Teach me about suspension!
I've been reading all over this forum for a few weeks now and I have learned a lot but I still have lots of questions.
I've searched but have not gotten some exact answers. If is a thread already containing my answers i would greatly appreciate being redirected to it.

So I've figured out there are so much more than just getting coilovers and you're done.

so.
Where to start...
I understand that springs put a load of stress on your struts and since the length of it is shortened its not good for the struts itself, so coilovers seem to make more sense, but still does not fix the problem with mushrooming strut towers. How necessary are the strut tower defenders if I lower my MINI? How effective are these defenders?
Also how necessary are the adjustable rear control arms? I see that most people do not have them. Is that safe for the car? Is the mod purely for handling enhancement?
Also, I don't really understand what spacers are. I believe that they reduce rubbing, but what are they exactly? What do they do to accomplish this?
One last thing, the rear sway bars, strut brace, and the end links(also don't really understand what they exactly are...) are not necessary at all, correct? They just help reduce body roll and people usually install sway bars when they install coilovers because everything is out and it is easy to access?

I think thats all the questions that I had...
I'm sorry that these are really noob questions but I really started knowing nothing of suspensions or cars to that matter.

Thanks, and really, if my questions are already answered in another thread a kind referral will be appreciated.


oh p.s
How much does installing coilovers usually cost?
Is it easy to go back to stock if I wanted to?

 

1. Springs do not put a load of stress on the struts and shocks. The springs are what actually support the weight of the vehicle and set the ride height (or, where you are in the suspension stroke if you will). Lowering springs change the position of the car in relation to the stroke - your OEM struts/shocks are good for ~1" of lowering based on our testing, and will still provide adequate stroke. The struts and shocks are designed to dampen the oscillation and provide control of motion. The bumpstop is intended to keep the strut from bottoming out, and we trim those during install of lowering springs - there is a considerable measure of safety built into the system. Now, if you go too low on the OEM struts/shocks, you may bottom them out - this will kill the valving and lead to premature failure.

Coilovers are a better option IF you want a completely engineered suspension (assuming the company did their homework), want a lower stance, AND want ultimate performance. This assumes, of course, that you properly set them up - this means installation, setting ride height, and then a PROPER CORNERWEIGHTING and an alignment. The part that a LOT of people skip is the cornerweighting. Unfortunately, many people seem to think coilovers are now just to slam your car for looks, which is counter to what they were originally intended to provide you. If you install coilovers and just set the ride height and get an alignment, you're missing what coilovers provide for you in the first place. And, you can actually end up with a car that might look good, but handles like complete crap. I will almost guarantee that 95% of coilovers installed are on cars that have never been on the scales for cornerweighting - those people are all missing out on what the car could actually handle like with the same suspension.

Neither will help you with mushrooming. In our opinion, mushrooming is just part of BMW/MINI ownership. Just lowering the car, in and of itself, will NOT contribute to mushrooming. You must hit something very hard with the wheel, and it can happen with the OEM suspension. In our engineering opinion, putting a plate on top of the system re-distributes the force along the seam weld, which can and will pop. Practically, we've seen it happen on cars with strut braces after going off at the track. Personally, I'd rather get out a chunk of wood and hammer out the mushrooming then get a seam weld fixed (but that's JMHO). It's quite a simple process.

2. Adjustable rear control arms are suggested in order to return a lowered car to proper suspension geometry in the rear (one set to replace the lowers), whether you lower it with springs, springs and new struts/shocks, or coilovers. You "can" drive it around without them and rely on what you can dial out with the OEM adjustment. It just might not offer "optimal" camber and handling. If you want to track the car, replacing both upper and lower gets rid of known weak points in the rear suspension.

3. Are you talking about wheel spacers? Wheel spacers are really only necessary if you have a wheel with an incorrect offset for the MINI, you want to stuff on a wider tire that might interfere with the suspension, if you need to clear a big brake kit, or if you just want a wider track. They simply space the wheels out from the hubs (at the cost of wearing out your wheel bearings quicker).

4. A rear sway bar not only reduces roll, but changes the handling characteristics of the car. This is a highly recommended compliment to a good suspension that allows for fine tuning, with the intention of pursuing a neutral handling (at least that's what we prescribe). You'll get flatter cornering, but also better cornering performance. A strut brace does nothing but look pretty under the hood on the MINI. And finally, the OEM endlinks are fine to a point - which is, until they break. And, they do break. Aftermarket endlinks provide more strength, and some provide the ability to offer adjustment in length to dial out any preload. Preload means the swaybar is loaded more on one side than the other (say, because you sit in the driver's seat) - this will cause it to be more effective in that direction, and initially, less effective in the other direction. To be honest, replacing the endlinks is one of the last things I would do (unless the OEM ones break), as this is a very subtle suspension mod (although people can and do report that the car feels completely different after installing adjustable endlinks and dialing out preload).

