993 RS tyre pressures
993 RS tyre pressures
Author
Discussion

sleep envy

Original Poster:

62,260 posts

277 months

Monday 30th January 2006
quotequote all
Had a quick leaf through the owners manuals but can't decipher the German and it's all in new money anyway.

What's the 'recommended' cold weather pressures and what are the pressures people have experimented with.

The car is running on Pirelli Assimetrico all round if that makes a difference.

Agent Orange

2,078 posts

268 months

Tuesday 31st January 2006
quotequote all
used those tyres , great for wet ,dry and reasonable wear rate ..........probably alone in this, but as long as ur suspension standard i went for 30-32 all round hot to work amd back ................probably means starting 27.5 front and 26.5 rear unless u rubber the road at every set of lights or very high speed flat out on M/ways !

sleep envy

Original Poster:

62,260 posts

277 months

Tuesday 31st January 2006
quotequote all
Cheers Vic

houlbt

740 posts

293 months

Tuesday 31st January 2006
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On this subject... kind of, what Geometry settings do you guys have on your car for a track setup.

Looking at mine (done not too long ago) I have -1.1 camber front, -1.2 camber rear, +5 caster front. I'm off to Silverstone beginning of Feb for my first foray into a 911 on track.

TH

sleep envy

Original Poster:

62,260 posts

277 months

Tuesday 31st January 2006
quotequote all
Tom - I take it you'll be holding onto it then?

Also, are you doing the run on Sunday?

houlbt

740 posts

293 months

Tuesday 31st January 2006
quotequote all
Hi there... the car is for sale at the right price (isn't anything) but other than that no I'm not rushing to sell. Had my eye on this if I sold it - www.pistonheads.com/sales/62566.htm

RE Sunday.. I'm not on the lists - and not sure how to get on them, I'll email the relevant gents again now.

Tom H



>> Edited by houlbt on Tuesday 31st January 13:00

sleep envy

Original Poster:

62,260 posts

277 months

Tuesday 31st January 2006
quotequote all
Tom - YHM

johnny senna

4,073 posts

300 months

Tuesday 31st January 2006
quotequote all
Lads,

I run mine a bit higher on the road than Vic does. On the track, I use the pressures Vic says, start at 27, get up to 31 hot.

But in cold weather, I thought you were supposed to run 911s in cold weather with 32 front and 37 rear? Any comments?

sleep envy

Original Poster:

62,260 posts

277 months

Tuesday 31st January 2006
quotequote all
johnny senna said:
But in cold weather, I thought you were supposed to run 911s in cold weather with 32 front and 37 rear? Any comments?


Yep, that's what Tom @ H&S set mine at last weekend for the run back to Blighty.

Just curious to see what everyone is running at the moment, pressures are always a black art especially this time of year.

johnny senna

4,073 posts

300 months

Tuesday 31st January 2006
quotequote all
sleep envy said:
johnny senna said:
But in cold weather, I thought you were supposed to run 911s in cold weather with 32 front and 37 rear? Any comments?


Yep, that's what Tom @ H&S set mine at last weekend for the run back to Blighty.

Just curious to see what everyone is running at the moment, pressures are always a black art especially this time of year.



It's just with lower pressures, I would worry about the inside edge of the tyres getting worn out due to the neg camber setting most people run on the 993 RS.

aceparts_com

3,724 posts

269 months

Tuesday 31st January 2006
quotequote all
Underinflation will cause more problems than over inflation. I always find that lower pressures make the car 'feel' more secure when in fact higher pressures make the car react quicker and safer in probably all circumstances. I'll try and find a link to an interesting website all bout it...... I'll shut up now.

Agent Orange

2,078 posts

268 months

Tuesday 31st January 2006
quotequote all
Doc ur not trying hard enough , track days start at 23 and 24 u ll soon be 30plus on a reasonable dry day .............sometimes a pound or even two extra in the fronts makes for interesting stuff, very sensitive honest

johnny senna

4,073 posts

300 months

Tuesday 31st January 2006
quotequote all
Agent Orange said:
Doc ur not trying hard enough , track days start at 23 and 24 u ll soon be 30plus on a reasonable dry day .............sometimes a pound or even two extra in the fronts makes for interesting stuff, very sensitive honest


