[country soul]

Hi, I have a  Massey 135 straight axel model.Does anyone know  the extent to  which the front wheels should be "toe in"( I believe that's the term) ie the wheels are wider apart at the top than they are touching the ground  .The extent on mine seems significant and its wearing the tyres accordingly.
Is there  some means of adjustment?

[mab]

if the tyres are wearing on the outside edge that would suggest toe-in - although, to be pedantic, that is an error in the tracking - and to correct it you adjust the track rod length (i.e. the front wheels are wider apart at the rear than at the front. By default i'd adjust tracking on a tractor to parallel the wheels.
 The wheels being further apart at the top than the bottom is called 'camber' I think. I'm not sure you can adjust camber on a tractor, but it shouldn't cause an issue with tyre wear.

[valmet10]

are the kingpin bearings ok

[henchard]

Toe in on a MF135 should be around 1/4 inch I believe.

If it starts to get excessive it is usually down to wear in the steering components.