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MG Midget and Sprite Technical - Panhard rods

HI, pal in France has asked for advice - any evaluations or critiques as to which is the better of the Moss and Peter May versions (for half-elliptic car)?
David Smith

Mine came from winners circle here in the usa, and I had to modify it right out of the box, it was designed for lower cars, not standard....but I love mine, it should have came from the factory with one

Mine bolts on the right axle shackle plate with a rosehymn jointed bar, (seld and booted) to the other side of axle then bolts to an inverted L shaped plate that is bolted back across the boot floor along the front of the gas tank....it took some fiddling adjustment but it holds everything rock solid... all tho I do need to now replace some rubber suspension as its getting weak tired and sloppy the tires are rubbing the swa panals just a bit in spirited turning

Prop
Prop and the Blackhole Midget

I have a Frontline panhard rod. It was a must to stop my alloy wheels touching the (square) wheel arches. One end of the rod attaches to the plate under the right hand spring. As this requires a tube to be welded onto that plate Frontline supplied me with a replacement plate with the necessary tube already attached. It definitely improved handling.
Chris Hasluck

I fitted the Peter May version on my 1965 AHSprite.

It took about an hour, you use the 'three legged' bracket as a template to drill the holes in the boot floor.

You need to remove the bottom spring hangar plate from the right hand side rear spring and weld a tube on to it.
(See photo).

I then fitted the panhard rod and spent a bit of time centring the axle in to the body (reason for rod is wider alloys) then took it for a blast and wished I'd fitted before !!

All the parts were in the kit, the rod itself is aluminium with rose jointed ends.

It's that good it's worth going without beer for !!!
Malc


Malc Gilliver

thanks; Chris is the Frontline / Moss one rose-jointed?
David Smith

looks to be by its picture online. I think they all will be as a rubber joint in that sort of system reduces the effectiveness.
Rob Armstrong

I'd recommend Peter's + I wrote a feature for MG Enthusiast magazine on this subject which I can recommend (by obtaining a back issue and contacting me for any amended thoughts!). If using rose joints/rod end spherical bearings it's worth fitting dirt seals (I may have a couple spare). Also it's crucial the bar is absolutely level and using or not using lowering blocks etc can throw the whole design out. Not least the taller the tower the lower the bar sits and the better the car will handle.
Daniel Stapleton

Rob,

I think for road use a rubber rod end would be fine, something like this type of thing http://rubberpartscatalog.com/home/products/vibration-control/rod-ends/J-21275-16 as they can provide the rotational flexibility and be stiff laterally. When I built a Watt's linkage for my Sprite I used rubber bushes for the lateral links, one Triumph TR6 inner wishbone bush and one Spitfire inner wishbone bush per link and no qualms about the lateral stiffness at all.
David Billington

David S
The frontline PR is rose jointed.

Chris
Chris Hasluck

+1 for the PM one.

I wouldn't worry about the rod ends, I think rubber would be pretty poor compared.

When I first fitted mine I slid a 6 inch length of mountain bike inner tube over each joint and then tightened up each end with a tie wrap to act as a gaiter. Worked fine but since then I've not bothered and leaving them open also seems fine. Not that I do a lot of miles!
john payne

You can get 'rubber' type rod end bearings so if you go for a rod end bearing (rose is a brand name) and find them too harsh you can swap them out to rubber.

Have a look at Aurora Bearing's web site for a bunch of info on bearings and Seals it for seals and rubber rod ends: http://www.aurorabearing.com/index.html

http://www.sealsit.com/
Daniel Stapleton

thinking about it more, a lot of 'modern' PH rods are rubber mounted, I think the Scimitar Watts linkage was rubber mounted too. Quite like those rubbery rod ends :)

Though I have a solid rod ended RTL on mine and it doesn't seem too harsh.
Rob Armstrong

I fitted a Panhard rod to mine Frogeye. Nice job to do, but was of very little benefit to roadholding. Apparently the quarter elliptic springs are already stiff enough by themselves?
J.W. Vlaanderen

My experience with fitting a Watt's linkage to my frogeye was that it definitely improved the handling, the 1/4 elliptics, while stiff, do move laterally under hard cornering.
David Billington

Is there a noticable difference between a watts link and a panhard rod ?
What would people fit given hindsite and experiance etc....
Andy Phillips (frankenfrog)

The disadvantage of the Panhard rod is less than the disadvantages of the Watts. I'm sticking with the Panhard rod.
Daniel Stapleton

I protected the ball bearings against mud with 2 rubber gaiters as delivered with track rod ends. (see photo) And yes the handling improved a lot although I bought the Panard rod to stop the wheels from touching the arches. The Panard rod gave less body roll. I even had to diminish the diameter of the front ARB to compensate for it and to get a neutral behavior in fast corners again. I do have the Peter May version. I needed a drill, one hour and spanners.

