Upgrading Suspension on BMW E90

[RobM77]

I've just bought a 2010 E90 320d ED and it's great. It satisfies my needs of being quiet on the motorway (16" wheels), not too grippy (16" wheels!) and good mpg (I'm averaging close to 70mpg...). I also already have 16s with winter tyres fitted. The trouble is that the ride and handling isn't very good; it understeers quite a lot and bounces up and down like a pogo stick on bumpy lanes. I want to uprate the suspension, but what I definitely don't want to do is upsize the wheels, I want to stick with 16s.

Can anyone comment on my options? The BMW specialist that I use says he can fit 'sports' suspension or 'M Sports' suspension, but I understand these are designed for 17" wheels - would I run into problems running 16s? I presume the car would be lowered by 13mm (half in inch) compared to standard M Sport and ED, which both run 15mm lower. M Sport cars also appear to have wider rear tyres, whereas I'd be running the same all round - any comments on that?

The other option is aftermarket - Bilstein, Koni etc.

Any thoughts?

[RobM77]

Thank you very much for your replies.

I'm not on RFTs, no, but this is standard for the ED. I agree entirely regarding these; my previous car, which I sold on Wednesday, was a pre facelift E90 SE and the RFTs were fine. As you say, the tyre sidewall is a significant part of the suspension, so it's all tuned together. The ride when changing to my non-RFT winters was definitely worse.

My pre facelift E90 SE had really nice handling, yes. If I'm changing the suspension on my ED though then if the outlay is similar I'd like to go a stage further than the SE. Whilst on the motorway I value quiet and economic driving, on B roads and twisty roads I value handling above all else. I'm a huge fan of the E92 M3, but just can't justify the outlay given how little performance matters to me in a road car.

The Birds kit is of great interest, so thank you for suggesting it. I'd forgotten that they offered this. I've been disappointed by the focus on lowering and looks by other aftermarket kits, so this one's focus on road driving really appeals to me. I'll phone them on Monday.

[RobM77]

Thanks Wookie, I've just e-mailed Alpina UK.

My Birds quote was £1600 for springs, dampers and ARBs, that's parts only minus fitting. Kevin Bird said he would normally advise against uprating the ARBs without an LSD, but given the low power output of my car he thought it would probably be ok. The issue is the lightly loaded inside wheel spinning away the power.

[RobM77]

The Wookie said:

RobM77 said:

Thanks Wookie, I've just e-mailed Alpina UK.

My Birds quote was £1600 for springs, dampers and ARBs, that's parts only minus fitting. Kevin Bird said he would normally advise against uprating the ARBs without an LSD, but given the low power output of my car he thought it would probably be ok. The issue is the lightly loaded inside wheel spinning away the power.

Probably tells you all you need to know about the compliance of that setup!

Perhaps, yes! I could always go with just the springs and dampers. Apparently the springs are a touch softer than M Sport and they then spent a while speccing the dampers to suit.

BMW constantly surprise me. Sometimes BMW come up with a beautifully judged setup (e.g. the E90 M3, my old E36 328i Sport, and even my 2007 pre-facelift E90 SE was pretty decent), but sometimes they're awful: my ED for example is the worst handling BMW I've ever driven, and my Z4C would just never settle on a bumpy road; it was a 1320kg FE/RWD car with a super stiff chassis, so I've no idea why they couldn't make it ride in the same ballpark as an Evora or even a Cayman.

[RobM77]

Thanks for the insight.

I've heard back from Alpina. They tell me that they're 'a manufacturer of exclusive automobiles' and are not 'a tuner or supplier of accessories'. They pointed me to Birds or Schnitzer.

[RobM77]

An update for you: I've done a fair bit of research over the last few months and yesterday had Birds springs and dampers fitted, together with their anti-roll bars, and this morning I had a full geo done. The difference, as you can imagine, is startling. I had been putting it off due to the cost of the Birds kit (with the ARBs it was £1600 in parts alone!), but recently my suspension had degraded to the point where it was actually quite dangerous, especially towing (I tow a covered trailer with an all up weight of 1350kg), and given the cost of MSport suspension and its mixed reviews I figured it was worth spending a bit more given the Birds kit's overwhelmingly favourable reviews.

So, relatively it's obviously a complete revelation. In absolute terms though, compared to other cars I've driven (including M3s), I'm extremely pleased with it. Of particular note are the uprated anti-roll bars, which curb roll to a huge degree in corners.

I realise it's a bit odd having a wheezy diesel engine with suspension like this, but given my obsession with handling and disinterest towards performance, it suits me perfectly.

I was initially worried that the much lower unsprung mass of my 16" wheels and eco tyres would prove too different to Birds' customer's usual 19"ers with sticky sport tyres, not to mention my car's much lower kerb weight, but it feels fine to me. Sure, it's probably slightly more optimal on a big fat 335i, but until someone designs suspension specifically for a 320d running on the smallest wheels and tyres possible (which isn't going to happen!), it's the perfect solution.