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MG Midget and Sprite Technical - rear shock conversion

hi, wonder if anyone can help. a few years ago I found a midget in a scrapper, burnt out. It had a spax conversion on the rear so I took the brackets off but the shocks were shot. I'm planning to put them on now and have heard mini front shocks will fit, ebay sells them for £35. Any thoughts?
p sewell

I use mini front shocks

I think you may get them for less than that if you shop locally

I think I paid about £15

Dont use the Spax brackets

if you study the relative motion there is remarkable little damping action when they deflect because they ride sideways rather than up and down giving very little movement around their axis

Unless I have been looking at the wrong brackets (which happens!)

I swapped the spring platform doodahs left to right and vice versa and refitted them upside down to allow the mini shocks to reach and fit well

HOWEVER

if I were to do this again, I wouldnt. The lever arms should be fine unless you have weak ones AND plan competitive driving

I often consider reverting to my old levers, which is why I still kept them

Just a personal "thing"

HTH

ps the picture shows the bracket as is now
but these are not the mini shocks, these were an earlier attempt, AVOs were too much shocker for the job IMO


Bill sdgpm

thanks for that bill, forgot to mention that the shocks I was looking at were gmax gas filled which would account for the price, have you ever come accross them?, I did notice when I was looking that they do look like they cant over quite a bit.
p sewell

here is the best artical I know on the subject of rear shock conversion...use it fast, As Im not sure how long it will stay up now that bob has sold his midget,,,,

good luck, it will answer all your questions


Prop


http://82.44.126.36:76/shocks.htm
Prop

DO NOT USE THE GMAX SHOCKS ON THE REAR OF A MIDGET!!!!!!!!

sorry for the caps point needed to be made

the Gmax shocks are way to hard for the midget rear

I have spax adjustables on there and have them 1 or 2 clicks from the softest setting.
They do the work great but if you have functioning leverarms they will do the job just as good and save you the money

setup of a midget is soft at the rear hard at front.
Onno Könemann

I can only confirm to Bill and Onno.
I'll go back to the armlever setup after a too bumpy ride with telescopic dampers. The reason I choose telescopics in the first place, was that I had to replace a broken spring some years back and decided to go all telescopic. They're good on perfect roads, but only offer lower backpains on lesser surfaces. The rearend of the Midget is simply too bouncy. Complicating though may be the fact that I made my 1500 bumperless and therefore a lot lighter at the backend?
To me, it was the only 'improvement' that was a disappointment. No comparison to the FL frontsuspension.

So, probably within a few weeks, watch e-bay...
Rolf

I'm 100% with Bill's analysis of the Spax bracket geometry - at full bounce they have very little effect so if you are travelling two-up with luggage over an uneven road then the ride is a nightmare. One of our Midgets came thus equipped and has had the lever arms refitted which has greatly improved it.

To be fair to Spax, the reason the brackets are positioned like that is that there is not enough room to mount them more upright and yet still have enough overall shock length to give the amount of travel. In our K Midgets, which competing over sometimes testing unsealed surfaces need something better than lever arms, we have solved this by fitting turret which allows for a longer upright shock.

And as Onno says, they can't be over stiff or the car will swap ends very readily.


Paul Walbran

thanks for that gents, I'm pleased I didn't just go for it before asking.
p sewell

Not a totally essential point (so why make it?) the mini shocks will not actually allow the full "up-n-down" movement of the axle either.

I haven't found this to be a drawback but essentially the upper "bump stop" never sees any "bump" to rebound and the leafsprings never drop to full extension. The mini shock has to absorb full "bump" internally and stop droop before the full spring relaxation point

As I said I haven't had issues with this but it may be a technically "bad thing"

(in honesty, with the better springs I'm now running my car is damned near enough perfect for the uses I put it to)
Bill sdgpm

If you want to stcik with levers, my preference also, you could source a pair of adjustable levers if you feel the need to tinker with set up.

