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7 seater tyre pressures vs 5 seater

Posted: Wed Oct 10, 2018 11:12 am
by Chrispy
Hi all,

Looking around to make sure I'm running the correct pressures for the 7 seat setup.

I found this post http://xdrivers.co.uk/forum/index.php/t ... #msg118469 which matches my 19" wheels but I believe his car was a 5 seater - does the 7 seater require different pressures with the extra weight?  Otherwise is a 28 psi front / 32 psi rear sufficient?

I'm talking unladen here - not 7 people in the car and a boot full of ironmongery.  :)

Cheers,

Chris.

Re: 7 seater tyre pressures vs 5 seater

Posted: Wed Oct 10, 2018 5:47 pm
by Emigrant
I've read a lot about this and everyone says put in maximum pressure.
I run 2.9 bar rear and 2.5 front. I have even tyre wear and it's 5 seater.

Re: 7 seater tyre pressures vs 5 seater

Posted: Thu Oct 11, 2018 12:08 am
by Graeme
Not sure who "everyone" is.  Go by the pressures recommended on the plate on the B pillar by the driver's door.  High pressures when only the driver in will quickly lead to central wear on the rears especially, as well as making the ride exceptionally hard.  I only use the higher pressures recommended when towing along with a boot full of awnings and poles etc, or if I have a full load of passengers.
GRaeme

Re: 7 seater tyre pressures vs 5 seater

Posted: Thu Oct 11, 2018 2:31 pm
by Emigrant
Just 90% of what I read on the web. 90% say run the maximum recommended tyre pressure.
I've done that for a year now on new tyres and have even wear across all 4 tyres.
Is it harsh? Yes it is but, I'm sure all 20" wheels with rubber band run flats are.

Re: 7 seater tyre pressures vs 5 seater

Posted: Thu Oct 11, 2018 2:54 pm
by pcdee
[quote="Emigrant"]
Just 90% of what I read on the web. 90% say run the maximum recommended tyre pressure.
I've done that for a year now on new tyres and have even wear across all 4 tyres.
Is it harsh? Yes it is but, I'm sure all 20" wheels with rubber band run flats are.
[/quote]I've run my 20's on max for the last 5 years and they've been fine.

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Re: 7 seater tyre pressures vs 5 seater

Posted: Thu Oct 11, 2018 6:15 pm
by X5Sport
Only ever run standard pressures and never had any problems.

Re: 7 seater tyre pressures vs 5 seater

Posted: Thu Oct 11, 2018 6:55 pm
by Huxsta
We have a 7 seater. 39psi all round 365 days a year.

Re: 7 seater tyre pressures vs 5 seater

Posted: Thu Oct 11, 2018 9:41 pm
by Chrispy
I think the B pillar plate can be a little hard to interpret - not sure if it's just me?  And it doesn't seem to differentiate for the 7 seater vs the 5?

28 psi front and 32 rear seemed low to me too.....

Re: 7 seater tyre pressures vs 5 seater

Posted: Thu Oct 11, 2018 11:55 pm
by Graeme
Mines a 7 seater and all I have to do is find the wheel and tyre size on the car  n the boxes on the left and read the pressure, given in BAR,  in the appropriate boxes for up to 4 occupants or seven +luggage.  Not rocket science!

Re: 7 seater tyre pressures vs 5 seater

Posted: Fri Oct 12, 2018 6:46 am
by X5Sport
Each version has it’s own plate, and you would think that the manufacturer would know what pressures to use based upon thousands of hours of testing.  The tyre wear is even.  More issues with wear seem (from what is on here at least) are the result of incorrect wheel alignment at build - BMW’s tolerances are somewhat wide!

Higher pressures can also change the circumference of the tyre and lead to transmission issues.  My X6 very definitely doesn’t like the highest pressures when running on ‘*’ rated winter tyres.  Dropping the pressure just a few pounds when the payload is lighter again stops any droning.

It also softens the ride again - well as much as it can be softened with RFTs anyway  ;)