will a QD hub go on any swing arm?

[snowbeard]

I'm considering getting a QD hub to put on my 1960 super rocket basketcase.  it came with a full width drum brake wheel, but since I've got a QD on my spitfire, I'd like to keep thing similar (read interchangeable when something goes wrong!)

thanks!
 

[RichardL]

Snowbeard,

I think the biggest problem will be the side on which brake pull occurs. Half-width rear drums pull from the left with a solid rod. Full- width pull from the right with a cable attached to a lever arm that runs through the hollow swingarm spindle. OK, so say you abandon the hollow spindle. The brake pedals are different and, unless you have one of the bikes that BSA made in the transition, you probably do not have the boss through the frame where the brake pedal mounts for use with the left-side rod pull. As far as I can tell, they did build some early full-width types in frames they had left over from half-width days. Don't be confused by the sidecar attachment point, if you have one (point, not sidecar). The brake pedal boss goes straight through the frame tube. Not that such a boss could not be added, I did it on mine (a whole other long story I could share in photos if you or others need).

Please let us know where you go with this.

Richard L.


 

[snowbeard]

ah, interesting.  this just get more and more fun 

so I looked at my super rocket swing arm compared to the spitfire,  it has two, almost boxes, welded on the left, probably related to the chain guard? one about three to four inches top to bottom, the other maybe two. 

the right side has a lug around the swingarm about midway back, with a bolt hole thru that.  I couldn't imagine the sidecars mounted to the swingarm tho, so I doubt that's what it is for.

if I remember correctly, the rear wheel I was looking at had a lever assembly that was cable operated, but I looked at so many parts yesterday my head is spinning.  more on that later.

thanks!  I'll see what was true and check back, but I did see that the holes are nearly exact, so at least the axles will fit the swingarm at least!!

thanks!!

[RichardL]

Snowbeard,

Here is a photo. You don't have pillion loops on the red frame, so, no chance of similar sidecar mounting point, shown braced in the corner. The point where the left-side brake pedal boss goes through the frame is right where the pillion loop would meet the frame. If you decide to go this way, I would dimension mine for you so you can get the position without the loop.

Richard L.

[tombeau]

Gosh.
My pedal is attached through that sidecar boss.  I assumed it was correct. In those pre internet (for me) days. It was almost impossible to find pictures of A10s showing the primary side. Photographers always being seduced by the timing side chest.

Years ago a mate fitted a Starfire back wheel to his A10 framed Tribsa using the original cable operated brake swinging arm  . He said it fitted fine, but he was not the... umm..."fussiest" of people  when it came to working on his bike.

Cheers,
Iain

[RichardL]

Iain,

Maybe I'm missing something here. Looking at really old photos of your bike (with the cafe tank), it appears you have a full-width rear hub, in which case the brake pedal would be on the shaft passing through the hollow swing-arm spindle. Perhaps you've done a half-width conversion, for which I see no photo, and you then proceeded to mount the brake pedal at the sidecar attachment point (as I did as an interim measure until I got around to providing the correct boss). I suppose that you, or whomever, fashioned a bushing so that the brake pivot could use the oversize hole. Again, this is speaking from experience, as I fashioned such a bushing from scraps of thin-wall steel tubing wrapped around the pivot mounting bolt. Assuming such a half-width conversion, an original brake rod would have been too long. Also, the pedal is too close to the foot peg and ergonomically difficult, causing you to bend your ankle too far when braking.

Does any of this sound familiar?

Richard L.

[tombeau]

Ha!
Well done Richard.

I did convert the bike to half width hub, using a B31 swing arm and pedal and a hub that turned out to be plunger or rigid A7.
The brake rod is plunger A10, it was bought in a hurry to get the bike on the road. "I'm out of swinging arm ones, I can sell you a plunger one but you'll need to shorten it" said Ian from Lightning Spares a the time. A friend did make me up a bush, something else I had completely forgotten about. As for the ergonomics, never noticed, but it's now probably going to bug me every time I brake. Thanks

I also found going through my photos that I rarely take a picture of the primary side either.

Cheers,
Iain

[scotty]

Snowbeard,

I don't have a definitive answer to your question but here's a couple of photos that I took last year when I started to tear down my A10 rolling basket case bitsa.

You'll see what I think is the brake pedal boss hole thru the frame tube ,that richard described,  where the pillion loop meets the frame.

Although my bike has half width brakes front and rear, it looks like my frame has a carrier on the timing side pillion loop that would be for the rear brake cable as used by the full width style brake  ????

Cheers

Scotty

[RichardL]

Scotty,

I think your swingarm is just in place for a simulation of assembled appearance. By the looks of the hole exposed behind the incorrect bolt posing as a spindle, that hole might well accept the hollow spindle for full-width brakes. The hole at the juncture of the pillion loop and frame tube was certainly put there for a brake pedal but lacks the through-frame tubing that forms a stable boss for landing the brake pedal pivot. I think this would explain why there is a cable carrier on the right side.

Richard L.

[scotty]

Richard,

Well spotted on the S/A pivot pin !  The bike was loosely assembled by previous owner to enable a bit of "rolling".

Is it possible that at some point in this bikes life it underwent a rear brake conversion from full width rear brake to half width rear brake?.
If so, based on your comments, it would appear that they missed the mark with the pedal installation.


Attached is a pic of the frame as she is now (with a solid S/A pin, new silent blocs, new rear shocks )

Funny thing is, since snowbeard started this thread, I went to check the frame thats been in my shop for a while and ...errr... ahem.. the hole for the rear brake pedal has gone  .  I can only think that the shop that straightened/powdercoated the frame filled it in by mistake and I've only noticed it 6 months later 

So like snowbeard, I am possibly looking at some sort of rear brake mods and I like the idea of continuing with the side brake rather than having to get a full width hub, new hollow s/a pin, crossover shaft etc.


Your pics/info on your boss installation would be great to see.

Cheers

Scotty

 

[RichardL]

Scotty,

From this picture, it is clear that you have a solid swing-arm spindle, as used for half-width rear brake. Wiggle that swing-arm to be sure it is a snug fit on the spindle and not one with the oversized bushes required for the hollow spindle Also, verify that the hole through the spindle flanges (word?) are the correct siize for the spindle and not oversized. (Apologies if these are obvious points.)
 
I will try to dig up the photos tonight. They got archived when I changed computers. I have a feeling I am going to wish I took more thorough photos. Who knew that two members would be simultaneously interested in this?

Richard L.

[snowbeard]

ok, so the swing arm should be fine but it's the brake boss that will screw me. I think I can live with that, as Tombeau  says, some of us are less picky than others.

here's a pic of my boss on the spitfire, just for reference in the thread.

it'll be awhile till I get to the build, so I'll just have to see what I end up with I guess.