heavy rider spokeless integrated hub motor. Discuss?

[cycleops612]

I have reflected a lot on the fact that so many great candidates for bikes are handicapped further by exceeding mainstream bicycle design weight limits.

Whatever the bike chosen, i read that big riders main weak spot is the rear wheel.

re the below link (Proof of concept only):

its a cast spokeless wheel with the hubmotor integrated

I assume cast wheels are stronger (and a bit heavier - in this case, maybe not).

I am pretty sure they would be stronger. Integrating the rotor into the rear wheel is better structurally. it adds strenght but no weight. 7kg for both wheels including motor it seems.

the wheel issues in forums were ~spoke issues, and on the rear? It could be that the wider/weaker rear ~axle creates more flex, to the detriment of spokes.

I am pretty sure they have a 24" in their range (or i have seen on alibaba), which u could live with as a smoothish riding diameter, and ought be

Immensely strong.

many may just want a rear wheel kit - screw the front.

wider rims would seem desirable for big riders.

Xellent heat dissipation

https://www.alibaba.com/product-detail/2015-new-design-26inch-Integrate-e_1407942039.html

just saying. I advocate mid drives, but most choose hubs. the link is just an example i managed to find. there are others but 26" seems scarce.

For a heavy new kit buyer, it kills two birds with one stone. The motor and a v strong wheel. Simple.

btw, surely the absence of spoke holes/heads in the spokeless rim is a good thing, structurally and for the tire tube?

[moderator edit to fix pic link]

 

[Chalo]

Cast wheels can't be trued up after suffering damage. They have lower strength to weight ratio than wire spoked wheels. Yes, they can be made stronger than regular bicycle wheels, but only at the cost of being much heavier.

The wheels you link to are most likely much heavier AND much weaker than conventional wheels built for strength. And when they get bent, they'll stay bent.

 

[cycleops612]

Yes, a badly damaged rear wheel does mean a new rotor/wheel the same (the stator could be swapped over at no cost).

Its a valid choice to go for better less repairable tho.

If i damage my axial mid-drive bikes frame, its the same situation - its customised for the Bofeili motor. I accept that, as its so much better - 24 gears e.g.

sensible road commuters want NO PROBLEMS, not more easily fixed more likely problems. Respokes are not fun for most of us. We have lives .

wheel wobble post disk brakes aint the problem it was for rim brakes. Vibrations at ebike speeds should be minor.

nor is "heavy and works vs light and doesnt" a hard choice.

as i said, the integrated hub nets weight savings outside the usual wheel weight comparisons.

I havnt bent any wheels in ~20 years of urban commuting, and much of that was 28" racing wheels.

but yeah, good point, the wheel/motor IS a proprietary combo should you ever destroy the rim.

 

[dogman dan]

I'd rather have a really well built spoke wheel for a heavy load, than a cast wheel designed for normal bike loads.

You need to look at moped tires, spokes, and rims perhaps.

I would go with a one piece cast wheel for a 16" tire though.

 

[spinningmagnets]

Larger diameter wheels are better for tackling obstacles like large potholes and curbs, however...for strength, smaller diameter rims are inherently stronger. A 16-inch single-wall aluminum moped rim is very strong, and fairly light. It can seat a 20-inch bicycle tire (to give you an idea of the actual size). There are weak 20-inch rims, strong 20-inch BMX rims, and very strong 16-inch moped rims.

Having the weight of the motor in the rear wheel puts more stress on the wheel/spokes/rim when you hit a bump at full speed. To ease that stress for reducing breakages and getting "bent", add a fatter tire, add rear suspension, and if possible, move the motor onto the swingarm (out of the wheel).

One way in which Chalo has made a historic mark on ES is that there was a time when broken spokes were leading builders to use thicker spokes, and the problem only got worse. Chalo was insistent that quality spokes/nipples/rims that were properly tensioned would spread the load over many spokes. Thick spokes have no flex (rigid), and looseness on several spokes will focus all the stress of a pothole-hit onto the few spokes that are the tightest.

 

[MadRhino]

Yep. Scooter/motorcycle hub motors with integrated wheels 13 to 16 in are very tough and low maintenance. Yet there is a weight penalty, not only from the wheel but also from the tires that are fitting them.

As for supposed weakness of a spoked wheel, I remember in my youth that we had some spoked wheels on farming equipment. If you can pull a spoked wheel half ton seeder behind a tractor on a rough field reliably, I don't see why a spoked wheel is not enough for any ebike with a big rider. If it isn't, it is because it was not built properly for the task, not because it is spoked.

Yet I can understand that some might be fed up with cheap wheel building, failing repeatedly. I build my own wheels that are pretty lightweigh for my bikes, still they survive very hard riding and daily hits in mountain trails.

 

[cycleops612]

I, and I hope others, remain unconvinced by the few relevant counter arguments.

TBF, w/o relevant specs on loads, costs and respective weights, its hard for any of us to be conclusive.

but if the rear wheel is the weak spot for a given big riders bike, then cast seems stronger, and by integrating the alloy motor housing in the casting, the hub+wheel weights could be similar.

it may e.g make an extra 20kg doable on a given bike.

if u habitually bend wheels and rebuild them cheaper than new cast wheels - fine, stick with spokes.

Most just want a bike that works, and gets them to work.

But if i were big, and considering a rear hub kit for an existing bike, then a rear wheel 500w+ cast integrated hub seems simple and neat - worth considering anyway.

As to "a hard riding wheel" - WTF. It seems to me the last thing you want is flex. Thats what the posts all complained of. It was flexing that led to broken spokes and wheels. Its the tires job to flex.

As to this dead easy respoking, these guys are talking extra spokes (heavy gauge), custom hub motors presumably with extra spoke lugs, and heavy duty rims. To get a custom expert build is not cheap or certain.

