featherbed type rear wheelUp to Singles
featherbed type rear wheelPosted by john_evans1 at October 02. 2016
Since I bought my 63 m50 the rear wheel has has 1/4" play at the rim.
Suspecting faulty bearings i stripped the hub to find they were fine. It appeared however that the spacer and shims were past their best.
Replacing bearings,shims and all spacers leave me with exactly the same play in the wheel.
I can now compete with race teams in respect of speed of removal,strip down and replacement but have achieved nothing!
I doubt my mot tester wouldbe impressed though!
Any idea what the problem may be would be zppreciated.
Hi John. You can see the rim move, but could it be that the rim is moving due to loose spokes, and in reality the hub is solid?...just an initial thought.
The only other things it could be is the rear wheel spindle is thinner than it should be for some reason and/or the speedo drive side spacer is too short so when you think you have the wheel done up tight there is in fact no real compression of the spacer by the swinging arm. There should also be a small spacer between the inside of the speedo and the inner of the right side bearing ....check there is one fitted too. This all gets squeezed together once the long bolt is tightened to become a rigid axle.
I am certain the movement at the periphery of the rim is originating at the hub.
I know I have spacers in the speedo drive and one on the outside. Tightening the stub axle and main axle as firmly as possible faiks to eradicate the play.
There is a limit to the number of times I can remove the bearings safely as the spacer upon which they sit is easily damaged..why do they bevel the edge?
The spindle is uniform in diameter but my micfometer is a cheap one so I will not pubkish the size. It does the job in comparing like for like so is ok for my use.
I may have to make a new spacer and bore it to give a close fit to the shaft and see if that works..unless there are any other ideas?
So if we assume is all well on the right side (speedo side) it could be loose on the left side but as long as you have the correct spacer fitted and the brake plate pulls up rigidly to the swinging arm, the hub really cannot wobble after the full compression is applied by the long spindle bolt that, as I said before, pulls the whole assembly together as one long rigid tube so to speak. Even if the spindle is slightly too thin you would have to exert quite a force on the tyres to wobble the wheel but then again, with that long leverage there is a slight possibility that it could rock the hub on an under-size spindle as the face of the bearings slide across the faces of the spacers.
BTW, the 3 x hub nuts on the studs merely lock the brake drum to it so it can be driven securely and shouldn't make any difference to wobble but see what effect, if any, occurs when these are loose and then tight.....Les
thanks again. Your description mirrors my own understanding of the assembly..It really is a silly setup but we know it works well...normally!
I will have to do another strip down to check things again but unlike a jap type wheel you really cannot see what is ok and what is not until all is bolted up squarely.
Re the hub bolts!I have checked them.I tend to suspect a bearing issue.They were from a well known supplier but there was no name on the box plus they were cheap. Constant removal etc does them no good.I wonder if the inner sleeve has developed play only evident under load?
Certainly the plastic shields are looking the worse for wear!
Re: featherbed type rear wheelPosted by john_evans1 at February 10. 2017
The saga of play in my rear wheel has nagged me. The original right hand spacer was distorted hence I made a new one 2mm longer which eradicated the play. The speedo drive then appeared rather stiff but I left well alone whilst having a rethink.
not having the dimension of the standard spacer I bit the bullet and bought a new one only to find it was not square,,.008mm out end to end. This is actually shorter than the original!!
needless to say,when installed the excessive play was again evident. More thought led to examination of the speedo drive,a smiths unit. Comparing it to a spare AJS unit I noted differences. I fitted the spare,tightened up the spindles and low and behold...no play!
all appears fine though I have to assume the ratio is still 2/1. We shall see how things progress but I am quietly confident.
Sadly there is no make stamped on the unit currently fitted.