Front Wheel

mdt-son said:

OK. I have never seen a 2x2 dimple pattern, but the Commando Mk3 rear rim actually has a 3x1 dimple pattern (I had not realized this). The design is peculiar and I am curious why NV devised this pattern, since the similar conical hub from Triumph/BSA featured a traditional 1x1 dimple pattern. This is the ideal arrangement.

Quote: Every wheel has a set of spokes which is actually a group of four sets. All wheels contain four sets of spokes, two for each hub side, or flange. One set that pulls and one that pushes. This is what creates the cross pattern and gives the wheel its strength. End of quote.

By all landmarks, the equal number of push/pull spokes from each flange results in an alternating dimple pattern, left-right to the rim bead (1:1). Even the heavier and more powerful T160 used a 1:1 dimple pattern, albeit with a cotton reel type hub. NV cocked it up, because on the Mk3 one set of spokes regularly looses tension. Maybe this is why Bill Becker laced his rear wheel using a normal 1x1 dimple pattern, which shows it IS possible even when using the stock Mk3 rear hub.

Bill Becker's pristine Norton Commando Mk III

It’s hard to improve on the Norton Commando. But Bill Becker, creator of the lovely Aermacchi Sprint we featured a little while ago, has taken the iconic British motorcycle to a new level. Bill bought the Commando on eBay as a project bike with a rebuilt motor and powder coated frame. Everything...

www.bikeexif.com

If I ever need to rebuild my rear wheel, I will do it this way.

Sorry for stealing this thread which was about the front wheel.

-Knut

Click to expand...

Knut,
Thsee are pictures of my Buchanan rims and SS spokes. Laced them myself and copied the pattern from the existing rims. They were within .002” axially and radially. Tightened spokes by feel/sound. Probably close to 20,000 miles on them now. Never had a loose spoke and appear to be as true as when I laced them. Rear pattern seems to be the same or similar to Bill’s. These are the first and only rims I ever laced up. Also the Buchanan weld joint is minimal.
Pete

L.A.B. said:

Not that peculiar as the T140 disc rear rim was also 3x1 dimple pattern.

Mystery Wheel

I thought this might be a MkIII rear wheel but someone pointed out it’s not. Now I don’t know what it could be. Four bolts on each side but it’s defin not symmetrical. Thought?

www.accessnorton.com

Click to expand...

Thank you Les, I stand corrected.
The dimple in the middle of the three positioned on the drive side would have been on the disc side normally. The design intent may have been to provide a more direct load redistribution in the event of braking (the spokes in the middle of the group of 3 dimples would have been under tension. ) To me it seems they sacrificed lateral wheel stiffness by doing so. Modern retro bike rear wheels with a disc brake are designed with 1:1 dimples, but the two planes of dimples and spokes are pulled further apart using the MT type of rim.

- Knut

Deets55 said:

These are pictures of my Buchanan rims and SS spokes. Laced them myself and copied the pattern from the existing rims. Probably close to 20,000 miles on them now. Never had a loose spoke and appear to be as true as when I laced them. Rear pattern seems to be the same or similar to Bill’s.

Click to expand...

Thanks for sharing. Good to hear the rear wheel holds up.

By copying the existing pattern you may have positioned the dimples a little unfavourably. It looks that way at the rear wheel at least. I think a revised lacing pattern requires a different dimple/hole design. Granted, those shouldered alloy rims don't provide much space for oriented dimples. It looks like Bill used a rim with a wider bead.

- Knut

Front wheel back on. Managed to scratch the new rim in a couple of places, putting the tyre on. Need better irons. Not deep though. I managed to get the offset inside 1/16" off 0.5 inches. Other than the Weld joint, no wobbles, less than a mm out of true. Couldn't get it any closer, as some of the spokes were getting a bit too close to tight. The tyre looks to be holding pressure after a couple of hours. Will check it again before I ride. So, I think I'm there. Another first!

Thanks for all the advice and info.

mdt-son said:

Thanks for sharing. Good to hear the rear wheel holds up.

