19" wheels

I've been told running two 19" wheels (stock) can cause higher speed weaving - tank slapping. Anyone know of this?

Welcome. The weave/wobble slapper can happen, but the 19"s are not the accepted cause. Search and read...

Yes that is true but only discovered after building 50000 Commando's.

Yep, don't blame the wheels, so many other factors will cause weaving or shake.

Ashley

Checked your steering bearings lately ?

All later Commandos use those simple ball bearings, which are not really designed for hard use/side loadings.
If they wear, then the steering may not be all that flash.
1st thing to look at anyway...
And inexpensive and simple to replace.

Are you actually getting a weave, or is this just reading angst ??

Rohan said:

Are you actually getting a weave, or is this just reading angst ??

Click to expand...

Jose is back, next post will be about the worlds straightish Commando. :lol:

Rohan said:

Checked your steering bearings lately ?

All later Commandos use those simple ball bearings, which are not really designed for hard use/side loadings.
If they wear, then the steering may not be all that flash.
1st thing to look at anyway...
And inexpensive and simple to replace.

Are you actually getting a weave, or is this just reading angst ??

Click to expand...

+1

The sealed ball bearing steering neck design with no provision for preload is a horrid design, (as far as I know, the ONLY motorcycle on the planet so equipped) and will be retrofitted with tapered rollers this winter. JMWO :mrgreen:

concours said:

The sealed ball bearing steering neck design with no provision for preload is a horrid design, (as far as I know, the ONLY motorcycle on the planet so equipped)

Click to expand...

It is VERY inexpensive to replace them though.
And fairly simple to do so.

And while they are new and in good condition the steering is not affected by that 'horrid' design.

Another Norton example of where it shouldn't work, but does.
Quite well too...

rags said:

I've been told running two 19" wheels (stock) can cause higher speed weaving - tank slapping. Anyone know of this?

Click to expand...

No , thats 16 " . :lol:

Rohan said:

concours said:

The sealed ball bearing steering neck design with no provision for preload is a horrid design, (as far as I know, the ONLY motorcycle on the planet so equipped)

Click to expand...

It is VERY inexpensive to replace them though.
And fairly simple to do so.

And while they are new and in good condition the steering is not affected by that 'horrid' design.

Another Norton example of where it shouldn't work, but does.
Quite well too...

Click to expand...

Oh, yes it is. The sealed ball bearing with a spacer between the inner races gives NO preload, check for yourself by performing the industry standard steering head bearing test. Put the bike on the center stand, (front wheel off the ground) push the handlebars toward either side and let go. They should continue to the stop but gently, not flop with a bang. Report back. :mrgreen:

Thats a test for taper bearings though, not steering quality ?
Is there any suggestion Commandos with new steering bearings have a problem with them ??

I've got older bikes with steering dampers (remember those ?), with a large knob that you can tighten to firm up the steering action.
Modern tires have largely made them redundant ??

Keeping your steering bearings greased and in good condition has never gone out of fashion, however.
And BEWARE the indented steering bearings, because it will steer like a notchy so and so...

P.S. If they are so bad, why have you waited 40 years, until this thread, to be going to change them.... !

rags said:

I've been told running two 19" wheels (stock) can cause higher speed weaving - tank slapping. Anyone know of this?

Click to expand...

the-commando-weave-t13165.html

wobble-and-weave-t19025.html

126 mph on salt, you can lock it now Jerry.

fastest-production-pushrod-750-bonneville-t20840.html

rags said:

I've been told running two 19" wheels (stock) can cause higher speed weaving - tank slapping. Anyone know of this?

Click to expand...

Why, yes this is absolutely true. But then that's part of the "charm" of old British bikes.
If they didn't try to kill us with tank-slappers then they'd do it with locked-up transmissions or broken split rear axles or "widow-maker" cracked frames. If we didn't have a "death wish" we'd all ride Honda's.

(OK, most of that was a joke)

Thats a test for taper bearings though, not steering quality ? Preload is a design requirement in every other motorcycle neck. "steering quality"... not familiar with that test.
Is there any suggestion Commandos with new steering bearings have a problem with them ?? Yes, I suggest that it is A FACTOR with the weave.

I've got older bikes with steering dampers (remember those ?), Yes, I have some too. :roll: with a large knob that you can tighten to firm up the steering action.
Modern tires have largely made them redundant ?? A friction damper was/is a pisspoor attempt. Like a trailer truck with a DRY 5th wheel, constant stiction/correction, crabbing down the road.

Keeping your steering bearings greased and in good condition has never gone out of fashion, however. Of course, maintenance 101. But, you can't grease them , just replace them.
And BEWARE the indented steering bearings, because it will steer like a notchy so and so...



P.S. If they are so bad, why have you waited 40 years, until this thread, to be going to change them.... !
Well, It's like this. 40 years ago the bike I was riding HAD ball bearings with a provision to increase the preload. I only lusted after a Commando then.
Fast forward to two years ago, I bought a tapered bearing kit for the Cdo. After inspecting the components, it was going to add 3/16" to the bearing stack, (NOT a drop in replacement) and I decided to abort , (it was close to spring, headed on a trip) and I'll need to mill the triple trees (yokes) to allow proper fitment. I've had the notion since I first laid eyes on this stuff....

The Commando has to be alone in having sealed ball race bearings which would never have an option for pre loading and then loading them axially.
Any bike with adjustment is like most others right up to today, cups with loose or captivated balls.
The danger with those is folk who over load them until the lubricant cannot get between the ball and race/cup.

19 inch wheels have bearings though, maybe the OP's Commando has a wobble due to the oil cooler being off centre.
Some strategically placed bits of 'Nana's wool via sticky tape may find the culprit.

No need to get narky - plenty here didn't know there is a patch of dead air behind the front wheel. ?

From "Powered by Dunstall"
"A fine handing machine in stock form, the changes made to the Dominator's Featherbed frame were minimal, although chrome plating was an option. Citing lessons learned by the tuners at Bracebridge Street, Dunstall placed a matching 19” wheel on the Dommie's twin shock swinging arm (fitting most with Girling dampeners) and retained the Norton's Roadholder tele-fork, often knitted with external springs and gaiters. Another catalog item, Dunstall's steering dampener ........"

This is likely why the Commando was given two 19" wheels. Paul Dunstall was hired on as consultant for the Commando design team. As to who the Bracebridge Street tuners were , I'm guessing Doug Hele would be one of those Paul watched and learned from early on.

Glen

The Vincent had 20's both ends ?

worntorn said:

retained the Norton's Roadholder tele-fork, often knitted with external springs and gaiters. Another catalog item, Dunstall's steering dampener ........"

Click to expand...

Just what bike were Dunstall referring to here ?

And why did they go with external fork springs - on short roadholders ??
Is there any wisdom for that move.

The Manx used them - but used different damper units inside the forks.
And different fork tubes and different sliders also.