Flip


Flip Brühl

Ive never had or driven a watts, but I sure like the pan hard rod

Prop
Prop and the Blackhole Midget

got an RTL. It's awesome. No wheel catching with 185 tyres on 6 inch wide minilites at the back. Solid cornering attitude and much improved traction. Need a bigger engine now to get back to power > grip. Doesn't fit that well though and needed quite a bit of tweaking.

Followed an escort (ford variety) up honister pass with a PH rod and could see it pulling the rear axle all over the place on large suspension deflections. Didn't look that clever so cadged a cheap RTL when one came along, after being ready to make my own Watts.
Rob Armstrong

Daniel.

What are the disadvantages of a Watt's linkage other than the lower link possibly being susceptible to damage. I've only bent the lower link once and not by much and it was the result of driving over a large dead animal, not sure if dear or dog. The advantages are symmetric behaviour unlike the Panhard which is asymmetric and can be felt with larger suspension travel. Also with the Watt's linkage you have a choice of RC fixed or moving in relation to the CG, many had the centre link fixed to the axle so the RC moved in relation to the CG but at the time I made mine it was thought better to fix the centre link to the body so the RC was fixed in relation to the CG giving a constant roll moment.

Until the other day I hadn't come across the Scott Russell linkage, see http://en.wikipedia.org/wiki/Scott_Russell_linkage , looks like it might be interesting to investigate. Also the woblink shown here http://www.oocities.org/markianfox/suspension.htm .
David Billington

I'd be interested to hear what the disadvantages of a watts linkage are relative to a panhard.

Malc
Malc Gilliver

Weight is the only one I can think of at the moment, and complexity. I wanted a woblink cos it sounds cool but couldn't see how to get it to fit :(
Rob Armstrong

Flip,

Having seen your post my comment would be that fitting a Panhard rod shouldn't effect the body roll if situated correctly but having looked at your photo it looks to be mounted too high for a quarter elliptic car resulting in the Panhard rod fighting the springs in roll resulting in greater rear roll stiffness. The most extreme case I've seen of this was on another quarter elliptic car where the Panhard rod was even higher being fitted just below the boot floor across to just below the bump stop resulting in serious oversteer as the rear end was almost locked in roll. I didn't drive the car but even as a passenger it could be easily felt. Was the kit you fitted meant for a quarter elliptic car as Peter May does a kit for both quarter and semi elliptic cars although I don't know the details of how they differ.
David Billington

Flip, I like your gaiter, much better than my bodged attempt!

Flips Panhard doesn't look to far out to me, difficult to see in the photo but it seems to be parallel to the axle which is how it should be.

I'd never noticed any disadvantages to the Panhard (apart from having to re weld it on every time the ride height is changed!) until last year when I was driving on a particularly uneven road. It was one of those roads that must have subsidence as it had lots of dips in it. Anyway the bump steer was terrible with car wanting to go in every direction but straight on!

I think they transform the handling of the car, even if I had a standard road midget I think I'd still fit one.

john payne

John,

My point was that it looks too high to me so is trying to make the axle move about a different roll centre to that which the springs want so the two are fighting producing a stiffening effect when the body tries to roll. Being parallel is fairly irrelevant if it's not located correctly.
David Billington

I have the PM one, albeit on a 1/4 elliptical car, installation was fine (albeit the tripod is tight round the tank but that's just a fact of life) and it works well. I would thoroughly recommend anyone (certainly with a 1/4 e car) get one if they do anything more that potter.

Daniel or anyone else, do you know anyone in the UK who sells elastomer / rubber rod ends?
Jeremy Cogman

David, you lost me at 'roll centre'!

There isn't really anything else you can do when you are using a kit as the body mounting point is fixed unless you modify it. So getting it parallel is about all you can hope to achieve.

I don't really know exactly where it should be but mine is pretty well parallel and height wise it gets in the way of the filler plug on the diff if thats any help!
john payne

I have to add to my comment about the Panhard Rod that I fitted FL suspension (front and rear) before I did the conversion.
This made the biggest improvement.
J.W. Vlaanderen

Yes, if the ride height changes you need to re-check the Panhard is still absolutely level.

No known source of rubber rod ends in the UK but probably to buy direct from the USA - I regularly do this for various odds and sodds that are of US origin but sold in the UK.

The panhard rod can be deliberately situated below the centre line of the axle in order to lower the roll centre. In fact I can't think of a good reason not to do this, especially with fairly stiff rear springs.
Daniel Stapleton

my link lowers the roll centre to about 2 inches below the bottom of the diff. It's increased the rear roll stiffness somewhat, which seems to load up the outside front tyre a bit more, but feels a lot better planted at the back.
Rob Armstrong

This thread was discussed between 29/05/2014 and 05/06/2014

MG Midget and Sprite Technical index

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