H: Hubs, Wheels and Tyres Rear Drum Runout - what is an acceptable figure?

[vibrac]

When I bought my basket case D the rear drum moved along the axis of rotation! On examination the drum bolt holes had elongated into slots at least 3/8" long. This had obviously been going on for ages as rear tire was completly bald. It is amazing what abuse these bikes could take when they were worth pennies and now we (a collective we) worry about 5 thou...

 

[Bill Thomas]

Maybe because it's not easy to get a spanner on the nuts,
So not getting tight enough to start with ?.

 

[Old Bill]

Bill, perhaps when we were young we didn't bother to check for tightness, now we are older artritis prevents us, personally l get my young son to check them because if he doesn't he knows i will moan at him, yours, grumpy old git of west wales............

 

[Bill Thomas]

Yes , Let your Son scrape His knuckles, We don't heal as quick !.
I think it's another thing on Vincents , That is not the best,
I think Marcus threads the alloy Hub holes ?,
So just bolts from inside the drum,
Maybe if they were steel Hubs ?, Might be a better idea.
For many years now, Even when I was a mechanic, I try and wear cotton gloves,
Or I burst tiny blood vessels in my fingers on narrow sides of spanners, When doing up,
Or undoing tight nuts, Very painful.

 

[Old Bill]

Tight nuts can indeed be very painful !!!

 

[Peter Holmes]

I am sure this has been discussed on the forum previously, but I think we all agree the standard method of attaching the brake drums to the hubs is a bit of a pain, especially if you have the 10 hole variety, so Marcus taps and helicoils the hub (I believe) but with that method you cannot avoid not having the standard non turning bolt heads, whether that be eccentric bolt heads or filed down hexagons, I have seen both, are they both standard factory fitments?

But if you are prepared to lose the non turning bolt head, I think Marcus uses socket cap heads, why not simply use a socket cap head long enough to put a nylock nut in the normal position, you would only have to engage and hold a stationary spanner whilst tightening the bolt with an allen key, I think the last time this was discussed two concerns were raised, 1, was the weight gain of 5-10 nuts, I discount that on a road bike, 2, was whether the socket head cap bolts were of sufficient strength to be used for this application, I don't know enough (or anything for that matter) about metallurgy to offer an opinion, but presumedly Marcus does know enough, and has done some pretty high mileages, but I don't know how many of those mileages have been done with his modified hubs.

 

[vibrac]

With deference to Marcus and to the most important goal of saving weight ( I place that above looks most days) I cannot think that the Phils in the original design would not have gone to all the trouble of custom plain (No drive!) eccentric headed bolts and locking nuts (both expensive items ) if they did not feel the hassle of nut securing in confined space was necessary. Having said that I conceed they did not have the luxury of modern threaded inserts

 

[b'knighted]

My belt & braces system with helicoiled hubs is to put a shake proof washer under a plain nut to lock the Allen screws. I believe that Marcus wires the heads of his Allen screws.

 

[Old Bill]

l think Vibrac is bang on the money; as PEI stated in his book motorcycle engineering; we only had thirty years of design experience to work with so it follows that after all these years many design and engineering solutions have evolved and make yesteryears construction seem questionable. ln my opinion back in the day the Vincent was the very best motorcycle available both in construction and aesthetic appeal but like all things times change and new solutions come along. Personally l think if you want incredible performance, fantastic braking and amazing handling etc just go buy a new modern bike, if you want a slice of motorcycle history then a Vincent is simply the best, but there's nowt wrong with enhancing the basic machine. Must close now, the grandkids say its dinner time so l am going to get in my high chair ready to be fed, happy days!!

 

[Peter Holmes]

Ian, what is the benefit of shake proof washers over nylock nuts?