13 replies to this topic

[Tremelune]

It's time to do the whole suspension on my EV conversion, a 1992 Rover Mini SPi. I want to confirm some assumptions and invite discussion as to whether or not I should deviate from the "norm" given that my car is heavier in the rear vs the front as compared to stock. I'm on 10" wheels for added ride quality, though I would prefer to be on 12" wheels if the ride wasn't so harsh (or, ideally, to find a set of 10" with a larger diameter than usual).

 

This is my sanity check. Current favorite is to get a set of four standard cones from Minispares (as well as Protech dampers front and rear) and see how it goes. My car is used 80% on potholed city streets 20% on bumpy mountain road, so ride quality is of the utmost importance over handling.

 

It’s hard to make a good call on any of this stuff without having spring rates or dynos of the various options, so maybe I’m just pissing into the wind…but isn’t that what car forums are for...? Anyway, read on for a regurgitation of my research…Thoughts?

 

Springs/Cones

I'm aware of three main candidates that might fit the bill:

 

Standard

High-quality reproductions from Minispares. The, ah...standard.

 

Red Dot

These are performance oriented, with differing reports as to harshness vs a new standard cone from Minispares. Some say it's stiffer ("but worth it"); some say it's about the same ride quality because they are longer (which equates to more travel). It's very hard to glean a spring rate/dyno from numerous anecdotal accounts...

 

Smootha Ride

These are purported to be the smoothest-riding system, but they seem like old tech, to the point where they're maybe a bit smoother than standard, but with way worse motion control. They also preclude the use of high-quality modern shocks. Seems like the compromise isn't worth it, even for my crappy roads?

 

Shocks/Dampers

After much research, I've narrowed it down to two (though I’m open to others):

 

KYB Gas-a-just

These seem like the bang-for-buck champions, with great ride quality reported. Smoother than standard dampers, I wonder...?

 

Protech adjustable

These seem to be the cat's meow. Softer than stock at the softest setting, and stiffer than the KYB's at their stiffest setting. The only compromise seems to be cost. I'm leaning towards these, as it will allow me to change weight in the future with some amount of flexibility that doesn't require replacing more parts.

 

Weight Distribution

My Mini before conversion:

 

Front 1,000 (64%)

Rear 575 (36%)

Total 1,575

 

After:

 

Front 925 (56%)

Rear 725 (44%)

Total 1,650

 

Do you think this is enough of a change that I’d want to use different springs front vs rear? Like, standard cones up front and red dots in the rear? Or would that just be a wonky mismatch in spring rate front vs rear? I’ve also read that adding a “mild” helper coilover in the rear (instead of just a damper) would stiffen it up in a manner that was easily adjusted/controlled.

 

Edited by Tremelune, 22 March 2021 - 03:48 PM.

[lordcakes]

Summing up then, you want the best ride quality for a car that has more even weight distribution than factory. If ride quality is most important, go for the standard cones from minispares all round. The smootharide system I believe uses non-genuine cones and can also be a bit wallowy. I would also suggest some hi-lo's so that you can tailor your ride height.

The weights you have shown above, whilst a deviation from standard, are within a person's weight. Saving a bit at the front should make life easier for the suspension components (ball joints etc) and your additional weight at the back is just like having another person on the back seat. I don't think you need a different setup front-to-rear, some people have fitted the red spot cones to the front and standards at the back but your front is a bit lighter so the standard cones should be great all round. Remember that some cars were heavier/lighter than yours from the factory and still had the same cones fitted across the range (apart from hydrolastic of course)

I have never used anything but standard shocks on mine but many people recommmend the adjustable shocks.

[GraemeC]

Think of it this way - the standard design had to be a compromise across all situation from the car having just a driver through to it having a full family of 4 plus their holiday gear.  You are probably in a position to optimise to a tighter operational envelope, but not at either of the above extremes.  I'd suggest your weight distribution is better than a standard car and somewhere in the middle of what Issigonis was designing to. 

 

Some people already run 'mismatched' cones in a standard car - ie red dot front and standard rear.  Especially in cars that are used for fun and don't have rear passenger weight so need softer springing on the rear to get the best road holding.