By copying the existing pattern you may have positioned the dimples a little unfavourably. It looks that way at the rear wheel at least. I think a revised lacing pattern requires a different dimple/hole design. Granted, those shouldered alloy rims don't provide much space for oriented dimples. It looks like Bill used a rim with a wider bead.

- Knut

Click to expand...

Might be the picture.
Nipples are straight and no bending of the spokes where they exit the nipple. Pretty confident they are correct.
I have seen incorrectly laced wheels. They are pretty obvious
Pete

mdt-son said:

By copying the existing pattern you may have positioned the dimples a little unfavourably. It looks that way at the rear wheel at least. I think a revised lacing pattern requires a different dimple/hole design.

Click to expand...

The Mk3 disc rear wheel can only be laced one way as far as I can tell because the disc-side inners locate in grooves in the hub.

Mart UK said:

Need better irons.

Click to expand...

Or rim protectors (I always use them).

I seem to be having a bit of a run of the wrong sort of luck!

I went to put my new speedo cable on. It looks like my speedo drive on the rear hub, has failed. The nut holding the cable goes round with a ring of alloy, that looks to have broken off the body of the drive. So it's not undoing.

Do I need to remove both sides of the axle to remove the speedo drive, or can I remove the drive from the left hand dummy axle, whilst holding the wheel, rear sprocket and chain in place?

Mart UK said:

Do I need to remove both sides of the axle to remove the speedo drive,

Click to expand...

Yes.
The (brass?) sleeve that is rotating with the nut can be fixed in position.

L.A.B. said:

Yes.
The (brass?) sleeve that is rotating with the nut can be fixed in position.

Click to expand...

I can't see how I'd do that? If I've understood how it fixes, It looks like it once had a 'node' that fits into a 'notch' in the drive body (appols for my lack of tech vocabulary). I think it has been damaged, when my cable broke, or maybe caused the cable to break. The notch has a rough face, it looks like it has sheared and the node is missing, so it's just a ring. I tried to grip the ring, to undo the cable, but it's too narrow.

Mart UK said:

can't see how I'd do that? If I've understood how it fixes, It looks like it once had a 'node' that fits into a 'notch' in the drive body (appols for my lack of tech vocabulary).

Click to expand...

The housing is crimped into a groove in the sleeve (the vertical indentation) and can often be re-crimped (but care is needed or the housing may crack) or can be drilled and locked with a self-tapping screw or the sleeve removed then fixed with epoxy, JB weld etc.

Thanks @LAB. I think it is beyond that. It has perished (tempted to quote a Monty Python parrot sketch), it has ceased to be and I will have to get a replacement. Probably after pay day.

Mart UK said:

I think it is beyond that.

Click to expand...

What makes you think so (I'm not arguing, only trying to establish what has led you to that conclusion)?

What do the gears look like as it seemed to have been working until the cable broke (wasn't it?) so a clean, re-lubricate and fixing the sleeve could perhaps bring this particular dead parrot back to life at least for a while longer.

Yes it was working fine, until it broke. The case of the drive has cracked and sheared, about 1/4 of the circumference. I can't get the old cable out. I've got the rear wheel off now and undone the speedo cable from the speedometer. I'll have a closer look on the bench, but I don't fancy it failing on a run and wrapping round the axle.

L.A.B. said:

The Mk3 disc rear wheel can only be laced one way as far as I can tell because the disc-side inners locate in grooves in the hub.

Click to expand...

Question was about the Mk3 dimpling pattern (3x1) and the possibility of altering this pattern. N-V designed the wheel hub for a brake disc with a large offset, pushing center line of the rim about 15 mm (0.6") towards the right of the hub centerline between the two spoke "flanges". Consequently, the disc side spokes have a shallow angle towards plane of rim center, wherease on the drive side the angle is larger. This is amplified by the larger flange. Thus, the drive side spokes are linked to left side dimples while the disc side spokes are linked to one left dimple drilled at the centerline (inner spokes), and one right dimple drilled centric (outer spokes). This is a result of the shallow angle mentioned before, not the grooves in the hub. The 3x1 dimpling pattern cannot be changed. As mentioned before, lateral stiffness suffers due to the shallow angle of disc side spokes to plane of rim center.