Aye Vic, you are right, but I tend to start at 27, get up to 31 ish, then let air out over the day to keep them at 31 all round. I don't like venturing out onto the track first thing on really low pressures in case I damage the tyres.

flemke

23,439 posts

265 months

Tuesday 31st January 2006
quotequote all
Agent Orange said:
Doc ur not trying hard enough , track days start at 23 and 24 u ll soon be 30plus on a reasonable dry day .............sometimes a pound or even two extra in the fronts makes for interesting stuff, very sensitive honest

I must respectfully but strongly disagree with what I think you're advocating.
If you start with pressures significantly below the proper level and then drive on them to raise the tyre temperature and thus pressure, the time tyres spend below proper pressure will damage the sidewalls as well as abrade the inside edges. I used to do it that way, which is simpler than the tedious iterative process of starting high and bringing them down, but I learned from regrettable experience of the problems that that technique can cause.
Start high and bring them down, Within reason, try to avoid any running at pressures that are below what is correct.

993rsr

3,657 posts

277 months

Tuesday 31st January 2006
quotequote all
Flemke, what issues with the tyre did you have from running them at low start pressures. I do remember reading on another thread that the information came from Olaf Manthey so has a degree of credence to it!

nervous

24,050 posts

258 months

Tuesday 31st January 2006
quotequote all
houlbt said:
Hi there... the car is for sale at the right price (isn't anything) but other than that no I'm not rushing to sell. Had my eye on this if I sold it - www.pistonheads.com/sales/62566.htm

RE Sunday.. I'm not on the lists - and not sure how to get on them, I'll email the relevant gents again now.

Tom H



>> Edited by houlbt on Tuesday 31st January 13:00



psssst... thats a link to an ultima....and PLEASE stop putting up pictures of really tasty porsches, its all i can do to not buy them all. well, that and the court order stopping me.

flemke

23,439 posts

265 months

Tuesday 31st January 2006
quotequote all
993rsr said:
Flemke, what issues with the tyre did you have from running them at low start pressures. I do remember reading on another thread that the information came from Olaf Manthey so has a degree of credence to it!

Your memory is correct.
Have experienced very excessive wear on inside shoulder/hinge (which many of us will have had), as well as damaged carcase. When you're going full-chat up Kesselchen and your rear tyres start to make an anomalous rumbling noise, it gets your attention.

Agent Orange

2,078 posts

268 months

Tuesday 31st January 2006
quotequote all
Hmmmmmmm cant deny i ve been warned about what ur saying, in my case ive not had a problem over many years, though this starting level usuallly only on dry warm days and i tend to spend 2/3 laps minimum warming up pads /discs and tyres .............i was warned starting that low might roll a tyre off the rim.I ve only done the edges thing [inside edges] when i had to use an rs for and one of the GT2 s to drive to work and back for several months , did 2 sets of rears before i realised how quick they werer disappearing................guess the Doc cant go wrong starting ,as he says abt 27 and progressively letting then down as necessary?? Sorry left out , but hope its pretty obvious , both cars were on quite aggressive settings, had mainly been used for track use ............tyres at norm settings to and from the track.

>> Edited by Agent Orange on Tuesday 31st January 19:35

flemke

23,439 posts

265 months

Tuesday 31st January 2006
quotequote all
For 993 RS CS, my friends and I have settled on 32/33 hot on circuit (Cups). We tend to run 35/39 cold on the road, so upon arriving at circuit we would initially lower only to 33ish in that semi-cool state, do a lap and lower, do another lap and lower, etc.

Olaf has told me a great deal about cars. Someday he may be wrong, but it hasn't happened so far.

zub

87 posts

256 months

Tuesday 31st January 2006
quotequote all
The manual recommends pressures of 2.5 bar front, 3.0 bar rear, which if I recall is 36 / 44psi or something like that.

On the track I always run around 32-36 front, 32-34 rear depending on conditions, and always drop down to the right pressure (ie start at just below these pressures, go out, tyres warm, come in and drop to the right pressures, rather than inflating up to these pressures).

I sometimes use a pyrometer to check the temp gradient just to make sure the middle temp isn't wildly out from outer and inner, but to do this properly you have to come in from a flying lap rather than take the car on a cool down lap. In very cold and wet conditions, I usually run higher - as much as 38-40 at the front in order to get some temperature in the tyres, esp with Cups which need temperature to start working effectively.

Hope this helps.