I adjusted the chain slack today. It had 3cm of freeplay. I thought I'd go "one notch" tighter (on the little markings on the swingarm) and see how it looked. Oops! Way too tight. It turned out that going a slight 1/2-notch tigher brought freeplay down by a half centimeter. Those notches are useless... way too inexact.
Which brings me to: it's easy to get the chain side where you want it. But how do you adjust the right side to be sure the wheel is straight. I remember from my last adjustment, that just using the little marks didn't seem quite straight. I think I ended-up measuring something to finally get the rear wheel straight, but I can't remember what I measured... only that it seemed much more accurate than squinting at the hashes on the swingarm.
http://bikepoint.ninemsn.com.au/portal/alias__bikepointau/tabID__5766/BikeArticleID__117252/BikeTipType__Setup/DesktopDefault.aspx
This a link to a site that might help.
I had various bikes over the years and never used anything more than the marks to make sure the wheel was straight.
Many people complain that the marks are not that accurate. In some cases they might not be, but in the great majority of cases they are
adequate enough.
well if the tire was straight to begin with, just tighten both bolts evenly. like 1/2 a turn each
the bolts coming straight out the back of the swing arm. loosen the bolt on the right side. then tighten the two rear bolts evenly like stated above. the notches on the side are used to aline them perfectly .
I get a general measurement by looking at tick marks. I then count the threads on the adjusting bolt. After that, I double check it with my handy ruler. Easy peasy.