MK3 rear axle (2017)

[madass140]

I've been asked a few times about a one piece axle for MK3, I dont have a MK3 rear wheel or parts at my disposal
only the parts drawing to go by, so hence a couple of questions.
The main axle is 17mm apparently
The stub axle is also 17mm but has a 9/16" thread, so what is the thickness at the 2 flats where it locates in the swingarm?
it appears it is a lot less than 17mm?
The axle slots in the swingarm are both the same size? 17mm or ???
Don

 

[L.A.B.]

Re: MK3 rear xle

The axle slots in the swingarm are both the same size? 17mm or ???

Approximately 17mm (RH) and 14.4mm (LH).

 

[madass140]

Re: MK3 rear xle

thanks, so the chain adjusters are different?

 

[L.A.B.]

Re: MK3 rear xle

thanks, so the chain adjusters are different?

No, they are the same.

Although the dummy axle has flats, I'm guessing the shaft diameter is also (approx.) 17mm.

https://andover-norton.co.uk/en/shop-de ... dummy-axle

I hope this makes sense.
The flats on the dummy axle are wide enough to allow the shaft (so 17mm x 14.4mm section, approx.) to pass through the LH inner adjuster plate, swingarm axle plate and also protrude slightly beyond the LH outer adjuster plate which is why the thick washer 06-5984 is required.

 

[madass140]

06-5984 is the washer for the right side.
If the flats on the dummy axle is approx 14.4mm then it would not be able to do its job if the adjuster and swingarm slot is 17mm or am I missing something?

 

[Mr. Rick]

The LH swingarm slot is not 17.. It's 14.4 or so, as Les mentioned earlier.

 

[madass140]

ahh, ok, getting clearer now.

 

[norcomm76]

I can send you a drawing of the axle Mk3 either in dwg or in pdf.

 

[L.A.B.]

06-5984 is the washer for the right side.

The Mk3 rear wheel parts book drawing is not accurate, there should be two "27" washers, one under the nut, the other under the hexagonal head of the spindle/axle.

Mk3 parts book rear wheel list;

"27....06-5984....Washer....2.."

 

[madass140]

well that makes it a bit clearer. Well from what I can see, the only way to fit a one piece axle is to revert to a 9/16" axle which in
one way a step backwards going to a smaller diameter and it would entail different bearings and spacers . All a bit cost prohibitive.
If I had my own MK3 I may consider a one off for myself at bugger all cost. I think we have to shelve this idea for the time being.
Are the MK3 axles known for problems, I've never heard of any.

 

[cliffa]

Hi Don,
as a relative newbie to Commando ownership, can I ask what the benefits of the one piece axle are?


Cheers,

cliffa

 

[kommando]

can I ask what the benefits of the one piece axle are?

With the 2 piece axle the longer axle can snap at the transition from plain shaft to the end thread right at the root of the first thread. By going to single piece axle you remove the weak point.

 

[madass140]

some may not agree but many have had axle breakages because of a combination of things, such as , not the best design having a relatively
small diameter axle (9/16") and threading it in to the other half of the axle assembly (the stub axle) sometimes these threads will strip or
the long axle will break at the end of its thread, remember that the root diameter of the thread is only about 1/2" so it doesnt take much
ill fitment to put stress on the axle. It is not the best design and that combined with incorrect fitment can often lead to problems.
My one piece axle does away with the stub axle and the long axle passes right thru , like any normal axle, I make the thread end just before it
clears the swingarm outer plate so there is no weak or vulnerable point that is liable to break. ie: there is no threaded portion of the one piece axle
within the inner width of the swing arm.
I dont think adjusting the chain with the axle adjusters is doing the 2 piece axle design any favors.
I'm sure others will chime in with opinions how they have never had an issue with the standard setup, I havent. but I believe one axle is better than two.
Don

 

[cliffa]

Makes sense, especially if it's only 1/2" at it's thinnest part :shock:

Thanks both for the explanation. I'll be checking mine.

