502 not turning in well?

[dobber]

Just been racing at TORCH this weekend for the first time. My car seemed ok but no turn in and grip round bend, i was forever understeering.
I am running the JT Steering bridge so i have got something helping it
What camber and toe set up should i use. I also wonder if my slipper is too light, how have people set theirs up for astro. If i hold 1 front wheel it does not drive all wheels. Any thoughs are much appreciated?

Also does this fit the 502X?
http://www.ebay.co.uk/itm/Tamiya-539...item588e9c3e64


Cheers!