20" wheel tyre pressures

2.9 V6 24v TFSI - 444 bhp
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DAMO1234
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20" wheel tyre pressures

Post by DAMO1234 » Mon Jun 04, 2018 3:16 pm

Hi

Does anyone know recommended tyre pressures for Conti Sport Contact 275/30 ZR20 (97Y) XL? Badge on driver's door doesn't seem to show that particular tyre.

Many thanks in advance.

D

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RS Owner
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Re: 20" wheel tyre pressures

Post by RS Owner » Mon Jun 04, 2018 4:44 pm

it's on my door, but only as a winter tyre, and mines an RS5 so not much use to you :bigblink:
Current : 2018 F5 RS5 (Let's Fire Up the Quattro)
Gone : 2017 M3 CP
Gone : 2007 B7 RS4 ( :kissmyrings: )

PieterZ
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Re: 20" wheel tyre pressures

Post by PieterZ » Tue Jun 05, 2018 6:33 pm

I don't think the brand matters? I inflate the front at 2.8 bar and the rear at 2.5.
That's the 2 person load pressure.
More people and load is a different pressure.
All black B9 RS4

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Paulm
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Re: 20" wheel tyre pressures

Post by Paulm » Tue Jun 05, 2018 9:03 pm

With these really skinny tyres I think its a compromise around grip and wheel damage. They need to be hard enough to stop wheels damage over pot holes but soft enough to give enough grip. I run 32psi (2.2bar) on my BM, I don't care about the wheels I want max grip. I have tested with a infrared temp gauge and get equal reading across the whole tyre at 32psi.

Go buy one only a few quid and do some testing, very easy to do. Its how I used to get my kart tyres at the correct temp when racing. No point the centre of the tyres being 30degC and the outer and inner at 15deg C
BMW 540i
2018 GTR
F90 M5
X3MC
RS3 Saloon
RS7 FL best car I've owned. No faith in turbo oil screen (turbos failing) or sticking oil scraper ring causing missfires.
F10 M5 LCI still no rear grip lol
S7 black Edition Too big and heavy
S3 8V FL DSG 310ps, road noise is a joke
RS3 8P Rubbish
C7 RS6 Fantastic car but missed playing
GTR R35 800bhp, too extreme, crazy fast though
911 Turbo Remapped. Hated it
F10 M5, awesome but no rear grip
RS6 V10 700BHP crazy
Porsche Cayenne Turbo S 600bhp

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dhali
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Re: 20" wheel tyre pressures

Post by dhali » Tue Jun 05, 2018 9:36 pm

Good info there .

Markp
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Re: 20" wheel tyre pressures

Post by Markp » Wed Jun 06, 2018 7:01 am

Paulm wrote:
Tue Jun 05, 2018 9:03 pm
With these really skinny tyres I think its a compromise around grip and wheel damage. They need to be hard enough to stop wheels damage over pot holes but soft enough to give enough grip. I run 32psi (2.2bar) on my BM, I don't care about the wheels I want max grip. I have tested with a infrared temp gauge and get equal reading across the whole tyre at 32psi.

Go buy one only a few quid and do some testing, very easy to do. Its how I used to get my kart tyres at the correct temp when racing. No point the centre of the tyres being 30degC and the outer and inner at 15deg C
Really skinny? My GT3 runs a 235 front tyre and has grip to spare - at least on road. And sorry to appear an old fart, but adjusting your tyre pressures by measuring your tyre surface temps for road use is daft. On circuit yes, on road no - unless you constantly drive like a loon you will end up with too high pressures for good all round, all weather performance.

DAMO1234
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Re: 20" wheel tyre pressures

Post by DAMO1234 » Wed Jun 06, 2018 9:39 am

very helpful. many thanks all.

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Paulm
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Re: 20" wheel tyre pressures

Post by Paulm » Wed Jun 06, 2018 12:53 pm

Markp wrote:
Wed Jun 06, 2018 7:01 am
Paulm wrote:
Tue Jun 05, 2018 9:03 pm
With these really skinny tyres I think its a compromise around grip and wheel damage. They need to be hard enough to stop wheels damage over pot holes but soft enough to give enough grip. I run 32psi (2.2bar) on my BM, I don't care about the wheels I want max grip. I have tested with a infrared temp gauge and get equal reading across the whole tyre at 32psi.

