer at the track (IR, not probe). Good numbers are 37F front, 33F rear hot. Cold, the tires should be like 31/29. So, yes, the RS tire pressure recommendations seem high. Maybe to score higher EPA numbers? 

Regarding Toyos: 
- On the street they are OK. Conti DWS have a more comfortable ride, but the Toyos handle better when pushed, which isn't saying much. The only other comparison I have are the RS-3's, which just isn't fair. 
- When hot they get greasy very quickly, and there goes your grip. 
- With track use they wear well for the 1st 50% of tread. After that, the tread wears absurdly fast and they have no usable grip whatsoever. I was basically all-wheel drifting my last track session on those tires.


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## - Jeremy - (Feb 23, 2006)

LongviewTx said:


> That's me. No point of reference.
> 
> i wonder then how much more awesome this car can be on the track...
> 
> would u consider a bridgestone re-11 as a good replacement for track and road optimization?


 I used RE-11's last year and absolutely adored them. Now there's the Pilot Super Sport and I'm not sure which one I want to use next. I think the PSS have a higher terminal grip (lateral G's) but their sidewalls are not as stiff as the RE-11's. They also have a higher wear rating, but I didn't find the RE-11's to wear fast anyway. The One Lap of America event was dominated by the PSS so that may be worth noting. 

Either way, you can't go wrong. Both are exceptional street/track tires and should be an impressive upgrade over the Toyos. But, like I said, brakes should be upgraded before tires on the TT RS. One will get you killed, the other won't. 

- Jeremy -


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## LongviewTx (Dec 26, 1999)

TTracing said:


> ... I started at 35 up front,and was at 45 at the end of the first session.
> 
> Immediately reduce to 40.(40 is what you try to keep with the slick Hoosier).At the end of the second session,I'm back at 43. Again,I reduce to 40. Third session,I totally finished destroying the brakes,fluid boiling,pads burned,rotors blue..After going straight at the hairpin,I directly drive home.
> Next morning,I check my pressures,expecting 27 up front...No,it's at 33 ...


 same, story, i went on track first session at oem settings. pressure after 1st = 45, (25 min session), dropped 3 psi to 42 anf left for rest of weekend, psi monday morning cold 32 
(front referenced). 

oem for street driving does seem to be great, its driving aggessive that psi alterating is a must. i think there are too many variables to make a blanket statement on the optimium pressure


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## 32vSC (Oct 11, 2009)

I just got back from a morning of following a Boxster Spyder through twisties and can confirm that: 

32/30 is not totally wrong 
the Toyos really do suck (as compared to the OE Tires on the TTS (ContiSport Contact 3 and I don't hold Conti tires in high regard)) 

Based upon scrub and handling, I'd say that there might be something to the 3 PSI stagger for the RS. Or maybe the Toyos suck. 

However, ambient temps were in the mid-60s. Maybe I never got the Toyos to a good operating temp. 

For those playing a home, keep in mind that track driving and mildly-energetic street diving (and auto-cross) may all need different cold (starting) pressures. So, your results may vary. 



[*]Or, understeer transitioning to neutral. Hard to tell the difference sometimes. Too easy to get so used to understeer, then neutral handling is a surprise.


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## M this 2! (Feb 8, 2012)

My car is different as it's a mkI. But it's a very similar biased and after 100k miles and trying Mich PS1s, PS2s, Kumho MX, Toyo R1Rs, Toyo RA1, and Toyo 888s (later two being track rubber). That coming off the track at 40 seems to be pretty perfect. For the street, 38ft/32rear gives great feel, feedback and wear. It also makes it very tossable and can get smooth drop throttle oversteer. I'll bet you guys running the softer front psi settings on the street will notice worse handling but softer ride. The beauty of tire pressure.....it's free to adjust if you don't like a setting. What I say is to start with extremes. Go to the lowest cold setting for the street and drive it around. Then go out and try it at the highest and see if it got better or worse. When you find which end of the spectrum you prefer, fine tune from there. 


I'd guess the factory gave the car an edgier and more aggressive psi recommendation over the S, per the nature of the vehicle.


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## pal (Aug 16, 2000)

This is what I found for engine weights- RS has about 70 lbs more engine weight but then the TTS makes up for that a bit with a heavier DSG. 


