From memory I don't think my road Clubman has any bump stops at all on the rear, I cannot remember fitting any.
Anyhow I have 2 hydro stops here so will be fitting them in the near future.

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Cheers Dave.

Just some bracing (not all) per Vizards' book on the front and rear subframes. Just did it when I was building the locost clubman chassis - had the steel and well practiced with the mig welder.

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1970 Mk2 Cooper S under restoration

Front roll centre correction:
https://youtu.be/Jgdpdtk3LSw?si=_KGzlh15m_P0UD_A

The hydro bumpstops take a bit of work (there was a thread on here back in the day, I think Dr Mini had some input..)

I should say a bit more about what I was trying to fix and what I felt it achieved.
After I got my mini going with new cones and not significantly lowered it felt great except for quick (as previous 100km/hr) turns, the car felt like it couldn't decide if it was going to hook into the turn as expected or throw the rear out. It didn't do this on my 998 clubby, and on slower quicker initiated turns I couldn't feel it. I think the new cones were softer and meant there was a period when cornering before the rear settled hard on the spring which made it feel indecisive, the clubby didn't have it because the cones were pretty hard, and it didn't show up on the slower quicker initiated turns because it was thrown against the outside cone before I noticed.
The hydro bumpstops gave it something to settle against before the cone, you run them pretty close to contact like 1cm or so...

I also think it has to do with the skewed roll thing, where the mini is set up the opposite of conventional wisdom which is one of the things that lead me further down the rabbit hole... I can go further but it is less tested and more my theories etc...

From what I remember of the install you buy the hydro bump stop kit as standard, it bolts into the hydro arms so you need to drill and tap a hole for the mounts into your dry arms, you are trying to position the bumpstop to contact a flat section of body above the arms about 2/3rds the way down. You may need to bend the seam / pinch weld slightly to the side so it doesn't cut the bumpstop, it doesn't really matter though. The standard dry brake lines are run on top where you want to put the bracket but you can grind off the rivet that holds the bracket mounting the brake lines on and twist it around the arm to the bottom and secure it in place ther by tightening up some hose clamps around the arm. It sounds a bit dodgy but it stayed in position and worked. I think I could drill and tap the arms with the car on the hoist without taking the subframe out...

Best thread I could find...
https://www.ausmini.com/forums/viewtopic.php?f=2&t=38254&hilit=comp+rear+bump+stops

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Roads need more corners
A Deluxe(CG13DE), 2 Clubbies(998 and 1275) and 2 Morris 1100Ss

I've read this thread with interest since the bit about the front roll centre for a mini being higher than that of the rear was somewhat intruiging, and not what I calculated myself and showed in my BMC Engineering Companion book. I thank the contributor who provided a link to the You Tube video as to where this notion might have come from.

I watched the video, and to my mind, the guy's computation for the roll centre of a standard car is incorrect. His method is OK, but the way in which he has drawn the lines from the suspension ball joints doesn't agree with what a standard car would be. in fact, it looks more like he's taken these lines as the lines through the upper and lower arms where they attach at the tapered studs and nuts at the wheel hub. The actual point of rotation (see image below) appears to me to be at the ball joints, not the nut. When you draw lines in the "prescribed manner", you get a roll centre as shown in my picture, and, if one (as in all these cases) ignore the change of dimensions with tyre deformation and linkage geometry which happens in a real roll, the front roll centre is lower (as would be expected) than that of the rear.

Regards
Tony

Dave, dry cars don't have bump stops (as standard).

I think many people use HiLos to drop the car into the weeds. Which, IMHO, is not really a good idea. Bob Holden told me years ago that he to jack up the rear end of his race cars a bit to reduce understeer. (Unfortunately I don't remember how much and from what datum:( Common wisdom for the front was that you shouldn't go lower than drive shafts parallel to the ground. This means that the inner end of the lower control arm is higher than the outer end... which is what the GpN guys are going for and what fuzzy is doing with his extended lower ball joints (kits used to available from several UK suppliers but I haven’t seen any advertised lately)

As stated earlier, adjustable suspension (at least at the front) is necessary to get all the angles right (not that I ever adjusted mine once they were set properly…. other than at the next wheel alignment:). Shock settings and tyre pressures can also have a significant effect. Note that race settings and road settings are not the same. Comfortable usually doesn’t equal fast..and fast track settings are probably not fast road settings - BTDT (roads are usually lumpier).

