Brake shoe lining length query

[Paul Gasson]

Hello,

I have to get a spare pair of brake shoes re-lined for my 1950 NH and noticed the parts book says different lengths of lining for front and rear, does it really matter? I think the casting is the same reference but the complete shoe and lining also have different part numbers.

Front lining only 4105-38 should be 6 5/8" long

Rear lining only 4387-38 should be 5 3/4" long

Any thoughts please.

[Keith.owen]

Hi, see the blog on single width shoes, in which Nev and Roger provide valuable insights!

[Roger Gwynn]

You have the lengths round the wrong way, it should be long lining on the rear. This is something I had never noticed having concentrated on the shoes! I think the reason will be the different amount of force that is applied on the two brakes with much more on the rear. Even the lining used on road bikes work better when they are warm so there is an optimum pressure to be aimed at and if a greater force is applied to obtain the same pressure it should be applied over a larger area. Force is the total effort applied and pressure is the force per unit area, I think that is right, I left tech college a long time ago!

[Paul Gasson]

Oops, sorry Roger, you are correct I switched the part numbers around. So less braking material at the front, maybe still concerned about front wheel lock ups as well? I appreciate your reply regarding forces.