Quote:
Originally Posted by Michael Moore
....You are thinking of Horst Leitner's ATK sprockets, and that does actually reduce the variance in squat geometry a significant amount on a long travel dirt bike. There's less variance to cause problems on short travel so the net change there from the ATK is not as great
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Michael,
Thanks for the detailed response.
As you referenced that the ATAC was used on dirt bikes, I do recall seeing them on road bikes and reading about the merits of such an install. But as mentioned previously, as good as they may have worked, they did not last long in the market, and thus my comment that they may have fixed a problem that did not exist from a practical standpoint, still stands.
Quote:
Originally Posted by Michael Moore
....A commuter bike with 8 BHP that never exceeds 45mph can probably work adequately with an amazingly wide range of settings. You could even go with a hard tail, eliminating chain geometry concerns, and use a cushy seat instead. My concern is for people who start hacking away when they have little to no idea that what they are proposing to do has any effect at all. A crash at 45mph can still put you in the hospital or morgue..... |
Well said.
From a practical standpoint, even a speed of 65 mph does not cause much squat in the rear because it typically takes about 8 hp to run at this steady state speed on a typical motorcycle. This also means that there is not much "load" on the rear swing, and thus the largest forces on the swing-arm arm from road imperfections, and/or cornering forces, as cornering would put more load on the suspension compared to 8 hp steady load (and resultant compression).
This still means at the acceleration I will be taking off at, the rear end squat is simply not much of a factor. In fact since one on a FF would be sitting lower in the frame, the overall CG is lower than a stock bike, and thus cause even less squat at the same acceleration.
I think if a person had no idea what they are doing in this regard, the project probably would not come to fruition in the end. At least I hope so.
Let's say a person botches the swing arm geometry, and it has a terrible amount of squat. The only time the motorcycle will be able to accelerate at full throttle, is with the bike upright. In other words, accelerating in a straight line.
Now let's say the squat allows the suspension to reach full compression. What will happen? Right, the under carriage will scrap hard enough to counter act the acceleration, and will quickly inform the rider that he/she has an issue to contend with. LOL!
Now if the same rider was foolish enough to try the same trick in a corner while being bent over at 45°, well then the rider would get a nice view of the road from the side of their helmet, as the under carriage would drag hard enough to make itself known very quickly.
I think this is what you are alluding to above.
Jim.