Discussion
There are a lot of different opinions as to what makes a Mini handle, but as I was asked to post something on this here goes:
First of all, let's get the difference between road holding & handling covered. Road holding is the measure of absolute adhesion under specific conditions. Handling is a somewhat personal opinion of the controlability and drivability of the vehicle under more general conditions. Thus, what makes for super roadholding on a racing Mini will probably be useless for a road car.
I have some limited experience with racing Minis and these are normally lowered with very stiff damping, very wide wheels, big neg camber front and back, and other little tweeks.
Most people on this forum are probably most interested in getting the best from their Mini under normal road conditions. A Mini will never be exciting on a motorway, so let's set up to suit what the Mini is best for, i.e. twisting 'B' and minor roads and lanes with other than very smooth tarmac surfaces.
The first thing is to run at the standard ride height as the Mini has so little suspension travel to begin with you can't afford to lose any. On my rally cars I usually raise the front about 0.75" and the back by 0.5" and fit a long sump guard.
Ensure that the back and front sub-frames are firmly installed with no free play anywhere. On later Minis ensure that the rubber front sub-frame mounting bushes are replaced with the proprietory nylon ones. This is probably the best handling mod you'll ever do.
Change all the front suspension bushes for the latest polypropylene/nylon ones. On a rally car I don't usually do this with the front of the tie rods as it puts too much shock load into the mounting 'ears' on the front of the sub-frame, I simply change the rubber ones very frequently. Also, it can be a good idea to weld in a triangular reinforcing plate onto the 'ears' to prevent these from bending.
Fit 1.5 degree negative camber bottom arms (not 2.5 degree) and check that the top arm bushes are OK with no free play.
Fit adjustable tie-bars and set the front castor to between 2.75 and 3 degrees (you will need to visit a good tyre shop to get this setting done properly - more of this under rear settings). Set the front track to absolutely straight ahead i.e. no toe-in or toe-out.
Fit adjustable front dampers, I usually use SPAX at 3 clicks up for starters, then work from there. Check that the damper brackets are bolted solidly onto the bodyshell. Make sure there is no play in either the hub ball joints or the wheel bearings.
So far so good, and not particularly expensive.
Now for the back.
Ensure that the radius arm bushes have no play. Repair kits are relatively easy to install and the only special tool you need is a 13/16th reamer. It's worth buying one to do this, as you can then help out all your friends. A lot of people bring their rad arms to me after fitting the bushes and I just power ream the bushes out for them.
Measure the rear wheel camber. It's so easy, all you do is to get a piece of absolutely square 1/4" thick plywood, about 18" x 24" and, having parked on a flat and level piece of concrete, you put the board up against the tyre. Measure from the edge of the board to the edge of the wheel rim at the top and at the bottom wheel. Compare the two measurements. If they are identical the camber is 0 degrees, i.e. ideal. If the top measures up to about 1/16th" more than the bottom this is OK. If it doesnt, then, by trial and error, you file out the hole in the outer radius arm bracket and keep on re-fitting and checking until you get within these two figures. The one thing you mustn't have is ANY positive camber. Once you have got the slot right you fit a thick 'penny' washer and mig weld it in place to keep the correct setting.
Now comes the most critical setting of all in the Mini handling arena - you must have the rear wheels toeing-in by between 1/8th" and 3/16th". The visit to the good tyre shop mentioned above will enable this to be measured at the same time as the front settings are done. Once you have the measurements, you can then correct them as necessary. You do this by either shimming with thin sheet metal, or by filing or grinding the mating faces of the rear radius arm outer brackets (the ones you just filed out). If you take a couple of 16swg (0.064" thick) small plates of sheet metal to the tyre shop, measure as standard, then slacken off the attachment bolts and slip the bits of sheet metal in between the bracket faces and the sub-frame and measure again, this will tell you the total amount of change 0.064" on each side will give. Thus you can work out how much to add or grind off. With a really good tyre shop their alignment machine can give you a front to rear measurement so that you can even-up the settings. For example, on my Cooper 'S', I had to add one piece of 16 swg sheet to the rhs and 18 swg (0.048") to the lhs.This gave me just over 1/8th" toe-in and spot-on fore and aft alignment. It's just a question of trial-and-error till you get it right.
