545i 18" Sport Pkg - Wider Tires !!! [Archive] - Bimmerfest - BMW Forums

: 545i 18" Sport Pkg - Wider Tires !!!

02-12-2007, 07:37 PM
Just bought an 05 545i with Sport Pkg and 18" Rims.
Upgraded from 01 540i with M Pkg with Nexen 255/40/R17 on the rear.

The 05 545i has Run-Flat Dunlops sized 275/35/R18.
Since the are run-flats, there's no spare or jack.

I would like a larger footprint.
Maybe a 285 or 295 on the rears.

Anyone upsize their rears?
Are there good run/flats in the above sizes?

Not a Dunlop fan.


02-12-2007, 08:36 PM
Is the reason you want wider rear tyres because you want the car to understeer more? The 545i should have enough understeer as it is, so increasing the rear width (having the rear grip more) will increase it. Consider keeping the stock setup - engineers tested to make sure it was optimum.

In fact, I find sometimes my 530i with the same tyres all around to understeer more than I'd like. And that has a lighter engine to boot!

02-12-2007, 10:18 PM
check the trunk - there should be a spare and a jack. It is included on the 5-series even though they have run-flats (unless Canada is different)

02-13-2007, 08:15 AM
My former 01 540i with the M-pkg handling was unreal (which is to say typical for a BMW ride).
I had the tires upsized 1-size to 255/40/R17 and it made a difference to both the feel and look of the car.

The 05 545i has the sport pkg and the handling is also unreal, maybe even better feel with the ARS.
I find, however, that BMW intentionally dials the suspension to a nuetral stance.
Without adjusting the caster or toe-in I can get a little more forgiving understeer and sticky rear-end by upsizing the tires.

With the larger tires, it will definitely "stick" better and the looks will be improved.

I'm just very partial to a Bimmer with a large footprint at the back.
It represents the sportiness of the car.
Just a personal choice.

Doug, no spare, no jack.
I've asked the dealer to look into why.

Anyone else buy an 05 545i with run-flats and not get a spare in the trunkwell ???

02-13-2007, 09:29 AM
I don't have a 05 545 but I do have an 07 550i and it came with a spare and jack. However, I do agree with you about the wider rear giving the car a more aggressive and sportier look.