05 Z4 suspension hard on my back, HELP

[kmancars]

I posted my problem on the CA. section but I would like to range wider. I just bought this beautiful car, first timer to sports cars at age 62! It is a AT with sports suspension only 34k miles. I learned a hard lession bringing it home about 60 miles. My back felt like I had been on a dirt road in a 1913 car? I know the 18" stk rims and RFT tires are involved. I must soften the ride at the expense of some speed handling. Please point me in the right direction thank you all very much.

[jzmundy]

Firstly, congrats on your Z!

Now, as far as "softening" the harshness out of the ride, there are several different approaches, as far as I know.

Non-runflat tires - Can't say much about these as far as personal experience goes because I'm still on my stock 18" runflats, but I've heard nothing but praise from those who have gone to non-runflat tires. Not only may it soften the ride a bit, but they're lighter and run truer (no tramlining) than the stock Potenza's.

Smaller wheels - This is pretty much a given, but a simple switch to standard tires on your 18's may warrant the same effect without sacrificing looks!

Springs - Now, I understand the Z is already a low car and perhaps the last thing you'd want is for it to be even lower. However, I, along with others, have installed lowering springs (Eibach, H&R, et al.) and have noticed a somewhat dramatic change in ride characteristics while "cruising." The springs lower the car about 1" or so from sport suspension height and softens the harshness of the car on highways but also tightens the car in the twisties.

I hope this helps, and I'm sure you'll get more recommendations from other members!

Best,
Zach

[xg3]

Stiffer springs soften the ride? thats hard to grasp, sorry.. if anything, it would make the ride even more harsh.

[jzmundy]

Originally Posted by xg3

Stiffer springs soften the ride? thats hard to grasp, sorry.. if anything, it would make the ride even more harsh.

The Eibach's are progressive. Don't know about H&R. Don't knock it until you try it.

Edit: I guess I also should note that I'm still on stock shocks - aftermarket shocks most definitely would have an effect and/or alter my perception I presume. However, as it rides now, it is undoubtedly less harsh than stock.

[misterawa]

Originally Posted by jzmundy07

The Eibach's are progressive. Don't know about H&R. Don't knock it until you try it.

Edit: I guess I also should note that I'm still on stock shocks - aftermarket shocks most definitely would have an effect and/or alter my perception I presume. However, as it rides now, it is undoubtedly less harsh than stock.

Eibachs with the Koni adjustables, adjusted all the way to soft, along with smaller wheels (16s or 17s) and non-run flat tires should improve the ride quality...but not to be compared to a soft, floating ride on a mercedes or lexus.

Good luck!

[kmancars]

The suggestions from you folks is appreciated. The change out of RFTs appears to be a good move. If I put a good road tire(what kind?) on the stock 18"s it would be the most cost effective first step. Or move to a 17" stock or custom wheel and road tire. If move 1 does not do it then move 2 would be more $$$$ and another set of tires. What do you fine owners think?

Step 3 would be to do suspension work, but I do not want to go there yet as I am a rooky in sports cars.

[DerekSelmanRacing]

If you were in Havasu, I'd let you try my 17" set with non rft just so you could get a feel before spending $$$.

I just thought of this; we'll be at Buttonwillow Raceway next weekend. If you wanted to drive up Saturday or before noonish Sunday, I'd let you try my 17's. Currently shod with somewhat worn and noisy Kumho's, but you'll get a good idea. I also have 2 front 18" dot-r (race compound) lightly worn fronts I'd let go fairly cheap. Whatsa matter with all you people in Redondo Beach?

[kmancars]

Again thanks to all members of this forum. The problem in Redondo is too many miles on this body. But these Z4s are fine rocketships.

[DerekSelmanRacing]

No, I meant isn't there a member near Redondo who would let you try his wheel/tire combo?

Of course, my 17's will be off the car @ Buttonwillow since they're my street set and I'll have Hoosiers on the car...make's it easier.

[kmancars]

Thanks for the good thinking, members. Misterawa looks like you did some smart mods, nice looking machine.

[blender]

Thoughts:
Tire pressure can have a drastic effect on ride quality in my experience, at least with non-RFTs. Try them 2-3 lbs under the recommended pressure.

I second the suggestion to Lose the runflats ASAP for tires with bigger sidewalls and/or on 17" rims. Run them a little soft for a bit and see how that works.

IMHO, Softer springs will give you a smoother ride at the expense of some body roll and cornering capability.

good luck!

Rob

[kmancars]

I am happy to see my post is still alive. What does IMHO mean? Thank's

[UncleScottie]

Originally Posted by kmancars

I am happy to see my post is still alive. What does IMHO mean? Thank's

"In My Humble Opinion"

As suggested in earlier posts, try before you buy. People's ideas of good ride quality vary greatly and has a lot to do with the other cars they have driven or drive on a regular basis. There is a thread over on Bimmerfest where a gentle with a Z4 coupe is looking to soften up his ride as well. However, he is already running non-runflat tires on 17" wheels with the base coupe suspension. I test drove a base coupe with the stock runflat tires and thought it rode amazingly well, so it just goes to show how much our taste can vary. Of course, my previous rides included an S2000 and a WRX with firmer than stock struts.

[flibuoy]

I am curious and will follow this thread: at 65, having broken my back twice, I am surprised OP had trouble with his back in 60 miles! I have an '03 with Sport suspension on RFTs and although I find the ride shall we say ...firm...it is not harsh at all and I have yet to feel it bottom. I can, from experience, agree with replacing stiff walled RFTs with something more giving and maybe playing with a lower pressure. The Eibachs et al I have had on a variety of rides and have yet to see a softer ride. Better yes, softer no. Maybe on the Z4 that is true with a good progessive spring.

One thing I might bring up is seat position...not only in Z4...by raking back the load is lightened a bit on your butt and more evenly distributed to your back. Seat bottom tilt, supporting your thighs when in driving position, will help as well. This would be my first "correction" and see if it helps. My wife has a bad bad back and she is a whiner too...she could take my '01 Miata in small doses as passenger and zero tolerance as driver, however she absolutely loves the seat/ride of the Z4 so there might be hope for you. John