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MG Midget and Sprite Technical - Bent anti-roll bar

Any suggestions as to the simplest way to straighten a slightly bent anti-roll bar? The near side seems to have been bent backwards, and now rubs slightly on the wishbone. Would it be best to remove it, or could it be pulled straight whilst still fixed?

Jonathan
Jonathan M

Personally I'd replace it as they're not really that expensive.
frogeye Gary

Anti roll bars by design are notoriously difficult to bend. :)

You will not bend it in situ and I would expect only by the application of heat would you bend it off the vehicle. Unfortunately that would be the end of it as an anti roll bar!

If you are convinced it is bent and not just slipped out of position then buy a new up rated bar from a whole host of suppliers
Robert (Bob) Midget Turbo

are you sure it's the ARB bent and not just drop link (s) moved

if you tried bending the ARB in situ it would probably just move the drop link

no PlusGas or heat for this problem then :)
Nigel Atkins

Its also possible that at some stage the front has grounded on a speed hump or similar. This can distort the metal strap that holds the rubber mounting bush so that it is skewed backwards. The ARB only needs to be forced back by a small amount for the drop links to start to rub on the lower lip of the bottom wishbone pan.
Guy Weller

Jonathan,

I'd be inclined to remove it and determine where the bend is, most likely it'll be easier to straighten with a press off the car.

Robert (Bob),

Heat won't necessarily ruin the bar as the rear ARB I have on my Sprite I bent hot and it has been fine. I wasn't sure at the time if it would be OK so I tested it by bending through more than the range it would see on the car and no set occurred and no problems seen subsequently. The bar started life as a rear ARB off a Vauxhall Chevette so a production bar but seemingly good material. Of course this may not always hold true.
David Billington

David B.
I know this is a bit of a thread hijack but I am interested to know how a rear ARB is fitted to a Sprite, is it a common modification or very beneficial?

Any comments welcomed.
Cheers
Steve Lowiss
s lowiss

I forgot about the mounting bush straps being possibly bent - also has your bar got the stops fitted
Nigel Atkins

I was going to suggest the same as Guy.

I'm interested to know how well a rear ARB works on a Spridget. The Austin A35 had a rear ARB as standard, but it tended to lift the inner rear wheel in corners, leading to loss of traction.
Dave O'Neill2

Me, me, me too ..........interested to know how well a rear ARB works on a Spridget.

What was the A35 ARB like anybody got piccies ? Or piccies of one fitted to Spridget.....David ?

In fact I have a Chevette ARB on the shelf somewhere (just have to rmember where the shelf is !)

I too can verify that heat doesnt always ruin a bar, my car has run one with welded ends for the last 10 yrs. (the ends were turned thro 90deg and shortened.)

Ian
Ian Webb '73 GAN5

Many years ago I had an A35 van, and I still have the Haynes manual from that time (about 1967?). I don't recall a rear ARB and the Haynes manual makes no mention of it. But that said, the chapter on the rear axle is lifted straight out of the Haynes Sprite manual - which I believe was the first one that he did wasn't it? Maybe a rear ARB was an optional extra - as was the front ARB on early Spridgets.

I also have a manual for the Chevette (I also owned one of those) That shows an illustration of the fixing arrangement for the rear ARB and for the Panhard rod. The Chevette was a surprisingly good handling car, given its somewhat dated specification when it was in production. They made very good rally cars though rather outshone by the Escorts which benefited from the huge investment by Ford.
Guy Weller

Yes I too have modified a roll bar by welding brackets to each end (this was a MG Metro one that I fitted to my midget) and yes it did not destroy it, but I just wanted to add a disclaimer in case someone warmed one up and then found it tempered. :)

However we are now moving to a discussion about handling and my take is this

If you lift a rear wheel then the FRONT ARB is not stiff enough

However if you lift a front wheel then the back needs a stiffer ARB.

So you need to make sure a front wheel lifts (Big ARB) before worrying about a rear bar. :)

Not seen many Spridgets with large enough bars to lift a front wheel?
Bob Turbo Midget England

But you always want the non-driving end to lift the wheel first, otherwise you'll lose drive on the driven wheel in the air. But not first by too much.

The other relevant consideration is that we have independent suspension at the front with a wheel angle we can vary, but live axle with the wheels at a fixed angle at the rear.
We can counter weight transfer at the front by introducing a bit of negative camber to set the outside wheel at a more favourable angle to the road. At the rear we don't have that option.

Here's a pic showing how the tyres distort under cornering, which a bit of negative helps counter at the tyre's footprint.

