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E89 Tyres

Specific discussion about the E89 2009 Z4 (sDrive35is, sDrive35i, sDrive30i, sDrive23i)
Hellequin
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E89 Tyres

Post by Hellequin » Fri Oct 27, 2017 11:31 pm

How do you find the right tyre pressures for NRFs?
59 plate sDrive23i 2.5

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bob4333
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E89 Tyres

Post by bob4333 » Sat Oct 28, 2017 8:15 am

I suppose the lid's going to come off the can of wriggly things anyway so here goes. It's an honest question.

Trial and error to see what suits you best is going to be the only way but the range seems to be between RFT pressures at the top end and about 34F / 36R at the bottom.

I started at RFT pressures but the car felt vague at speed. Tried the other extreme with 32F / 34R which didn't quite do it for me. I'm now on 34F / 36R, which is better but I reckon another 2 psi in the rear tyres will be about there.

This is on 19" 235 section fronts and 265 section rears. Wheels are 8.5J and 9.5J

Busterboo
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E89 Tyres

Post by Busterboo » Sun Oct 29, 2017 11:25 am

Which tyres are you using?
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john-e89
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E89 Tyres

Post by john-e89 » Sun Oct 29, 2017 11:43 am

MPSS’s on my 19” 326 rims, superb tyres, very very supple and fantastic grip.

I run them at car factory pressures having played around with them. I found even 2psi noticible and for the worse either way, proabably more so too high than too low, the car seemed to feel twitchy, but I would think it’s down to which tyre you fit to find your ideal pressure, maybe start at factory pressure then take it from there.
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E89 Tyres

Post by Baza » Sun Oct 29, 2017 12:04 pm

bob4333 wrote: Sat Oct 28, 2017 8:15 amTrial and error to see what suits you best
Yes I agree, It also seems to depend on the tyre you are using I found on my previous set of Vredestein Ultrac Vorti The car felt better at a lower pressure than my present set of MS 4's which I run at 34 front 36 rear .
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S Drive 3.0i E89 2009 Space Grey Coral red Int 18" 295 wheels

Busterboo
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E89 Tyres

Post by Busterboo » Sun Oct 29, 2017 12:17 pm

bob4333 wrote: Sat Oct 28, 2017 8:15 am ... I started at RFT pressures but the car felt vague at speed. Tried the other extreme with 32F / 34R which didn't quite do it for me. I'm now on 34F / 36R, which is better but I reckon another 2 psi in the rear tyres will be about there.

This is on 19" 235 section fronts and 265 section rears. Wheels are 8.5J and 9.5J
Which tyres are you using?
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bob4333
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E89 Tyres

Post by bob4333 » Sun Oct 29, 2017 1:16 pm

Busterboo wrote: Sun Oct 29, 2017 12:17 pm
Which tyres are you using?
Continental Sport Contact 6

Pbondar

E89 Tyres

Post by Pbondar » Sun Oct 29, 2017 2:59 pm

bob4333 wrote: Sun Oct 29, 2017 1:16 pm
Busterboo wrote: Sun Oct 29, 2017 12:17 pm
Which tyres are you using?
Continental Sport Contact 6
I’m running those on the standard pressure suggested on the door bulkhead...they seem A OK :thumbsup:

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bob4333
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E89 Tyres

Post by bob4333 » Sun Oct 29, 2017 5:12 pm

I'm about 1200 miles into the assimilation process. The front feels OK now and I agree a 2 psi change is noticeable.

In terms of ratio F/R the pressures I'm currently on (34F/36R) are are way out of wack with those of the original RFT's. It's an interesting exercise that doesn't appear to have a universal answer although opinions seem to run very strongly.

Definitely work in progress. :driving:

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