For the camber you can buy adjustable brackets and these are great. However, you don't need to spend the money and for some areas of motorsport (historics) they are not allowed. Finally, fit adjustable dampers on the rear and if SPAX start off at 2-clicks and work from there.
Believe me, all this is really worth the effort.
The only other thing about the handling is wheel size. It is well established that 10" wheels are best for general handling and for road use I have always found that a 4.5" or a max. 5" rim with 165/70 x 10 tyres are the best. Try tyre pressures of 34 psi front and 32 psi rear. A 12" wheel is not quite as good, but the 13" really does detract from the handling and is more for those for whom appearance is more important than performance.
I have never tried a rear anti-roll bar except for just driving a car with one 'down the road'. The old adage has always been that if you increase the roll stiffness at one end, you increase the road holding at the other end. Thus a rear anti-roll bar should increase the over-steer and make the car turn-in better.It sounds the sort of thing to fit to a track racer to kill the power-on understeer. I guess it's a matter of personal choice. My cars turn-in fine when set up as above, so I've never wanted to fit one. On a rally car it's just something else to break off on the rough bits!
Handling is always a matter of personal opinion and others may have different and conflicting views. All I can say is that the above suits my driving style and in Historic Rallying I think my Mini is as competitive as any other in this country.
I hope that all this helps. Let's have a discussion!
First of all, let's get the difference between road holding & handling covered. Road holding is the measure of absolute adhesion under specific conditions. Handling is a somewhat personal opinion of the controlability and drivability of the vehicle under more general conditions. Thus, what makes for super roadholding on a racing Mini will probably be useless for a road car.
I have some limited experience with racing Minis and these are normally lowered with very stiff damping, very wide wheels, big neg camber front and back, and other little tweeks.
Most people on this forum are probably most interested in getting the best from their Mini under normal road conditions. A Mini will never be exciting on a motorway, so let's set up to suit what the Mini is best for, i.e. twisting 'B' and minor roads and lanes with other than very smooth tarmac surfaces.
The first thing is to run at the standard ride height as the Mini has so little suspension travel to begin with you can't afford to lose any. On my rally cars I usually raise the front about 0.75" and the back by 0.5" and fit a long sump guard.
Ensure that the back and front sub-frames are firmly installed with no free play anywhere. On later Minis ensure that the rubber front sub-frame mounting bushes are replaced with the proprietory nylon ones. This is probably the best handling mod you'll ever do.
Change all the front suspension bushes for the latest polypropylene/nylon ones. On a rally car I don't usually do this with the front of the tie rods as it puts too much shock load into the mounting 'ears' on the front of the sub-frame, I simply change the rubber ones very frequently. Also, it can be a good idea to weld in a triangular reinforcing plate onto the 'ears' to prevent these from bending.
Fit 1.5 degree negative camber bottom arms (not 2.5 degree) and check that the top arm bushes are OK with no free play.
Fit adjustable tie-bars and set the front castor to between 2.75 and 3 degrees (you will need to visit a good tyre shop to get this setting done properly - more of this under rear settings). Set the front track to absolutely straight ahead i.e. no toe-in or toe-out.
Fit adjustable front dampers, I usually use SPAX at 3 clicks up for starters, then work from there. Check that the damper brackets are bolted solidly onto the bodyshell. Make sure there is no play in either the hub ball joints or the wheel bearings.
So far so good, and not particularly expensive.
Now for the back.
Ensure that the radius arm bushes have no play. Repair kits are relatively easy to install and the only special tool you need is a 13/16th reamer. It's worth buying one to do this, as you can then help out all your friends. A lot of people bring their rad arms to me after fitting the bushes and I just power ream the bushes out for them.
Measure the rear wheel camber. It's so easy, all you do is to get a piece of absolutely square 1/4" thick plywood, about 18" x 24" and, having parked on a flat and level piece of concrete, you put the board up against the tyre. Measure from the edge of the board to the edge of the wheel rim at the top and at the bottom wheel. Compare the two measurements. If they are identical the camber is 0 degrees, i.e. ideal. If the top measures up to about 1/16th" more than the bottom this is OK. If it doesnt, then, by trial and error, you file out the hole in the outer radius arm bracket and keep on re-fitting and checking until you get within these two figures. The one thing you mustn't have is ANY positive camber. Once you have got the slot right you fit a thick 'penny' washer and mig weld it in place to keep the correct setting.
