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SuspensionSprings, struts, coilovers, sway-bars, camber plates, and all other modifications to suspension components for Cooper (R50), Cabrio (R52), and Cooper S (R53) MINIs.
Anyone here have experience with ball joint spacers. They increase the angle of the lower control arm, thereby raising the roll center. If the companies that make them are to be believed, they are the cat's meow. I'm looking for feedback from people who have driven a car that has them installed.
Actually they are all marketing unless you are prepared to correct for bump steer. When you install them and run the suspension thru it's range of motion...you will get (if memory serves me right...did this long ago)something like 3/8" additional TOE OUT/side when you compress the suspension fully. So something like 3/4" of total toe out at he front under heavy braking. BTW stock is pretty close to zero toe change.
To use these properly you also need to correct/space at the tie rod by a similar amount...this BUMP STEER Correction...which require special tie rods and spacer. Have never seen these for sale for a MIni (many other cars, BMW etc are available). So unless you are prepared to make your own setup (like I did). STAY AWAY.
Actually they are all marketing unless you are prepared to correct for bump steer. When you install them and run the suspension thru it's range of motion...you will get (if memory serves me right...did this long ago)something like 3/8" additional TOE OUT/side when you compress the suspension fully. So something like 3/4" of total toe out at he front under heavy braking. BTW stock is pretty close to zero toe change.
To use these properly you also need to correct/space at the tie rod by a similar amount...this BUMP STEER Correction...which require special tie rods and spacer. Have never seen these for sale for a MIni (many other cars, BMW etc are available). So unless you are prepared to make your own setup (like I did). STAY AWAY.
Could you post pictures of what you did, please? I am a mechanical engineer, so I fully understand what you're saying about the relationship between control arm & tie rod angle. I also have a full CNC machine shop at my disposal, so I can fabricate pretty much anything.
Basically you replace the tie rod with a threaded sleeve and a rod end. Then there is a tapered stud that fits to the steering arm on the knuckle. You then shim between the rod end to correct for the bumpsteer....in the case of my Mini the distance between the rod end and the steering arm is about the same thickness as the ball joint spacing (which makes a lot of sense).
I tried an available stud (https://www.summitracing.com/int/parts/aaf-all56286), but the taper didn't match the Mini steering arm and it fractured where the taper meets the threads. I didn't have access to a matching reamer to correct the taper in the steering arm, so I decided to just drill out the taper to 5/8" and now I just use a bolt thru the arm/rod end and i shim between the arm and the rod end. Hasn't broken in 2 years track use.
I'll post a picture of my bolt solution if I get a chance when I pull the car out of storage. BTW when you use the full height of the ball joint spacer, It limits you to minimum 17" wheels. I may remove my setup and go back to stock so that I can run 15" wheels this season.
Are these what you are talking about?? (photo below)
Since the Steering knuckle is mounted to the strut... how would correcting lower arm angularity, returning it to a more 'neutral' position, affect bump steer?
Wouldn't keeping the lower arm in a more or less stock position regardless of the height of the car help minimize tuck in, hence bump steer??
Sincere questions in search of sincere answers.
If by "ball joint" spacers... Cut7 is referring to something else... I'd like to see what that is?
Yes those are the units that we are talking about/that I use.
Bump steer is a suspension engineering term that basically refers to changes in toe-in/toe-out while the suspension is being compressed. A lot of suspension and shock people refer to suspension compression as bump and extension of the shock as rebound. This may be where we are not on the same page, you may be thinking of some other concept.
When you compress the suspension you have 2 arches of a circle acting: 1 is the lower control arm/ball joint arm/leaver and 2 is the tie rod/steering arm. Both those arches need to follow the same path have the similar arches and not create any change in toe during bump/compression. This is simplified, but the basic concept.
Anyway: if you install just the spacers, remove the coil spring, use a bump steer guage https://www.joesracing.com/media/Pro...e-5-Lug-3.jpeg
and measure toe change....you will find with all the spacers installed, that the side/wheel/tire will toe out about 3/8" on one side thru the full range of motion of the strut. Yes, I did actually do this, since my car was behaving very strangely under braking (it's a dedicated track car). It would track wildly...no kidding with 3/4" in toe out as the suspension compressed
Yes those are the units that we are talking about/that I use.
Bump steer is a suspension engineering term that basically refers to changes in toe-in/toe-out while the suspension is being compressed. A lot of suspension and shock people refer to suspension compression as bump and extension of the shock as rebound. This may be where we are not on the same page, you may be thinking of some other concept.
When you compress the suspension you have 2 arches of a circle acting: 1 is the lower control arm/ball joint arm/leaver and 2 is the tie rod/steering arm. Both those arches need to follow the same path have the similar arches and not create any change in toe during bump/compression. This is simplified, but the basic concept.
Anyway: if you install just the spacers, remove the coil spring, use a bump steer guage https://www.joesracing.com/media/Pro...e-5-Lug-3.jpeg
and measure toe change....you will find with all the spacers installed, that the side/wheel/tire will toe out about 3/8" on one side thru the full range of motion of the strut. Yes, I did actually do this, since my car was behaving very strangely under braking (it's a dedicated track car). It would track wildly...no kidding with 3/4" in toe out as the suspension compressed
Bravo! Well done! You saved me from doing a bunch of work. I have done this type of thing on many cars in the past (& had to put spacers in or do other mods to correct for bump steer). It always amazed me that the factory couldn't design the correct geometry in the first place (it's not that difficult). But from what you're telling us, Mini actually did a pretty good job of minimizing bump steer. Is that correct?
By the way, 3/4" toe-out would indeed cause all sorts of wild & unpredictable behavior.
No kidding about the unpredictable behavior...I knew better than to install the spacers...but who would have thought 3/4" toe out...a small amount you can live with.
mountainhorse..just because someone sells something, doesn't mean it actually works or is of benefit...don't get me started..silicone IC boots, cowl scoops, crap IC the list goes on...It is always buyer be ware. You need to talk to people who know what they are doing, not just selling things to make money. But in fairness to retailers (I owned a store for a while) customers often want what they want and I like money just like the next guy. You can't talk sense into some people...even if you have science on your side.
Mini changed the inner ball joint location on the R56. Pivot point is higher up on the subframe...which gives a better control arm angle when the car is lowered.
I've been toying with the idea of grafting an R56 subframe and electric steer from an R56 onto my R53...bit of a welding etc project...need to measure a bunch of stuff, but it might just work for suspension geometry and eliminating the R53 power steering pump. Likely only a matter of time before mine gives up the ghost.
No kidding about the unpredictable behavior...I knew better than to install the spacers...but who would have thought 3/4" toe out...a small amount you can live with.
Any amount of toe-out causes the vehicle to behave unpredictably. Setting the toe correctly is the single biggest improvement you can make. And on that note, it's always best to measure in degrees, not millimeters or inches.
When your a small budget racer...string alignment works just fine and easy to carry to the track.
True. And once you know what the degree measurement converts to on your particular vehicle, you can use the string method. If you're careful, you can obtain reasonable accuracy. But if you have the equipment to measure degrees, it's always better, IMHO.
True. And once you know what the degree measurement converts to on your particular vehicle, you can use the string method. If you're careful, you can obtain reasonable accuracy. But if you have the equipment to measure degrees, it's always better, IMHO.
I use string and a caliper to measure mm, then basic trig to convert to angles.
02-02-2020, 12:38 AM
