MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Leaf Springs

Looking forward to fitting these bad boys, will be interesting to see how they stack up against the standard steel items.


brian s

cool where did you get them from?
Onno K

Brian, they look fantastic - huge weight saving. Pricey I expect. Are carbon springs FIA approved for classic racing or do you have to retain the same spring medium?
Nick Nakorn

They are a composite Nick and they weigh about 2.5kg each spring.
Onno, I got them from flex-form in the States www.flex-form.com.
brian s

Keep us updated on how they work.
Are they going on a road or track car?
Onno K

They are for a road car that has a few tweaks to it. Fitting and use is going to be over the next few months as Im reshelling the car and trying to fit it in between the short breaks that I get whilst working offshore, but watch this space.
brian s

awesome weight savings!

Whenever I have looked into composite rear springs the available spring rate was always way too high, even after cutting them down to the very narrow width used on a midget.
75 ~ 80 lb/in is the stock spring rate. A racing car, much lightened, would want even lower than that.

Please tell us, what is the spring rate of your composite springs?


Thx,
Norm
Norm Kerr

The guys there supply a few racers with high rate springs, however, I wanted higer than standard but not as high as the racers. I think I went for about 100-120lbs, but i also listened to their advice on rates.
brian s

I've been looking for something like these for ages!

Please keep us posted when you get them fitted!
john payne

How much do they cost?
Lawrence Slater

They were $425US or at today's exchange rates £253 for the pair and that includes the bushes. Spring rates are about 135-145lbs.
brian s

And only 1" wide


brian s

I wonder if they can do quarter elliptic springs too
G Lazarus

holy crap!
Those things are going to ride like a wooden wagon, they are about 2x as stiff as what was in there.

For best handling of a solid rear axle, independent front suspension car, you typically want the rear soft and the front stiff.

Let us know how those rock hard springs do in your car. I suspect your cornering will suffer (not to mention ride quality). Hopefully the tradeoffs will be acceptable to your taste.



Norm

Norm Kerr

Well Norm if the cornering does suffer then I can pretend it's an American car. As we all know they are only designed to go in straight lines.
As for the spring rates it's about one and a half times stiffer. But that's the beauty of trial and error. I've had my car for 26 years and I love to experiment.
brian s

I have 100lbs coils on my Midget (now on the ground) and they feel about right, still soft but a tad firmer than the 86lbs leaves..
Nick Nakorn

They don't give much info on the website. Does that price include/exclude shipping?

How long relative to steel, would they be expected to last, before losing tension?
Lawrence Slater

What I thought was interesting, according to the website, they never loose the arch shape

With them only 1inch wide...id think a panhard rod is going to be mandatory....id also be curious how they perform in keeping the axle from twisting laterally or if ladder bqrs will be needed also

With those being an inch wide, I wonder if they cant be off set towards the center of the car to get more tire clearance for wheels that have a deeper off set

Should be a fun project....im looking forward to its progress

Straight line....nah, left turns only

Prop
Prop and the Blackhole Midget

"How long relative to steel, would they be expected to last, before losing tension?"

Composite springs last nearly forever, compared with steel.

I remember watching the durability testing being done for Corvette composite leaf springs, at a testing lab in Detroit, back in the early '80s. The normal life expectancy for steel springs was on the order of 1.5million cycles, or thereabouts.

The composite springs had been tested to multiples of that, and they still had not failed, or lost anywhere near the % of spring rate as was normally expected in an automotive spring.

The testing staff told me that when they did (finally) "fail", what they did was split longitudinally. The result is that not only were they way lighter than steel springs, but it would actually be pretty difficult to even notice if one did break, because a longitudinal split would be so relatively modest a performance change, compared with what is usual when steel springs fail.


Cool stuff!

I just wish someone made them soft enough for use in a car as light weight as ours.


Norm
Norm Kerr

Norm, theie website suggests they are made to your spec that you put on the request form.
David Smith

This thread was discussed between 19/04/2014 and 20/04/2014

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.