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

Spqreddie

Well Known and Active Website User
VOC Member
Hello!
I am finishing rebuilding my rear wheel.
Unfortunately I didn't check the individual components before to start.... (Hub faces and drum faces and holes), but mounted all the parts as they were.

I have the following reading now. Are these acceptable?

Side 1:
  • Side movement ( measured on the external diameter - Drum flange) = 18 cent of a mm (7 Thou if I got the conversion right!)
  • Vertical (measured in the internal diameter of the drum) = 7 cent of a mm (2,7 thou)

Side 2:
  • Side movement ( measured on the external diameter - Drum flange) =12 cent of mm (4,7 thou)
  • Vertical (measured in the internal diameter of the drum) = 13 cent of mm (5,1 thou)
  • Chain Sprocket mounded on drum on side 2= 38 cent of a mm (15 thou)

Rear Hub Allignment.jpeg
 

vibrac

Well Known and Active Website User
VOC Member
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...
 

Old Bill

Well Known and Active Website User
VOC Member
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

Well Known and Active Website User
VOC Member
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.
 

Peter Holmes

Well Known and Active Website User
VOC Member
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

Well Known and Active Website User
VOC Member
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

Well Known and Active Website User
VOC Member
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

Well Known and Active Website User
VOC Member
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!!
 

Black Flash

Well Known and Active Website User
VOC Member
To cut a long story short, I can only quote Frank Griffin:

When it comes to Vincents, never assume anything, control everything!

There have been so many parts reproduced over decades and there have surely been not so good parts that left the factory.

Never just fit or use a part without carefully checking it. Believe me, I have learnt my lessons over the years. Swarf in new big end quills, anti sumping valves that stick, hubs that were so tight, they cracked when cooling down after fitting outer bearings, eccentric pdc on spoke flanges, I could carry on a long time and these were all new parts.
 

b'knighted

Well Known and Active Website User
VOC Member
Ian, what is the benefit of shake proof washers over nylock nuts?
As the Allen screws are already tightened into the Helicoils, Nylocks may tend to loosen them. The plain nuts, acting as locknuts, spin on easily and are held, just nipped by the shakeproof washers. I would not replace the Simmonds nuts this way without the use of the Helicoil..
 

Spqreddie

Well Known and Active Website User
VOC Member
I have found that radial play can be up to 0,1mm without so much intermittent brakeing, that is with a 2x2 LS set up. axial wobble is to no problems at all. execpt for the sight of it....
i guess for standard set up even 0,2mm radial is OK, as the unstiff set up forgives a lote here...

note hovever that the MOSTimportant is the flat surface of the HUB, The SPOKE flange DRUM. mostly i had to re-machine, also with NEW parts, i alwas say I buy 90% and the other 10% in quality i do myself. it works V.v. timewise though. if not flat, one gets cracks in the drum, same with the spokes, just grind a bit away on the spot, when interferring.

if bolts dont fit, i have a hand reamer 8 mm (oh sorry Mr Bananaman 5/16") this has a conical part. (use it in a drill press for perpendiculair reasons) But first try and find the position of parts, so most bolts fit.
Und der Berndie hat recht, but if a bit of radial play is there no problem, it cant go far, and braking force in Nm is not that much, it will hold on friction even mountain down.
All in all its just comon engineering.
Thank you Vincent,
Getting a figure at last. I have less than the mentioned 0,20. So I will use the whell as is and remeasure after some running in.

Thanks!
 

Bill Thomas

Well Known and Active Website User
VOC Member
I am a bit weak, But I like to get them a bit more tight, Than I could with that idea,
As had been said , If they are not tight enough, Could have trouble,
Even with Sprinting and Road Racing, Never had one come loose.

Another thing I have found, Doing up a nut and bolt, Via the bolt, Always found I could get it tighter,
at the Nut end ?.
 

Bill Thomas

Well Known and Active Website User
VOC Member
Don't worry it takes a while, Welcome,
Bill.

You know this is just the Forum, Have you joined the Vincent HRD owners club ?.
If so when ?, Can't see you on the newest members.
Cheers Bill.
 

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