90 replies to this topic

[darkrider]

If I just use driving the the car around town mostly driving alone, would that work? That's if I were to fit coils.
 

Edited by darkrider, 24 April 2020 - 08:41 PM.

[nicklouse]

Just don’t expect them to work as well as the rubbers. You will either have a Mini that handles like a Boat or you will have a Mini that shakes and vibrates over any minute imperfection. That is the problem with linear springs there is no progression.

 

the number of people who went WOW springs and fitted them and ended up buying new rubber cones is massive.

 

they just do not work as a direct replacement.

[Algordo1100]

Can a vehicle of the size, weight,power and dimensions of a mini be made to work with coil spring suspension?? Of course! Look at some Japanese kei cars, or Issigonis' own 9X!

Can we take a car designed to run on rubber springs and substitute coils?

Well, no! It's obvious isn't it?. Coil sprung vehicles are designed as such from the ground up. We can no more replace a mini's rubber cones with springs than we could replace a coil spring designed car with rubber and expect good results.

Edited by Algordo1100, 25 April 2020 - 08:20 AM.

[Spider]

Thread revival ! 

 

To keep what I think is relative info together, I thought I'd post this here;-

 

 

I have removed the actual force numbers from this graph as I'm not sure M-parts or Minitastic (if they are still around) would appreciate me posting them here, none the less, a picture says a thousand words as they say and the realities of Minitastic Springs are laid bare here.

 

I've put in an Original Cone here (those made by M-parts) for a base line reference.

 

Looking at the Front Suspension of a Mini, there's near enough 150 mm of travel. Translated by leverage ratio to the Knuckle Joint, that's 39 mm, so to add some margin to that, I took this to 40 mm. On top of this travel, the rubber cones are preloaded my 9 mm of travel, that's the force holding the arm down when there's no weight on the wheel and why we need to use a Cone Compressor Tool to fit the Rubber Cones - and Coil Springs.

 

I've shown here Compression and Decompression Rates, though these are not truly reflective of the real world because - as shown in the graph - the rubber cones have a self damping rate. I was more concerned with actual 'spring rates' when doing this particular series of tests so there was a 30 second delay between moving to the next position to be measured and recording the rate. In a real world situation, the difference between the Compression and Decompression Curves is much greater.

 

The New M-parts Cone I have left to 'mature' for 2 years before carrying out this test. The Used Cone I took from my own Moke, it had been fitted since 2012 and then removed in 2016, then sat on the shelf until April 2020 when I tested it, so it will have 'come back' some way since being removed. In the 4 years that it was fitted, it hard a considerably harder life than most rubber cones will ever see in their whole fitted life.

 

Looking at the Minitastic Spring, what's clear here is;-

• They only have 26 mm of travel when new
• They do settle
• They are a Stressed Design. What I mean by that is when taken to their normal full travel (coil Bind in this case), when left to relax, they are shorter than when started out, so the Spring has bent.
• They do loose rate with use. I was kindly given that Coil by a member here for the purposes of testing. It had been is his Mini Van for a few years. I had it for about 2 years before testing, so it will have relaxed a little back to it's original height. It has only been able to do this because they also settle over time.
• The New Minitasitic Spring was kindly supplied to me by our Club President, also for testing purposes.
• Coil Springs have a linear Rate - until they hit Coil Bind
• Coil Springs have no self damping qualities

[Aly-g]

A year ago I posed a similar question and got very similar responses to the above. My old donuts had seriously deteoriated to the point when the car was sitting on the front bump stops so something needed doing.
After a long and thorough deliberation I decided to fit fast road springs and Gaz dampers which were really easy to fit once I'd got the old donuts and trumpets out
Initially I was delighted with them but as the year went on I became more disillusioned. I found the car had lost some of its character as it was so smooth, I didn't like the increased mechanical noise of the metal springs sitting on metal hilos connected to metal suspension arms. There was also a slightly noticeable increase in roll when taking corners quickly, not effecting road holding but not what you would expect in a mini
So about 2 months ago I decided to buy 4 new Avon donuts and fit them, only took a couple of hours to do each side so did the job in a few evenings after work
The car now feels like a mini again, it's bumpy even when the road isn't it corners as fast as it goes straight with no noticeable roll and is a little quieter.
So which do I think is better, well at the moment I'd say new donuts would be my preference but when I'm older (I'm already pretty old but not yet retired) and can't stand the bumpy ride anymore then I'd be happy to fit coils and accept the change in character to allow me to continue mini-ing in some comfort for many more years
All the above is my own opinion, based on my own subjective experiences. Hope they are useful to someone
Cheers

[Aly-g]

This is the most helpful post on this subject, I think it is the what the original asked for....!
Arguing about which is best, rubber or springs does not really help anybody, people have modded cars since they were first made,does it matter if the car is not original specification ? Only if its a trailer queen kept to win trophies and not used very often, each to their own I say, I have made my car the way I like it and will always do so.

