8 replies to this topic

[Kerrin]

Need a bit of advice/discussion from any handling gurus out there.


My mini is running 10x5" exacton (1100 special)wheels which were origionally fitted to drum brake cars. but my car runs with minisport 7.9 four pot calipers and front disks based on the 8.4 setup. The rears are minifin spacered drums.

Due to a visit from the rust fairy, I need to patch or replace the sills, so have decided to start a bit of a winter mini rebuild. the wp arches have been removed and I want to have a rethink on the styling.

The handling really isnt up to scratch and it feels like it oversteers the steering does not self straighten it is not precise meaning overtaking is a bit hit and miss.
I have adjustable front arms set to (hopefully) 1 degree negative camber and 3 degrees caster, the rear is standard, the front and rear tracking is correct with normal track gauges (I dont have a 4 wheel laser alignment setup ) and there s no obvious wear or problems.

Minilite appear to sell wheels with either "S" or normal offset (disk or drum brakes) and this is starting to make me think my incorrect offset may be affecting the handling.

I was thinking that the car may handle better with 4.5" "S" offset wheels, which would allow me to get rid of the arches, the car has a mk1 style grille anyway so it may suit the car better.

Anybody know if the Minispares minilife 10 x 4.5 wheels are "S" offset?

The car is running a 1380 motor with a fair bit of power and it really needs to be tamed to make it more fun to drive. I realise the easiest way would be to take it to icklemini but just cant afford the boat trip!

Any comments welcome.

[Cooperman]

The best wheels for you are probably the ones Mini Spares sell as the 4.5" Minilite 'ST-type' as fitted to the rally cars of the mid-60's. You don't need wheel arch extensions and the steering geometry is as close to the original design as it's possibe to get when going from the original 3.5" wheels to 4.5".

[Kerrin]

The best wheels for you are probably the ones Mini Spares sell as the 4.5" Minilite 'ST-type' as fitted to the rally cars of the mid-60's. You don't need wheel arch extensions and the steering geometry is as close to the original design as it's possibe to get when going from the original 3.5" wheels to 4.5".

Is this the one we are both talking about?

Minilife Wheel

Just checking

[GraemeC]

That is 'S' offset so would fit your brakes without arch extensions.

You may find increasing your caster to nearer 5 degrees will improve your self centering effect.

[Kerrin]

Yes I will give 5 degrees a try on the caster and see how it changes the handling, thanks.

Would fitting rear adjustable brackets and giving some rear camber help the oversteer or will this just make the car more marginal and difficult to drive. I have the brackets but not fitted them for fear of making it worse.

[GraemeC]

Adjustable rear brackets may give an improvement, dependant on what settings you have now.
Lots of oversteer indicates you may have toe out on the rear, which isn't good for a road car.

[Cooperman]

Adjustable rear brackets may give an improvement, dependant on what settings you have now.
Lots of oversteer indicates you may have toe out on the rear, which isn't good for a road car.

Make absolutely sure that you have 1 mm to 2 mm toe-in on the rear wheels and zero to 0.5 deg negative camber on the back. That is probably the most necessary thing to get a Mini to hold the road, kill the 'roll-oversteer' and improve the overall handling. Get the rear right before seeking to improve the front. I just set a Mini up last weekend by shimming and filing the rear rad arm outer brackets. it was surprising how far out the settings were - it had positive camber and zero toe-in and the front was not in line with the back. It's amazing what you can do with two long pieces of wood, a rectangular plywood board, a tape measure, a file and a couple of large washers. Even 'low-tech' methods can work when setting a Mini.
And yes, that is the best wheel you can get in 10" for a 165/70x10 tyre.

[ado15]

Wheel offsets won't affect over/understeer.

On the front it changes the scrub radius which is the distance between the centreline of the tyre on the ground and the point at which the steering axis passes through the ground. Increasing the offset also increases the scrub radius. The most notable effects of this are torque steer, wandering under braking and 'kick back' through the steering.... all basically the same thing but acting under different circumstances.

[Kerrin]

Adjustable rear brackets may give an improvement, dependant on what settings you have now.
Lots of oversteer indicates you may have toe out on the rear, which isn't good for a road car.

Make absolutely sure that you have 1 mm to 2 mm toe-in on the rear wheels and zero to 0.5 deg negative camber on the back. That is probably the most necessary thing to get a Mini to hold the road, kill the 'roll-oversteer' and improve the overall handling. Get the rear right before seeking to improve the front. I just set a Mini up last weekend by shimming and filing the rear rad arm outer brackets. it was surprising how far out the settings were - it had positive camber and zero toe-in and the front was not in line with the back. It's amazing what you can do with two long pieces of wood, a rectangular plywood board, a tape measure, a file and a couple of large washers. Even 'low-tech' methods can work when setting a Mini.
And yes, that is the best wheel you can get in 10" for a 165/70x10 tyre.

Ok I see where you are coming from, I do have a set of tracking gauges and have checked the front and rear (but wondering now if the rear is toe out as the gauges would be backwards on the rear) using them facing forward under the car would prevent confusion I will check it again.

I have checked motorcycle rear wheels for true to the front wheel by using a string line but could not work out how to apply it to my mini. can you give me some more information on how you checked yours, I am thinking along the lines of a rectangle frame and lots of measuring with the car right in the middle.

Really warming to the 4.5" wheels now, as it will save a lot of messing about, and save drilling more holes in the body to change from WP arches to the standard plastic type.

Thanks again for the help, I am getting re-motivated to sort it out.