Do rear spindles break often?

Neverever heard of the standard Norton two piece rear wheel spindle breaking in 41 years of riding Commandos.

Mine broke after 50,000 miles, can't remember the exact mileage. I remember Mick Hemmings from whom I got the replacement suggesting he'd broken a few, but under racing conditions. So for the average Commando owner I think it wont be a problem. Having said that I'd avoid stainless steel as the component strength is compromised for the sake of appearance. It's funny how bikes loaded with stainless never seem to get wet. Also if your spindles are ok why replace them? just re plate if tatty.

Years ago there was prolonged correspondence in 'Motorcycle Sport' between Middleton and Molnar. I can't remember the specifics but it seemed at the time that each accused the other of supplying wheel spindles in an unsuitable grade. It was enough to make me decide that I'd stick with standard.

I snapped a Mk3 spindle early on - when unscrewing it - but the bike in general had been subject to all sorts of internal and external bodges by previous keepers (six keepers over the first seven years) so I put that down to owner abuse and haven't seen a problem since.

It left the threaded section tight in the stub-axle so presumably there was some existing thread damage there.

Mine snapped, it was a stainless item that was on the bike when I purchased it. I think it still in the old bits drawer that I have. Since fitted standard item with no issues.

Hi, I hope Andy Molnar will not mind me repeating something he wrote about stanless steel wheel spindles a while ago:-

Stainless Steel Wheel Spindles â Andy Molnar (Editedfrom RH 105)

I have just got round to reading Roadholder No: 101.

I am very concerned to read the letter from Mr. Leadbetter(page 2) ref: Stainless wheel spindles. I donât know which idiot started thisrecommendation to use 431 for wheel spindles, I see that it cropped up again inthe recent âClassic Bikeâ.

431 is about the WORST material that you could make a wheelspindle from. It is a 17/2 Mortensitic steel which has a very high yield point;but has an exceptionally low IZOD value of only 15-25lbs.ft.

A lot of rubbish has been written about stainless steelspindles. The trouble is that most people are just not technically competent,and do not understand the difference between high strength (which 431 DOES have)and toughness. The latter is the main requirement for wheel spindles.

Tensile strength refers purely to the ability of a materialto resist a force along the axis. I hope it is obvious to readers that this isNOT the loading mechanism in wheel spindles. 431 is of course ideal for highlystressed studs etc. where the loading is axial. There is no way I would everride a bike with spindles in 431.

Although I am not prepared to reveal the grade that we usein our wheel spindles, I can say that the impact strength is 50-80lbs.ft(compared with 35 for original) and they are undoubtedly strong enough. Shortlyafter fitting a pair of my own stainless spindles - I ran my Dommie into theside of a car (not recommended) and considerable damage resulted â smashedyolks, fork sliders and wheel hub, bent stanchions and frame. 30,000 mileslater I am still using those same spindles.

So to recap, I would strongly recommend that you buy suchcritical items from a competent company. The spindles should be made from oneof the austenitic grades and if it is magnetic then it will be martensitic andpossibly 431 â I would not use such a spindle, and cost is no argument â 2spindles for a Commando cost just £15.50p.

Andy Molnar, Herts.

Hello all. I have been reading on ACCESS NORTON SITE about the rear wheel spindle braking and was wondering is this such a coman thing to happen?? there is someone who makes a single peice rear spindle to replace the two peice Norton item but he is in the Phillipines so does someone in the UK make such a thing. I also wondered about the stainless steel ones sold by Middleton and Son on Ebay has anyone any experiance with those? I plan to replace my spindes front and rear as part of my rebuild so if the rear is a problem area now is the time to do something about it or is it just few unlucky owners that this happens to?? thanks for your time Karl

I get the idea that broken rear wheel spindles are something which has happened on very rare occasions. In these days of the internet, rumours travel far and wide, and the broken Commando spindle one is no exception. I have no intention to replace the stainless spindle on my 1969 S Type, but since that year did not have a cush drive in the rear hub I would expect it to be less prone to breakage than later models.

I wondered about the conversation, too, never having had a wheel spindle break on road or track since I started riding Commandos in 1977 on pre-850Mk3 motorcycles. I suspect the stainless aftermarket stuff may be responsible for the discussion.

That said, I remember breaking Mk3 spindles in the early days- not a frequent occurence these days, can't remember when I last sold one. This was due to the design which I think was reviewed later with more of a radius from the threaded to the plain section.

All pre-Mk3 850s and all others don't, to the best of my knowledge and considerable riding and racing experience, break spindles.

While I was supporting the Roadholder with the odd bit of Tech advice I had three people contact me to mention that their Commando rear wheel spindle had snapped at the threaded end where it entered the rear drum brake bearing. So I presume this was only related to Commando models fitted with a rear drum. The common fact, in all these cases, was a failure of this bearing in its sprocket/drum housing. Two of the owners had previously bought Stainless Steel spindles along with other Stainless components to spruce up their machines.

I am not too certain whether the bearing failure led to an overload of the shaft or the use of Stainless Steel contributed to some extent. This was a rare event compared to the 5 unfortunate riderswho reported buyingand fitting a Stainless front wheel spindle which subsequently snapped.Overall, I actually came across more owners whohad broken a swinging arm spindle and lived to tell me about their experience!!!