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swing arm pivot location
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Posted by: semi old guy---------------------
what roll does the swing arm pivot location (or the swing arm angle with the ground) play in the rear suspension action?
Posted by: svi---------------------
The angle of the swing arm affects suspension travel under power. When the arm is angled down from the pivot to the wheel spindle thrust from the wheel works to extend the suspension (anti squat). Depending upon suspension softness, the amount of power and acceleration, and the sprocket sizes an optimum amount of anti-squat will give the best traction and feedback to the rider.
Posted by: semi old guy---------------------
notice the ktm 4 strokes (maybe all ktms) have a steeper than normal angle...like the old ATKs.
Posted by: KTM-Lew---------------------
Semi old guy....thats why they have to run the chain so it looks loose. It isn't actually looser than on a Jap bike. If you could set the angle of the swingarm on a jap bike to the same reading he chain would be as loose.
Did that make sense? 
Posted by: Jeremy Wilkey---------------------
Which is all the reason why free sag is such a big issue on the KTM, The geometry of the swingarm also impacts the acerlation of the shock as a function of the interaction to the bump.
BR,
Jer
Posted by: semi old guy---------------------
the weird thing is why did KTM choose to run such an angle. I'm sure it came from ATK because I recall some time back KTMs development of a linkless 125. I think Horst L was involved. It's a radical departure from the normal rear end although it may not necessaraly look like it. the fact that it's linkless is nothing compared to the swing arm angle IMO.
Posted by: semi old guy---------------------
I would guess that the big KTM 4 strokes don't break up under power through acceleration bumps?
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