XRAY - Model racing cars

I guess that maybe I'm a bit anal about doing things like setup. I believe for a setup to be of any value, you must be able to duplicate it with as much precision as possible.

One aspect of the Xray that seems to defy that notion is the Diffs. When asked, most people will give you a recommendation that the Diff should be this way or that way, looser or tighter and that how much is a matter of experience and trial/error. Manuals are the same.

That's not good enough for me. If something is to be "so tight" then that degree of tightness should be quantitative. IOW, in the best of worlds we should be able to say precisely how much. to say simply that the diff should be "so tight" is relative and without the requisite experience, "so tight" will be utterly meaningless.

There is a means of measuring tightness in degree and that is the amount of torque applied to the device in question. With the diffs and even the layshaft it should be possible to tighten the diff to some setting in a given torgue range by using a torque wrench or screwdriver. This setting may not be the same for all diffs, but a starting place/baseline could be established, in say Nm (or some fraction therof), and fine-tuned from there using the same system of measurement. That measurement could be recorded, stored and recalled for future reference. That would take much, if not all, of the guesswork out of adjusting diffs and layshaft one-ways.

So am I the only one to have considered this (I doubt it) or has someone actually gone out and used a torque device to set their diffs. If so, what have you found or established?

Or, am I simply being overly anal and barking up the wrong tree here?

</chaz>

I'm definitely on the same wavelength. I'm pretty good at memorizing the "feeling" of something like the tightening of diffs, but this past week I hadn't changed my diffs in a month and I honestly had to guess what my version of "loose" and "medium" meant for the rear and front respectively.

Is there anything possible like an adjustable diff with "notched" or otherwise indicated increments of the tightening screw? I would say the first car manufacturer to have this type of diff would definitely be a "leader" in inovation, like say xray...?!?

Refer to your setup book. and bench test the setting. Remeber your hands have more tourqe than there is on track. You can let it slip in your hands, and get a very smooth feel when you turn 1 tire. It will feel to loose but when on track it wont slip because there isn't as much traction or tourqe as when you bench test with your hands.

This a good place to start, then drive and see if it slips, if its way to loose your will hear it.

This is a good way to go for rubber tires when traction is always an issue.

BUT for FOAM tires and when more traction is available I would run the rear a little tighter. Still it should feel very free during the bench test. and not as tight as the front in general.

This is why the tourqe value dosn't seem practical.
Because the tire choice as well as the traction available have control of the best setting for the diff's

IMHO
Rick