Steel centre pneumatics:

One piece, continuous precision welding gives a strong, wobble free wheel.
Centres up to and including the 500x6 are manufactured from 1.8mm (1/16”)
steel, and the 650x8 is of 2mm (1/ 8”) thick steel
[NOTE: some of the cheaper centres on the market are manufactured from
steel as thin as 0.6mm (1/32”)]

Bearings:

‘Deep Groove’ shielded bearings fitted to a toughened heavy duty housing
enables true running and extra strength (NOTE: Deep groove bearings can
last up to 3 times longer than normal pressed bearings).

Tyres:

4 ply (6 ply on HWY tread) for longer, rougher life (many imports use 2 ply).

Tread Patterns:

For wheels pulled or pushed at low speeds (not driven) the
tread pattern is not critical. the following are standard;
other patterns can be offered by negotiation.

IND: The normal industrial tread, a round profile with an even pattern
for general use.
LUG: Strongly marked cross lines on a fairly flat tread surface. Good for
running in straight lines.
KNO: This knobbly pattern is often preferred for outdoor use, where its
strongly marked tread takes a good grip on soft ground.
DMD: Diamond shaped pads on a flatter surface. Often used in rougher
construction sites. Good for softer grassed surfaces, but may become
clogged with mud.
GRA: A wide tread, designed specifically with ride-on mowers and
associated equipment in mind.
Will traverse virtually any surface they come across.