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MG Midget and Sprite Technical - retrofit tub shocks
Hi, Finally got back to the midget over the weekend and took one of the rear shocks off to get better access to the rotten corner. They're totally rusty so no idea what they were. Anyone any ideas? I've heard that mini front ones are the ones to go for but can't be sure. The eye-to-eye measurements are 10" compressed and 15" extended. Anyone able to check if that's a mini shock? Without going to the effort/expense of adjustable ones, what sort of damper rating should I be looking for? It only gets road use and the drivers are far less capable than the car so I'm thinking something reasonably soft. What counts as reasonably soft?! Thanks for your help, -Craig -edit- that, of course, should be TUBE shocks...! |
C Robertson |
Mini rear shocks have the right stroke and are not too firm, they fit to the axle at the lever shock's mount with a 1 inch spacer. and can be fitted just off the vertical through a hole in the rear axle tunnel. The area around the hole needs to be reinforced, which is quite easy to do if you can weld. Graham. |
Graham P |
I am using Monroe ('cos they were cheap) Mini front shocks. They have the eye fitting top and bottom so just bolt on. Top fits onto the bolt that normally carries the rubber axle strap. This didn't need reinforcing on mine, although the metal around the upper bump stop plate which is prone to rusting, does need to be in good condition. |
Guy |
Already got the mounts, etc, just looking to replace the existing tube shocks as they're pretty ancient & crusty. Thanks for the recommendation, Guy, I'd seen monroe & emailed their tech support but still waiting for a response. The UK main dealer was very prompt in their response but knew nothing about the tech. They did give me a UK phone number for tech support so will try that also. Sounds like a similar setup to mine though, so Mini rears are what I'm after. Thanks chaps! -Craig |
C Robertson |
Craig, Mini rear ones have a vertical bolt fitting at the top. Mini fronts have a horizontal eye at the top (as at the bottom) So it will depend what the current arrangement for mounting that you have is. |
Guy |
Ah, that'll be why the front ones are used then. Cheers! -c |
C Robertson |
Hi all, this is very interesting.. My plan for my renovated midget was to use the mini shock conversion. I replaced the old shock/rebound strap brackets during the rebuild. To unsure they would be up to the stress I seam welded the brackets rather than the measly 3-4 spot welds I found holding the old bracket to the floor. Anyhow the details I got from the web were to take of the brackets on the axle where the rebound strap attached and swap sides while also turning them upside down, thereby increasing the distance between the two fixing points for each shock. Then the suggestion was to use front shocks from a classic mini. However, have trialled fitting these and they look way short.. so either I have the incorrect shocks, or the brackets didn't need switching? Any ideas? Cheers Tim |
T Dafforn |
Does it have to be Monroe - these Sachs seem remarkably cheap on ebay? http://tinyurl.com/bthf88z Jeremy |
Jeremy 3 |
Jeremy, The only reason I used Monroes is that they were cheap on e-bay at the time. They worked for me, that's all. Presumably the measurements are the same on all makes since they need to fit the Mini front mountings. Cheap ones may not last as long, or may be less controlled, but to me they would be a good start point for road use at least. Tim, when fitting mine I did the same thing about swapping the bottom spring plate over. And the mini front shocks were just right for my car. The point here is that the vertical distance between the top and bottom fixing brackets is critical in relation to the total available travel of the shock unit. With the car at rest, normally laden, the shock needs to be part way between its extended and compressed limits. In practice there needs to be more movement available from this point in compression than that in extension. As far as I can remember - I have it written down somewhere - the length of travel available is about 4 1/2". And so the at rest point needs to be around 1 3/4" compressed, leaving around 2 3/4" further compression available before the shock "bottoms out". Depending on your car's normal ride height (1500 or lower earlier model? ), or is the suspension modified / lowered / or sagging - these will affect the relationship between the units that you fit, their travel and how you arrange the mounting points. You can get a fair way with this by measuring the car and doing sums, but in the end it will need to be trial and error and road test for your car. My set up cost under £20. Alternatively, buy a set from Moss or Frontline for around £300 more. http://tinyurl.com/ckgese2 |
Guy |
Hi Guy, My car is a 1970 1275 and is lowered. It is not sitting at its final level as it is completely stripped. I'll do some measuring when it comes back from respray. Tim |
T Dafforn |
Cheers Guy, I'm tempted by the price - also under £20 for the pair as well as any potential ride/handling improvement. Did you reinforce the top mounting point by any chance or is that not really necessary? Thanks Jeremy |
Jeremy 3 |
Tim, Mine is a 1971, 1275, so the same as yours. It is also lowered a bit. Jeremy, I did a major rebuild/ reconstruction of this car which included new metal around the rear inner wings, boot floor, bump stops etc. Specifically, I replaced both of the large triangular plates that hold the standard shocks and form the mounting point at the top for the axle straps (which I later used for the tube shocks) When I fitted those plates I seam welded to the floor, the box section over the axle "hump" and to the rear bulkhead, so they were all new metal and pretty solid. There has been no visible deterioration in the mountings in50,000 miles+ although I know of at least one other BBS'r who has had the top mounting split and tear away from the floor - they will get a fair bit of a hammering in use. To me, the cheap shocks work well for a road car. But then I am also a fan of the standard lever shocks - if they are in good condition. Often they are not, which is why people fit tube shocks and think they have vastly improved the handling! I don't think that would be necessarily so if the originals were in proper condition in the first place. Adjustable shocks are probably better, but for a tight budget, road car, to me they are just expensive bolt-on-bling. |
Guy |
Thanks for the link on the Sachs, Jeremy, they look a good deal too, I've seen Sachs recommended as near-OEM for the golf so their stuff should be reasonable. -Craig |
C Robertson |
and that makes three as mine is also a 71, 1275 but standard ride height. Thanks for all the info Guy, it would seem (no pun intended) you've ensured the mountings will be robust enough to take the forces generated by the shocks with the seam welding. Mine's a Heritage shell so the metal is good but only intended to take the occasional weight of the axle if the rubber straps are fully extended - my guess is they'd snap before the mountings failed? I am tempted though as telescopics are more efficient and the current ones are getting a bit soft but may end up whizzing them off and checking the oil as the front ones had only a tiny amoung of grey gunk in them when examined! Thanks again, Jeremy |
Jeremy 3 |
This thread was discussed between 02/04/2012 and 04/04/2012
MG Midget and Sprite Technical index
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