- Knut

mdt-son said:

Question was about the Mk3 dimpling pattern (3x1) and the possibility of altering this pattern. N-V designed the wheel hub for a brake disc with a large offset, pushing center line of the rim about 15 mm (0.6") towards the right of the hub centerline between the two spoke "flanges". Consequently, the disc side spokes have a shallow angle towards plane of rim center, wherease on the drive side the angle is larger. This is amplified by the larger flange. Thus, the drive side spokes are linked to left side dimples while the disc side spokes are linked to one left dimple drilled at the centerline (inner spokes), and one right dimple drilled centric (outer spokes). This is a result of the shallow angle mentioned before, not the grooves in the hub. The 3x1 dimpling pattern cannot be changed. As mentioned before, lateral stiffness suffers due to the shallow angle of disc side spokes to plane of rim center.

- Knut

Click to expand...

Sorry Knut, not sure I've followed; are you referring to the front or rear wheel? I had thought the offset is only on the front wheel? Which on a mk3, doesn't use a 3x1 rim, as the dimples alternate either side of the centre line. So, all left side (drive side) spokes originate from dimples on the right side of the rim, slightly increasing their angle to the hub and vice versa.

The rear wheel should be the 3x1 pattern, and isn't on mine.

Mart UK said:

Sorry Knut, not sure I've followed; are you referring to the front or rear wheel? I had thought the offset is only on the front wheel?

Click to expand...

Rear wheel, as is shown in L.A.B.'s post. Oh yes, the Mk3 rear wheel has rim-to-hub offset too, though not as much as the front wheel offset. Sorry for going off-topic.

- Knut

Got it, Thanks.

mdt-son said:

Question was about the Mk3 dimpling pattern (3x1) and the possibility of altering this pattern.

Click to expand...

You did, however, say...

mdt-son said:

I think a revised lacing pattern requires a different dimple/hole design.

Click to expand...

...and which I (also Pete Deets55 judging from his reply) understood you to mean altering the Mk3 rear wheel spoke lacing pattern.

Looking at my Mk3's rear wheel, lacing the hub to a 1x1 rim would certainly be possible with little or no change to the dimple hole positions except perhaps for a minor change to the RH outer's dimple hole as the RH inner would then be angled to a RH dimple instead of LH.

L.A.B. said:

...and which I (also Pete Deets55 judging from his reply) understood you to mean altering the Mk3 rear wheel spoke lacing pattern.

Looking at my Mk3's rear wheel, lacing the hub to a 1x1 rim would certainly be possible with little or no change to the dimple hole positions except perhaps for a minor change to the RH outer's dimple hole as the RH inner would then be angled to a RH dimple instead of LH.

Click to expand...

You are correct, I used the word "lacing pattern", but actually meant bore/nipple position. Sorry about that.

As for the possibility of lacing the hub to a rim having a 1x1 dimple pattern, I think this would require a rim with a larger bead than offered by the Jones/Dunlop design. Some of the limiting factors are the punching tool size, and aiming for the nipple head to interact with the dimple contour as much as possible. Pushing the dimples far out on the circular bead you will end up with nipples having point contact only, which is a recipe for stress concentrations and subsequent cracks. Reducing the dimple (punching tool) size may yield a little more freedom.
Aluminum rims of the non-valanced design (e.g. Behr) have a flat cavity which enables more freedom in positioning dimples and bores.

The net effect of this exercise for the Mk3 rear wheel would be detrimental IMHO, as the spokes would be positioned closer to a plane coincident with the RH "flange". Maximum lateral stiffness dictates plane of nipples to be as far away as possible from plane of the corresponding flange. This is realized in adventure bikes made by BMW, Moto Guzzi and possibly others by locating nipples in the flat sections of MT rims, and for half the spokes at each flange, crossing over to the opposite rim side. Jaguar used a similar design on their spoke wheels for the E-type.

- Knut