[HighlandPete]

Originally Posted by JD6

If the ride improves as well as the handing with these springs, that suggests that BMW haven't done a great job. The case for these springs sounds quite compelling

BMW's brief for the xDrive is clearly different from what some are wanting from the chassis. With a higher centre of gravity and what must be a softer spring as it has longer spring travel, (not seen any comparisons for exact spring rates) there will be a different ride. How that translates to ride definition of "the same", "better", "no worse", or "improved" is often very personal. We'd need some instrumentation to measure the body frequency and wheel frequency to say for sure 'what is what'.

Often a more controlled body, feels more comfortable, although in reality it is a firmer ride. BMW have often got it wrong for UK driving, secondary ride not too settled. Some models have a very jittery ride on standard suspension, whereas the sport suspension has stopped that behaviour at the cost of a more tightly controlled body and a slightly firmer ride. Often that feels so much better, and we forgive the lose of a bit of ride quality.

I agree RFTs are still part of the problem, even if they are much better these days. A tyre is a primary suspension component, so if we have a tyre which has less compliance, it will show through on testing surfaces.

HighlandPete

[JD6]

Good to hear, thanks cjm

[JD6]

Pete - I completely agree that what we consider a good ride is subjective. When one person fits a modification like this and says it is a big improvement, I remain cautious. It could be post purchase rationalisation. When about a dozen take a very similar view, it looks pretty compelling to me, particularly if the other experiences they describe match my own.

I remember test driving an E60 530d soon after it was launched. That was my first experience of runflats. At some point I drove over some cats eyes at about 40. For a minute I wondered if the tyre had come off and I was running on a rim. The first generation of runflats were just terrible.

They have come a long way, but there is no doubt that they are still a compromise. Perhaps I will follow others here and ditch them when I need replacements.

[madmal007]

I'm very interested but concerned about suspension travel when carrying four adults or negotiating speed humps (my car park at work has loads). Has any one got any experience of this?

[Tengocity]

Originally Posted by madmal007

I'm very interested but concerned about suspension travel when carrying four adults or negotiating speed humps (my car park at work has loads). Has any one got any experience of this?

I've had them for about 10k miles with all sorts of loads, on all sorts of roads, never had any issues so far.

[matk]

I think with all the negative views on non run-flats BMW should give us the option to fit at factory or not. They should not be standard fit IMO

[....,,,,..,,..]

Originally Posted by matk

I think with all the negative views on non run-flats BMW should give us the option to fit at factory or not. They should not be standard fit IMO

Bit of a pain for a company to handle that, multiple stock items and dual approvals process for run flat car and non.

A lot of the negative views are from older versions.

That and a small number of forum people.

I accept the run flat ride v the risk of a flat.

Let's face it our are pretty shoddy as it is.

[Tengocity]

Originally Posted by Brigand

Bit of a pain for a company to handle that, multiple stock items and dual approvals process for run flat car and non.

A lot of the negative views are from older versions.

That and a small number of forum people.

I accept the run flat ride v the risk of a flat.

Let's face it our are pretty shoddy as it is.

Sorry have to disagree with this. You can spec your car from new, be it paint, leather, extras, engine, gearbox and drivetrain... Surely choosing tyres would be no different?

Eco choices, or sportier?
Run flat or non run flat?

And that you can't choose m performance extras and wheels from factory is a farce... Especially the wheels- forces people to buy wheels they don't want, then have to sell at a loss.

[....,,,,..,,..]

Originally Posted by Tengocity

Sorry have to disagree with this. You can spec your car from new, be it paint, leather, extras, engine, gearbox and drivetrain... Surely choosing tyres would be no different?

Eco choices, or sportier?
Run flat or non run flat?

And that you can't choose m performance extras and wheels from factory is a farce... Especially the wheels- forces people to buy wheels they don't want, then have to sell at a loss.

I agree that's how it should be, however I believe they have to pass various certification and approvals process on standard car and tyres form part of this.

Just wait for next round of Eco 'improvements' manufacturers will likely ship with Eco tyres as standard to get that emissions tick in box.

Apart from that there is a finite limit on what actual stock you want to hold.

Run flats saves them stocking inflation kits etc, less warehousing and less spend on static stock.

[matk]

Originally Posted by Tengocity

Sorry have to disagree with this. You can spec your car from new, be it paint, leather, extras, engine, gearbox and drivetrain... Surely choosing tyres would be no different?

Eco choices, or sportier?
Run flat or non run flat?

And that you can't choose m performance extras and wheels from factory is a farce... Especially the wheels- forces people to buy wheels they don't want, then have to sell at a loss.

Agreed mate we should be able to put m perf alloys with non runflat tyres if we choose too, even if there was a delay to have to wait to order the items separate. But they wont as the production line would stall if they offered too many options.

[cr55]

How much have dealers charged for fitting the AC springs ?

[Msportman]

This was my recent reply to a fellow forum member who was asking on my personal experience of the ACS springs:



On my car the comfort was actually improved as there was less wallow and front end dive under braking.

They are well suited to the car and it now corners much flatter than before. It was a big improvement on the 320d. It's still no GTI as it's a family sports estate and to totally transform handling I would suggest a full blown suspension set up from ACS , KW or Bilstein if you are looking for ultimate handling.

The 335d will be slightly heavier on the front end but I am confident you will be pleased.

The ride height did come down to sensible levels. It is not slammed and rides lower than a stock 330d. The front is lower and it ha taken a fair chunk of gap away from the ride height.
The design of the front arch doesn't aid the visual stance of all F30 /31 and even the new M3/4 look somewhat raised



I would highly recommend them!


My car incidentally does "Not" have adaptive chasis although BMW still call it Msport for the Xdrive.

I don't know how much different the damper is to the normal two wheel adaptive chasis set up but to me it runs superbly and the springs have tied it down nicely on the front. It runs on the 18 inch Bridgestone runflats and the ride after coming from an A4 Sline is great. It's leagues ahead of the E90 I had previously which was very jittery even on 17's.

I've had Bilstein and KW Clubsports which were superb on other cars which were hot hatches but don't expect a go kart ride. It's subtle and sporty with a nice flat ride but enough give in the travel to make it great for the UK roads.

I hope my M4 will be the same for long distance trips!!

[Lorcan]

Originally Posted by cr55

How much have dealers charged for fitting the AC springs ?

Most seem to be around £650 all in, including the springs.