Rear toe?

[james3004]

Any ideas where I can get some shims from?

[alga]

I just clamped a long spirit level to the spindle and measured how much it diverges from parallel with the side of the chassis. I cut shims out of a beer can. The can was 0.1 mm thick and each shim was worth 0.1° or so.



Simple trig: If I get 8 mm divergence over 550 mm, the toe for that wheel is arcsin(8/550), that's approximately

8 / 550 * 180 / 3.14 = 0.83°

8 / 500 is really the sine of the angle, but in the vicinity of 0 sin(x) is close to x, then 180/pi just converts radians to degrees.

P.S. Toe in millimetres means the slant between the front and rear of the tyre of some unspecified size. Sierra tyres are about 57 cm in diameter. You can use the same trig to convert that into degrees.

[flyerncle]

I will get flack for this but here goes,the suspension mounting points are fixed so shim's will put tension on wherever it is fixed or mounted,you can bet that it will break at the wrong time and the only sure way to make it adjustable is with rose joints or eccentric washers and bolts.

[wylliezx9r]

Originally Posted by flyerncle

I will get flack for this but here goes,the suspension mounting points are fixed so shim's will put tension on wherever it is fixed or mounted,you can bet that it will break at the wrong time and the only sure way to make it adjustable is with rose joints or eccentric washers and bolts.

I've got custom lower wishbones fitted on my car, which are adjustable for toe. Think they were manufactured by 3GE when they existed.

[MikeB]

Caterham racers have been using shims for years with no problems/

[twinturbo]

must be value beer if the can is only .1mm .

TT

[Jimmyd]

[quote=alga;98287

Simple trig: If I get 8 mm divergence over 550 mm, the toe for that wheel is arcsin(8/550), that's approximately

8 / 550 * 180 / 3.14 = 0.83°

8 / 500 is really the sine of the angle, but in the vicinity of 0 sin(x) is close to x, then 180/pi just converts radians to degrees.

P.S. Toe in millimetres means the slant between the front and rear of the tyre of some unspecified size. Sierra tyres are about 57 cm in diameter. You can use the same trig to convert that into degrees.[/QUOTE]

Let me get this right, the diameter of the outside edge of my rims is 410mm so if I have a variance of 2mm over this diameter I get,

2/410*180/3.14 = 0.28 degrees of toe

If I want 1 degree of toe I need 7.25 mm variance,

7.25/410*180/3.14 = 1.01

I'm I correct?

J

[robo]

Originally Posted by flyerncle

I will get flack for this but here goes,the suspension mounting points are fixed so shim's will put tension on wherever it is fixed or mounted,you can bet that it will break at the wrong time and the only sure way to make it adjustable is with rose joints or eccentric washers and bolts.

+1

The face plates that the bearing hub bolts too is never properly flat anyway because of the distortion when welding, I am going to flash them off on the mill when I sleeve the hub down to fit the bearing carrier. I am thinking of a redesign of the lower wishbone to have two outer adjustable joints that could deal with toe and camber and leave the top one solid. I wont be shimming behind these bearings because they are ali.

Bob

[alga]

Originally Posted by twinturbo

must be value beer if the can is only .1mm .

I tried several brands of domestic and imports, looks like 0.1mm cans are the norm now.

Albertas

[alga]

Originally Posted by flyerncle

I will get flack for this but here goes,the suspension mounting points are fixed so shim's will put tension on wherever it is fixed or mounted,you can bet that it will break at the wrong time and the only sure way to make it adjustable is with rose joints or eccentric washers and bolts.

I agree with you, it's not the cleanest solution. If you're worried about stress and deformation of the bearing carrier, you can stagger the shims to make the slant more gradual. However, both the upright and the brake back plate are painted, so there is no precise metal-on-metal contact anyway.