Tyre pressure adjustment

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fazzy
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Tyre pressure adjustment

Post by fazzy » Sat Jul 13, 2019 12:19 am

What tyre pressure are you guys running in your GTi's?
According to the manufacturer sticker on the door sill, 18" tyre should be 2,8 bar (41 psi) front and 2,6 bar (38 psi) at the back.
I have fount that running the recommended tyre pressure, the car is jumpy at speed and the tyre is not fully in contact with the surface.
So I have decreased the pressure to 2,4 (35 psi) in front and 2,2 (32 psi) at the back and it's substantially better.
Curious if anybody else has experimented with different pressures?
Attachments
86F7C6DD-A74D-452A-9FDF-F04DC8907FA7.jpeg

green justin
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Re: Tyre pressure adjustment

Post by green justin » Sat Jul 13, 2019 6:01 am

At 2.4 bar front, the tyres looks abit flat.

monkeyhanger
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Re: Tyre pressure adjustment

Post by monkeyhanger » Sat Jul 13, 2019 8:24 am

The standard recommended tyre pressures seem way too high, probably set that high to help meet an emissions target.

Are you still running 215/40 R18 tyres that came with your car? When I swapped out the rock hard and poor grip Bridgestone Turanzas for Michelin PS4 225/40 R18, the tyre fitter recommended 33psi off the car, equating to 35/36psi on the car. They feel much better. I would expect 215 with tyres to be running at a higher pressure than 225 width - maybe try 38psi if still on 215s?

Looking at your pic, the lack of dusting on the tread towards the shoulders of your tyres does look like slight over inflation to me.
Last edited by monkeyhanger on Sat Jul 13, 2019 9:20 am, edited 1 time in total.

fazzy
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Re: Tyre pressure adjustment

Post by fazzy » Sat Jul 13, 2019 9:18 am

monkeyhanger wrote:
Sat Jul 13, 2019 8:24 am
The standard recommended tyre pressures seem way too high, probably set that high to help meet an emissions target.

Are you still running 215/40 R18 tyres that came with your car? When I swapped out the rock hard and poor grip Bridgestone Turanzas for 225/40 R18, the tyre fitter recommended 33psi off the car, equating to 35/36psi on the car. They feel much better. I would expect 215 with tyres to be running at a higher pressure than 225 width - maybe try 38psi if still on 215s?

Looking at your pic, the lack of dusting on the tread towards the shoulders of your tyres does look like slight over inflation to me.
Yeah, I'm still running stock 215/40/18 Truanzas
I enclosed the pic because it is clearly visible that standard pressure is actually overinflation.
Like Green Justin said: at 2,4 bar (35psi) the tyre looks a bit flat. I reckon, because more of the tyre surface is actually making contact with the road...

S_94
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Re: Tyre pressure adjustment

Post by S_94 » Sat Jul 13, 2019 11:15 am

With the MPS4s each tyre was reading at 36.5psi when I checked last week.

Rosinfield
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Re: Tyre pressure adjustment

Post by Rosinfield » Sat Jul 13, 2019 5:07 pm

Maybe it's different for the 17 inch tyres on my car. But it feels very comfy at pressures slightly above those recommended.

monkeyhanger
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Re: Tyre pressure adjustment

Post by monkeyhanger » Sat Jul 13, 2019 6:56 pm

Rosinfield wrote:
Sat Jul 13, 2019 5:07 pm
Maybe it's different for the 17 inch tyres on my car. But it feels very comfy at pressures slightly above those recommended.
The 17" wheels come on Michelin Primacy tyres, which are decent, flexible, comfy tyres.

The stock 18" tyres are Bridgestone Turanza, which are rock hard, noisy and inflexible.

Anyone that has changed their Turanzas for Michelin PS4 will find once again that they're comfy and flexible.

That's the main difference - Michelin tyres are comfy at lower or higher pressures, the Turanzas aren't.

Rosinfield
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Re: Tyre pressure adjustment

Post by Rosinfield » Sat Jul 13, 2019 8:48 pm

Indeed, Primacy 3

S_94
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Re: Tyre pressure adjustment

Post by S_94 » Sun Jul 21, 2019 11:59 am

For the guys who have swapped tyres to the MPS4's...

