Minitastic Springs what happened

[snoopy64]

Hi, I’ve been in a couple of cars with minitastic springs… what happened to them? They were a really nice predictable ride.

[mab01uk]

Probably withdrawn from the market because from an Engineering point of view fitting such small coil springs into the tight space available in a Mini subframe designed for rubber cones (or Hydrolastic displacers) means the limited suspension travel can result in the spring coils binding, compressing so they touch and eventually you have serious issues with things breaking....


More photos of broken springs, etc in this TMF thread:-
https://www.theminiforum.co.uk/forums/t ... ?p=3677392

[snoopy64]

I’m glad to say both vehicles are still going strong 15 years later from the time the company was based in the lt rissington … they did seem to be a quality product… I think the original guy was Japanese and was also developing a power steering unit

[minibitz]

Think I've swapped out around 4 sets over the years due to springs breaking. Don't know what brand they were. Went back to rubber cones.

A lot of 90's Japanese Rover Mini imports we get here in NZ arrived with them fitted.

[Spider]

None of the coil spring replacements that were on the market came close to having the 'travel' needed to replace the cones is likely why. Martin posted a photo as one example (of 100's).

On even moderate suspension compression, the coils bind, then something's gunna give, be it popping the tower top off or broken springs. They are bad news and respectfully, you are having yourself on if you think you can use them in a road car without risk. On test, I found the Minitastic Spring the worst of all that were tested,with them loosing height on their first full compression, meaning that they are an over stressed designed.

I'd love to say they work and that 'it can be done' but it can't. I spent many month working with a Spring Engineer, we tried lots of different designs, including bee-hive and double springs. In the end, after around 30 something tries, he turned to me and said ' ever thought of using rubber ? '

Take them out and assign them to the bin.

[Polarsilver]

just a thought as alternative to Cones & Springs .. what about Belville Washers ? .. they are a cone shape spring steel washer & when assembled opposite to each other & then allow the pair or multiples of Belville Washers to act as compression springs (maybe my description is a bit off ) .. i have used them many years ago to act as pre loaded compression springs & have also seen them used in Agriculture Equipment.

Further thinking that Belville Washers were installed in the Morris Marina Door Section at the Cowley Factory Assembly process these were the Jigs that the Door Panel & inner Door Frame component parts were clamped into .. Then the Door was spot welded.. with the Door when finished the Holding Clamps came off and the assembled Door released & "popped up" due to the Bellvill Washers that were installed underside. ( Sorry another bit of useless info ):oops:

[mab01uk]

Another unsuccessful attempt below to better the rubber cone. Found this in some of my old paperwork, the advert is from around 1998/99. Price quoted was £75 pair....

[Spider]

(Defelx) What were they thinking,,,,

Here's a graph of some of the tests that I did showing characteristics on compression and rebound with a few rubber cones and also the Minitastic Springs. There's a few items to note from this, the first being that the rubber cones have a damping quality ('shock absorbers' built in), the same rates but different compression heights of the Minitastic, showing it's stressed design, and the short travel available from the coil springs. Considering the front suspension, the arm has a movement of just over 140 mm at the ball joint socket, with a leverage ratio to the knuckle joint of 4.45:1, there's just a bit over 32 mm plus some pre-load is needed so the car doesn't sit too low (the rubber cones have 9 mm here), so more than 35 mm of spring travel is needed, as you can see, the coils fall well short.

The coils are harder than the rubber cones, but feel softer as they have no damping, so the reality here is the ride is harder, just under dampened. When the coils are fitted, the high body roll etc is easy to notice - lack of damping.