[Spider]

You may have to be prepared to try a few combinations to settle on something you are happy with.

 

I'd suggest stock cones, Hi-los, with a 80 - 85 mm Flange in the Front, I can't see that you'd want to change from that.

 

I'd start with Stock Cones in the Rear and a Van / Pick-up Trumpet - maybe with a Jacking Ring to adjust the ride height. It would also be worth trying Red Spot Cones here however, that would likely entail going to a Hi-lo, while I like in 'in principal' idea of, I don't see any on the market that would stand up to the weight you have, so this change might be a tricky one to accommodate. The other item to try is a stock Cone and a Coil-over Assist unit (basically a Coil Over with a Light Spring - 40 to 70 lb/in rate), however, this would entail modifying the wheel arches to give more space to fit them.

 

I feel that the KYB Gas Adjust would be a sensible choice of damper.

[nicklouse]

Total mass is not up by much. Distribution is not too different. I would start with standard or the Evo rubbers with the Genuine HiLos.

 

shocks the KYB gas adjust as your wheel mass is not changing.

[Tremelune]

Cool, I think I'm in the realm of sanity.

 

Evo cones...? Where do they fall compared to the others? By the description, it seems they're Red Spot cones for people who don't want HiLos...I think HiLos are something I very much would want for my car.

 

I'm replacing a set of steel coils with weird trumpets, so the cost is a wash.

Edited by Tremelune, 22 March 2021 - 07:16 PM.

[Spider]

Evo cones...? Where do they fall compared to the others?

 

You'll find them too soft in Rate for your Project.
 

[Revd]

Cool, I think I'm in the realm of sanity.

........By the description, it seems they're Red Spot cones for people who don't want HiLos...I think HiLos are something I very much would want for my car........

I don’t think anyone fits Red Spots without Hilos - the ride height is just too SUV. Not all Hilos are created equal, I opted for MED, not the cheapest but well engineered for the money

Edited by Revd, 22 March 2021 - 10:15 PM.

[cal844]

Cool, I think I'm in the realm of sanity.

........By the description, it seems they're Red Spot cones for people who don't want HiLos...I think HiLos are something I very much would want for my car........

I've got hilos and red spot cones, it works well, actually I need to lubricate the threads on those or it'll never come off lol

[Tremelune]

 

Evo cones...? Where do they fall compared to the others?

 

You'll find them too soft in Rate for your Project.
 

 

 

Wait, Evo cones are softer than standard cones...?

[nicklouse]

 

 

Evo cones...? Where do they fall compared to the others?

 

You'll find them too soft in Rate for your Project.
 

 

 

Wait, Evo cones are softer than standard cones...?

 

I would guess they have tried to go for a more compliant ride as that is what people seem to want now.

 

I was not expecting this.

[Tremelune]

I spoke with someone at Mini Spares about the cones, and he said this:

 

Red Spot - Better motion control and an improved ride over Standard cones, due to an increase in travel—there's just more rubber being compressed, so it can do it more slowly—and that's why they need HiLos.

 

Evo - Basically Standard cones with better rubber so they last longer. Same ride quality and motion control. He also recommended HiLos with these as well, though I didn't get into specifics as to why.

 

So. My steel coil springs and unidentified dampers are going to be replaced with a set of Red Spot cones and ProTech dampers.

 

I'm in desperate need of an alignment, but I don't want to do it until I'm at a stable ride height (since ride height affects alignment). Figure a few hundred miles on janky roads will settle things up?

[nicklouse]

Don’t forget as the Reds are higher you have to wind the Hilo’s right in. And you don’t get any more travel unless you raise the suspension.

[Tremelune]

"Travel" wasn't the best word, as that's determined by the bump stops or tyres rubbing.

I got a response from an email I sent them last week... Neil Booth says the Evo cones will ride smoother than the Red Spots, so I'm gonna give those a whirl instead.

...I need two Minis so I can do side-by-side comparisons.

Edited by Tremelune, 06 April 2021 - 04:27 PM.