Front fork springs

trophy · Post by **trophy** » Wed Dec 30, 2009 11:42 am

Hi All. Hope you had a good Christmas. Road conditions here in the Lake District not conducive for two wheel transport but ideal for two legged rambling round Tarn Hows.
However, back to business. Can anyone advise which way round the front fork springs (slightly progressive ?) should be fitted on my 1957 G9? As fitted the coils tighten up towards the lower end, but is this correct? Indeed, does it matter which way round they are fitted?

itma · Post by **itma** » Wed Dec 30, 2009 12:12 pm

close coils to the top

trophy · Post by **trophy** » Wed Dec 30, 2009 7:10 pm

Many thanks Ken

Chazzyb · Post by **Chazzyb** » Wed Dec 30, 2009 9:51 pm

quote:
close coils to the top

Why? Not arguing, just curious. Dual rate springs in other bikes of mine are fitted this way too, but nothing has ever said why. Is it about unsprung weight or summat? Closer coiled end will be heavier so you don't want that bouncing up and down as the forks move, perhaps?

Eric · Post by **Eric** » Wed Dec 30, 2009 10:36 pm

This is only an educated guess but perhaps it is so that the spring force becomes more progressive the more the forks move.

Early movement will occur in the more open coil section that is nearer to the point of movement. As movement increases these coils will become closer and closer until finally moving the stronger close wound spring at the farthest point away from initial movement.

Samuel · Post by **Samuel** » Thu Dec 31, 2009 4:09 pm

Progressive compression will occur either way round so I think it must be to reduce mass movement / unsprung weight.

Eric · Post by **Eric** » Thu Dec 31, 2009 4:22 pm

Samuel what you say is correct. What I forgot to say is that early movement will occur in the more open coil section that is nearer to the point of movement and lighter, so it is to do with unsprung weight.

The other way round would move the heavey tighter wound coils but initially not compressing them, so they would be unsprung weight.