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MG MGB Technical - Sway Bars and Bushings

A little help from the group please! I'm trying to decide how to proceed on my '67 BGT. I have a 3/4" sway bar and rubber V8 bushings installed right now. The ride and handling are great. But it's time to replace bushings and in seems the current crop of rubber is of very poor quality. So...

I think I'm going to move to Superflex poly bushings on this car. While I do appreciate the increase in handling and steering response poly bushings offer, I also use this car as a daily driver. Being an enclosed coupe I want to keep road noise to a minimum, and ride quality at a reasonable level.

Now my two questions...

To control road noise, would it make sense to run poly bushings all around except for V8 rubber bushings in the lowers?

Would ride quality be increased by retaining rubber sway bar bushings rather than poly?
Steve Simmons

Steve - The Superflex poly bushings come in a variety of grades or "stiffnes" if you will. Go to their web site http://www.racecar.co.uk/superflex/ to see the offerings that are availble. The only problem is which of the grades will give you the ride and handling characteristics that you are after. Cheers - Dave
David DuBois

I've been there and understand the various shore ratings. But natural rubber is still reported to have superior sound and vibration damping characteristics, unless my information is flawed!
Steve Simmons

Steve, I admit my midget isn't the quietest car around, no comparison to a GT, but even with nylatron bushings in the front A frames and upper trunion and urethane bushings in the sway bar and links I don't think that I noticed any real incrase in road noise when I upgraded the bushings. Yes the ride is a bit harsher, that's the nylatron bushings (no give), but I didn't really notice any extra sound from the road. I'd think that with the poly bushings you'd still be relativly quiet and comfortable.
Bill Young

Steve:

I've been using and recomending the black poly bushings available from Moss for many years. They are a softer poly than the typical Ricky Racer stuff but hold up really well. After using a number of different designs including V8 ones I stand by that recomendation.

Kelvin.
KJ Dodd

I've gone both ways and would recommend using V8 bushings in the lower A arms and good quality rubber bushing at all other places. I find the poly bushing too firm.

Andy
Andy Preston

The rubber sway bushings I had were horribly worn and have been replaced by blue superflex poly...nice and tight now, and with the assurance they won't wear out or go bad anytime soon (unlike rubber).

I've also got blue superflex on the rest of the front and rear suspension. The only places I have rubber are the front spring eye bush (couldn't be bothered swapping the ones that came with the springs over, and I figure that location is less critical and they'll last as long as the springs anyway) also rubber on the sway bar ends (same reason).

I haven't noticed any increase in road noise or ride harshness - but the rear in particular is much more certain in cornering.
Curtis Walker

Steve

I have exactly as you describe, V8 inner wishbone bushings and superflex poly bushes everywhere else. Noise, vibration etc is fine. Only thing is to make sure you grease the rear springs bushes well or they squeek.

Grant
Grant

Steve,

I know of several people in the UK with superflex all round, and I am heading that way. I have just rebuilt the rear suspension on my car (including the rear spring front eye bush!) and am hugly impressed by the improvement, but I am comparing with old worn rubber. I used then everywhere, even the spring pads. One of the main advantages touted in the UK for Superflex is that they are between rubber and some of the cheaper poly bushes for harshness of ride. That is to say they give an excellent compromise between ride and handling. In fact I have a friend who fitted V8 bushes to the front of his car. He was impressed. Two years later (on a daily driver) they needed replaced! He went with superflex and found them to be very similar in characteristics to the new V8 bushes (but obviously much better than the worn ones!). I am looking forward to getting them on the front of the car. The fit of the bushes was very good as well. In the UK they just sell you the MGB parts, rather than expecting you to fiddle around with shore ratings (after all most of us won't know enough to make the best decision about this!). I would expect the US stokist could also supply a recomended set for the MGB.

Cheers
Iain
I D Cameron

Iain,

I can confirm that at least in this part of the world (Aust/NZ), Superflex (called Superpro down here) sells the bushing sets as kits 'for MGB' - with what they deem is the appropriate hardness. You can of course still order verying shore grades if you wish.

There were also kits for sale in the UK, I recall, when I was there a year ago.
Curtis Walker

I spoke via email with the guys at Superflex. They no longer offer various shore ratings for MGB as they did the last time I bought a set. Now there is a pre-determined set up which specifies 90 shore for all bushings except leaf pads, which are 80.

For the archives, here is the official break down of Superflex shore ratings...

Guide to Hardness Selection:
70 Shore: Typically subframe mountings where low NVH is a priority and situations where compliance is desirable

80 Shore: Typically wishbone, radius rod, non coil over shock eye bushes

90 Shore: Typically leaf spring eyes or more heavily loaded wishbones & radius arms, trunnion bushes where replacing rubber

95 Shore: Typically intensely loaded coil over shock bushes, trunnion bushes where replacing nylon – red only
Steve Simmons

I used the blue, softest grade (for road use) poly bushings and found them to be less harsh that the rubber. They also hold the front suspension together more firmly than rubber I think. This is not a contradiction, it is to do with the way they are fitted/designed. They have two halves which are pushed in from either end over a stainless tube. When you tighten up the castellated nut the bushes are held very tightly in place, dead centre.
Steer clear of the red and yellow (except on the sway bar) which are for race tracks.
Peter
P.N. Sherman

Superflex bushiongs are no longer designated by color. They are all blue regardless of shore rating with the exception of 95-shore which only comes in red.

The last set of Superflex I ordered were either 80 or 90 shore and were red, but that was ten years ago.
Steve Simmons

This thread was discussed between 21/02/2007 and 23/02/2007

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.