420d vs 435d suspension
Discussion
4 months ago I sold my 645 and got an Xdrive 420d Gran coupe, I'm doing a lot more miles now and it was the sensible decision.
The 420d is, obviously, a lot slower. It's also a bit boaty in the corners, where the 645 would corner pretty much flat the 420 leans.
This is actually annoying me more than the lack of power. I noticed it a little on the test drive but it's become more noticeable in daily use.
As far as I understand getting the Xdrive means that you don't get the slightly lower/firmer M Sport suspension and get SE suspension instead.
Do the more powerful variants of the Xdrive 4 series (435d) have better suspension or would I need to go RWD for something that will allow me to corner without excessive lean? I'm not talking extremes here, things like dual carriageway roundabouts seem to be a bit much for it.
The 420d is, obviously, a lot slower. It's also a bit boaty in the corners, where the 645 would corner pretty much flat the 420 leans.
This is actually annoying me more than the lack of power. I noticed it a little on the test drive but it's become more noticeable in daily use.
As far as I understand getting the Xdrive means that you don't get the slightly lower/firmer M Sport suspension and get SE suspension instead.
Do the more powerful variants of the Xdrive 4 series (435d) have better suspension or would I need to go RWD for something that will allow me to corner without excessive lean? I'm not talking extremes here, things like dual carriageway roundabouts seem to be a bit much for it.
RobM77 said:
This is essentially the difference between SE and M Sport. Years ago, SE was fine and M Sport was very firm, but both have softened now to the point where I can't cope with SE at all and find it awful, whereas M Sport is really good. Better than both, in my humble opinion, is Birds, but it costs money and may invalidate your warranty (may... I don't know that).
The other thing you'll notice is the reduced weight over the nose on the 420d compared to the 435d - with the right suspension the handling should be fantastic.
I don't have to worry about warranty, it's 5 years old. Bought it mainly for 12K a year commuting. I don't expect it to be this floaty, it's certainly the worst I've encountered out of 9 BMWs including X5s. Annoyingly the test drive didn't really encounter the sort of high speed corner that really shows it up.The other thing you'll notice is the reduced weight over the nose on the 420d compared to the 435d - with the right suspension the handling should be fantastic.
So my options are,
Live with it - free but it's annoying me already.
Upgrade the suspension to what BMW really should have fitted in the first place. Schnitzer springs are £338 plus fitting, so probably around £500 total and get's good reviews. This should solve most of my issues with the car, apart from the lack of thrust that I knew about while buying.
I'll ask the mechanic for a quote to fit springs when it goes for an oil change next week.
Or I could buy a RWD BMW again, been looking at 5 and 6 series but I'll need to add about 4-5K to the pot to get something a similar age with the most powerful diesels. Only issue with them is that I'd loose the practicality of the hatchback and 4WD.
Also my wife is likely to hurt me if I change the car again after 4 months.
RobM77 said:
I had a day's test drive in an F30 a while ago, looking to change from my E90. I'm really glad I did, because the SE suspension was truly awful. I wrote a review for Pistonheads, but it was so scathing I didn't publish for fear of the backlash. Your post is making me wonder if the incoming vitriol would have been worth it to pass on the info to people who would benefit from knowing.
Birds on my E90 cost me £1500 plus fitting, so it's not cheap. That did include ARBs though, which imho were the best bit - the cornering was so flat, yet the car was so supple in a straight line. I bought it when in your situation with my second E90 - the first's SE suspension was fine, but the LCI was all wallowy (I think this is when the softening of all models started).
It is a proper chunk of change, however if it's a car you intend to keep and do miles in it's not that horrific. I've had a look on the Birds website but they don't list much for the 4 series with smaller engines, I imagine a phone call would sort out what could be fitted to give the flat cornering I'd like. I did wonder if bigger anti roll bars would be the answer to keep things in check while being driven enthusiastically.Birds on my E90 cost me £1500 plus fitting, so it's not cheap. That did include ARBs though, which imho were the best bit - the cornering was so flat, yet the car was so supple in a straight line. I bought it when in your situation with my second E90 - the first's SE suspension was fine, but the LCI was all wallowy (I think this is when the softening of all models started).
I don't think I'd be willing to chuck £2k upwards at a car as I do tend to change them regularly, this is my 21st car in 25 years of driving. I've stopped owning two at once though!
.
The annoying part is that the 14 year old 6 series was so good, obviously it was initially a far more expensive car (and it had active anti roll bars) but it cornered flat all the time, while being steerable on the throttle.
I miss it... I've even been kind of looking at the last of the E63 shape 6 series knowing full well that they're old cars that in my case needed a lot of expensive maintenance, but they're so nice when they work properly. And 18mpg isn't that bad really..
RobM77 said:
Birds don't list the smaller engined models because they don't get much business from people like us who care about handling but are less bothered by straight line performance. My 320d was great on their Birds kit though. They did insist I had an LSD if I got the ARBs, but with the '20d's power and torque I didn't have an issue with traction.
I've sent an inquiry to Birds, might as well see what they think. I'll put the reply in here when it comes back.Birds got back quickly
“Yes, the SE spec. is a bit soft and floppy, whereas the M-Sport is
uncompromisingly harsh. Ours sits somewhere in the middle in terms of
ride quality, but is in a different league in terms of body control over
fast bumpy roads.
The kit cost is £1089.85 + VAT and shipping, but if you ever find
yourself in this area, we'd be happy to demo one of our cars to you so
you can confirm what you will be getting, and we could do the install
for £1562.35 + vat within 6 hours total.”
They also recommended ditching the run flats, which I’d been planning to do anyway.
The higher performance models may be better in the first place.
