13 replies to this topic

[joyce1bro]

Okay so left side suspension gave way and I'm looking at options. I will replace all four corners as I'm unsure of the condition of the others. I would either get new hi lo's with new red dot cones all round or new adjustable coilovers. I'm leaning toward the latter as I have had a lot of them on my other vehicles. This will be a road car with some limited track time. I have heard people say they are very different on a mini to a modern car? Questions are how have you found them on the mini? Handling compared to the cones? Setup? Faults? Would you ever go back to rubber cones? I'm also wanting to hear from people that have fitted them without reinforcing the mounting points? Worries? Was set on spax adjustables on minispares but after some reading would go Protech.

[benjy_18]

for mostly road use, your better off staying with the cones and hi lo's

for coilovers you need to carry out quite a lot of strengthening to the rear turrets as you will be putting all the rear suspension load through them as opposed to the standard system of loading the subframe.

imo coilovers are only really for a track car.

im using them on my project but it will be a track car used rarely on the road.

regards
Ben

[smudger068]

Stick with the standard suspension, the aggro and cost with putting coilovers on the rear etc, id go standard, as you dont know what spring rates you want etc etc

[Tommyboy12]

Well I have SPAX coilovers front and rear (offset) with no reinforcement and I have never had an issue. The turrets are fine and I am not worried about them in the future provided the dreaded rust doesnt weaken the area (which it isnt at the moment). I use mine purely on the road although it has seen a few track days.

I cant comment regarding fitting as I didnt fit them but I have adjusted them which is easy enough. Use the special tool to wind the springs up and down and then adjust the shocks to match.

They are ok if youre not driving all the time. The major fault is that they are too hard for me. I find myself crashing along any road with a bump (so all of them!). The problem is to soften them up you have to lower the car (giving more travel to the springs) or change spring poundage. My car is already as low as I can go and I think they are on the softest springs!

If I break a coil or the car comes off the road for an overhaul it may be worth changing them back to cones to save my back but they are fine for the occasional use my Mini gets.

[joyce1bro]

Great info tommyboy, all of my cars have been pretty stiff so Im not really to worried about it also know about the "C" spanner!. How much use does she get, daily driver? and how long have you had it? My car is in New Zealand and we dont get the dreaded rust you guys have and just recently the car has been taken back to bare metal rust proofed and resprayed. Im wondering what the cost would be to reinforce the front and rear but also wondering who out there hasnt... As for spring rates I discussed this with Protech and they have everything for me.

Edited by joyce1bro, 22 April 2013 - 01:27 PM.

[Tommyboy12]

The coilovers have been on for 6 years now. Ive owned the car for 4 years. I used it as a daily for about 2 years but now its a second car so maybe sees 50 miles a week. While it was a daily it was seeing 35-40 miles a day. I keep an eye on the areas around the coilover mountings but Ive not seen any stress fractures or creasing and I doubt I will any time soon. Its one of the few jobs the previous owner did properly!

[tiger99]

You don't see fatigue until it bites, probably causing an accident. It is well-established fact that the standard front and rear damper mounts are both completely unsafe if asked to carry spring and damper loads instead of just dampers. For a start, the 1/4" bolts at the front are woefully inadequate, nor are the rear turrets.

I bet that you have no idea of the actual peak loads involved, or the shear strength of a 1/4" bolt.

A Mini thus modified WILL suffer structural failure, the thing that you can't predict is exactly when, as it depends on how it is driven and how smooth the roads are.

[Tamworthbay]

Whilst I agree with tiger that they are not good for road use and on our project car the mounts will be strengthened, I would point out that the sheer strength on a 6mm bolt is enormous. We were lucky enough to have Lola Cars as a major sponsor for our electric race cars. This meant a chance for a good poke around their Le Mans cars and other cars. You won't find much above a 6mm size on their suspension. The major issue is whether the load is in single or double sheer. The standard set up on a mini front damper mount is single sheer. It only takes a little work to change this to double sheer and make it pretty much bulletproof. Then you have to follow the load paths through the inner wing and see if you are happy with that. I wasn't, so developed a new inner wing arrangement that spreads the loads much better. I wouldn't use them on the road as they are truly awful on anything other than a really smooth surface. To be honest the main reason for us using them is that we can play with suspension setting and let the students see the effects in real time with datalogging set up, otherwise it would be cones all round.

[Leics1275]

Slightly away from the topic, but would/has anyone tried the rubber replacement coil springs ??

Would these be any better ?

[HUBBA.HUBBA]

Anyone had fun and games with the front coilovers. I'm getting the bottom bracket knocking onthe subframe where the bump stop used to be and the car's not particulary low. The ride height before was much lower with normal hi - lows on, without it even touching the rubber stop.

[tiger99]

That is inevitable with coil springs, because even the variable rate type does not have the rapidly rising spring rate of the rubber cone, and there is no combination of rates that will work correctly, either they are ridiculously hard and give a terrible ride and poor roadholding, or they cause the problem you are having.

 

By the way, the bump stops are vital, and without them you will break a ball joint eventually, possibly causing a serious accident and certainly damaging the car. Your insurance will be void if you drive the car in a state like that, so I strongly suggest that you revert the suspension to the configuration which Issigonis originally designed, with rubber cones, which is all that will work properly with such short wishbones and limited travel. Unless, of course, you manage to fit a Citroen style hydropneumatic system, which uses automatic control of ride height to keep the suspension workingh in its useful range despite changes in load.

[HUBBA.HUBBA]

That is inevitable with coil springs, because even the variable rate type does not have the rapidly rising spring rate of the rubber cone, and there is no combination of rates that will work correctly, either they are ridiculously hard and give a terrible ride and poor roadholding, or they cause the problem you are having.
 
By the way, the bump stops are vital, and without them you will break a ball joint eventually, possibly causing a serious accident and certainly damaging the car. Your insurance will be void if you drive the car in a state like that, so I strongly suggest that you revert the suspension to the configuration which Issigonis originally designed, with rubber cones, which is all that will work properly with such short wishbones and limited travel. Unless, of course, you manage to fit a Citroen style hydropneumatic system, which uses automatic control of ride height to keep the suspension workingh in its useful range despite changes in load.

Out of interest, if the bump stop was removed from a orginal coned set up would it knock?

[tiger99]

If you remove the bump stop from a standard rubber cone setup, you can undeed break the ball joints, but only under extreme conditions, as the rising rate of the rubber spring discourages an extreme amount of suspension deflection. However, if you are using rubber, and have lowered it ising a HiLo, or a shortened trumpet, then the risk of broken ball joints returns. Actually, the risk is still there, even with bump stops, because on a seriously lowered car they are liable to get such a hammering that they rapidly fail.

 

Take a look at the little bit of rubber that is the bump stop, in comparison to the spring or cone, and estimate how much of a hammering it will survive.

[HUBBA.HUBBA]

Coilovers have a integral bumpstop, or at least they should have..........

There probably is one, but i don't think it is even touching that. The bottom bracket for the bottom of the coilover ( that sits over the ball joint) knocks the part of the sub frame where the bump stop used to bolt to. And this is at a height where the car is riding HIGHER than before when i was using hi/lows?!