Space age Alignment

[Number_Cruncher]

>>So does continually compensating for road camber affect the uniformity of tyre wear?

I'm not sure.

I would suspect that there is an effect, but that other forms of tyre wear are more dominant - but I don't know this to be true.

 

[television]

>>So does continually compensating for road camber affect the uniformity of tyre wear?

I'm not sure.

I would suspect that there is an effect, but that other forms of tyre wear are more dominant - but I don't know this to be true.

Possibly just a little, the car does want to slide very little into the camber

 

[kth286]

On this cambered road question there is a CASTOR spec for my 124 generation car that states that the measurement is different one side compared to the other.

This probably compensates a little BUT it is often stated that Merc want the car to veer into the side of the road in event of driver drowsiness, as opposed to car veering into middle of road into oncoming traffic.

Castor for those unfamiliar is like you see on the front forks of a motor bike that has the front wheels well forward compared to normal.

My car has a high castor at around 10/11 degree compared to normal cars of that generation at around 5 degree max.

Gives relaxed high speed straight line travel, but conversly not so quick at turning from lock to lock in the twisty stuff, again depends what is wanted I guess.

 

[michaelj]

In addition, Mercedes specify a spreader bar is inserted between the front wheels to simulate the actual forces as per the situation when driving. (rear drive cars force the front wheels apart on the move, and the compliance of the rubber bushes allow that to happen, but when a car is static the wheels are not in their normal driven state hence the need for a spreader bar when setting the geometry up).

Was that done ?

Exactly. I remember being told many (many!) years ago that the only reason for setting up the front wheels with toe-in was to make sure that you never, ever got toe-out, (which, as we know, feels most alarming).

 

[Number_Cruncher]

>>was to make sure that you never, ever got toe-out

Plenty of cars have a toe out tracking specification.

 

[michaelj]

Really? never knew that. on the front? why would they do that?

 

[roofless]

a not so hi tec alignment job http://mercedes-diy-alignment.blogspot.com/ it's just not the same is it

 

[Number_Cruncher]

Really? never knew that. on the front? why would they do that?

It tends to be on front wheel drive cars, where the steering torque produced by the drive tends to toe the wheels in.

 

[television]

Yes, my V70R toes out

 

[wheels-inmotion]

>>For the domestic vehicle we do offer a Kinematic image by applying dynamic stages to the suspensions "compression/droop", with today's software this is hardly rocket science.

You'll have to explain that.

>>For the domestic vehicle

You only do this for British vehicles?

>>a Kinematic image

What do you mean by this?

>>by applying dynamic stages to the suspensions "compression/droop"

and this?

>>with today's software this is hardly rocket science.

Software alone can't tell you how a loaded suspension is going to move (unless it's design level software, which I very much doubt will be used outside of manufacturers and research institutes).

No, it's not rocket science, but, it's not everyday practice either.

Hello... Cheers for the welcome.

Why are you being such an arse?.... If members have a chance to gather an understanding of chassis dynamics then surely this would be a valuable addition to the clubs knowledge bank? I have little time personally to wast arguing about the structure or composition for a reply regarding chassis dynamics "domestic or not"! But i do think you should stand back and look how your detrimental hostile posts may discourage valuable conversation around this topic.

I think we have been here before?.... If you are serious on this topic then i suggest you roll your neck back and pull your pants down!

 

[Number_Cruncher]

I thought it was fairly clear, I was asking for some clarification. However, you don't seem to want to provide it.

>>I think we have been here before?

Yes, when you tried to baffle users on another forum.

 

[wheels-inmotion]

I thought it was fairly clear, I was asking for some clarification. However, you don't seem to want to provide it.

>>I think we have been here before?

Yes, when you tried to baffle users on another forum.

"Baffle" i feel honored....

Sorry to the topic starter but Mr Cruncher what is your pedigree? If your topic is chassis related then maybe we could duff it out in the correct arena, it's hardly polite to pollute this thread with innuendo's.

That's a "pull up" your pants and take this topic elsewhere statement!

 

[Number_Cruncher]

You made a post in this thread.

I asked for clarification.

Instead of engaging with the questions, you started trying to tell me how to wear my pants, which is a bizarre, unprofessional, and utterly underwhelming response.

 

[S.Speed]

Its actually me that started this post by saying how very, very pleased I am with the work carried out by Wheels in Motion..
I have absolutely no connection with this firm other that being a customer last week.
I say again I highly recommend them to people having issues with steering / tyre wear..
As with everything in life we have choices..
I chose to use this companies services and have not regretted it at all..
You may choose to "use a bit of string" if your uncle was scrooge..

So to Wheels in Motion, I thank you for a job well done.

Simon Speed

 

[michaelj]

It tends to be on front wheel drive cars, where the steering torque produced by the drive tends to toe the wheels in.

Well thank you; I've learned something, even if I can't quite visualise it. I can see how rear drive might push the wheels to toe out (because of the castor), so we toe them in to correct, but I can't get my head round how the torque from front drive would toe them in...Anyone got a simple, intuitive explanation with no long words in it?

 

[S80]

Michael,

Put your forearms out and imagine you're supporting a weightlifting bar. Then 'tweak' the ends of the bar in a forwards wheel motion - you should be able to sense your wrists 'toeing-in' as you do so.

A bit of a crude analogy, but I think that's what's going on with the driveshafts/stub axles under FWD.

 

[Number_Cruncher]

>>I can't get my head round how the torque from front drive would toe them in.

There are two main possibilities.

One is offset - where the centre of the tyre's contact with the road, and the point where the imaginary extension of the hub's swivel axis down to road level are displaced laterally relative to each other. Side to side, this usually cancels, and isn't felt by the driver. If, however, a tyre has low pressure, then this is the mecahnism that feeds a steering torque back to enable the driver to feel it.

The second is the torque due to the angle of the driveshaft relative to the hub. There's the torque in the driveshaft, and the torque in the outer part of the CV joint - to make the torque turn through this angle, a third reaction torque is required (just like a triangle of forces, but with torques instead). This reaction torque has a component which acts to steer the hub. This is the main mechanism behind torque steer, but, if the car's driveshafts were completely symmetric, it would balance out, and the driver wouldn't feel any torque steer - each wheel would still be subject to the steering torque though. (This is the same as the weightlifting analogy as written by S80)

Sorry - some long words were difficult to avoid, and I aknowledge that's a weakness in the way I write about technical matters - if any are preventing you seeing what I've written about, please ask.

 

[kth286]

Perhaps........................................

rear wheel cars are pushing the car................ and front wheels splay out


Front drive cars are pulling the car................. and front wheels pull inwards (front of)

 

[television]

Sorry - some long words were difficult to avoid, and I aknowledge that's a weakness in the way I write about technical matters - if any are preventing you seeing what I've written about, please ask.

It has been good having you on board, you have given me many a thing to think about, and I have altered some of the answers that I give now. It can only be for the best

 

[Xtractorfan]

Maybe he wants ur pants down so that he can toe you in the ass ...with his foot ..

lads its only a forum and there are many opinions, and it is good when someone finds technology that works and passes that info on to others.. I would certainly use such technology if it were available locally to me..tho it is expensive, but cheap if it stops premature wear on tyres and provides safe and secure driving