Hollow Rear Axle?

[wa5vhu]

I have been watching the single wheel trailer thread, wanting to do the same myself however I don't weld. I would like an easier route and see that most single-wheel trailers use either a custom (welded) hitch assembly mounted to the frame or a simple skewer through a hollow rear axle.

What are your thoughts on replacing the solid center axle with a hollow one, assuming the correct diameter could be found?


Thanks!

Charles

 

[wa5vhu]

No thoughts or comments?

 

[L.B.S.]

I don't think that the rear axle on our bike is a large enough O/D diameter to allow for a hollow one, that provides enough I/D room for the dimensional mass needed for the through rod of a trailer, but that has utterly zero basis in fact, just pure speculation, I'm afraid, sorry...

 

[itlives]

My thoughts , too L.B.S.

 

[hojo]

I'm no engineer, but my thoughts are if Honda could cut the weight with a hollow axle or the cost of the metal, they would do so.

 

[showkey]

^^^^^^^^^^^^^^^^
Big assumption that the hollow axle would be cheaper ...............hollow would lighter .....BUT.......my gut say the solid axle is cheaper ???????

 

[maxwellian]

Yeah, thick wall tubes are generally more expensive than rods. Forging the hex head on a rod should be simpler than putting one on a hollow tube as well. I think the solid axle is economical, as reducing unsprung weight wasn't a big design priority on the NC.

It seems to me, the trick would be finding the point where the hollow axle is thick-walled enough, but the trailer skewer isn't too thin. Maybe if you could find dimensions of one made for a similar weight bike.

Are you trying to adapt an existing trailer that mounts by skewer to the NC?

 

[Cigar Mike]

I was thinking about drilling and tapping both ends of the bolt and using shoulder bolts. That way the axle bolt stays solid when the shoulder bolts are installed. I would buy another axle bolt to try that on.

 

[wa5vhu]

Thanks for all the suggestions! Drilling and tapping the solid axle might work. I measured my axle at about 18 mm on the threaded end so I'm guessing it is likely a 20 mm bolt, which is ~3/4". Drilling and tapping for 3/8" x 24 would take half of the 3/4" on the ends, not sure if the actual squared area would equal that. With 3/8" x 24 studs I could screw on some Bob Nutz and use a modified Ibex trailer or something similar. I may pick up an extra axle and give it a try.

Charles

 

[maxwellian]

I really wouldn't trust a BOB trailer at highway speeds. They're pretty lightly constructed.

 

[Cigar Mike]

Thanks for all the suggestions! Drilling and tapping the solid axle might work. I measured my axle at about 18 mm on the threaded end so I'm guessing it is likely a 20 mm bolt, which is ~3/4". Drilling and tapping for 3/8" x 24 would take half of the 3/4" on the ends, not sure if the actual squared area would equal that. With 3/8" x 24 studs I could screw on some Bob Nutz and use a modified Ibex trailer or something similar. I may pick up an extra axle and give it a try.

Charles

The reason I was thinking shoulder bolt was that the shoulder is because the shoulder bottoms and provides greater strength than a straight bolt. Also a 1/2" shoulder bolt taps for a 3/8" bolt. I was wondering if a safety pin of some type would be a good idea to prevent the shoulder bolt from backing out?

 

[wa5vhu]

I really wouldn't trust a BOB trailer at highway speeds. They're pretty lightly constructed.

I think you may be right. I have read where at least one BOB trailer was used on a motorcycle but it is pretty lightweight. That could be an advantage to keep me from putting too much in the trailer.

The more I think about it I believe I will get some 3/4" conduit and try to make a hitch that mounts over to the passenger foot-pegs and up to the Givi sidearms near the seat. I could use a single-wheel or a two-wheel trailer by changing out a plate where the hitch-part would be. I could make this for the price of the conduit and a used bender.


Charles

 

[maxwellian]

Sorry to be such a buzzkill, but I wouldn't trust 3/4"conduit for much of anything. Even the stuff the BOB is made out of is much heavier and stronger, probably Cro-mo. It's really just a few weak points on the BOB that aren't up to hitting a bump at highway speeds (attachment points to bike and wheel) As to EMT, you could chop up old huffy ten speeds and have better tubing than electrical conduit. I've seen people build stuff out of it, but it's light, can have defects, and isn't rated for any load.

I was looking at the moto-mule, it mounts at the axle or swingarm. On some bikes with a 3/8 skewer through a hollow axle of similar outer dimensions to ours. I think that part of your idea is feasible. The BOB trailer could be beefed up, but I think it would require welding. The moto-mule looks like it would adapt with only minor fabrication, not sure what other options are out there for single wheels. This page shows a few of the ways it mounts: moto-mule.html

 

[wa5vhu]

Sorry to be such a buzzkill, but I wouldn't trust 3/4"conduit for much of anything. Even the stuff the BOB is made out of is much heavier and stronger, probably Cro-mo. It's really just a few weak points on the BOB that aren't up to hitting a bump at highway speeds (attachment points to bike and wheel) As to EMT, you could chop up old huffy ten speeds and have better tubing than electrical conduit. I've seen people build stuff out of it, but it's light, can have defects, and isn't rated for any load.

I was looking at the moto-mule, it mounts at the axle or swingarm. On some bikes with a 3/8 skewer through a hollow axle of similar outer dimensions to ours. I think that part of your idea is feasible. The BOB trailer could be beefed up, but I think it would require welding. The moto-mule looks like it would adapt with only minor fabrication, not sure what other options are out there for single wheels. This page shows a few of the ways it mounts: moto-mule.html

I really like the Moto-Mule and have twice asked if they have a hitch solution for the NC and have not gotten a response. I would buy the hitch and trailer off-the-shelf if I could but so far no one seems to have a hitch available.

My primary use for the trailer is to go from home to the beach and back on our yearly vacation, some 240 miles round trip. The wife will pull our motorcycle camping trailer with her Spyder but that camper won't carry quite enough cargo for us. A second trailer behind my NC plus some very (very!) lightweight stuff in my top box and side cases should be enough room. So I'm not too worried about long-term reliability.

If anybody knows someone at Moto-Mule see if you can get them to sell a trailer and hitch to a customer?

 

[maxwellian]

Even more espensivo, but for more ideas at least, There's the trail tail.

Trail Tail

Their older KLR650 mount looks interesting, very similar axle and swingarm.

Looking again at the motomule hitch for the KLR. It too might work if the swingarm cross section is close enough. If I were you, I'd see if I could find a pre-08 KLR or its parts to measure axle diameter and swingarm end cap dimensions.

 

[wa5vhu]

Even more espensivo, but for more ideas at least, There's the trail tail.

Order Now

Their KLR650 mount looks interesting, very similar axle and swingarm.

Looking again at the motomule hitch for the KLR. It too might work if the swingarm cross section is close enough. If I were you, I'd see if I could find a KLR or its parts to measure axle diameter and swingarm end cap dimensions.

I like the MotoMule KLR650 mount and I have tried twice to contact them but they haven't responded to my queries. I don't think the axle size matters as I would just need to remove my end caps and put those on, as long as the existing bolts are long enough. If the KLR parts are too tall and/or wide I could always file them down.