Datsun Roadster Forum-311s.org

Not that I've heard (oops, Gary just posted)... but I am quite happy with my flex form springs using the 2inch blocks... they match perfectly with the comp spring ride height if the spring eyes are turned over (not a problem or concern regarding strength). Does require some minor modifying of the mounting plates if you use generally available lowering blocks because they are just a bit too long, and you need to get longer U-bolts. Custom blocks could be made to eliminate that problem. Not a lot of miles on them yet so no comment on durability. I would also recommend a stiffer rear shock such as the KYB Gas-adjusts over the GR-2s which were too soft.

I think they will work fine if you have a stock rear end set up... I believe Gary's issues stemmed from the upgrades he has made for racing, namely a pan-hard rod (or was it a Watts linkage?).

I bought them from Gary.

Right now I am in the process of putting comp front springs on my car. When I get it off the stands (might be a while) I will see what the front and rear ride heights are. Remember I have factory rear leafs that have been re-arched by a shop in town (see photo) so the back rides pretty high. If it's not to my liking I'm going to try the mono-leafs next.

Here's a shot of the rear w/ 15" wheels and 55 series tires.



Cheers
James

James, how about you measure your ride height before and after? Take the measurement from the middle of your axle to the wheel arch. That'll settle concerns that people have.

Make sure you make whatever changes are available to your shocks. It doesn't work to change spring rates so much without changing shocker stiffness to match.

Keep in mind that whilst it looks cool, lowering any car by 2" or more is likely to be detrimental to it's handling. There are issues not only with the roll centre dropping under the level of the ground, but also with wheel rate geometry at the front. If your front lower wishbone is describing an arc that is higher than parallel with the ground, every mm it moves up, the effective spring rate (edit: *at the wheel*) is *dropping*.
Used correctly, the steel monoleafs are a superb handling upgrade, capable of dropping lap times significantly.

Can you describe exactly what you mean by "from the middle of your axle to the wheel arch."

I shouldn't be in trouble w/ the comp springs up front as they are widely used. It sounds like the rear springs are getting a pretty big userbase too. As for shocks, I have plain jane KYB GR-2's now so they will be compressed a bit.

Cheers
James

measure the distance from your wheel center cap, straight up to the fender lip
-how will you make changes to your current shocks front and rear to take advantage of the new leafs?
-How will you make changes to your front springs to take advantage of the new rear leafs?

I have the GR2's on old very stiff comp springs. I think the softer shocks and stiff springs make a nice balanced ride. It's less harsh over the same bumps than my wife's 2010 Mini.
It seems the monoleaf and composites being a softer ride would need the additional damping to reach the same overall ride?

Right now my main concern is getting my cylinder head done, my exhaust O2 sensor installed and manifold ceramic coated, and getting everything back together. I have "meantime work" going on which is putting on the front comp springs and GR-2's. I am not going to put the rear mono-leafs on right away. I'm also thinking I'll get my seatcovers done and headrests done and installed as meantime work too.

Cheers
James

st3ph3nm wrote:Used correctly, the steel monoleafs are a superb handling upgrade, capable of dropping lap times significantly.

I was doing so lite reading on rear leaf spring suspensions. (this was a "racing" site)

I found for a mono spring it is important to keep the arc in the spring.
1 1/2-2" lowering blocks gave the best side grip and forward bite.
Use a slider in the rear, not a shackle.
The front of the spring should be lower than the back.

Has anyone tried a slider?

fj20spl311 wrote:

st3ph3nm wrote:Used correctly, the steel monoleafs are a superb handling upgrade, capable of dropping lap times significantly.

I was doing so lite reading on rear leaf spring suspensions. (this was a "racing" site)

I found for a mono spring it is important to keep the arc in the spring.
1 1/2-2" lowering blocks gave the best side grip and forward bite.
Use a slider in the rear, not a shackle.
The front of the spring should be lower than the back.

Has anyone tried a slider?

I've been tempted by a slider, but I'm not totally sure how to mount them. Do I make a spacer to lower the slider to the stock height, or do I go ahead and mount the slider directly to the frame? I don't really want to just run out and buy a set of sliders, knowing my luck I'd end up buying some crappy ones that are worse than what I currently have.

I'm hopefully (weather depending) going to try some ballast weight in the back end on Sunday. It may just make the back end of the car heavier, but if nothing else, it will help balance the car better. I'll see how things play out.

Will

Will,
I don't know for sure about changing the height of the rear mount.
The slider should be mounted so it's "inline" (points toward) the front mount.

I might have to shoot Lou an email and see what he thinks seeing as how he came up with the mono-leafs for the roadster. I think a panhard rod would be a very good thing on sliders to keep the back end from binding with a side load.

Might be worth following up on.

Will

SLOroadster wrote:I might have to shoot Lou an email and see what he thinks seeing as how he came up with the mono-leafs for the roadster. I think a panhard rod would be a very good thing on sliders to keep the back end from binding with a side load.

Might be worth following up on.

Will

I would think the panhard is mandatory to combat sideloads.

Folks,

You don't want the front of the spring lower than the rear (whoops not front sorry for the typo)! This induces bump steer. Don't go there, this is not a good idea...

Mike

Mike Unger wrote:Folks,

You don't want the front of the spring lower than the front!
Mike

huh?

Mike Unger wrote:Folks,

You don't want the front of the spring lower than the rear (whoops not front sorry for the typo)! This induces bump steer. Don't go there, this is not a good idea...

Mike

I remember reading that, they used to use long shackles on Pintos to correct it.( How To Make Your Car Handle, by Fred Puhn. a must read, but the math hurt my head.)