Cor blimey guv! i only wanted one of them horses with a sring underneath to play on in my garden...... me and my big mouth eh tony --- In doc-uk@xxxxxxxxxxxxxxx, Martin Gutkowski - DMC Ltd <martin@...> wrote: > > Hi All (esp Mark) > > I've driven a lot of DeLoreans now, and more than one with old front > springs on the rear. I also have moderately lowered rear suspsnsion on > my own car, by about an inch with Grady's (former) shock setup. > > 1) Front springs on the rear make the rear too low IMO, in fact > sometimes lower than the front. Anything lower than where the control > arms are level is a bad idea IMO. > 2) On my own car I've eaten 2 sets of back tyres in 10,000 miles thanks > to the lower setup (toe-in is correct and although I'm a fan of > wheelspinning, so is Chris H and he's done more miles on one set :- ) > I've got adjustable lower links on my other car and the wheels sit > noticably straiter at the back. > 3) A softer ride on the rear makes an unbelievable difference to the > ability to lose the back end, in a similar, but more predictable way as > loose trailing arm bolts do. I've recently had two cars in at the same > time - one Stage 1 and one Stage 2. The Stage 1 car (less powerful) was > far too tail-happy. The difference was front springs on the rear, and I > can vouch for the rest of the suspension on both cars, and both had the > same set of pirellis. > 4) In playing with the adjustable suspension we do, you can make the car > thoroughly dangerous (but a great drift machine, if you're into that!) > by stiffening up the front and softening up the rear. It's quite surprising. > > " > > The rear suspension uses the 'Second Order Lever' It has its fulcrum and effort(spring) in opposite ends and the load in the middle, just like a wheel barrow set up. > > The front suspension uses the 'Third Order Lever' The fulcrum and load are at opposite ends this time with the effort(spring) is in the middle, such as a shovel. > > " > I'm not entirely sure how you can apply lever principles to the rear > suspension because as I see it, there isn't one. The weight of the car > is passed directly to the hub carrier at one end of the lever. The other > is just a pivot. There's no multiplication involved unless you look at > the angle of the spring/shock which in this case is only non- vertical to > get it out the way of the tyre, hence needing a slightly stiffer spring > than if it were vertical, at a ratio exactly proportional to the angle > of the spring/damper compared to the vertical (at a guess, but it's > probably as near to no difference as makes no odds). That's "moment of > forces" stuff and Newtonian physics, IIRC, but it's a while since I did > my A-level Maths and Physics!). > > The front suspension is a second order lever, although dealing with a > multiplication of effort rather than a division of it. > > You're absolutely correct that all other things being equal, the rear > spring can be weaker for the same effort, given the geometry. > Unfortiunately all other things aren't equal because someone had the > bright idea of plonking the engine over the back wheels :-) > > http://www.tiscali.co.uk/reference/encyclopaedia/hutchinson/m0017416.h tml > > Martin > > > > Nick Tomlinson wrote: > > > > > I personally tried the front springs on the rear trick, but this resulted in too wallawy, too soft a ride for my liking. Just a basic test like pressing down on the bodywork showed this. > > > DOC UK Website: www.deloreans.co.uk Unsubscribe: doc-uk-unsubscribe@xxxxxxxxxxxxxxx ** Unless otherwise stated, all messages posted to the group are assumed public and may be printed in the club magazine ** Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/doc-uk/ <*> To unsubscribe from this group, send an email to: doc-uk-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/