Now comes the most critical setting of all in the Mini handling arena - you must have the rear wheels toeing-in by between 1/8th" and 3/16th". The visit to the good tyre shop mentioned above will enable this to be measured at the same time as the front settings are done. Once you have the measurements, you can then correct them as necessary. You do this by either shimming with thin sheet metal, or by filing or grinding the mating faces of the rear radius arm outer brackets (the ones you just filed out). If you take a couple of 16swg (0.064" thick) small plates of sheet metal to the tyre shop, measure as standard, then slacken off the attachment bolts and slip the bits of sheet metal in between the bracket faces and the sub-frame and measure again, this will tell you the total amount of change 0.064" on each side will give. Thus you can work out how much to add or grind off. With a really good tyre shop their alignment machine can give you a front to rear measurement so that you can even-up the settings. For example, on my Cooper 'S', I had to add one piece of 16 swg sheet to the rhs and 18 swg (0.048") to the lhs.This gave me just over 1/8th" toe-in and spot-on fore and aft alignment. It's just a question of trial-and-error till you get it right.
For the camber you can buy adjustable brackets and these are great. However, you don't need to spend the money and for some areas of motorsport (historics) they are not allowed. Finally, fit adjustable dampers on the rear and if SPAX start off at 2-clicks and work from there.
Believe me, all this is really worth the effort.
The only other thing about the handling is wheel size. It is well established that 10" wheels are best for general handling and for road use I have always found that a 4.5" or a max. 5" rim with 165/70 x 10 tyres are the best. Try tyre pressures of 34 psi front and 32 psi rear. A 12" wheel is not quite as good, but the 13" really does detract from the handling and is more for those for whom appearance is more important than performance.
I have never tried a rear anti-roll bar except for just driving a car with one 'down the road'. The old adage has always been that if you increase the roll stiffness at one end, you increase the road holding at the other end. Thus a rear anti-roll bar should increase the over-steer and make the car turn-in better.It sounds the sort of thing to fit to a track racer to kill the power-on understeer. I guess it's a matter of personal choice. My cars turn-in fine when set up as above, so I've never wanted to fit one. On a rally car it's just something else to break off on the rough bits!
Handling is always a matter of personal opinion and others may have different and conflicting views. All I can say is that the above suits my driving style and in Historic Rallying I think my Mini is as competitive as any other in this country.
I hope that all this helps. Let's have a discussion!
Cooperman - great write up. Would you allow me to use it on my website (www.minispecial.com) if I credit you for it?
miniman said:
Cooperman - great write up. Would you allow me to use it on my website (www.minispecial.com) if I credit you for it?
No problem Miniman, I hope you find it of help. Minis are not my main business, actually I'm a former aerospace design engineer, but now I have a technical recruitment company in Hitchin. However, I do lots of work on my own Minis and sometimes build engines for other people who want a properly built engine, not a bodge job like some I have seen.
Cooperman's article is at
www.minispecial.com/technical/articleindex.asp
Thanks to Cooperman for letting me use it!
www.minispecial.com/technical/articleindex.asp
Thanks to Cooperman for letting me use it!
miniman said:
Cooperman's article is at
www.minispecial.com/technical/articleindex.asp
Thanks to Cooperman for letting me use it!
Thats a nice little site you have there James.
Oh, and re my indicator issues and your kind offer of the switch for testing I was driving to work this morning and they started working again!
miniman said:
Thats a nice little site you have there James.
Anything you want put up there, send it over!
I think I'll be doing more reading from there rather than updating but if I take advantage of KAD's 4 pot offer they have at the moment then I may send over some build photos or the like...
Something very obvious, but which many people forget, is that if you want to decrease the time to cover a certain twisty piece of road, the best way to do it is to improve the cornering velocity. Thus, if you are able to go into a corner 5 mph quicker, maintain that 5 mph extra velocity through the corner and thus exit 5 mph faster, your terminal speed down the next straight will be around 5 mph higher (ignoring aerodynamic drag effects - too complicated). So your average speed on that piece of road will also be around 5 mph higher. However, if you just increase the engine power you will be going through the corner 5 mph slower and will probably need an extra 10 mph terminal speed down the next straight to achieve the same average speed overall.
