Rear hub

[a10rgs]

Hi,

can anyone tell me to which bike this hub will belong?

Many thanks
Uwe

[trevinoz]

Are the crinkle ends the same size or different?
Could be 1954/5 A7, A10, B31/33

[a10rgs]

Hi,

no the crinkles are of different size! That makes me wonder because
my other hubs have the same size crinkles!

Uwe

[MikPowl]

It looks like there's a locking ring on only one side?  If so, looking at the D/Fly drawings it would seem to be an early hub off and A/B series. Also, there don't appear to be any rivets holding the two sections to a central internal spacer. My own 1954 plunger hub has lock rings at both ends and is rivetted with large head rivets. There's an ad online from MikesClassics in Oz that shows an apparently identical new hub part 67-6021 which is sold as a splined hub for a 47/48 A7.  Hope this helps?

[a10rgs]

Hi,

yes thread only on one side and no rivets! Looks the same as the one from MikesClassics (67-6021)!

Many thanks
Uwe

[Rex]

When I was after a new rear hub for my '51 I was told to be wary of ending up buying a later 1960s hub for a Starfire or whatever.
Similar but not interchangeable. I know the later bikes had speedo drives on the rear wheel rather than from the gearbox.

[Swarfcut]

  If it is a very early A7 it is a rare part, from a time when front and rear wheels were interchangeable.

  My guess is that with only one locking ring it was originally off a Swing Arm A or B Series bike. This type can be adapted to fit a Plunger model, the bearing OD is the same for both, but the bearings are different as the Plunger spindle is greater diameter than the S/A Spindle. Rear Speedo drive wheels with crinkle hubs  from later Unit ranges can also be coaxed to fit Plunger bikes....the crinkle hub and splines are basically one thing that stayed the same.

 Swarfy.

[a10rgs]

Hi Swarfy,

for me it looks unmodified and as I understand A and B model crinkle hubs have
the same size  crinkle on both sides! This one not!

Uwe

[limeyrob]

I just did a google images search out of interest and there seem to be several quite different looking crinkle hubs being claimed to be the same part number.  It could be a trick of the camera but it looks to me that there is some confusion and mis-identified hubs about.

[JulianS]

You can see some of the differences (but no dimensions) between the rigid, plunger and swinging arm crinkle hubs on BSA service sheet 212.

You can see it on,

https://bsa-info.nz/service-sheets/

It is 19 pages.

The later hubs have an external thread where the speedo drive flange screws on, often the flange still in place. The pre units have no external thread here, just a push on cover which may or may not come off easily.

[Swarfcut]

 Correct Rob. There are minor variations, the spline size and internal bore being about the only constant.

 Had a look at the parts book 49/53 which lists spoke part nos and lengths. Rear wheel up to 1950 has identical spokes each side, part 67 6008. Spokes  change for '51/52, and again for 53.  These spokes then continue into the first of the S/A bikes with crinkle hub/drum sprocket.

  Spokes.. Part Nos. and Lengths.

   Model Year     Rear Rim        Left Spoke    Right Spoke

    1949              WM2-19         67 6008        67 6008

    1950              WM2-19         67 6008        67 6008

    1951              WM2-19         67 6017        67 6016

    1953              WM2-19         65 6303        65 6302

   All other things being equal, by which I mean the wheel offset stays the same, the differing spokes would make me think the crinkles were the same both sides pre'51, and different crinkles meant different spoke lengths each side later on. But we're talking gnat's Knackers.  Anyone know if the crinkles are the same both sides or differ on other model ranges?

   67 6008                     10 Gauge, length 7 29/32"

   67 6017 & 65 6303...  10 Gauge  length 7 27/32"      Left side

   67 6016 & 65 6302...  10 gauge  length 7 29/32"       Right side

  The internal centre tube is shorter on S/A wheel type (One locking ring, left side.  No internal or external thread on right side). Adapting this wheel to fit a plunger bike requires the  correct bearings and centre spacer. The bearing cover and right side spacer to the frame lug will also require a bit of lateral thinking....get the right bits if you can, it's far easier. As is putting the whole issue to a professional wheel builder and substituting hassle for money.

 Swarfy.

[berger]

i have a rear crinkly hub i think it's plunger , it is threaded both ends and has the rivets , the right side of the threaded part sticks out a bit from the edge of the crinkle bit. i don't think it does on my swinging arm hub in the bike.  it has a part number and i think!! it is 67-0256 or 67-6256. the only part numbers i can find in a book are for hubs complete with bearings and they don't match this number. any ideas people?

[Rex]

Changing the subject slightly, other than replacing the teeth in the brake drum teeth, (which mitigates but not solves the problem) has anyone ever devised a work-around for backlash due to spline wear on the hub?
On Triumphs it's usually possible to try the drum in all the possible positions to find the one with least slop, but that doesn't seem to work so well with BSA's.

[trevinoz]

Crinkles of same size are early.
Different sizes would seem to be a 1954/5 hub, swinging arm.
Late versions of this hub, RGS & Gold Star for example, have the domed rivets.

[Tomcat]

This hub is the same as the hubs on my 1948 A7 and I believe them to be correct for '48 and '47, also they are interchangeable front to rear.