On a website (I forget the link), a guy put a spring from a mechanical pen on the shaft that holds the spyder gears inside a T-Maxx diff.....what exactly does this do and what performance advantages does this give you? Seems to me that the spring would push the gears away from the ones on the sides making it easier to slip and grind away.......

It actually would make the diff harder to slip.L.S.D-limited slip differential or a posi.This is basically how it is done on full size cars, but I dont know if it would actually work on an R/C car.So long as you could make sure the spring wont fall into the spider gears it couldn,t hurt though.

It'll work, the HPI rs4 3 rtr,ss,evo all has them, and they have optional spring rates to put in.

Well I just put a spring in my rear diff and it seems to work sort of ok but not what I expected. It does lock the loose wheel better then my front diff with out the spring but we will have to see how it performs once more snow melts.

It's all about the spring rate C-Racer.

You could also just fill the differential with silly putty and make a posi rear (and/or front with the ST's).

Yea I know but I don't have too much of a selection of spring rates with pens

Anywho it does the job and doesn't totally lock the diff and thats what I want. I wont know how it does untill I run it though.

SARCASM!!!!

Dude, I burst out laughing upon reading that. Congradulations, there ain't a whole lot of people with enough wit to make me do that outloud. Kudos.