Run Flats to Normal Tyres on 20" Wheels 2006 X5

dobbor1 · Post by **dobbor1** » Tue Oct 09, 2012 12:52 pm

Hi,

I have been to see Kwik Fit today and they have informed me that by changing from run flats to normal tyres will not affect the tyre monitoring system as it monitors the ride height of the vehicle rather than a pressure sensor. Is this true or a bag of Sh*t?

Also, it is possible to change the rear tyres from 315/35/R20 to the same as the fronts 275/40/R20?

The wheels were put on as a factory option by the guy who bought the car new in 2006 and has sports suspension.

Thanks Jeff

Rusty · Post by **Rusty** » Tue Oct 09, 2012 2:15 pm

The pressure monitoring system on the facelift E53 is done via the ABS sensors. If one particular wheel is rotating at a different speed to the others under normal driving conditions (not braking, cornering etc) it will flag an error message to get you to check the tyres. There are no sensors within the wheels as were fitter on earlier models.

As for changing the tyre size - are the rears a different width rim to the front (most are - mine included)? ie 10.5 rear 9.5 front?
If so then I think it unlikely that you are able to fit the same size tyres front and rear.

Some tyre websites have a tyre size calculator to show the different types that will fit - give some a go.

HTH

Cannondale · Post by **Cannondale** » Tue Oct 09, 2012 2:46 pm

I guess you could fit the 275,s to the rears if you got a spare set of front wheels.

But why would you want to?

The 315,s look so good on the back.

Richard...

CondorX5 · Post by **CondorX5** » Tue Oct 09, 2012 3:46 pm

My 315 sleds have been safely packed away for months now as I didn't have the time or energy to swop them back and take the winters off this year! They may look good, but that's about all - i don't enjoy skidding around in very cold or wet conditions on a pair of sleighs! Plus the ride on the Vredestein Wintrac 18" tyres is so much nicer

. No street cred in a ditch! The 20's have Vredestein Sessantas fitted which are a great improvement on the ride quality of the Diamaris and Bridgestones I have had in the past, though, must make mental note to remember to fit them again when spring 2013 arrives!

X5Sport · Post by **X5Sport** » Tue Oct 09, 2012 3:49 pm

They're talking the usual rubbish that a Sh!t Fit Fitter does!! If it was ride height based the system would alarm at every bump as the sidewalls flex!! As said, it's done via the ABS.

Not a good idea to put 275s on those wheels as you run the risk of having the sidewall 'pop' off it's bead rim if you 'nudge' a kerb. X5 'Sport' is supposed to be staggered if on the 20" rims (as it is on the 19" too). Only the base model with the 17" rim was identical front and rear.

dobbor1 · Post by **dobbor1** » Tue Oct 09, 2012 3:56 pm

Thanks guys,

Ok, lets say the rears are 10.5 and I stay with the 315's which I love the look of anyway. Am I ok to change them to non run flats when the time comes to replace them? I guess what I am getting at is, will running non run flat tyres cock up the tyre sensor?

Jeff

X5Sport · Post by **X5Sport** » Tue Oct 09, 2012 4:02 pm

Have you got an E53 (Mk1 X5) or E70 (Mk2 X5)?

E53 was standard without RFT
E70 was standard with RFT - but you don't have to keep them. Of course you'll need some tyre goo or a spare!!

dobbor1 · Post by **dobbor1** » Tue Oct 09, 2012 5:40 pm

Mine is the E53 model. So will I will be ok with Non Run Flats on the 20's?

X5Sport · Post by **X5Sport** » Tue Oct 09, 2012 5:47 pm

They were not supplied with RFT's by default. You may have a set off an E71 X6 (or an E70 but those wheels don't fit without added spigot rings) which do have RFT. You'll be fine with normal non-RFT tyres. The ride will be a bit softer too, and you should also already have a (17") spare wheel. No problem..

Richard

dobbor1 · Post by **dobbor1** » Tue Oct 09, 2012 6:08 pm

Brilliant thanks.

Raj · Post by **Raj** » Wed Oct 10, 2012 7:55 am

As others have confirmed Kwik Fit are muppets, don't put 275's on the rear 10.5j rims (unless you want a proper euro look, stretched tyre) and bin the RFTs with no issues.

XSeries-forum

XSeries-forum