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henks

Rear Axle Nut Alternative?

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henks
So I've done a bunch of searching on here, and it sounds like it's hit or miss with the fuji style nuts used for the rear axle, as far as threads being destroyed when removing the nut.
 
As a racer, I'm constantly removing my rear wheel to swap tires.  And I really don't want to keep a pile of new axles/fuji nuts in case one of them gets fubared over the course of a wheel change.
 
The purpose of this thread, is I'm wondering if anyone knows the thread size/pitch for an alternative....a castle nut (castellated nut).
Castle_Nut.jpg
 
What my idea is to use one, along with a washer.  Once tightened to an appropriate level, mark the axle (on the threads), then drill a hole through the axle completely, and using a spring clip as a retainer to keep the castle nut essentially locked in place.
s_l300.jpg
 
 
 
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-Chris
Central Roadracing Association #286E

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markstertt
M18 x 1.50 and your idea is good, also easy enough to get a cotter pin in there, or could use an elastic stop nut or do a search on line and you'll find a few more examples of castle style titanium nuts much cheaper than some others.
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yamahaha
Most of my old motorcycles had the cotter pin setup. Not sure how bike makers thought they could improve on that.
 
Next time I have to change a tire, I'll take the axle and nut up to Fastenal and see what they got.

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henks
Thanks for all the great replies, guys. Looks I missed a few threads when I searched.
 
The purpose of the spring clip that I posted is I would have it tethered via safety wire to prevent from a standard cotter pin from somehow vibrating loose on the track.
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-Chris
Central Roadracing Association #286E

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markstertt
The correct sized cotter pin should be a fairly close fit to the hole in the bolt and slot in nut, once the tails are bent over it won't fall out, if real worried you can get a wrench or crows foot on the nut and tighten it against the cotter pin so it can't even wiggle or vibrate. The pins you show wouldn't be my first choice for this application.

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pattonme
the pins are tremendously more convenient than cotter pins. No bending with pliers, no having to keep a stash on hand when metal fatigue causes the legs to snap off, and also big and obvious. As bullet proof and secure? Absolutely not.
 
The only reason it has to be safety wired is to FORCE people to actually torque the axle nuts before going out onto the track. a clip dangling on 3+" of safety wire is very easy to spot from afar.

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markstertt
the pins are tremendously more convenient than cotter pins. No bending with pliers, no having to keep a stash on hand when metal fatigue causes the legs to snap off, and also big and obvious. As bullet proof and secure? Absolutely not. 
The only reason it has to be safety wired is to FORCE people to actually torque the axle nuts before going out onto the track. a clip dangling on 3+" of safety wire is very easy to spot from afar.
Ah, I see that makes sense for racing and in all actuality if that axle nut is torqued to 70+ ft. lbs. it isn't going anywhere with or without the cotter pin, so as an easy to spot indicator then I guess that works. For the street, where we don't change tires, gearing etc. all that often then I'd go cotter pin but coming from aviation we don't reuse cotter pins so I do keep a stash on hand. After 30+ years you end up with a lot of AN hardware laying around, a lot of it having gone through my washing machine. 
I looked at the probolt site, good stuff and although I've had zero trouble with the stock lock nut, I do like the idea of either a stainless steel or Ti castle nut and cotter pin. Thanks for that info Matt.
 

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henks
Thanks guys. All great info here.

-Chris
Central Roadracing Association #286E

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gregjet
Personally I would recommend against a Ti nut , especially for the torque required unless you are going to replace them at regular intervals. Titanium is notorious for galling the threads and loses its holding power. At the very least liberally use copper grease.
Ti is great for lower torque applications where strength and lightness is required but lower torques can be used.

Go forth and modify my son...go forth and modify...

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henks
So stainless would be the way to go then?

-Chris
Central Roadracing Association #286E

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gregjet
That is my personal opinion. If you were racing and replacing regularly Ti would be fine. Personally for a road bike "set and forget", I'd be happier with Stainless than Ti. But even stainless is not as strong as proper hi ten steel in an axle situation, but should be OK IF you torque it carefully and lockwire it. Part of the problem is the relatively few number of threads holding on the nut to spread the torque load over because they are quite shallow nuts.

Go forth and modify my son...go forth and modify...

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pattonme
I also think Yamaha's torque specs are insane. ~45ft/lb front, ~60 rear is more than plenty IMO.
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markstertt
I also think Yamaha's torque specs are insane. ~45ft/lb front, ~60 rear is more than plenty IMO.
Couldn't agree more, the first time I undid any of the nuts or bolts on this bike I thought 'holy crap' Yamaha surely doesn't want anything coming loose. Then when I used my torque wrench to tighten the rear axle  to Yamaha specs I stopped short. I now use my own lower torque and have reused the same nut over and over and wonder if the high torque may have something to do with people having issues with that lock nut and axle, like gregjet said, not a lot of threads on that nut to spread out the torque load. I have more than enough threads showing on my axle to use a deeper nut if desired too. I'm not opposed to plated steel, stainless or ti, the only problem I've encountered with galling is stainless on stainless but then I don't have much experience with titanium so will leave that up to poster.  

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gregjet
The softer Stainless can be a bit of a galling problem, but at that size I think properly torqued and greased and lockwired should be fine. Some of the 30x stainless can be a bit soft. 316 is pretty good and there are now some hi ten stainlesses. But for reliability I think Hi Ten steel, grease and lockin mechanism of some sort. Galvanic corrosion could be a problem where salt environments such as near the sea or where they salt the roads. Or in industrial areas with high acid content in the air.

Go forth and modify my son...go forth and modify...

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