Steering, Suspension, & Brakes

tips, technology, tools and techniques related to non-driveline mechanical components

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coolmg
Mark Cooley

(15 posts)

Registered:
06/22/2008 08:02AM

Main British Car:


leaf springs movement
Posted by: coolmg
Date: February 04, 2009 08:18PM

200HP V8 and the rear end does move tires scrub as it goes around corners so a panhard rod is in the works. My question is I have a new set of springs for a GT will they do anything to help my roadster's stability with the new panhard rod, I read that somewhere?


kstevusa
kelly stevenson
Southern Middle Tennessee
(966 posts)

Registered:
10/25/2007 09:37AM

Main British Car:
2003 Jaguar XK8 Coupe 4.2L DOHC/ VVT / 6sp. AT

authors avatar
Re: leaf springs movement
Posted by: kstevusa
Date: February 05, 2009 09:58AM

You can check out the Handling & Drivetrain Sections. There are threads on leaf springs and panhard bars. Probably more info there.
SAFETY FASTER!



Edited 2 time(s). Last edit at 02/05/2009 11:24AM by kstevusa.


MGBV8
Carl Floyd
Kingsport, TN
(4120 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB, Buick 215

authors avatar
Re: leaf springs movement
Posted by: MGBV8
Date: February 05, 2009 05:27PM

GT leaf springs will likely be stiffer. Consensus is, keep the back end setup soft.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6069 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: leaf springs movement
Posted by: BlownMGB-V8
Date: February 05, 2009 06:06PM

There are a few things you can do with extra springs. Let's say the GT springs make it sit too high but you'd also like it stiffer and better torque resistance. One possibility might be to take an old full length leaf and mount it upside down above the main leaf. Or take half a leaf and mount it below the spring pack at the front as a cheap traction device. Imagination can go a long ways here.

Jim


Moderator
Curtis Jacobson
Portland Oregon
(4495 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: leaf springs movement
Posted by: Moderator
Date: February 05, 2009 06:32PM

From all my research, which lately has included talking to a number of people who race MGBs, the rear springs should be sprung softer (not firmer) for best handling. Stock GT springs have an extra leaf, compared to roadster springs, so that's going the wrong way. (The real racers remove leafs.) However, if you soften your leaf springs as they recommend, you may encounter two problems. First of all, you're more likely to have your axle bashing the bump stops. (The racers modify their cars to accommodate more axle travel.) You'll also probably worsen "tramping". In other words, during hard acceleration or braking, the front part of the leaf spring assembly will try to deflect into an S-shape and then spring back, producing wheel hop all the while. For that reason, people install some device to combat spring wind-up. There are many options for that. I think about one third of the cars in our photo gallery have some sort of anti-tramp bars under the springs. Lorenz Hassenstein went further, and also has a pair angled inboard to help keep the axle centered! Racers, who are willing to modify the bodywork over top the axle prefer a single rigid link forward from the top of the differential (as shown on both Ken Bierman's car and also on Les Gonda's racecar). A final option which I have no experience with is the spring-loaded traction device Bill Guzman recommends (see below).

In any case, from personal experience (and with nearly perfectly unanimous agreement from the racers) I strongly recommend Panhard rods and I haven't seen one yet that seemed too robust for the job.

There's another way to help reduce side-to-side movement of the axle: stiffen up the bushings at both ends of the springs. Urethane bushes probably make sense on a road car, but apparently racers usually go with metal-to-metal bushes.

Here are a snapshots and links to stuff mentioned above:

[www.britishv8.org]
(note: this photo shows both conventional and angled-in anti-tramp bars in one shot... Lorenz has LOTS of power to get down!!!)
http://www.britishv8.org/MG/LorenzHassenstein/LorenzHassenstein-EA.jpg

[www.britishv8.org]
http://www.britishv8.org/MG/KenBiermann/KenBiermann-CF.jpg

[www.britishv8.org]
http://www.britishv8.org/MG/LesGonda/LesGonda-CD.jpg
(note link above driveshaft)

http://www.britishv8.org/MG/LesGonda/LesGonda-CJ.jpg
(Panhard brkt on axle)

http://www.britishv8.org/MG/LesGonda/LesGonda-CK.jpg
(Panhard brkt on body)

Bill Guzman's spring trick: [www.britishv8.org]


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6069 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: leaf springs movement
Posted by: BlownMGB-V8
Date: February 05, 2009 09:39PM

>From all my research, which lately has included talking to a number of people who race MGBs, the rear >springs should be sprung softer (not firmer) for best handling.

But, at the same time you would probably want to stiffen up the shocks and in some cases you may find that doesn't work, for instance if the car has been lowered and you must navigate over humps at speed, with the possibility of going airborne. There comes a point where the shock extension rods will be destroyed in short order.

At any rate, just pointing out that there may be some options not usually thought of. Maybe useful, maybe not.

Jim


RobertE
Robert Edgeworth

(77 posts)

Registered:
02/19/2008 08:27AM

Main British Car:


Re: leaf springs movement
Posted by: RobertE
Date: February 10, 2009 09:33PM

I'm a big fan of Lorenz GT, definitely wish I had the time to get my car near that condition.

I have two questions though on his rear suspension setup, I was wondering if anyone could answer.

1. What model Koni's is he running?

2. How effective are the anti-tramp bars + diagonal bars in preventing side-to-side axle movement?

Thanks for any help.

Robert



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