Tamiya XR311 Project
Page 3: Upgrades!
The biggest weakness of the XR311 is that it has no external damping for
the suspension. The torsion bars and joints do a reasonable job
of slowing the rebound, but nothing like a real damping system would
do. It happened by coincidence that RC Channel released a
suspension upgrade set (for an 8 year old model) the same week that I
was already planning to build my XR311. This was obviously meant
to be. I bought the suspension kit, the oil shocks, and the metal
under tray and commenced upgrading.
Here's the front suspension before and after the upgrade. The
suspension arms and steering knuckles have been replaced with metal parts
and the flanged bushings have been replaced with ball bearings. A
metal shock tower has been added as well as a set of small oil
dampers. The front and rear metal brackets are original as is the
steering linkage and servo saver (hidden down inside the
assembly). I think you'll agree that it is a thing of beauty.
A similar process is performed on the rear suspension. Besides the
addition of shocks, the rear end upgrade also replaces the gearbox
cover with a metal unit making for a full field of view of bling.
All mechanical parts of the gearbox are still original including the dog
bones. Original steel JIS hardware is replaced with stainless hex
hardware.
Although not part of the same upgrade kit, I also replaced the clear
under tray with a sheet aluminum version. This probably offers no
actual benefit, but it ties the whole metal chassis look together.
The right hand image shows the completed upgraded chassis which looks
really, really good.
The weak point of the upgrade kit is the ball socket design. The
balls are captured in a one-piece plastic socket and the instructions
warn you not to try to remove the balls from the socket. One of
mine suffered a failure of the socket as shown before I even installed
it. Thankfully, the rod end for the servo link was not really
necessary so I was able to steal that one to complete the
suspension. The right hand image shows everything that was
replaced. Virtually all of the original plastic parts have been
removed. The only exception is the steering linkage.
The driveability of the model is much improved after the upgrade.
It probably doesn't matter whether the arms are plastic or metal, but
the addition of dampers really helps. Plus it looks awesome.
©2019 Eric Albrecht