A proper installation of coilovers, from a shop that knows what they are doing, should run ~$500-800. That would be installation, setting ride height, cornerweighting, and alignment. IF they don't mention cornerweighting, I would find another shop. IF they don't have good scales, I would find another shop. You want them to shoot for 50/50 cross-weighting with the equivalent weight of you in the driver's seat (and/or any other weight in the car that you might "normally" have). If you ask them to shoot for this and they have no idea what you're talking about, I would find another shop. And finally, make sure they actually SHOW you the setup numbers.

With coilovers, you can take your car back to stock by simply re-installing the old suspension components. HOWEVER, you would need another alignment.

 

Excellent write-up, thanks! Although I've already done some suspension mods I learned a few new things..

 

i also agree.

excellent write up. you provided information that a fairly new member wanted to know where other people would say "go do a search"

not only was it a great write up, you provided the information without doing any sales pitching. for that, i highly respect you.

-nam

 

WOW!! thank you so much for the information.
I quickly read over everything (going to work now) and i really appreciate the time you put into this. I'm sure this will be helping so many more people out there.
I'll read it more closely when i get home.

Thanks again!

 

That was a great explanation. Thanks so much for taking the time to write that out.

 

Here is a great link to different types of suspension.

http://www.carbibles.com/suspension_bible.html

Current MINI uses a MacPherson strut up front and a single trailing arm in the back.

The really neat part of this site is the discussion of the Moulton rubber suspension found on Classic Minis, and for those who'll scroll down further Moulton's Hydroelastic suspension.

 

Here is a very good series of articles that were in Sport Compact Car not too long ago.

They do a good job of starting from the basics and moving into more and more in-depth topics. You cannot simply learn suspension theory overnight; it is an intricate web of moving and interacting geometries. Don't be discouraged if you don't get it right away, it takes even a modest but intelligent engineer years to effectively absorb and apply it!

 

i almost want to say make this a sticky but im not a smart guy when it comes to suspension. but i do know when i see that a thread is very very informative

 

Thank you so much for the write up! I made the mistake of NOT having my car cornerweighted and guess what? It goes back to the shop tomorrow to have it done PROPERLY! It looks pretty, and handles better than stock, but just feels a bit off.

 

Alright. I just read it over again carefully.
I must thank you again.


Springs somehow scare me with the different stories that I have heard from friends and I think that I will avoid them. I've read your thread of your springs and I see that it has lots of very good feedback, but if I decide to lower my car I feel that I want a larger drop than your springs offer.

Back to the coilovers, from what you wrote it seems that I wont be needing any of the control arms, sway bar, etc, if I am not planning to be tracking my car or extremely hard driving? As long as I get a good installation.
I feel that my car handles well enough stock, and a bit of body roll reduced by the coilovers will be sufficient for my needs.
It really surprised me how you say that strut braces are for cosmetic purposes because a lot of people seem to have them in this forum.

So to summarize, if I get good coilovers with a good installation I (hopefully) never have to worry about anything happening to the suspension.
I'm really sorry for making you restate yourself to really simple terms, but as you can see I am afraid to make "real" mods to my car.

thanks to SK8BRD and ryephile also. I don't think I have the attention span to read the sites right now, but I have them bookmarked and I will get to reading them soon.

thank you again for everyone that helped. :thumbsup: :thumbsup:

 

very useful.
Thanks for the info

 

It's no accident that TSW is so highly respected. I can't say enough good things about them.

Get coilovers, and if you intend on lowering more than 1 inch or so, get rear control arms, otherwise your geometry in the back will be off. Rear swaybar is also good as well. I'd recommend coilovers, camber plates, rear control arms and a rear swaybar (and i like the adjustable endlinks, they made a noticeable difference on my car)

 

I would say that the lower control arm decision should be based on how low you're going to go... if it's less than 1", you might be able to get by without them. However, most coilovers will lower your car from stock right out of the box, since they have shorter bodies (there are some out there which allow you to adjust the effective length of the bodies, so I'm not sure "all" wouldn't get you back or close to stock - this depends on the brand you go with).

I'd wager you'll end up closer to a 1.5 - 1.75" drop. In that case, I would go with the adjustable control arms (lower) in order to get the rear camber at least back to OEM specs. Otherwise, you may observe premature tire wear in the rear (on the inside shoulders). And, leave everything else out of the equation for now - just coilovers, adjustable rear control arms, and a good install (cornerweighting and alignment).

