[smaceng]

So I got this 240Z last year and have been enjoying it since then.
I already have replaced the diff (noisy), adjusted clutch, and replaced oil pressure sender.
The problem is that the ride is too stiff. Tires 225-45-17, front sway 1 in. dia., rear 7/8 in. dia., and springs feel rock hard (can barely push down on the fenders at all).
This is my plan: Replace wheels and tires 15 inch with 205-60-15 tires. (Can one get any good performance tires anymore in 15, I'm not having much luck). Thinking of VTO wheels, black spokes, chrome rim. Replace springs with new +30% stiffer, OEM height from Z Car Service. Keep the sway bars for now. Handling is very good now, don't want to lose to much.
Does this seem like a good plan?
Your opinion would be appreciated. Thx Scott in CA

 

[steve240Z73]

Falken Azenis RT615K+ comes in 205 50/R15. https://www.falkentire.com/tires/passenger-car-tires/azenis-rt615k-tire

 

[oregonipa]

Are the bushings poly or rubber? Poly will be a harsher ride. Maybe look at some adjustable shocks when you replace the springs...

 

[smaceng]

Yes, bushings are rubber. Good idea to look at adjustable shocks.
I'm also thinking to just replace the springs and the bushings first, and then see how the ride is.
I can always change wheels later.
Thx
Scott

 

[theghosttanker]

If you add stiffer springs, you need to use a strut made for stiffer springs.

 

[zmanofwashington]

If you have KYB shocks they will work fine on lowering springs and/or stiffer springs. Make sure that your TC bushings are rubber. Poly TC bushings can bend the TC rod or even crack the frame. Poly bushings are fine to use in every other position. By comparison poly bushings will stiffen the ride up a little compared to rubber but not all that much. Keep in mind that a lot of the bushings aren't available anymore in rubber, and rubber bushings are a lot harder to install. Harder to install means more expensive in this case.
Look close at your springs with the car jacked up in the air. You need to identify the spring manufacturer if you can. See what color they are and if they have any writing on them. Kind of hard to do I know. The best springs for a better than stock ride without going real stiff is to use Eibach springs. They're a progressive rate so they're fairly normal when you're driving regular and the harder you push it in the corners the stiffer it gets. They're the best of both worlds. Definitely keep your sway bars. Going to adjustable shocks can help soften the ride some but they're a little more than twice as expensive as KYB shocks are. Yes the adjustable shocks are nice but unnecessary if you're wanting a softer ride. Changing to 15" rims and tires will make a lot of difference as far as the ride goes not to mention make the car a little less on the road noise. Try your rims and tires first and see how it rides and go from there. As far as pushing on the fender goes remember that these are a sports car and pushing on the fender may work on a Cadillac but that's a luxury car and needs a soft ride. The same rules don't apply when checking the suspension stiffness. FYI, I noticed that your front marker lights are on backwards. The thick portion goes towards the front for the front lights and towards the back for the rear lights. One last thing, congratulations on your purchase and welcome to the Z world. Z man of Washington

 

[smaceng]

Thanks for the info Zman. Yes I will turn the front side lights around.
So I ordered a set of springs that were advertised as 30% stiffer than stock.
Since I have the back up in the air, I figured that I would check the diameter.....480 inch.
So what are the new springs.....also .480. arg!
So the question I have if anyone can help me, what is the diameter of a STOCK rear spring.
Maybe I just need to get my sway bar mount fixed and see what the ride and noise is like. Right now I am chasing my tail. Cheers, Scott

 

[smaceng]

So I looked in the Haynes Manual, the there it was.....stock specification for wire diameter for the rear springs is 0.449 inches. So indeed, I already have heavy duty springs, as I thought. Maybe used ones will do the trick?

 

[Los Al]

I have Eibach (progressive rate) springs and Tockico shocks on my '71. Very happy with setup. Also, went to 16" rims with 205/55 tires. Nice ride now. More options on 16" tires. Good luck with whatever you decide.

 

[datsun240z71]

My 71 240Z has the probably "no longer available" European market springs, cut by about 3/4 of a coil in front, Tokico Illumina adjustable shocks, poly T/C rod bushings and front sway bar endlink bushings, and an Addco 1 inch front bar. Plus front and rear strut bars. Been like this for MANY years.

Recently swapped the Nissan 14 inch 280ZX 6-spoke wheels for 16x7 KONIG Rewinds and Continental tires.