Technology

Tyron has developed both multipart rubber runflat inserts and MultiBands to keep you moving safely in the event of a puncture, blow-out or ballistic attack. Our designs have come following extensive discussion with end users, vehicle OEMs and testing. How do all these work?

Why rubber not composite;
How do runflats work?
Rubber has three particularly significant advantages.

Firstly, rubber absorbs shock from impact resulting from kerb strikes, pot holes and operating in a hostile environment. Rubber drastically reduces the vibration and stresses transmitted through the runflat to the wheels, axles and drive shafts with little change to the handling of the vehicle whilst retaining a degree of comfort for the driver and passengers.

Rubber is a compliant material and prevents the damage caused to the tyre from impingement between the runflat and the inside of the tyre.

The third less obvious reason for using rubber rather than composite and probably the most important is the need for ‘Beadlock’.

Without adequate compression of the tyre beads against the flanges of the wheels (Beadlock) the vehicles are going nowhere. With only the ‘drag’ from the deflated tyres, the wheels will slip inside the tyres and that is on level ground, let alone trying to negotiate any obstacles or hills to complete its mission.

So why not use composite or hard material for Beadlock?
The answer is in the manufacturing tolerances of the wheels and tyres. According to Michelin there is a bead tolerance of +/-3mm on all their 20” military tyres, which produces a total bead variance of 12mm, add to this the wheel tolerances and there is variance of up to 20mm.

Composite runflats have to be under manufactured across their width, otherwise the runflat will break during installation or the wheel will not seal properly and therefore it is impossible to guarantee adequate beadlock to prevent the tyres from slipping or spinning on the wheels.

The width of the rubber runflat however is over manufactured to allow for these tolerances and during the installation, the rubber will flex and compress the tyre beads against the flanges of the wheels guaranteeing the beadlock.

In 2008 Tyron invented the world’s first ever multi piece rubber run flat, the All Terrain Rubber (ATR) runflat insert which can be fitted in the field, without special tools, to both military split rims and ordinary tubeless wheels, giving excellent off road capabilities. These have been both ballistically tested and for endurance to demonstrate that the vehicle can keep moving for more than 100km at speed.

How do MultiBands work?
In the event of a puncture or blow-out the Tyron MultiBand is guaranteed to “lock” the tyre on the wheel rim allowing the driver to retain control of the vehicle reducing the risk of an accident and to continue to a safe place to change the wheel or seek assistance, reducing the risk of personal injury.

Lightweight, so as not to affect fuel consumption, acceleration and braking and with no moving parts it does not affect the balancing of the wheels, maintenance free and fitted once for the life of the vehicle and its occupants.

Why do you need Friction Shield?
Friction Shield’s lubrication system is designed to further improve the performance of the world’s only multi-piece rubber run flat. At the heart of Friction Shield is a sealed lubrication system to stop it drying out, or becoming contaminated and is permanently attached to the run flat itself making it impossible to forget when changing tyres. The sachets burst following tyre deflation and provides the right amount of lubricant to ensure that the tyre is not damaged further by reducing the heat generated by friction between the runflat and the inside of the tyre itself, this enables the vehicle to keep functioning effectively over longer distances and higher speeds.

Forgetting the lubricant will reduce the runflat performance of any system by up to 90%!

Click here to download ‘Rubber or Composite Runflats for Military and Off Road Vehicles’ (PDF 769kb)