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Soaking Up Potholes?

Discuss your latest mods or ideas, and anything to do with the BMW X5 (E70).
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as400
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Soaking Up Potholes?

Post by as400 » Fri Jan 10, 2014 1:05 am

Obviously some potholes are massive and your going to feel the jolt even if your in a Rolls Royce but what combo of suspension and wheel/tyre option will do you the most favours with ironing out the usual holes we are plagued with at this time of year?....I'm guessing sticking with 18" to start?

Nat
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Re: Soaking Up Potholes?

Post by Nat » Fri Jan 10, 2014 8:14 am

Hi,


I would guess non run flat, high sidewall will be optimim, so think anything with a 50/55 series side wall.
There again a smaller wheel will " enter " further into the pothole so you could argue that a bigger wheel is better.
Its an expensive experiment , but Id start with non run flats to begin with. If thats still too hard then 19's with a 50/55 series side wall.
If thats still no good then an 18 with a 60 series side wall.......etc etc

I deliberately ordered an SE and I am on 20" runflats and I have to say that the ride is very acceptable on our rutted roads.
I tend to drive in a spirited fashion and have found this to be the best compromise for me. The sport was just too hard and crashed over the potholes. The SE has some good compliance without loss of handling. I am very happy with my choice.
On my old E53 I had 19 winters and the ride was more compliant over the potholes, but it also rolled/moved about a bit more...........not masses but it was noticeable.

Just my opinion of course.............

martin33100
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Re: Soaking Up Potholes?

Post by martin33100 » Fri Jan 10, 2014 8:44 am

[quote="Nat"]
Hi,


I would guess non run flat, high sidewall will be optimim, so think anything with a 50/55 series side wall.
There again a smaller wheel will " enter " further into the pothole so you could argue that a bigger wheel is better.
Its an expensive experiment , but Id start with non run flats to begin with. If thats still too hard then 19's with a 50/55 series side wall.
If thats still no good then an 18 with a 60 series side wall.......etc etc

I deliberately ordered an SE and I am on 20" runflats and I have to say that the ride is very acceptable on our rutted roads.
I tend to drive in a spirited fashion and have found this to be the best compromise for me. The sport was just too hard and crashed over the potholes. The SE has some good compliance without loss of handling. I am very happy with my choice.
On my old E53 I had 19 winters and the ride was more compliant over the potholes, but it also rolled/moved about a bit more...........not masses but it was noticeable.

Just my opinion of course.............
[/quote]Did you order your SE with standard suspension?, I bought a used SE and when I spoke to BMW regarding the suspension they said the SE comes with sports suspension unless its ordered with standard suspension. Wether that's right or not I don't know but what I do know is our X5 has a very hard ride on 20's and sports suspension. I do want to change to non run flats but the tyres still had 6-7 mm left on them when we bought the car so need to wear them out first.

tiger78
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Re: Soaking Up Potholes?

Post by tiger78 » Fri Jan 10, 2014 9:10 am

Ive got a 2012 Msport with 20" run flats on - for winter have dropped to 18" non run flats.  I cant actually notice any difference - apart from the 18" set I have had the car sideways a couple of times.

Majority of my driving is a and b roads which I know very well and there are certain lines you take for a smoother ride!!
The smaller the wheel - will effectively make the pot hole larger as mentioned above.  only thing you can do is not runflats and increase sidewall with smaller alloy

Nat
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Re: Soaking Up Potholes?

Post by Nat » Fri Jan 10, 2014 10:47 am

Hi,

Yes, SE with the M sport suspension delete box ticked.

Like a cashmere codpiece.................... :))

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Caesium
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Re: Soaking Up Potholes?

Post by Caesium » Fri Jan 10, 2014 11:35 am

Guys
Smaller alloys don't make the wheel smaller and make more of it go into the pothole.

My 20" alloys are the same size as 18" alloys in diameter when you include the tyre.

As the alloy gets bigger the profile of the tyre gets smaller to compensate, this is referred to as rolling radius.

The rolling radius has to remain the same otherwise the speedometer and odometer will not display the correct speed and the handling of the vehicle will be adversely affected.

Hope this helps understanding.
Currently :
2013 BMW E70 X5 40D MSport

Previously :
2008 BMW E92 335D MSport
2004 BMW E46 M3
2005 BMW E60 535D MSport
2002 BMW E39 530D Sport
The list goes on...

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Steamyrotter
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Re: Soaking Up Potholes?

Post by Steamyrotter » Fri Jan 10, 2014 1:12 pm

[quote="as400"]
Obviously some potholes are massive and your going to feel the jolt even if your in a Rolls Royce but what combo of suspension and wheel/tyre option will do you the most favours with ironing out the usual holes we are plagued with at this time of year?....I'm guessing sticking with 18" to start?
[/quote]

Buy a hovercraft and park the X on the back of it??
:P

Smaller rims will mean larger tyre sidewall and therefore more compliance when over the bumps.
Go too far and you could get a soggy drive around bends though!
If things were meant to be easy, then I will soon complicate them....
Please note...
Anything I say is only from my personal experience and knowledge..
I don't assume to know everything, and know there is a lot I don't know..
But then I could be talking bollox.. O:-)

leosayer
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Re: Soaking Up Potholes?

Post by leosayer » Fri Jan 10, 2014 1:21 pm

I've got 18" wheels fitted with non- runflats and standard (ie. non sports suspension). I still avoid potholes, but when I can't it soaks them up a lot better than it did with runflats fitted.

Aside from suspension and tyre sidewall stiffness, unsprung weight is one of the biggest factors influencing ride quality.

Run flats tyres can be many kg heavier than non-flats (6kg per wheel in my case)
20" wheels can also be many kg heavier than 18"s.

In general, a lighter wheel and tyre will give the suspension, and therefore your spine, a much easier time.

Also, make sure your tyre pressures are set correctly. Less air generally improves bump absorption.

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