Sorry if this is just stating the obvious, but it reinforces the old adage that you must sort out the suspension, handling and brakes before seeking more engine power. Also, if you just add power, you will be approaching each corner at a higher speed and will need more braking. Since braking is translated into heat the brakes will get hotter and the end result can be slower average speeds due to brake fade leading to earlier braking, slower cornering speeds and slower speed out of the corner.
Sorry if this is just stating the obvious, but it reinforces the old adage that you must sort out the suspension, handling and brakes before seeking more engine power. Also, if you just add power, you will be approaching each corner at a higher speed and will need more braking. Since braking is translated into heat the brakes will get hotter and the end result can be slower average speeds due to brake fade leading to earlier braking, slower cornering speeds and slower speed out of the corner.
I agree completly that handling is the key to quick progress, but I would approach it from the 'slow in - fast out' camp. This can only work if the handling is predictable and confident.
Improving braking should be the first mod made to any car IMHO.
Two quick questions if I may.
Will fitting a cage that picks up on A and B pillars etc improve the structural rigidity of a Mini enough to positively effect the handling?.
And what advice do people have on choosing and fitting an oil cooler?.
Improving braking should be the first mod made to any car IMHO.
Two quick questions if I may.
Will fitting a cage that picks up on A and B pillars etc improve the structural rigidity of a Mini enough to positively effect the handling?.
And what advice do people have on choosing and fitting an oil cooler?.
I've been thinking about welding in the roll cage on my next rally car and adding attachments to the tops of the A and B posts. It would certainly make the car much stronger, but if you ever need to change any body panels, like the outer sills, this would be much more difficult. Whether it would help in the handling department is another matter. In theory is should, but whether you would actually notice the difference is something else. You could only measure it on a track in a 'before' and 'after' condition.
On a decent tarmac road the slow-in, fast out principle is absolutely correct, but of course that is quite relative. The entry speed should be such that you take the corner smoothly without having to lift off in mid-corner to get more turn-in and get back onto the power as soon as possible, thus giving the best exit speed and terminal speed down the next straight. The beauty of the Mini is that if you do go in a little too fast, you just lift off, get a bit of oversteer, then get back on the power to check the oversteer.
Rauno Altonen, the famous Mini driver, used to say that 90% of corners look worse than they really are, so go into every corner a bit faster than you think is OK, then in 90% of cases you'll be quicker. However, he than left foot brakes in the other 10% and that is a very specialist technique which takes much practice on big open spaces. I can give you the theory if you wish, but I don't want to be held responsible for any damage whilst you are learning. I only use it when I get it well wrong on gravel roads!
On a decent tarmac road the slow-in, fast out principle is absolutely correct, but of course that is quite relative. The entry speed should be such that you take the corner smoothly without having to lift off in mid-corner to get more turn-in and get back onto the power as soon as possible, thus giving the best exit speed and terminal speed down the next straight. The beauty of the Mini is that if you do go in a little too fast, you just lift off, get a bit of oversteer, then get back on the power to check the oversteer.
Rauno Altonen, the famous Mini driver, used to say that 90% of corners look worse than they really are, so go into every corner a bit faster than you think is OK, then in 90% of cases you'll be quicker. However, he than left foot brakes in the other 10% and that is a very specialist technique which takes much practice on big open spaces. I can give you the theory if you wish, but I don't want to be held responsible for any damage whilst you are learning. I only use it when I get it well wrong on gravel roads!
SLiller said:
And what advice do people have on choosing and fitting an oil cooler?.
Sorry, I missed this. For normal road use on a 1275 cc car with no sump guard and fairly high gearing a 10 row should be fine. For a hot engine with low gearing and a sump shield I would go for a 13-row.
One important tip. When fitting the cooler across the front of the car you MUST make sure that the starter cable is not in contact with the cooler gills. The starter lead will wear through with the obvious results if you don't do this. Run the starter lead underneath the starter motor and make sure that all of the other wiring is well clear also.
P.S. Maintenance tip of the month - the easiest way to dismantle your radiator cap is to drop it into the fan when the engine is running!!!
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