10-30-2013, 12:07 AM
If you align the rear wheel with the front then the bike will track properly. That is the rear wheel will follow the front and the bike won't crab down the road like it has a bent frame. Worst case it will handle wonky and go through tires faster.
If you align with the front wheel then the sprockets (drive and driven) should also align and you won't have excessive chain wear (a "fix" that some XR650L owners do is replace the drive sprocket with one from an R model which has more surface area for the splines to register on to reduce the wear on the splines caused by a lack of a cush drive in the rear rim; this causes about a 3mm offset between the sprockets can causes excessive chair wear because the chain goes at an angle between the two sprocket - just like on a ten speed bicycle). Sprockets and chains for our bike are not cheap.
Now I also strongly suspect that most bikes are assembled properly with good parts so that aligning with the swing arm is good enough.
But to align the wheel with the swing arm is false confidence since the swing arm really does not care how it aligns with your drive sprocket or the front wheel and the wheel can be quite cocked in the swing arm and still function properly. Naturally things will only be pretty wonky if the swing arm was defective or your bike suffered a crash and it was bent (or the frame or both).
Now if you did align with the front tire and kept your chain aligned properly with the sprockets you can note where the adjusts end up on the swing arm which can tell you if the swing arm has issues. If things are really off then you should look to see where the problem is. Could be bent forks, frame, swing arm or messed up swing arm markings.
Kinda a twist of the "trust but verify" theme here.
If you align with the front wheel then the sprockets (drive and driven) should also align and you won't have excessive chain wear (a "fix" that some XR650L owners do is replace the drive sprocket with one from an R model which has more surface area for the splines to register on to reduce the wear on the splines caused by a lack of a cush drive in the rear rim; this causes about a 3mm offset between the sprockets can causes excessive chair wear because the chain goes at an angle between the two sprocket - just like on a ten speed bicycle). Sprockets and chains for our bike are not cheap.
Now I also strongly suspect that most bikes are assembled properly with good parts so that aligning with the swing arm is good enough.
But to align the wheel with the swing arm is false confidence since the swing arm really does not care how it aligns with your drive sprocket or the front wheel and the wheel can be quite cocked in the swing arm and still function properly. Naturally things will only be pretty wonky if the swing arm was defective or your bike suffered a crash and it was bent (or the frame or both).
Now if you did align with the front tire and kept your chain aligned properly with the sprockets you can note where the adjusts end up on the swing arm which can tell you if the swing arm has issues. If things are really off then you should look to see where the problem is. Could be bent forks, frame, swing arm or messed up swing arm markings.
Kinda a twist of the "trust but verify" theme here.