XRAY - Model racing cars

Hi Everyone,

I've looked at several setup sheets for the XB2 and noticed that many use shock upstops on the front, rear, and sometimes both.

My question:
Is this a variable for tuning the handling of the car? If so, what effect does it have?

Is there a bind in the front or rear that needs to be watched/avoided? Perhaps to mitigate chassis slap, or something else entirely?

Thanks in advance!

I do not much want you to help me a little bit.

I am very pleased to have the opportunity to come here.