1956 99 rear wheel offset

Yes John, how all mine are. Built to the centreline of the hub as you describe above.

The offset is on the front wheel.

The wheels need to be in line and theoretically centered in the front forks. This may not necessarily provide perfect handling if the center of gravity is not in the same plane. The Lawton/Wilson 650ss Race winner was not a good handler untill the wheels were offset to counter an imbalance.

Hi John. There might be an official figure but the only real way to know is to measure what it SHOULD be for your frame. The wheel needs to be central to the centre line of the frame. The front wheel if accurately built should be dead central to the forks centre line and as you would appreciate, this will be dead centre to the frame too.

You might think this is a lot of bother but you need to remove the rear mudguard. Then with a straight edge across the rear frame tubes directly above the wheel's centre, mark the centre of the bar anddrop a plumb line down to just above the tyre....The plumb-line should be dead centre with the tyre...you could also use a carpenters square to drop down squarely from the centre mark to find the centre position on the tyre top... Any difference is measured and noted. Then remove the wheel and measure the ACTUAL offset of the RIM to the face of either side of the hub and note this. With the two measurements you can correct any discrepancy by subtracting the difference and resetting the offset. A wheel builder will be able to adjust the rim if you supply this calculated figure.

Note...this method will ensure better accuracy than just rebuilding the wheel to an officialfigure....Les

Hi John. Yes finding the centre line is quite easy on a single top tube type frame but the Duplex Featherbed is more difficult. As far as I know each side of the rear frame is symmetrical , but as a check with the wheel out the plumb line should steady between the centre of the swinging arm. You can check the swing arm too by doing diagonal measurement from the pivot to the axle cut out's they should be equal and if not there is a chance that the swing arm is bent which can cause the mis-aligned wheel but a second check is to see if the chain run is dead in line from the gear box to the rear sprocket....Les

In the olden days, when we had MoT's, the front and rear wheels have to both be in line - rim to rim - or it failed, regardless of what 'offset' each needed. I'm not helping am I?

Hi Lionel. It is possible to line up the front and rear wheels with quite a bigrim offset error/s. *The giveaway is the rear chain adjusterswill beset with a big difference with the amount they are screwed in or out between the two. The limiting factor being that if the angle of the wheel is too far askew to attempt the alignment then the main spindle bolts always attempts to pull the wheel back to a more straighter angle in the swinging arm. If the rear wheel is too far over to one side between the mudguard , it is either that the swinging arm isbent or the wheel has been built incorrectly or the wrong spacers have been used.....Les

*NB: This misalignment can cause poor handlingdue to the fact that the slight turn of the front wheel that is required to allow the straightline alignment is in opposition to the straight ahead force that the forks castor angle is applying to the front wheel when the bike is in the upright position. The effect is noticeable when the hands are removed from the bars when travelling along as the bike will want to wander over to one particular side... quite common on Commandos

I built my slimline wheels in the forks front and rear . I centralised the front between the legs and did the same to the rear between the shocks. Kept it really simple. Seems to handle fine. If I found a tendancy to wander one way I would offset the front wheel to that side a few mm and line the back up to the front. Lining up the sprockets needs to be done first . In an ideal world the frame should be checked by an expert but as long as the wheels are both plumb and the forks look parallel its likely to be ok. I'm sure my head angle is reduced as its had a few bangs but it handles fine.