We always prescribe making changes to the car in baby steps - one mod at a time, in order to learn how the suspension dynamics change with each modification. Otherwise, you're just throwing parts on for the sake of throwing parts on (which, I'd wager, is why there are so many strut braces sold), and end up with a car that may not handle well (or, in the case of a track/AX junkie, either a car that covers up for poor driving skills, or possibly, a car that is scary to drive at speed).

So, your approach of coilovers first is fine (although I'd still suggest rear control arms, just to ensure you can get back to an OEM alignment) - then decide if you really need a rear swaybar or anything else...

And now, the caveats from a track junkie/AX perspective for the experienced track junkie or the track-junkie-to-be:

A rear swaybar is probably one of the biggest bang-for-the-buck handling mods, though, from the track/AX perspective... The other, even bigger one is camber plates. These two suspension mods alone are probably worth more time on course than nearly anything else you can do...

For a track-oriented progression, we would suggest taking it to the track bone stock first... Then, a rear swaybar w/ stock suspension and take it to some events. Then, camber plates w/stock suspension and a good alignment and take it to some events... Last, then decide on an aftermarket strut/shock + spring combination or a coilover set. Take that to some events and tune it in, possibly get a more aggressive alignment. And for the fine tuning finale, install the adjustable endlinks to neutralize preload... Take that to some events and have lots of fun.

This should ALL be done on street tires first for the track newbie. The first two steps should be done the same for experienced track junkies (in our opinion), although once you've done an event or two with the camber plates, feel free to swap over to an r-comp tire - the camber plates will keep you from killing the r-comps.

For the newbie, you can choose to run any wheel/street tire combination you want - just make sure they're street tires. A track newbie should not make this switch for quite some time, as even 2nd tier r-comps are less forgiving than streeties.

As far as brakes go - when you start to find the limits of the stock system (which are pretty freakin' good on the R56, which is considerably better than the R53), start thinking about upgrading.

As far as timing goes? Well, that depends on how many events your pocketbook can handle. I'd say that if you plan on doing let's say 6-8 DE's a year, this process of upgrades will take you ~1.5-2 years. If you do more, that will shrink, less it will grow.

Now, why would any company in the aftermarket parts biz prescribe a course of action that realistically means less upfront sales? We make no bones about this... One, we want you to learn about the limits of your car right out of the box first (even for experienced folks). Two, we want you to get seat time and learn solid car control skills (even for the street). Three, we want you to make informed decisions about what modifications to make and know WHY you are making them. Four, we don't want to see you get hurt driving on the street in a car with a crappy setup, or worse, stuffed in the wall or go off the track. We've been preaching this for years and will continue to do so. IMHO, one of the WORST things you can do is just go mod crazy right out of the box - and double-especially with power mods for the track, as I can almost GUARANTEE that this leads to bad habits for track newbies (and even some experienced track folks). I can't tell you how many times we've chased down lots more powerful cars with just a dialed in car and good driving, and the same goes for most of those that have done their mods in baby steps and gotten lots of seat time.

 

Below are my caveats to Scott's caveats, which are subject to further caveats.

Since I have the sport suspension with an 18mm rear swaybar, I've decided not to go to a 19mm. My father-in-law's analysis said only a 24% stiffness increase from 18 to 19. The stiffness jump from the standard 17mm to 19mm is much greater. Also the sport package ups the size of the front bar, which means the rear has to be upped also, but the numbers on a 22mm bar seem way over the top.

I did my first event bone stock, except for the OEM extra downforce antenna ball. Right out of the box, the car was outperforming much more expensive and powerful rides. Second event I did with upgraded wheels/tires, but still street tires, just wider. Not much difference in handling. Third event I did in the same configuration as the second. For the fourth, I was on the TSW prototype R56 springs. Huge difference! Much, Much faster. I've got the production version of their springs now, and an alignment that puts me about -2.3 rear camber, and -1.5 front camber. Camber plates are next, then maybe lower control arms and end links.

I've done mine all on street tires, although that includes some 205/50/R15 with a 120 wear rating.

Since I'm in an R56 Justa, I feel compelled to point out that the front Justa rotors are 11" in diameter while the S comes in at 11.6" the R50/53 front rotors are 10.9". The good news for the R56 Justa folk is that the calipers are common with the S, you just need different mounting brackets, rotors, and pads to get to that S stopping performance.

My put is that your instructor makes a huge difference in your learning curve. Try to get one who drives a Mini. Be sure to get different instructors for each event. I've even had different instructors on Saturday and Sunday. Everyone has different ideas, get a variety and develop your own personal style.