Swansen

title pretty much explains it all. i'm looking to make a cargo trailer for a motorcycle out of a bmx frame, not for heavy loads, just clothing/camping gear etc. i realize that even posting this is slightly silly, last time i checked no one cruised around on a bicycle at 50mph(well, i know the touring guys get going pretty good) but anywho. thanks

Bandera

Forget it, look for proper motorcycle luggage or a Uni-Go trailer.

Uni-Go Motorcycle Trailers

- Bandera IBA #

CACycling

I would assume most, if not all, would require the trailer to be licensed. Depending on where you are, getting what would essentially a bicycle trailer licensed for road use would be challenging.

capsicum

Bicycle tires are not DOT approved. The bearings themselves assuming a quality brand, could take over 100mph, IF properly greased (about30% fill and channeling type (#2 thickness lithium), as you approach 100% fill or with a non-channeling consistency the churning creates lots of heat at high speeds) and not overloaded (static or dynamic[impacts]) 100mph on a 26" tire is only about 1400 rpm the same size ball bearings are used in industrial applications up to 10,000rpm (with good lube engineering and testing)

fietsbob

A sealed bearing used in bike hubs might originally be made for Electric Motors so rotation speed was considerably higher ..

Swansen

thanks, already looked at all commercial options.

Yet, there is some grey area depending on size/use/etc. In my county it would require a plate unless it was for 'farm use' or something. Having something inspected is simple, been through it a few times with dirt bikes to street or rebuilt motorcycles.

Awesome, some of the old to mid skool flatland bikes were tanks, 14mm(1/2") axles as well. failure wouldn't take much to notice either. if it was running past its capacity heat would build up pretty quick.

yeah, i guess worse case is the hub fails and i have to replace the bearings with known high speed bearings.

FBinNY 

There's plenty of room on the speed front as long as the load is within reason (less than typical BMX rider/2).

If you were towing by bicycle this would be unregulated, but since you're using an MC as the tow vehicle, I suspect that there may be some regulation involved, but that's between you and the DMV of the state that the MC is registered id.

nfmisso

why not use a front wheel assembly from a small motorcycle? Then you can use DOT approved tires, reducing one hassle and a big safety issue.

Some expensive bicycle tires are rated for up to 50 kph for e-bike use.

Swansen

well, as far as other options. https://www.google.com/search?btnG=1...forums+pirelli

as far as dot tires for bmx wheels, https://www.myronsmopeds.com/category/parts/tires/] 16" moped tire for 20" bmx tire.

Bandera

Securely bungie a duffel bag on the passenger seat and avoid the inevitable nasty wreck w/ a make-shift "trailer".
Motorcycle carrying capacity has been well thought out over the last century or so, good safe kit costs what it costs.

-Bandera IBA#

Swansen

yeah, thanks for the concern. i have a fair amount of fabrication experience. Looking at the commercial options, there isn't anything special about their construction. Also, i've looked at a number of 'make-shift trailers' and same story, nothing special about their construction, some are just 'prettier' than others. Also my choice of materials seems 'prone to failure' its probably wwaayy stronger than a lot of options, again, only concern was if the bearings would hold up and yeah, people brought up DOT rubber, but i was already aware of that.

FastJake

FWIW, people have done motor-pacing on bicycles at well over 100mph. No idea if they were using special wheel bearings, but I suspect not. Those events were very short though. Keep them well greased and I think you should be fine.

I won't step into the tires/trailer design can of worms because I know nothing about that.

Swansen

well. i figured i'd update this situation. As it turns out, its common enough that rear hubs on BMXs use a 6001 bearing which is exactly what it used it a lot of moped wheels. Also, as mentioned in the thread here, yes, how the bearing is greased makes all the difference. Just finished up the design and have a few other projects to get to but i just needed to put this piece of information somewhere.

--edit--
scratch that... i was projecting. 12mm axles are kinda odd. However, my point still stands at least for 3/8 axle hubs. the balls are the same size, just the ID and OD are different size vs a 6001.

also, just for anyone wondering, used moped parts in the 16" range are NOT easy to come by. a very slim list run through ebay, but as far as anyone looking to be really safe. a few people sell cheap moped hubs, or there are some cheap spoked hubs that will accept a 6001 bearing and then just lace up any bmx rim.

FBinNY 

If it helps at all, bicycle wheels are SOP for precision road testing of cars, and calibrating their speedometers. Speeds of up to 80mph on a 26" wheel is par for the course.

IK dont think speed is going to be the issue, but bearing load ratings could be.

Swansen

yes. so i think i found my answer tonight. someone mentioned a moped wheel and i followed up. they are really hard to come by and the price doesn't really make sense, especially after a tire is figured in. 16" moped wheels are not common and the one thats are, are on a 3" wide rim. that doesn't help me any. However, BMX rims are really strong and i definitely have a good understanding on the speed issue. However, load bearing could be a worry. Also since tearing down a hub just to see what bearing is in there seems senseless. i have found a solution.trike hubs. which i wonder why isn't used on front hub, being there is no drive on the front, why not just place bearings in a body?? always wondered about that(thats what trike hubs do). Right, and they seem to come in a range of options to. something like 36mm OD and 12mm ID is a beefy bearing. haven't really found if they accept typical bike spokes or larger, but either way, looks like i'll be lacing a trike hub to a bmx rim i have laying around.problem solved.

Andrew R Stewart 

Not directly related to the Op's situation- There was a famous US made bike component company BITD that was testing their hubs behind a car. They built a swing arm like fork that attached to the rear bumper and drove around our area with various hub prototypes (built up in wheels, I only know about this since I worked at the LBS that built the wheels, but a few years later). The prototype hubs had issues because the forces that they saw during testing were different then when actually used on a bike. Seems that the leaning during cornering when riding is rather different a stress pattern then the side loads seen behind the car. Andy.

Swansen

thats actually pretty coincidental actually. initially i was thinking of doing a single wheel trailer that leaned with the bike. i was considering larger loads or a more utilitarian design(say hauling something small through the woods) and how two wheels would be needed to distribute the load. that makes me wonder though, what the actual issue was. small balls in the bearings, bearings being close together. hmm...

i've had enough front ends apart on vehicles to see the various wheel bearing designs and on some vehicles its hard to believe how small some of the wheel bearings are and how closely they are spaced. whats my point? there really isn't a whole lot of difference between the spindle/hub/bearing setup on bicycles vs any other application. Probably the only thing thats really common with various cycling bearings(or at least the most common choice) is that they are all ball bearings. Automotive applications use roller bearings, aside from the seal hub bearings which are so common now, and that seems to come down to whatever manufacture is doing. so i guess that almost entirely removes my purpose, as roller bearings can handle a load so much better than balls do(and thats parts of the success of the SFK bottom brackets)

hmm.. i don't know about road bikes or mtb, most BMX hubs have the inner race of the bearings supported at least to some degree. similar thing for tapered roller bearings or sealed hub bearings, the entire bearing is supported. from the looks of modern hubs(dunno, outside bmx at least) i'm not sure if the inner races are supported, which would cause issues with anything but a vertical load.

Reynolds 

I wouldn't worry about bearing ability to stand 1400rpm, but would make sure wheel is balanced, specially if it's 20".

Swansen

yes, thanks. i hadn't even thought about that, that would for sure prolong bearing life.