Cheers,

cliffa

 

[manx850]

I had one break almost in two, a lucky find.......one piece sounds a lot safer in my opinion, considering how many times they have been removed and replaced!...........

 

[jeffdavison]

If you build them, I will come.

JD

 

[mdt-son]

well that makes it a bit clearer. Well from what I can see, the only way to fit a one piece axle is to revert to a 9/16" axle which in
one way a step backwards going to a smaller diameter and it would entail different bearings and spacers . All a bit cost prohibitive.
If I had my own MK3 I may consider a one off for myself at bugger all cost. I think we have to shelve this idea for the time being.

Don and all,
Mk3 rear axle is really poorly designed. In the interest of safety i would suggest altering the swingarm by machining (milling) the LH swingarm slot to the same shape as the RH slot, thus providing a 17mm axle dimension right through. Sure, this is a non-reversible action, but a spare swinging arm may still be purchased by those wanting to return to originality in the future ....
Going by the image in the parts book, the S/A axle supporting plates are of identical outer dimensions. Maybe someone can confirm this as my bike is in a remote workshop.

Don, if you would like to make an initial sample along these lines, I volunteer as tester.

-Knut

 

[o0norton0o]

Don and all,
Mk3 rear axle is really poorly designed. In the interest of safety i would suggest altering the swingarm by machining (milling) the LH swingarm slot to the same shape as the RH slot, thus providing a 17mm axle dimension right through. Sure, this is a non-reversible action, but a spare swinging arm may still be purchased by those wanting to return to originality in the future ....
Going by the image in the parts book, the S/A axle supporting plates are of identical outer dimensions. Maybe someone can confirm this as my bike is in a remote workshop.

Don, if you would like to make an initial sample along these lines, I volunteer as tester.

-Knut

I did exactly what you suggested. I bought a second swingarm and had a machinist mill the slots out to use a one piece 17mm axle. In my case, I modified the swingarm slots to use a yamaha cast wheel who's axle size was 17mm.

IF the only part of the MK3 rear wheel assembly which is not 17mm is the axle slot, then it might be easy to convert an MK3 to a one piece 17mm axle. The 17mm yamaha axle I used in my modified swingarm is available on ebay for about $15. I also bought the axle spacers on ebay too.

I never had an issue with the 2 piece axle on my commando, but I always thought it was weird. Now that I have a 1 piece 17mm axle I have one less flaw to worry about.

 

[mdt-son]

I did exactly what you suggested. I bought a second swingarm and had a machinist mill the slots out to use a one piece 17mm axle. In my case, I modified the swingarm slots to use a yamaha cast wheel who's axle size was 17mm.

IF the only part of the MK3 rear wheel assembly which is not 17mm is the axle slot, then it might be easy to convert an MK3 to a one piece 17mm axle. The 17mm yamaha axle I used in my modified swingarm is available on ebay for about $15. I also bought the axle spacers on ebay too.

I never had an issue with the 2 piece axle on my commando, but I always thought it was weird. Now that I have a 1 piece 17mm axle I have one less flaw to worry about.

Excellent contribution, thanks!

Going by the bearing sizes, a one piece 17 mm axle right through should work just fine. All we need now is length and thread length.

Last night I played with the idea of upping a one-piece axle to 20mm, or designing a stronger two piece axle. While other parts could accomodate a 20 mm axle by machining the parts (esp. the sprocket), this would require a drive side hub bearing bore of minimum 42mm diameter which is not possible using the factory casting, save for the lockring 06-5548. Thus, either a custom hub or a third-party cushioned hub would have to be adopted (e.g., by RAD). I guess this venture is too radical for most of us, and if the 17mm axle works strength-wise for Mk1-2 models, it will probably work for the Mk3 too (though latter has more axle loading than the previous models).

-Knut

 

[madass140]

there is a bit more to it than just removing the old axles and sliding a 17mm axle thru the existing parts.