Question about Rear Wheel Alignment

This may be a dumb question, but I'd appreciate hearing from you experts. When installing the rear wheel, what's the best technique for making sure it's properly aligned? I've tried sighting from the rear, but find it difficult to determine if it's truly aligned with the front. Is this adjustment normally done just by sight, or do you set the left side according to chain tension, measure the adjustment bolt and transfer that measurement to the right?

post36522.html?hilit=alignment%20wheel#p36522 is one topic dealing with this very subject, there are probably more

Jean

Tommy Magliozzi made me do it. I was listening to Car Talk at the time.

Bonwit said:

This may be a dumb question, but I'd appreciate hearing from you experts. When installing the rear wheel, what's the best technique for making sure it's properly aligned? I've tried sighting from the rear, but find it difficult to determine if it's truly aligned with the front. Is this adjustment normally done just by sight, or do you set the left side according to chain tension, measure the adjustment bolt and transfer that measurement to the right?

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John,
There isn't any simple way to check the wheel alignment. I think the two rail system is as good as anything that doesn't involve removing parts and making a big production out of it. One thing I've have found however, is not to try to use landmarks like the adjustment bolts on the swingarm or the postiion of the wheel in the swingarm to determine whether the wheels are lined up correctly. They can easily mislead you.
I've made a big deal of trying to get this issue nailed down. I've got Hemmings adjusters on the front and back on both sides, with linkages at the head and under the swingarm so I can move things as needed. It's been on a frametable and it should be right. I've experimented with changes and never could tell any difference. The truth is that many modern bikes come with wheels that aren't in line and it doesn't seem to matter much. This is pretty interesting.
http://www.nortonownersclub.org/support ... el-offsets
http://www.nocnsw.org.au/wheel.html

ludwig said:

Forget the swingarm . line it up with the frame backbone .

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Isn't that hard to get to with the bike assembled?

I've fooled with this on every motorcycle I've owned from 125s to 1300s over 40+ years and I have concluded that it just doesn't make any practical difference if the alignment is not perfect. I've adjusted alignment where it was clearly, though not horribly, off and then put long straight tubes on the ground to make it "correct" and I couldn't tell the slightest difference in the way the bike felt. I quit worrying about getting it "exact" (whatever that is) some years ago and just align it by eye with no other aids. Seems to work fine. I wouldn't argue that perfect alignment might produce better tire wear or that last bit of race-track handling (in Nickey Hayden's hands, not mine) but my tires have always managed to get the ballpark mileage that one expects from the specific tire/bike/application. But this is just my opinion and, as others have noted, worth every penny that's been paid for it!

The rear wheel is a design oddity. First you have to consider the brake hub chain alignment to the gearbox sprocket. The brake hub is a seperate item and if you get the chain aligned properly, you then have very little room to move the rear wheel / tyre as the wheel hub is spiked into the rubber slots in the back of the brake hub. In effect when the long axle is screwed home, it is pushing the wheel hub into the 3 slots and setting its own alignment.

I've run the bike wheels into a steel U channel laid on the floor to get a reasonable constraint on the back following the front, screwed in the back axle and left it at that.

Mick

Here's a dead simple, accurate solution... Take a 3' length of string, tie a knot in one end, hold the knot at the centre of the swingarm bolt and stretch the string taught all the way to the axle bolt. Mark the centre of the axle bolt on the other end of the string. Now use this as your reference for the other side and Bob's your uncle.....

Thanks all for your helpful replies.

I've been doing this for nearly half a century, on race bikes, motocross bikes and road bikes. If they have a chain, just eyeball the chain and make sure it's straight, you won't have any problems.

I read the included technical article supplied by bpatton, many thanks! The bottom line is that the front and rear tires, if I read correctly, should be on the same centerline when you add or subtract all the offsets. I tend to concur as this appears to be the case my Mk III. When I align my Norton I have an assistant sit on the machine and hold it up perpendicular to the ground. I use a 14 foot length of string and tape its center as high on the rear of the rear tire as I can without fouling the undercarriage. Lying down in front of the bike I put tension on the two lengths of string and move them inward until each has just touched the forward bead of the rear tire; do this a few times until you are comfortable that your lines, now running beyond the front wheel, are completely parrallel with the rear tire. If the beads of the front wheel on both sides are equidistant from the strings then you are in alignment. It's quick and simple.

RS