Thread: ARM Stud and Idler Gears

Hi All,

Just finishing putting my ARM back together and some questions about the setup of the stud and idler gears.

Currently it has 20t stud, 80t idler and a choice of 50t or 44t to go on the input to the Norton box.

Should there be a spacer or collar on the input to the Norton box? The shoulder on the shaft and banjo mounting position are pretty close to flush?

Is this the correct configuration? The chart on the Norton box only mentions the stud gear teeth and nothing about the number of teeth for the norton box input shaft? Should there be another info plate on the gear train cover?

Thanks! Will post pics shortly.

Cant tell you exactly but there should only be 1 chart attached to your Quick Change Box,unless Hercus or someone else has modified it.

On the Gearbox chart for the Stud gear there should be 2 choices,1 for very course pitches and 1 for the finer pitches, this will be on the top row,this should be either your 50 or 44 tooth gear,I have a feeling this should be a 45 rather than a 44.

Under the top row in the far right coloum it should have a 20 tooth as the stud gear.

If the top row is showing the 50 as the stud then the 44 tooth gear you have will be the screw gear that attaches at the Quick Change and vice a versa if the Stud should be the 44 tooth gear.

You can sometimes find a spacer on the Screw gear shaft,this is normally around 25/30mm in diameter with a key way to suit.

A lot of times you will generally find that what ever gear is doing the driving on the screw shaft the other gear that you would swap with the stud gear is used in place of a spacer,saves the spare gear being misplaced.

Hi Pipeclay,

I think you are right on the alternate gear, 45 instead of currently fitted 44. I just picked up a 260 and it has 50 and 45 mounted on the norton box input shaft. I would assume that the gears to be used would be similar.