Front fork springs

[bikerbob]

I have a 1956 S/A A7 and a 1963 A65 the fornt forks on the A65 operate perfectly but the A7 is noicably much harder. Looking at the parts externally they are different to take into account wheel spindles and mudguard fitting, but the internals appear to be the same. So I am thinking maybe sometime in the past a previous owner has fitted sidecar springs to the A7. I am going to strip the A7 forks down over the winter and check everything over but how do you tell the difference between sidecar springs and normal springs are they longer or is the material thicker.what is the difference please.

[RogerSB]

This is my info taken from 1954 - 59 and 1960 - 62 parts books. (Edit: Repro springs, if true to form, could be slightly different).

[bikerbob]

Thanks for that Roger Iwill copy that and see what is fitted during the winter it gives me a starting point.

[Jules]

are you sure its not something as simple as different grades of oil??
there is lots of discussions in here about what oil and how much wrt the front forks, with notable (significant) effect on the front forks firmness....

[bikerbob]

I have the right amount of oil in both bikes as per BSA specs and both bikes have the same oil Silkolene grade 20 fork oil I have used this oil for quite a number of years in different BSA,s

[berger]

i have just found a spring that came out of my forks 40 years ago when i was told they were side car springs, 11 3/4 long 1 7/8 outside dia. nearest wire thickness is just under 7/32 or wire 3   5.4 to 5.5mm  19 and a 1/2 coils