Paul Walbran

As I recall, My parent's A30 had a rear ARB attached to the shock arms. So I think did the A70. I discovered oversteer at an early age in that A30, fortunately stopped with the back bumper 2" short of a lamppost and so avoided some tricky explanation ...
Paul Walbran

Steve,

It's not a common mod as far as I know as many don't think adding a rear ARB is a good idea but I would disagree although it depends on the circumstances. In my case a frogeye with FG front and a middle weight 5/8"? front ARB I was suffering bad understeeer in tight corners such as at Wiscombe so the rear ARB was beneficial in countering that and didn't have any downside I was aware of, still handled fine at Castle Combe. As I had fitted telescopic dampers to the rear the bolt holes for the rear lever arms were free and so with some steel angle bolted there the original ARB U clip and rubbers could be used to mount the bar. The ends of the ARB fitted modified LA damper drop links and connected to lugs welded to the axle turrets. The mods to the Chevette bar were bending the arms inwards and the centre propshaft dip to narrow it IIRC which would have most impact if the steel properties were ruined as opposed to altering the ends alone.
David Billington

Is this too much front end lift? :)

Me (#6 Midget), R Perry (#62 Sprite) C Groves Rockingham 2000

James Bilsland

Standard size arb is circa 60 quid. How much is the next size up?
Lawrence Slater

standard one is about 20 to 25 quid s/hand :-)
David Smith

Hi James

That could be a candidate for a rear ARB :)
Bob Turbo Midget England

In fact a result of lever arm rear shocks, slick tyres and a newly laid surface, That was the only corner it ever did that on.

Most tracks the faster race Spridgets can get the front wheel off the ground albeit only slightly...

That was a good car - died at Dijon in 2003 :o(
James Bilsland

As Paul said, A35 rear ARB bolted between the two rear shock arms with a bolt and a U-bolt each side.

How about...

Dave O'Neill2

Lawrence,
if you meant standard size front Spridget ARB is about 60 then that sounded high to me so I looked up MGOC Spares as just one example and they're 47.95 for the following three sizes - 9/16", 5/8" and 11/16"
Nigel Atkins

Seem to remember a standard 1275 bar in the back of the garage if anybody wants it their welcome - will have a bit of rust also i'm sure.

Also some new polybushes - came in the kit - I've got a larger size fitted.

R.
richard boobier

Just found this pic of A35 set-up on fleabay

Dave O'Neill2

James-
You'll spill your beer if you keep that up!
Great picture.

FRM
FR Millmore

Thanks Nigel, I checked on Moss, and was looking at the Euro prices. Whoops. In lsd it's 50.95 (well not exactly lsd, if you are old enough to know that I'm not talking about tripping), or rather 50.19s.0d.
Lawrence Slater

FRM, don't panic - any prospect of Morland's finest spilling and I would have slowed right down... ;o)
James B

alcohol is my only drug of choice

and specifically real ale

that's why I know Jame's tipple has been brewed by Greene King at Bury St Edmunds for a good number of years now
Nigel Atkins

Thanks all for your helpful advice. I've checked the brackets and compared each side, and there is no obvious sign of damage, both look the same. I did try reversing the metal clamps and it made no difference, which led me to conclude they were not out of shape.

Nigel, I'm pretty sure it's not the drop links, as I renewed both sides last year, but on one side it still rubs against the wishbone. And yes it does have the stops fitted.

I can only assume, as Guy suggests, that at some stage the car has been run into a kerb or similar.

I have tried straightening the bar off the car but it is pretty solid, and whilst it will flex a little, it is difficult to bend.

I think you are right Bob that it might be simpler to replace it.

Any thoughts on whether to upgrade to a thicker one whilst I'm at it, and are polybushes worth the extra cost?

Thanks again. And...how did we get from anti-roll bars to Greene King real ale?

Jonathan
Jonathan M

The usual cause of bars bent such that the ends move back is either crash or people (like tow truck drivers) putting a chain or strap on the centre of the bar.
The middle section should be dead straight and usually is not. But, the function of the bar does not care, the end position does.
You can straighten it with the bar fastened to something very solid, and a pipe over the end.
Or with a big hammer on an anvil or similar.
Or in a press.

FRM
FR Millmore

>>I'm pretty sure it's not the drop links, as I renewed both sides last year<<
yes I done that too only to find the curse of the rubbish rubber in them, to make matters worse I was told the original drop links just go on and on

Jame's >>Morland's finest<< - Morland's Old Speckled Hen is brewed by GK
Nigel Atkins

This thread was discussed between 21/06/2012 and 26/06/2012

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