Originally Posted by stubaxle
Hi, I just started racing a TCX, and it's fantastic! I just would like to put a gear diff in the back and retain the spool up front. I got a pair of 44mm dcjs with the car and would like to use them. I tried the longer HB POM outdrives and spec-r white ones but found them both unreliable. I was trying to find HB part 68769 long steel outdrives but they've not been in stock for ever. I would just like to know;
a) Which is the best Gear Diff to get, HB or SpecR and can I use the standard TCX driveshafts on the rear with each?
b) Is there a spool option or an outdrive option so I can use my short dcjs?
Get the HB gear diff. HB diff is spot on right out of the package. No voodoo required to prevent leaks. And yes the TCX 44mm driveshafts will work with the appropriate blade installed. The HB diff comes with blades that work on TCX(2.4mm pin) and TCXX(2mm pin) driveshafts.
As far as the spool goes. I have been using a Spec-R gear diff with a Spec-R locker installed as a spool. The HB spool, even with the long outdrives isn't optimal. The shorter 44mm driveshafts can pop out during suspension compression. Especially, if you're running the wider pivot blocks. The Spec-R unit is about a MM or so wider and it uses blades which help keep the driveshaft from popping out. It is heavier than the HB spool, but at least the driveshafts won't come out.
We need longer outdrives for the spool or longer DCJ driveshafts to fix the issue.
Perhaps someone else will chime in with a more viable spool solution.