Posts Tagged ‘noise comparison of radial and cross ply’

Cross Ply tyres versus Radial Ply Tyres

Cars make use of the radial tyres entirely but the ones fitted to motorbikes retain the cross-ply form of construction and even the tyre engineers state that radial tyres are not appropriate for motorbikes. This is in fact quite right as cars and motorbikes are very different and should have different tyre requirements. However, of late the radial tyres are considered to have benefits to offer to motorbikes as well.
Several piles of cord are laid on top of each other at a bias angle of 40 to 50° to make a cross ply tyre. This consequence in the creation of a cross at an direction of 80 to 100°. The layered and angled structure of ply tyres results in the tread not reacting in exact symmetry to that of the loads applied.
The symmetry is completely lacking in cross ply tyres and this can cause the tyre to run to one side nonetheless while rolling on a completely level and even surface. This effect is known as “Ply Steer”. The cross manufacture of the carcass efficiently forms parallelograms of thread imbedded in the rubber, this is not a sturdy form of construction and under driving or braking torque, upright load and centrifugal sound effects these parallelograms deform, which allows squirming of the contact area and tyre toss or diameter enlargement at elevated pace, reducing constancy and heating the tyre. Such heating eventually manifests itself as amplified rolling conflict.
By simple observation one can conclude that radial tyres create a greater and wider area of impression compared to the cross ply tyres. Such a fact highlights that radial tyres have better grip than cross ply tyres. Again in loaded conditions the radial tyres outscore the cross ply tyres as they have larger contact area with the surface of the road as they the tendency to become littile bit flat which is not the case in cross ply tyres.
Radial tyres contain less plies that is generally confined to one or two than the cross ply tyres that require three to four plies, so as to have greater flexibility in sidewalls. To maintain the entire tyre stiffness the reduction of sidewall height is required and thus results in lower profiles of 50 to 70 %. On the other hand the cross ply tyres make use of 90 to 100% of the profile. The lower profiler is an indication of having smaller diameter. The cross ply tyres have larger diameters in comparison to radial tyres of the same size. This trend contributed to the growth of 17” wheels while leading to the decline of the popular 16” wheels.
In the year 1984 radial tyres were introduced for the first time. The bias belted tyres were the most commonly used tyres until then. The cross-ply tyres were the next in line of production, which added circumferential belt plies. As and when the developments took place the older technology got replaced with newer ones giving way to improved tyre strength, agility and overall performances.