XRAY - Model racing cars

Here's a question that I hope finds its way to someone who knows what they are talking about.

Why, and what is the difference in handling effect if say I had a final drive ration of 8, and I had an internal ration from 20layshaft, 34pulley 1.7 - to 20 layshaft 38 pulley 1.9 - to 16 layshaft to 38 pulley 2.13

Some people have said it increases grip etc, but I cannot see the logic of this, because the final drive ration will remain the same.

I found that a lower internal, i.e. 1.9, even when used with the same FDR with 1.7 seemed to spool up quicker on acceleration.

Skiddins

Others seem to say the same, but it makes no sense to me, because the rotating mass is more with 38 tooth as opposed to 34 tooth diffs.

Also what is the handling as opposed to the accelerative effect

When Xray released the 008 they changed the 007 IR of 1.7 to 2.375 (rubber spec). This was a result of extensive performance testing and if I recall correctly the larger pulleys gave a freer running belt which, if you cast your mind back to say 27T Stock, helped you carry corner speed.

But the advent of non NG brushless speedos saw FDRs increase substantially and trying to reach the required ratios especially for the larger winds required the internal gearing to be larger, so XRAY produced an option to achieve 1.77

The 009 when released carried this IR forward.

Then at a later time an option was given to take the the IR to 1.9.(I cannot recall actually if this was with the 008 or with the 009) . I am not sure what brought this about but assume it was a compromise to get back towards the larger pulleys whilst still providing the capability to achieve the FDRs needed for brushless.

The T3 continued with the 1.9 IR as the base shipped IR

Now of course we have the NG speedos which have totally changed the FDRs back again and more. It is maybe surprising that the T3 011 did not ship with 2.375 but I guess you could say that one no longer needs that freer roll for corner speed given the power characteristics of current day powertrains

If you look into it, you will find that the reason why 38 tooth diffs with 16 tooth pullies was abandoned was because the belts weren't lasting as long as for 34/20. Reason for this was because of the smaller diameter pullies on the layshaft. 20 tooth layshaft pullies alleviated this.