Originally Posted by el salvador

If the R4 uses 9mm pivot balls then the RRR's should work, Kyosho part # VZW024V-8, (A Main Hobbies has them for $70 USD), either Lunsford or possibly Kyosho RRR Tie Rods, these are 46mm in length, #92415 would lighten the steering system.

Note- Xray and Capricorn use 8.4mm pivot balls if thats what the R4 would need.