“Yes, the SE spec. is a bit soft and floppy, whereas the M-Sport is
uncompromisingly harsh. Ours sits somewhere in the middle in terms of
ride quality, but is in a different league in terms of body control over
fast bumpy roads.
The kit cost is £1089.85 + VAT and shipping, but if you ever find
yourself in this area, we'd be happy to demo one of our cars to you so
you can confirm what you will be getting, and we could do the install
for £1562.35 + vat within 6 hours total.”
They also recommended ditching the run flats, which I’d been planning to do anyway.
The higher performance models may be better in the first place.
BFleming said:
SteBrown91 said:
All xdrive cars have SE suspension. A lot of people fit AC schnitzer springs to sort this out
The Schnitzer springs are made by Eibach. They're not the same as what you would buy from Eibach, but Eibach do know their stuff. For the 420d X Drive they sell these: https://www.eibachshop.co.uk/eibach-prokit-perform...£210.08, and they lower by 25mm front, 20mm rear. I've run Eibach stuff for years, nowhere near as harsh as M Sport suspension, but lower and slightly stiffer than SE springs.
For cornering I'd recommend swapping the ARB's for fatter ones. Your front ARB is 22.5mm; the one from the 430d & 435d is 23.6mm, so slightly stiffer. Go secondhand on these.
Anyhow, all this will come in (fitted) at well under half the price Birds charge. Never quite get the fascination with their stuff, there are a lot of alternatives out there.
The Birds kit is springs and shocks but not ARBs. The standard suspension feels ok on bumps etc, it's more the lean and lack of accuracy I don't like.
A bit of googling suggests that a rear ARB change is a bit of a hassle due to needing to drop the subframe?
smashy said:
Ok I believe lci was late 15 if yours isnt I feel your pain
Yup, pre-LCI. I think being miffed at making sensible decision about selling the 645 made me make bad decisions about buying this one. I'm normally pretty careful when buying cars but failed to spot that it was an N47 rather than the B47 (i thought the changeover was 2014), plus I've had a load of hassle due to the dealership being useless.
The current options appear to be (in order of cost),
1 - Just drive it and get used to cornering slower.
2 - The cheapest upgrade is lowering springs that will be firmer from the likes of Eibach, I might try this first as it's not a fortune. The only issue is that the roads around my work would be better suited to something with tracks fitted just now. Any option will firm up the suspension as that's kind of the point.
3 - Anti-roll bars. Not expensive in themselves but fitting won't be cheap if subframes need to be removed, and this can also have a big effect on bump absorption so not going extreme would be the most sensible approach so may take more than on e attempt before it makes enough difference.
4 - Birds BMW suspension. Expensive but they have a good rep and I could test drive a similar car before making decisions.
5 - Buy something else, possibly a 5 or 6 series. I was considering a 435 but if it's much the same it does put me off. I'd loose out on 4wd, the hatchback etc but gain on comfort and possibly handling. This is likely to be the most expensive option!
Thanks for your help, it's given me a lot to think about. The car is going into a trusted mechanic for an oil change on wednesday, He'll give me a condition report and I'll have a chat with him about options and associated costs too.
I may be going for a job that involves a 100 mile a day commute as well, up from the 30 I do now. If I do this is probably the ideal car for it as it's a lot of country roads in NE Scotland, having something frugal and 4wd would be overcome my want for a more powerful car.
Out of the 9 BMWs I’ve had 5 have been rwd. I live near Aberdeen so we get some snow most years, in fact it’s currently snowing.
I agree that rwd with winter tyres trump 4x4s on summer tyres, especially in the road roller sizes fitted to “sporty” SUVs, however 4wd does give an added element of traction if the conditions are poor or there’s mud on the road etc. Also sometimes the weather is bad in summer.
Winters also allow you to stop and steer in snow, unlike 4wd! The 420d has winters fitted just now.
Put it this way, if a car I like is available in 2wd or 4wd I’ll buy the 4wd version, but I wouldn’t go as far as buying a car I didn’t like as much just to get 4wd.
I’ll have a think about it, my gut reaction is to put a set of springs on the car and go from there, so I’ll get a price from the garage for fitting them once I’ve made sure there’s nothing wrong with the car now.
I agree that rwd with winter tyres trump 4x4s on summer tyres, especially in the road roller sizes fitted to “sporty” SUVs, however 4wd does give an added element of traction if the conditions are poor or there’s mud on the road etc. Also sometimes the weather is bad in summer.
Winters also allow you to stop and steer in snow, unlike 4wd! The 420d has winters fitted just now.
Put it this way, if a car I like is available in 2wd or 4wd I’ll buy the 4wd version, but I wouldn’t go as far as buying a car I didn’t like as much just to get 4wd.
I’ll have a think about it, my gut reaction is to put a set of springs on the car and go from there, so I’ll get a price from the garage for fitting them once I’ve made sure there’s nothing wrong with the car now.
Edited by Speed addicted on Monday 24th February 19:13
Well the current situation has changed slightly, fitted normal (non runflat) Michelin PR4.
As on previous cars the ride is improved, it’s not as drastic an improvement as the 6 series was as I think the 4 series suspension may be better tuned for runflats but on broken surfaces it’s better and the car feels more agile.
It still has the vagueness that’s annoying me but I won’t be doing anything else to it in the short term due to a mixture of not using it and the oil industry being in a fairly scary state.
As on previous cars the ride is improved, it’s not as drastic an improvement as the 6 series was as I think the 4 series suspension may be better tuned for runflats but on broken surfaces it’s better and the car feels more agile.
It still has the vagueness that’s annoying me but I won’t be doing anything else to it in the short term due to a mixture of not using it and the oil industry being in a fairly scary state.
Gassing Station | BMW General | Top of Page | What's New | My Stuff