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Forks Disassembled & basic measurements
Thank you all for your help and comments.
I opted to remove the spring and take some measurements (see pictures).
The spring size:
-Diameter: 31mm
-Length: 490mm
-Wire diameter 4.4mm
-Free Turns 48.4
-Fork Travel 150mm
Motorcycle weight: 130Kg
Rider Weight w/gear: 95Kg
To calculate spring rate I used the formula suggested bymtiberio
but it came out to small (perhaps the type of steel used) so I tried to calculate the spring rate using disk weights on a single fork leg:
-Pre-load using weights until it moved: 14Kg.
-Placed 70Kg in disk weights to 1 leg: compressed 103mm
Probably wrong, but I guess the spring rate would calculate to:
70Kg weight - 14Kg pre-load = 56 Kg net --> 103mm measured compression
56kg/103mm= 0.54 Kg/mm
Please help:
Next step is to add preload, but how much to start with 25mm (1 inch)? and place it at the bottom of the spring (it doesn't seem to have any pre-load spacer) ?
Also, the fork seems sluggish (rebounds too slow) I'll try 10wt oil.
Finally, If I could get cheap springs I would like to try several options.
I got a quote from Sonic Springs for 150 US dollars... not that bad if I was sure on the rate needed... too expensive to try... any other recommendations?
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