Is 35.0psi okay for each tyre? Checked mine this morning as I've done quite a few trips lately and they've dropped from 36.0 > 35.0 from the last time I checked (around 2 weeks ago).

fazzy
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Re: Tyre pressure adjustment

Post by fazzy » Fri Aug 02, 2019 7:06 am

Can anybody with a pre-gpf Polo GTi post a picture of the tyre pressure sticker which is stuck on the car?

l3rady
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Re: Tyre pressure adjustment

Post by l3rady » Fri Aug 02, 2019 9:55 am

S_94 wrote:
Sun Jul 21, 2019 11:59 am
For the guys who have swapped tyres to the MPS4's...

Is 35.0psi okay for each tyre? Checked mine this morning as I've done quite a few trips lately and they've dropped from 36.0 > 35.0 from the last time I checked (around 2 weeks ago).
Found 38psi fronts and 35psi backs work well for me on MPS4 tyres. The reason for the higher front pressure is due to most of the car weight being at the front and I very rarely carry rear passengers.

monkeyhanger
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Re: Tyre pressure adjustment

Post by monkeyhanger » Fri Aug 02, 2019 9:58 am

l3rady wrote:
Fri Aug 02, 2019 9:55 am
S_94 wrote:
Sun Jul 21, 2019 11:59 am
For the guys who have swapped tyres to the MPS4's...

Is 35.0psi okay for each tyre? Checked mine this morning as I've done quite a few trips lately and they've dropped from 36.0 > 35.0 from the last time I checked (around 2 weeks ago).
Found 38psi fronts and 35psi backs work well for me on MPS4 tyres. The reason for the higher front pressure is due to most of the car weight being at the front and I very rarely carry rear passengers.
35/36psi all round for me on PS4. 38psi on the fronts seems a bit high. Might want to check your tread depths and make sure they wear evenly, and aren't wearing out quicker in the centre of the tread.

I have 2 kids in yhs back of the car most days - dropping them off at breakfast club before school, on my way to work and when not doing commuter miles.

l3rady
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Re: Tyre pressure adjustment

Post by l3rady » Fri Aug 02, 2019 10:35 am

monkeyhanger wrote:
Fri Aug 02, 2019 9:58 am
35/36psi all round for me on PS4. 38psi on the fronts seems a bit high. Might want to check your tread depths and make sure they wear evenly, and aren't wearing out quicker in the centre of the tread.

I have 2 kids in yhs back of the car most days - dropping them off at breakfast club before school, on my way to work and when not doing commuter miles.
I carry a depth gauge and pressure gauge in the boot and check regularly. So far tyre wear seems even however only 500miles in so still early days. 38f/35r worked well for my last polo without uneven wear. I will report back if I decided to adjust if I start to see uneven wear.

monkeyhanger
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Re: Tyre pressure adjustment

Post by monkeyhanger » Fri Aug 02, 2019 2:45 pm

l3rady wrote:
Fri Aug 02, 2019 10:35 am
monkeyhanger wrote:
Fri Aug 02, 2019 9:58 am
35/36psi all round for me on PS4. 38psi on the fronts seems a bit high. Might want to check your tread depths and make sure they wear evenly, and aren't wearing out quicker in the centre of the tread.

I have 2 kids in yhs back of the car most days - dropping them off at breakfast club before school, on my way to work and when not doing commuter miles.
I carry a depth gauge and pressure gauge in the boot and check regularly. So far tyre wear seems even however only 500miles in so still early days. 38f/35r worked well for my last polo without uneven wear. I will report back if I decided to adjust if I start to see uneven wear.
Too early to tell at 500 miles, but at 4500 miles since I ditched the Bridgestones on the first GTI+, mine are wearing evenly at 36psi all round.

S_94
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Re: Tyre pressure adjustment

Post by S_94 » Fri Aug 02, 2019 6:47 pm

The person who fitted my tyres recommended me to swap the front and back tyres over at around 5,000 miles of use. Not sure if you guys would do the same thing?

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