7 replies to this topic

[AC&SONS]

Had the tracking checked on my son's 1977 Mini 1000 after fitting new tie rods, pins and ball joints.

The guy said they had adjusted the tracking to the correct tolerance, but the castor was out. In other words, the near side wheel is further back in the arch than the offside by approx. 10mm.

He said that it would be fine if the car felt OK; which it does, there is no pulling to one side or other strange feelings through the steering and the handling feels fine.

But I was just wondering what the long term implications would be. I assume that if the tracking is OK, tyre wear will be equal across the tread.

Even though I have spent money on new fixed length tie rods; would it be better to fit adjustable ones to bring the castor back where it should be; i.e. even on both sides; or will it be OK.

He will be using the car for mainly local journeys with no motorway or high speed work (after all; it's only a 998cc!!!)

Opinions welcome on this one please
Thanks

[dklawson]

If the shop based their caster determination on the position of the wheel in the sheet metal arch... I would not worry about what they said. If they based their measurement on fixed points on the subframe and a vertical axis... then I would worry. Who is to say that the sheet metal on your car is identical form left to right side. If the car has ever been in a front end accident the panel alignment could be off by quite a bit. Caster is an angle, not a fixed position.

That said, the three main variables are camber, caster, and toe (tracking). It sounds like they adjusted the toe for you. That will affect tire wear significantly. When set incorrectly it can also cause vibration. Camber is how the wheel leans into or away from the centerline of the car. When the camber is out of adjustment the car can pull badly from one side or the other... or the car can feel "squirrely". Because you are always compensating for that with steering corrections tire wear can be accelerated. Caster is a variable measured (more or less) by the angle (fore and aft) of the steering hub relative to vertical. The hub that the wheel is on has ball joints top and bottom. Draw a line through those joints and compare it to vertical. (This is the part of steering geometry I understand least). What I understand is that the caster angles need to be the same on the left and right. Each car will have a correct caster angle and when you deviate from that angle, the behavior of the road wheel relative to steering input changes. Incorrectly set caster can make steering very heavy or shaky.

So... drive your son's car and keep an eye on the tread wear. Remember that over inflation can cause the tread to wear away first on the middle of the tire while under inflation can cause the outer edges of the tread to wear first. If you find that the outer (or inner) edge of the tread is wearing without the other edge wearing, look carefully at the alignment and camber. In most cases the steering wheel is also going to give you feedback about alignment problems.

[racingbob]

if your concerned get some adj. camber arms and tie rods about 90 quid

and get it set up at a place that does fulll geometry setting 60 quid

that way you can get it right AND put a bit of camber on the front say 1 deg

i have 2 deg on mine but mine just a fun car

[AC&SONS]

Thanks for your advice; I will monitor the tyre wear and then see how things go.

Cheers

[AC&SONS]

Just a thought; I measured the distance between the hubs; i.e. centre of rear wheel hub to centre of front wheel hub and that's how I knew the difference was about 10mm. If this is the case, would that rule out any bodywork irregularities?

Any more thoughts?

Thanks

[yousmeg]

There is a test to do with drawing chalk on the floor and some other stuff that will answer whether the hub is really out of place

I wouldnt be surprised if it is just the bodywork

Im sure someone will come along with the proper name of this test and how to do it

[Wil_h]

Just a thought; I measured the distance between the hubs; i.e. centre of rear wheel hub to centre of front wheel hub and that's how I knew the difference was about 10mm. If this is the case, would that rule out any bodywork irregularities?

Any more thoughts?

Thanks

Wow, you have a good one, 10mm is nowt, I've seen a lot more than that.

[SolarB]

Just a thought; I measured the distance between the hubs; i.e. centre of rear wheel hub to centre of front wheel hub and that's how I knew the difference was about 10mm. If this is the case, would that rule out any bodywork irregularities?

Only if the rear subframe and suspension is straight.