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Query On Experimental Minis With Conventional Suspension


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#1 Mite

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Posted 18 October 2019 - 09:46 PM

Have read of more conventional suspension systems being looked at for the Mini both during its development (e.g. simple leaf-sprung beam back axle) as well as over the course of its production run (e.g. coil-spring suspension*), with claims there was little to no difference between them in terms of effectiveness with regards to Alex Moulton’s suspension systems**.

 

One question that immediately comes to mind is apart from cost how would BMC opting for more conventional suspension like leaf/coil springs or any other type used by rivals have impacted the Mini’s handling/ride let alone its giant killing reputation in motorsport?

 

Additionally how feasible would it have been for the Mini in say ADO20 / Project Ant form (along with other larger models) to have later carried over the 9X’s Polo/Golf-like front MacPherson strut and rear torsion beam axle suspension arrangement?

 

For owners who have converted their Minis to conventional suspension or others have driven such cars over the years. what is your assessment of a Conventional Suspension Mini? Is there a particular arrangement BMC in retrospect could have adopted at some point or as with Minis featuring larger sized wheels compared to the original 10-inches do you believe Minis with conventional suspension to ultimately be a blind alley over the original Rubber-Cone/Hydrolastic arrangement? 

 

*- One mention so far of a Mini with Coil-Spring suspension also included rubber-mounted subframes though not sure whether one without subframes was looked at.

 

**- Another experimental Moulton suspension arrangement tried in a Mini (before Issigonis ditched the Moulton suspension and apart from the Hydragas used in Moulton’s Mini and Minki prototypes) was apparently an 1800-type of Hydrolastic installation that did away with the subframes, however it is not mentioned to what degree this arrangement was improvement in the Mini over both the existing rubber-cones and Hydrolastic suspension. Is more known about this experimental Mini?  

 

 



#2 nicklouse

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Posted 18 October 2019 - 10:19 PM

no real idea where you are going with this but there is currently nothing available that replaces the rubber spring that works.

 

either there is no space or there is incorrect spring rates.



#3 Mite

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Posted 18 October 2019 - 10:45 PM

Am interested from both a historical point of view (the experimental conventional and other suspension alternatives were mentioned in Jon Pressell's Mini book) as well as partly inspired by the following AROnline article where a Mini was converted to coil-springs. - https://www.aronline...doctor-moulton/



#4 Spider

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Posted 19 October 2019 - 12:00 AM

I've done a fair bit of work in terms of reverse engineering on the Mini Suspension as well as access to some factory engineering data.

 

The Rubber Cones and Hydro set up was chosen at the time because of the compact nature of the suspension. There wasn't room to 'waste' or use up for conventional forms of springing. These systems also allowed for a very easy and simple means of gaining a non-linear spring rate. It did also mean that the system would be subject to very high bearing, pivot and spring seat loadings and that's in a large part, how the Mini came to have Subframes, the heavy cast Suspension Arms and Bearings within them (as opposed to simple & cheap bushes in pressed steel arms of most other systems). The Rubber Spring Medium allowed for a higher range of movement for the poundage than conventional springs can give.

 

I'm not aware of other springing methods examined or trialed in the development of the Mini.

 

 

I also read the AR-On-line article.

 

I'll just make the following 'points' in regard to that.

 

          What one person likes compared to the next is always subjective and a personal evaluation.

 

          There was no engineering comparisons.

 

          This was just one person's limited experiment and experience, i.e., it was not factory research.

 

 

My own subjective view is that Hydro rides wonderfully and can't be compared to anything else, but does suffer from Pitching in a Mini. Longer cars, like the ADO16 and ADO18 fair even better on it.

 

Dry Suspension in a Mini rides and handles very well, though, not as soft as Hydro. IMO, it's only downside is that compared to conventional suspension, it does require a higher level of maintenance.



#5 Mite

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Posted 19 October 2019 - 05:44 PM

Both the simple leaf-sprung beam back axle and coil-spring suspension were mentioned in Jon Pressnell's book (on pages 54 and 144 respectively) as something considered on grounds of cost (and in the case of the latter an attempt to get away from Dunlop due to the belief they were charging too much), though it is not clarified whether the leaf-sprung prototype retained the rubber-cones at the front or used another suspension system.

 

One wonders if Hydrolastic would have been more effective on the LWB Minivan/Commercials as well as if the existing Mini and Elf/Hornet instead featured the 84-inch wheelbase, could that have made all the difference on Hydrolastic being just as effective in a Mini as on ADO16 and ADO17 or would the Mini have needed to have been even longer for it to work?



#6 mab01uk

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Posted 19 October 2019 - 06:44 PM

**- Another experimental Moulton suspension arrangement tried in a Mini (before Issigonis ditched the Moulton suspension and apart from the Hydragas used in Moulton’s Mini and Minki prototypes) was apparently an 1800-type of Hydrolastic installation that did away with the subframes, however it is not mentioned to what degree this arrangement was improvement in the Mini over both the existing rubber-cones and Hydrolastic suspension. Is more known about this experimental Mini?  

 

Testing the rubber suspension system in the early prototype Minis without subframes showed that its monocoque bodyshell construction (the chassis and car body form a unit) could not withstand the high loading imposed by the cone and trumpet system (One ton static load and two and a half tons on full bump).Therefore separate front and rear steel sub-frames were designed by Jack Daniels to carry the drivetrain and suspension.

The BMC 1800 did away with the subframes but the larger bodyshell was exceptionally stiff with a torsional rigidity of 18032 Nm/degree, apparently this was greater structural rigidity than many modern cars up to the end of the 20th century.

 

The Development of The Mini - Jack Daniels (1993) :-

http://www.theminifo...k-daniels-1993/

 

orange-box-2.jpg

 

OrangeBox-PatCox_zpse58b82c2.jpg
 


Edited by mab01uk, 19 October 2019 - 06:50 PM.


#7 Mite

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Posted 19 October 2019 - 07:56 PM

 

**- Another experimental Moulton suspension arrangement tried in a Mini (before Issigonis ditched the Moulton suspension and apart from the Hydragas used in Moulton’s Mini and Minki prototypes) was apparently an 1800-type of Hydrolastic installation that did away with the subframes, however it is not mentioned to what degree this arrangement was improvement in the Mini over both the existing rubber-cones and Hydrolastic suspension. Is more known about this experimental Mini?  

 

Testing the rubber suspension system in the early prototype Minis without subframes showed that its monocoque bodyshell construction (the chassis and car body form a unit) could not withstand the high loading imposed by the cone and trumpet system (One ton static load and two and a half tons on full bump).Therefore separate front and rear steel sub-frames were designed by Jack Daniels to carry the drivetrain and suspension.

The BMC 1800 did away with the subframes but the larger bodyshell was exceptionally stiff with a torsional rigidity of 18032 Nm/degree, apparently this was greater structural rigidity than many modern cars up to the end of the 20th century.

 

The Development of The Mini - Jack Daniels (1993) :-

http://www.theminifo...k-daniels-1993/

 

orange-box-2.jpg

 

OrangeBox-PatCox_zpse58b82c2.jpg
 

 

 

Understand why subframes were added to the Mini during its development, though it seems the idea of a Mini without subframes was later revisited once more via an experimental Hydrolastic Mini with a subframe-less 1800-like arrangement before Issigonis opted for a Polo-like conventional suspension via the 9X prototype.


Edited by Mite, 20 October 2019 - 12:10 AM.





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