I would agree with most of fuzzies suggestions - although, fixed negative arms (IMHO) aren’t worth it as the real benefit of the adjustable kind lies in correcting the usual production tolerances rather than extra neg camber). I would also suggest caution with rear bump stops. Might be okay on the track but meeting a lump in the middle of a road corner can lead to a huge increase in rear spring rate... which is not good. It was a long time ago, but I think we used items called "Scandinavian" bump stops. These were higher and softer than the standard hydro items.

In the right place a 145/165 tyre combo can work. For dirt and tar ‘khanas I had a special set of rears (bald 145s pumped up to 50psi ). They worked … I have a Hay trophy ..woo hoo….

The other problem with adjustable settings is the old Box Brownie VS Nikon issue…. If you can adjust things you need a repeatable way of testing different settings. Otherwise you can waste money for no benefit.

Cheers, Ian

Of course all of this gets put in perspective when you are barrelling down the highway at 100kph, and realise your sump is sitting at 4 inches clearance and some of the vehicle tracks have formed 8 inch mounds in the centre.

LOL.

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Cheers Dave.

Thanks Ian, that is obviously why I don't remember fitting them.
I have all fully adjustable on the front and height and shocks on the rear. I kept the height pretty much standard because apart from anything else there is 2km of gravel road to my place. Once I have the sway bar of the van body I will have a good look at it and decide whether to try it on the Clubby or not.

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Cheers Dave.

I agree the lines should intersect the centre of the ball joints as this is where they pivot not where they bolt to the arms. That said I didn't really worry about where the roll centre ends up but rather that it goes down as you lower the car (and faster than the centre of gravity) so a lowered mini will have a greater distance between the centre of gravity and the roll centre (roll couple, I think of it as the lever the CG pulls on to roll the body) as such it will experience more roll. Just about every mini I see is lowered from what would've been standard if only because the cones have shrunk...

The rear roll centre for trailing arms is at ground level, there's lots of confusion between semi trailing arms, trailing arms and torsion beam rear suspensions. You can use a similar method to calculate the instant centre with semi trailing and trailing arms, if you intersect the axis of the axle with the axis of the arms pivot that is the instant centre. In the mini and any pure trailing arms the pivot axis and the axle stub are parallel and will never intersect, the instant centre is infinitely far away, therefore a line from the centre of the tyre to this instant centre runs along the ground, therefore where it intersects either the other side instant centre or the centre of the vehicle is at ground level.
Julien Edgar has many suspension videos and books but I can't at the moment find the one on trailing arms. I have implemented a semi trailing arm setup on my mini which has been approved by an engineer including all this theory as the basis so I'm very confident this is correct.
The goal of the implemented semi trailing arms was to raise the rear roll centre to a height similar to that of Vizard's white book when he talks about rear beam axles, except without losing my boot and maintaining an independent rear suspension.

I incorrectly called the bumpstops hydro, they are progressive competition bumpstops originally for hydro cars, (also shown in Vizard's white book) and I never really felt them crash or bottom out harshly in the time I had them installed, the front yes but not the rear.

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Roads need more corners
A Deluxe(CG13DE), 2 Clubbies(998 and 1275) and 2 Morris 1100Ss

The anti roll bar that started all this has a framework that follows the rear subframe.is this normal or indeed needed? The frame is not really connected to the bar rather it seems to be an afterthought.

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Cheers Dave.

I'd like to congratulate our friend from Armidale for a very clear description for the rear roll centre - and I agree with the explanation. I had taken the rear axles to be acting as if the pivot pins were one long beam axle, but this is over-simplistic since the stub axles are set back from these pivots. I've added a note to the list of corrections which (for all my books) have always been available for download on my web site. Unfortunately, I can't give a prize to those contributors who find a mistake but am grateful for quality advice. I think we are now in agreement for both front and rear roll centres and this is worth knowing.

Regards
Tony