- Joined
- Jan 1, 2009
- Messages
- 443
This topic has been discussed ad nausium in the forum, but as I am assembling my Mk3, and have just mounted the engine, I can't resist adding to the verbage.
The steady comprises two springs in parallel, each formed of 0.125" diameter music wire wound as a coil that has an 0.875" OD and a free length of 1". The manual calls for an initial set-up with two parameters, namely, an extended length of 1.5" and a clearance of 0.2"-0.5" between the bottom of the trunion and the bracket. Each spring has a spring constant in excess of 100 lb/inch, say 120 lb/inch. The 50% spring extension called out in the manual is consistent with the maximum extension listed in spring catalogues, and thus makes sense. With this extension, both springs exert a total force of about 120 lbs upward, which is approximately the weight of the engine, gearbox, and rear mounting, which are all rigidly connected. Many forum contributors have stated that the intent of the head steady is to statically unload the isolastic units; for this to happen, an extension of 0.5" is required, just as the manual states. This extension produces 0.080" of space between each coil winding, so you see a lot of air when looking at the springs.
When I set up the steady, I could not meet both parameters when using the first detent on the retainer (not enough clearance), and had to use the second detent. This is not how the bike was set up when I bought it, and is at odds with many readers who report using the first detent. Road testing is still a few months off.
The steady comprises two springs in parallel, each formed of 0.125" diameter music wire wound as a coil that has an 0.875" OD and a free length of 1". The manual calls for an initial set-up with two parameters, namely, an extended length of 1.5" and a clearance of 0.2"-0.5" between the bottom of the trunion and the bracket. Each spring has a spring constant in excess of 100 lb/inch, say 120 lb/inch. The 50% spring extension called out in the manual is consistent with the maximum extension listed in spring catalogues, and thus makes sense. With this extension, both springs exert a total force of about 120 lbs upward, which is approximately the weight of the engine, gearbox, and rear mounting, which are all rigidly connected. Many forum contributors have stated that the intent of the head steady is to statically unload the isolastic units; for this to happen, an extension of 0.5" is required, just as the manual states. This extension produces 0.080" of space between each coil winding, so you see a lot of air when looking at the springs.
When I set up the steady, I could not meet both parameters when using the first detent on the retainer (not enough clearance), and had to use the second detent. This is not how the bike was set up when I bought it, and is at odds with many readers who report using the first detent. Road testing is still a few months off.