Allan

[nicklouse]

This is the most helpful post on this subject, I think it is the what the original asked for....!
Arguing about which is best, rubber or springs does not really help anybody, people have modded cars since they were first made,does it matter if the car is not original specification ? Only if its a trailer queen kept to win trophies and not used very often, each to their own I say, I have made my car the way I like it and will always do so.

Allan

But you miss the point that they are not fit for purpose. They can not provide anything like the correct spring rates that the Mini suspension requires. They are either too hard to deal with small bump compliance or they are too soft to deal with max loading.

 

and all the ones available do not provide the travel needed without going coil bound. And that is a hard harsh ride not to mention possibly dangerous. Don’t you think that is they could have worked correctly they would not have been fitted originally? The technology for making springs and metal spring technology has not really changed much in 60 years.

 

but each to their own. 
 

springs can be good when used in a very defined set of requirements like completion cars. Track mainly. But then it is coil overs positioned totally differently to the crap kits being sold.

 

if you want coils for comfort you have the wrong car.

[Tornado99]

I think going with a torsion beam suspension would be quite unique. These I have used on boat trailers. Basically a pivot arm with wheel axle is jammed into a steel beam using rubber inserts. The pivot has to work against th rubber to deflect. Very simple, nice and smooth response and no long term corrosion issues as with leaf springs etc.

[Aly-g]

i did not know minis were specifically made to give a uncomfortable ride....? i thought they were built to a price and that's why they go rusty the brakes are crap and give a very hard ride ,very basic in fact, i had eight minis in my life and i love them i used do club road rally's in the late 60's ( Saturday night through to Sunday morning's ) I've had some nice comfortable cars including luxury Lexus but they do get boring after playing with all the toys for a few weeks....!  the mini is never boring ,it requires a lot of regular maintenance ( especially if it's 42 years old ) and it requires you to search for bits of road between the potholes when driving, lots of ahead driving . don't try telling me i have the wrong car, my other car is 32 year old E30 cabby, my better half's car is a 22 year old civic coupe,  i don't like modern day cars but at my age l would like to give my old bones a rest from being battered about is that so wrong ?

[Aly-g]

maybe  air ride if that is allowed, works well on most vehicles

[Tornado99]

What about the original hydraulic ride system? Perhaps still for the sheep 

[Spider]

What about the original hydraulic ride system? Perhaps still for the sheep 

 

Hydrolastic on Minis was very good. It was intended to fit this system to the saloons right from the start of production, however it hadn't been developed enough at that time, so it was another 5 years before it appeared on Minis. Great system, but must have cost BMC a bomb to be putting it on the cars they did. That there's still many cars riding around on it today, when the youngest is 50 years old now, is a testament to the quality of it. While it does give a super ride, sadly most of the main components are well and truly NLA now, so I wouldn't think it be wise to find the bits to fit in to a Mini that didn't already have it.

 

Regarding comfort of the Rubber Cone system, It is a little on the hard side I feel in a Mini, but it's a long way from awful, very long way. I have Rubber Cones on my Moke and find them very very comfortable. We had a trip a few years back, a mate and his son, Mitchell, tagged along in his 90 Series Land Cruiser, these are coil sprung and won many awards in their day for the comfort of the ride they give. A few days in to the off roading and Mitchell thought he'd see how rough it was in the Mokes. It didn't take long before he was giggling and from then on he refused point blank to get back in the Land Cruiser as the ride in the Mokes was so much better, just a bit noisier.

[mab01uk]

i had eight minis in my life and i love them i used do club road rally's in the late 60's ( Saturday night through to Sunday morning's )

 

Did any of your 1960's Mini's have Hydrolastic suspension? The smoothest best riding Mini's I have ever had were all Hydrolastic as were many of the BMC 'Works' rally Minis. The Mini only went back to rubber cones in the early1970's to save production costs.

Edited by mab01uk, 23 October 2021 - 08:37 AM.

[Aly-g]

Unfortunately none of my minis had hydrolastic fitted and I haven't been in a mini to experience the ride, I have driven a vandem Plas 1100 and that was very comfortable. I think as Spider said the hydrolastic system was very expensive, so it was ditched for a cheaper system which works but is far from perfect.


Allan

Edited by Aly-g, 23 October 2021 - 09:46 AM.

[Tornado99]

We have seen reports/pics of failed coil springs on minis used on roads. Presumably coils fractured from coil binding when hitting a good enough road bump. That alone would negate any advantages of springs to my mind. Fine for track race cars that do not need to deal with public roads.
There are several rubber cone designs/material densities to explore if you want greater ride comfort.