Les
l snowdon

I took my, Moss supplied, Spax conversion off a couple of years ago and put some NEW lever arms on and the improvement in the ride was very noticeable. And yes, I do corner quickly and on Hampshire and Sussex's far from billiard table roads.

Worth noting, and I know I'm a bore on this subject, that Peter & Chris May use levers arms all round on their highly successful racecars.
Jeremy Cogman

I'm in the market for some replacement tube shocks and would like to utilize the collective wisdom of this group. My problem is finding the correct length shock. I think at this point, I'd like to try the low cost, non-gas shock. Some suggest a Mini front shock. Are there any others? (This is for pleasure driving, not autocrossing). Seems like the Mini rear would be better, as the front is designed for more weight than the rear of a Midget. But, the mount is wrong for the Mini rear shock. Another question is how you are mounting your shocks. Most seem to have the lower mount below the springs, but in the article Prop mentioned, it looks like the mount is turned up. Also, my shocks are mounted between the rebound strap space, whereas in Bob's article, it looks like it is on one side of the bracket, as there is no sheet metal on one side of the mount. Is this just due to differences in different years? (Mine is '74). You can see that the dust shield is very close to the bracket, but there does not appear to be any evidence of contact. I don't know what kind of shock these are. Many years ago when I replaced them, I estimated compressed and extended length and this is what I got from some vendor. Is the way mine are mounted seem to be the "norm" for tube shock conversions? Seems the trick is finding the correct length with the correct compression and rebound specs.

Jack


Jack Orkin

Jack, my frogeye has mini rear shocks fitted, not the same as a 74 midget, but it might give you some ideas. Follow this link to the archives: http://www2.mgcars.org.uk/cgi-bin/gen5?runprog=mgbbs&access=&mode=archiveth&subject=97&subjectar=97&thread=200808242331585210
There are pictures of my setup there, about halfway down.
Graham.
Graham P 1330 Frogeye

There appear to be a number of diffferent length mini shox, this article might be of help.
If it was me I'd choose the gas Bilsteins for quality, and they also have the longest stroke at 165mm, you need all of that for the rear of a spridget.

http://www.calverst.com/cc110f.htm

Ian
Ian Webb '73 GAN5

Ian,

If they're true gas shocks ie monotube then you can mount them upside down for reduced upsprung mass, mounts permitting. I say true gas as when I was learning about these things 25 years or so ago a gas shock was a monotube shock, whereas these days it seems to mean anything which has a fancy gas over the oil in a twin tube shock, they typically can't be inverted.
David Billington

Ian

What model Bilstein are they?
Paul Walbran

<<use it fast, As Im not sure how long it will stay up now that bob has sold his midget,,,,>>
Hey Prop, I'm still here and still with Midget :o) She's just a little disabled at the moment.

Just a footnote to my website in that the conversion I did worked well for my RB1500 car but the same conversion is not so easy on an earlier model as the mountings are very different.
Bob T

It looks like conversions come in all shapes and sizes, requiring shocks of different lengths. And, looks like there is a difference in the 1500s and the earlier Midgets as far as mounting goes. The table at Calver's Corner is very useful. I just ordered some Unipart front shocks yesterday from Mini Mania but I'm afraid they may be too short. If so, I might be able to just swap the lower brackets so the mounting point is pointing up. We'll see in a couple of days. As usual, nothing is ever as easy as it first appears!
Jack Orkin

Paul

I believe the Bilstein number for the classic mini rear shock is B36-0380.
I have been checking availabilty is good in Europe but price is not !! about £80 GBP, I suppose that is each not for a pair.

I used them in the past on rally escorts and they give a very well damped ride but not hard, really allowing the axle to move up and down with the bumps, and thus grip the road.

Interestingly Bilstein list front and rear for sprites, any body know anything about those ??
Ian

Ian Webb '73 GAN5

This thread was discussed between 28/05/2009 and 06/06/2009

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