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MG Midget and Sprite Technical - A different front damper kit
|I spotted this on ebay and have not seen it before. Anyone know anything about it?|
|Its a usa minimania kit... but from what was discusswd several years back the shear points are screwed up|
|would be slightly better if the top connector for the damper was double shear, but that could very easily be arranged. The bottom wishbone link looks fine. It's quite cheap, almost worth a go.|
|Its an interesting alternative. I have seen this arrangement discussed online with photos of one installed on a car somewhere - I think it was someone in the USA who had made it.|
However it only addresses one of the three functional elements of the Lever Arm system - and arguably the one that the Armstrong unit does pretty well i.e. the damping. That of course assumes that the oil is topped up and the seals aren't damaged.
Where the Armstrong falls short is in providing a renewable inner fulcrum pivot. Once worn they cannot be easily replaced and in bad cases the lever arm pivot shaft can pull forwards out of the body of the unit. The third element is maintaining a consistent location of the upper trunnion that resists the twisting forces under heavy braking.
This tube shock system looks the business but only addresses the damping, leaving the other two, much more problematic issues unattended to.
|Is it okay that the top damper mount is at 90 degrees to the bottom one?|
As the suspension travels there must be a small amount of movement that the top bush would be absorbing. Rather than the top pivoting on it's bolt, in that arrangement it will be continually trying to bend the bolt?
Is that the shear issue Prop mentions?
|I can't remember from the previous thread but I think it was put that the dampers are front or rear Mini ones so to some extent the value of the kit lies in the quality of the dampers but I'm sure they'd do the job and could be improved/uprated if required at a later stage.|
|There was a thread on here a while back for this conversion, a trawl in the Archives may be productive?|
Some photos from their website
|Yes Jeremy, that's the same kit from the same supplier.|
My point was that there was someone several years ago who had developed this design in the USA as a DIY project. He had posted photos and dimensioned engineering drawings.
|I think I would share the concern about the strength of the top and bottom supports. The overhang at the top and bottom is significant, so the potential failure is more likely to be about bending than pure shear. The problem with the supports bending is that the damper will also see some bending, which it is not designed to do!|
The 'Classic Converts' link shows some very nice looking adjustable AVO dampers - I would not want them on 'full hard' with the original mounting design though.
Our Minor has a period Koni telescopic kit front and rear. The front dampers are on 'full hard' and the original top mount design had around 30mm of unsupported overhang, so failed a few years ago through bending stress reversals.
It has been strengthened to reduce the bending stresses and so far so good!
If the damper settings are soft on the eBay dampers, they may well be fine, but anything else I would want to increase both top and bottom support strengths.
|here's mine (in bits) Changing springs as an experiment. Still no lower fulcrum pin wear after 9 years of abuse. Took 1 shim out of one side pin, other than that, all good.
|The blue car in the classic converts thread was my race car and this conversion even under race conditions worked fine|
This thread was discussed between 14/12/2016 and 23/12/2016
This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.