R-Design Ride Quality w/ 20" Rims - Options

[cab]

Hello ALl,

I posted this in Swedespeed, but thought you might appreciate it as well here. We purchased a 2012 R-design T6 w/ 20" rims (U.S.A - see my Audi/BMW/Volvo thread) and have had it for about a week - maybe put 200 miles on it. The ride is definitely firm (as we knew from the test drives), and to be honest, I'm on the fence about it. The more we drive it, the more "used to" it we get. On the one hand, I appreciate how connected it feels and (relatively) flat it is going around corners. On the other hand, it can get a bit old on bumpier roads or even roads I wouldn't consider bumpy but have various expansion cracks,waves, etc. I am actually paying very close attention to the nature of the bumpiness in order to determine if I want to do anything about it. Options I will consider:

1. Just live with it (note: we are already getting more accustomed to it)

2. Wait until the Pirellis wear out and replace them with a more "passenger car" oriented tire like the Continental ContiExtreme DWS all-season. I believe these will ride a bit better. The XC60 isn't terribly heavy and I'll probably go with these exact tires on my M5 here in another month - and that car is about 2 tons. I've had them in a 17" on my wife's 530i for the last year with no issues. The M5 has a larger 18" rim with a very low profile tire (245/40 fronts - 98 mm sidewall, 275/35 rears - 96 mm sidewall)

3. Consider a tire with a slightly taller sidewall (keeping 20" rims). More specifically:
a. Baseline: Factory R-Design tire is 255/45-20 - this equates to a 114.75 mm side wall height; Factory T6 18" is a 235/60-18 - this equates to a 141 mm sidewall height
b. Move to a 265/45-20 tire with a little over a 119 mm sidewall height (note: will read 1.2% slow on speedo and might not fit rim width-wise)
c. Move to a 245/50-20 tire with a little over 122 mm sidewall height (note: will read about 2% slow on speedo, but should fit wheel rim easily)

4. Swap to "Regular" T6 springs, struts/shocks. I have actually researched the parts and it looks to be about $1000 in parts (4 new springs, 2 front struts, 2 rear shocks). Note: I am a DIYer and can do this myself. A similar thread of mine from a couple of years ago when I swapped springs and then struts/shocks not once but TWICE looking for a better combo on my '05 Pontiac GTO (aka Vauxhaul VXR8) http://www.ls1gto.com/forums/showthr...546&highlight= <== yes, I'm a bit overly sensitive to this type of stuff ;>

The short sidewall of the tire can be felt when hitting expansion cracks, etc. and what I'll describe as a general mild bumpiness. Certainly this contributes to the issues and magnifies everything else. However, based on my very early observations though I would say the suspension seems to be the bigger culprit as far as the general jostling about is concerned. I am NOT considering a smaller rim at this point simply because my M5 rides better with even less sidewall on the current Sumitomos (note: admittedly, BMW does have the ride/handling balance perfected however...partly because they surround everything with rubber!) .

If I do anything, it won't be right away as "getting accustomed to it" is easily as big a piece of the puzzle as anything else. The most likely next step would be #2 once the Pirellis wear out unless I decide the suspension just has to be altered. #3 is also a possibility (will probably come down to tire availability as much as anything else). I could just do the front struts/springs, but that would likely results ins some weird ride imbalance.

Anyway, I just thought I would toss this out here to get any feedback or perhaps assist some others.

[darbs]

another option to consider is getting smaller rims with the higher aspect ratio tyres. i'm on 18" in an SE Lux with 235/60 and notice the difference in the comfort provided by my tyres over my previous car which had tyres with 225/50 (notwithstanding the suspension and other differences).

if i was you though, i'd just try to stop thinking about it and get used to enjoying the positive side to it. if you put it out of your mind it won't be an issue. you may then find that once you're used to it, you'll miss it when you next go back to a softer set up.

[cab]

That is an option (smaller rims), but like I said I'm not inclined to try that at this point as my M5 has an even shorter sidewall and rides better (note: it is "better", but the M5 isn't a Lexus!). The rim cost is also not insignificant!

I hear you on just putting it out of my mind (and this is my approach right now). Now that I think back, a year ago I went from 16" rims to 17" rims on her non-sport BMW 530i and at that time I noted it rode a bit rougher...a few months later I couldn't even remember what it felt like with the 16s and the 17s had become the new norm.

I already promised my wife I wouldn't touch it...for at least a few months! She is going to do a short distance out of town trip on Thursday (about 225 miles round trip) so she will probably have some feedback after that.

[DesertDog]

I was thinking of going the other way - joining the dark side, with -2.5cm Eibach springs and 15mm spacers for starters...