Kyosho IF421-01 Front Hub Carrier Bush Set MP9

This is the bush set for Kyosho's front hub carrier on the Inferno MP9 and MP10, supplied as four bushings.

The bushes are the inserts inside the hub carrier where the hinge pins pass through, and they are the actual bearing surface the suspension pivots on. Kyosho makes them replaceable on purpose, so that when the pivot opens up you renew a cheap insert rather than the whole carrier.

Worn bushes matter more than their size suggests. Once play develops at the front hub carrier, the wheel can move under load, and that shows up as caster and camber that shift as the car brakes and corners. The practical effect is a car that will not hold a consistent setup between runs and feels vague turning in, which is easy to blame on shocks or the servo when the real cause is a few tenths of play in a plastic insert.

They are cheap and worth renewing whenever the front end is apart. Kyosho lists them across the Inferno MP9 and its TKI variants, MP9e and MP9e TKI, MP10, MP10 TKI3 and MP10e.