Go buy one only a few quid and do some testing, very easy to do. Its how I used to get my kart tyres at the correct temp when racing. No point the centre of the tyres being 30degC and the outer and inner at 15deg C
Really skinny? My GT3 runs a 235 front tyre and has grip to spare - at least on road. And sorry to appear an old fart, but adjusting your tyre pressures by measuring your tyre surface temps for road use is daft. On circuit yes, on road no - unless you constantly drive like a loon you will end up with too high pressures for good all round, all weather performance.
I was referring to the profile not the width sorry for the confusion. Its nothing to do with driving like a loon, correct tyre pressure is just that. your loon statement does not make sense, it suggests fast driving keeps pressure low where in fact fast driving will increase pressure. my pressure is set for summer weather @32psi. If I went to the track I would set the pressure lower prob around 28psi. If it was winter the 32psi I am running is prob a little too low but overall 32psi is spot on for over 90% of my driving. If you want the best performance (Grip and wear) out of your tyres it require a little work . Call it daft if you like that's your opinion and I have mine. M5 RWD its all about maximum grip in the rear. I have no grip to spare, believe me!!
BMW 540i
2018 GTR
F90 M5
X3MC
RS3 Saloon
RS7 FL best car I've owned. No faith in turbo oil screen (turbos failing) or sticking oil scraper ring causing missfires.
F10 M5 LCI still no rear grip lol
S7 black Edition Too big and heavy
S3 8V FL DSG 310ps, road noise is a joke
RS3 8P Rubbish
C7 RS6 Fantastic car but missed playing
GTR R35 800bhp, too extreme, crazy fast though
911 Turbo Remapped. Hated it
F10 M5, awesome but no rear grip
RS6 V10 700BHP crazy
Porsche Cayenne Turbo S 600bhp

Markp
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Re: 20" wheel tyre pressures

Post by Markp » Wed Jun 06, 2018 10:19 pm

Paulm wrote:
Wed Jun 06, 2018 12:53 pm
Markp wrote:
Wed Jun 06, 2018 7:01 am
Paulm wrote:
Tue Jun 05, 2018 9:03 pm
With these really skinny tyres I think its a compromise around grip and wheel damage. They need to be hard enough to stop wheels damage over pot holes but soft enough to give enough grip. I run 32psi (2.2bar) on my BM, I don't care about the wheels I want max grip. I have tested with a infrared temp gauge and get equal reading across the whole tyre at 32psi.

Go buy one only a few quid and do some testing, very easy to do. Its how I used to get my kart tyres at the correct temp when racing. No point the centre of the tyres being 30degC and the outer and inner at 15deg C
Really skinny? My GT3 runs a 235 front tyre and has grip to spare - at least on road. And sorry to appear an old fart, but adjusting your tyre pressures by measuring your tyre surface temps for road use is daft. On circuit yes, on road no - unless you constantly drive like a loon you will end up with too high pressures for good all round, all weather performance.
I was referring to the profile not the width sorry for the confusion. Its nothing to do with driving like a loon, correct tyre pressure is just that. your loon statement does not make sense, it suggests fast driving keeps pressure low where in fact fast driving will increase pressure. my pressure is set for summer weather @32psi. If I went to the track I would set the pressure lower prob around 28psi. If it was winter the 32psi I am running is prob a little too low but overall 32psi is spot on for over 90% of my driving. If you want the best performance (Grip and wear) out of your tyres it require a little work . Call it daft if you like that's your opinion and I have mine. M5 RWD its all about maximum grip in the rear. I have no grip to spare, believe me!!

Sorry Paul, came across badly. My point was that tyres naturally run hotter on the outer edge in road conditions (other than straight roads like motorways) and to get even temperatures across most of the tread you have to over inflate (relatively). But you are just taking a snapshot which won't cover all conditions. Hence the manufacturers' advise which is a compromise.
On track, where you can max the tyres out consistently ( as in your karting), it is worthwhile tinkering with pressures to get even temps across the tread. I guess you drive faster on the road than me ;)

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Paulm
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Re: 20" wheel tyre pressures

Post by Paulm » Thu Jun 07, 2018 7:59 pm

No worries. I understand what you are saying.

I did some testing over a few days. Best test i did was one rear 40psi and the other 30psi then gradually lowered pressure on the 40 and up on the 30 until I found max grip. Then some testing with the temp gun. Maybe not the safest approach but gave some very good feed back.

Nah drive pretty slow nowadays with the odd blast. Getting old😞
BMW 540i
2018 GTR
F90 M5
X3MC
RS3 Saloon
RS7 FL best car I've owned. No faith in turbo oil screen (turbos failing) or sticking oil scraper ring causing missfires.
F10 M5 LCI still no rear grip lol
S7 black Edition Too big and heavy
S3 8V FL DSG 310ps, road noise is a joke
RS3 8P Rubbish
C7 RS6 Fantastic car but missed playing
GTR R35 800bhp, too extreme, crazy fast though
911 Turbo Remapped. Hated it
F10 M5, awesome but no rear grip
RS6 V10 700BHP crazy
Porsche Cayenne Turbo S 600bhp

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