2.5 TFSI (RS) - 183 kgs (403.45 lbs) 
2.0TFSI - 152 kgs (335.11 lbs)


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## InTTruder (Mar 28, 2006)

32vSC said:


> One thing that's been nagging me for a while is that the TTS' door jam sticker lists tire pressure as......
> 
> But, the extra four pounds in the front seems like a recipe for understeer.
> 
> .......


 NOT CORRECT- 
Increasing tire pressure in the fronts DECREASES understeer. The tires generally ahve more bit, a stiffer sidewall, and crisper turn-in.

I've autocrossed and tracked my cars (including a TTQC and now my TT RS) and always increased the fronts. We adjust the rears to trim/tune the amount of oversteer we can generate.


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## 32vSC (Oct 11, 2009)

NOT, Not Correct...



InTTruder said:


> NOT CORRECT-
> Increasing tire pressure in the fronts DECREASES understeer. The tires generally ahve more bit, a stiffer sidewall, and crisper turn-in.
> 
> I've autocrossed and tracked my cars (including a TTQC and now my TT RS) and always increased the fronts. We adjust the rears to trim/tune the amount of oversteer we can generate.


What you write above is correct for an autocross environment.

What I wrote above (corroborated by others) is correct for a track environment.

The difference is that in a track environment the tires get up to temperature.

In an autocross environment the tires start cold and finish more-or-less cool (for typical short a-x "cone" courses.)

Pressure increases with temperature. Pressure effects contact patch size and shape. Temperature is generated by the flexing of the tire's contact patch and side wall. 

You'll note that corroborating posts mentioned hot tire pressures in the 40s. 

When you, prior to an autocross run, raise the cold tire pressure you are compensating for the fact that the tire will not get to operating temperature (and therefor operating pressure) during the A-X run.

On a track the tires do get to operating temperature.

Two different operating environments. Two different contexts in which to discuss pressures.

On the A-X course increasing pressure reduces understeer because when cold, the contact patch is mostly along the edges. When you increase pressure you're "pushing" the contact patch "down" in the center to get the same size and shape you would have if the tire was at operating temperature.

On the track, when the tire is hot, increasing the pressure further bulges the center of the contact patch and decreases it's size - away from the sidewall - and effectively makes the tire "narrower" and thus, decreases grip leading to understeer.


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## InTTruder (Mar 28, 2006)

I'll fall back to initially increasing F pressures to compensate for the additional heat and sidewall softness, and constantly adjusting throughout the day on track. In most cases, I've wound up with F pressures higher than the sticker, R pressures also higher than the sticker, and a F bias. I understand the physics both in terms of pressure and footprint, and would not advise 'abandoning' your tires after an initial bump up.

I still use chalk when I don't have a pyro available, and unless you get into serious camber adjustments, TP is the only tool available. Chalk will tell you if you've over-inflated or under-inflated the tires, whether on auto-x or track.

Et al- solid advice from 32vSC for initial setups; my advice is keep a log, monitor passively (chalk) or actively (pyro), and adjust constantly!


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## OrangeA4 (Oct 31, 2000)

just topped off the air in my tires on the TTS and my door sticker said 35f / 32r so 
Is there a difference in specs for different stock wheels?
I have potato peelers.


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## InTTruder (Mar 28, 2006)

See my TT RS track day report HERE-


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## InTTruder (Mar 28, 2006)

And I stand in AWE of 32vSC's previous judgement. On these tires, softer rocks.eace:


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## 32vSC (Oct 11, 2009)

InTTruder said:


> See my TT RS track day report HERE-



With the cold pressures at 32/32 on Sunday, once past the first few laps, did the RS feel neutral? 

Was there any tendency towards understeer or oversteer? Or perhaps, a different question: Did the rear feel tighter or looser on Sunday? Front? Was it any different for slow corners versus high-speed corners?


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## 32vSC (Oct 11, 2009)

OrangeA4 said:


> just topped off the air in my tires on the TTS and my door sticker said 35f / 32r so


Interesting.



> Is there a difference in specs for different stock wheels?


Yes. On the same car, narrower tires will usually have a higher spec pressure.



> I have potato peelers.


What size are potato peelers? Or, an easier question, what size tires?


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