Common sense dictates huge engineering advantages. Instead of ~40 weakening holes in the rim, the rim and "struts" can be precisely engineered into an integral whole. the rim is not perforated, and is supported evenly around its inner circumference. Even if not even, the rim can thickened to compensate in those areas.

Lateral strength can similarly be precisely calculated and executed.

Add in that weight economies can be achieved integrating the hub motor, and that wheels have generally shrunk from the traditional 28" to 26" (and big riders could compromise with 24"), and that mass engineering has improved and labour intensive methods like spokes become less attractive to busy riders - then maybe bikes will follow cars and dispense with spokes for stressed wheels.

I would prefer DD to geared as the example is. I would make it a rule to pedal til rolling speed to relieve stress on the nylon? cogs.

Many cog problems are heat related it seems. nylon gets softer when hot. NB the excellent heat dissipation of cast integrated hub wheels.

Incidentally, i notice well regarded xiongda 2 speed hub motors now come in cast wheel form - 22"? pretty awesome kit for the right app.

 

[markz]

having an already heavy motor, you can get away with using a moto rim, but the heaver the spoke does not translate to durability, quite the contrary from what I understand. Chalo, SpinningMagnets and others knows best.

 

[FluxZoom]

I am so glad this thread was started. I teeter back and forth on the same idea, has haunted me for months. Issue I have is strength, we speak of it very ambiguously. I just got a 1700g 16" steel moped rim in the mail today. I have a 1100g aluminum motorcycle rim, and some 400-600g double walled bicycle rims. I have no idea which is stronger than the other. The spokes themselves feel like a major variable within this discussion, and not just the spokes but also the idea of how tight they are and the probability they will loosen. In any case, I am soo desperate for tangible measurements, science, observations, something. I am literally pondering how I can measure how much weight various rims can handle.

To me, the ideal situation (perhaps necessity) is to build a wheel that doesn't ever need maintenance and won't ever come to getting dented up short of getting hit by a car or someone going at it with a sledge hammer.

I am no expert wheel builder and despite my best efforts trying out several local wheel builders has left me unwilling to try that avenue again.

What I am considering is using brutally strong rims, and somehow making it so the nipples cannot turn after the wheel is done. It's either this, or cast wheels. To be honest, I am thinking I just need to make a few bikes of each and see how it goes.

 

[cycleops612]

I am so glad this thread was started. I teeter back and forth on the same idea, has haunted me for months. Issue I have is strength, we speak of it very ambiguously. I just got a 1700g 16" steel moped rim in the mail today. I have a 1100g aluminum motorcycle rim, and some 400-600g double walled bicycle rims. I have no idea which is stronger than the other. The spokes themselves feel like a major variable within this discussion, and not just the spokes but also the idea of how tight they are and the probability they will loosen. In any case, I am soo desperate for tangible measurements, science, observations, something. I am literally pondering how I can measure how much weight various rims can handle.

To me, the ideal situation (perhaps necessity) is to build a wheel that doesn't ever need maintenance and won't ever come to getting dented up short of getting hit by a car or someone going at it with a sledge hammer.

I am no expert wheel builder and despite my best efforts trying out several local wheel builders has left me unwilling to try that avenue again.

What I am considering is using brutally strong rims, and somehow making it so the nipples cannot turn after the wheel is done. It's either this, or cast wheels. To be honest, I am thinking I just need to make a few bikes of each and see how it goes.

Yes, what i meant by "too hard to be certain"

numbers on load limits seem very well kept secrets, given the limited research time i had. i figured someone else could hunt up some links etc. I am happy to be refuted with valid info.

The future probably belongs to ~plastic "cast" wheels, but probably not for hub motors.

As u say, even if in theory spokes DO have advantages, the probability of wasting serious money via an incompetent builder is scary, and its all delay we would rather spend riding.

The prev poster may be correct about guage (tho strong new factory wheels come with heavy guage - a measure I can trust), but all agree extra spokes is a good idea for a strong wheel - which reinforces my point about uneven rim support using spokes. More spokes = more even.

I dont have a problem with spokes if they do the job, and they do - for a bicycle used sensibly - like a mtb with a sub 120kg total weight ate pedal speeds and ridden sensibly.

But a 500W+ motor and a 300lb rider doing 40kph is not what a bike was meant for. Anecdotal evidence is the back wheel is what gives first. Rear cast seems a good bet, and an integrated motor seems neater still. Thats all.

You dont give much detail, but 16" sounds very strong, spokes or not. More spokes for you, would need new hubs for the extra spokes i assume.

 

[markz]

I don't think its a matter of how strong the rim itself is, unless you plan on hitting curbs at top speed. The ideal is just buying a decent rim to begin with and lacing it with proper spokes that are not to thick and not to thin. Spokes would need to be a quality product too, Sapine I hear are good in the 12awg or maybe 10awg and thats a maybe.

https://endless-sphere.com/forums/viewtopic.php?f=3&t=85844&p=1256126&hilit=spokes#p1256126

https://endless-sphere.com/forums/viewtopic.php?f=1&t=85531&p=1251042&hilit=spokes#p1251042

https://endless-sphere.com/forums/viewtopic.php?f=1&t=85531&p=1250917&hilit=spokes#p1250917

https://endless-sphere.com/forums/viewtopic.php?f=2&t=84580&p=1237514&hilit=spokes#p1237514

https://endless-sphere.com/forums/viewtopic.php?f=8&t=82683&p=1216222&hilit=spokes#p1216222

https://endless-sphere.com/forums/viewtopic.php?f=1&t=40615&p=1215002&hilit=spokes#p1215002

 

[Chalo]

I seem to have to repeat it again and again: The higher the loads you put on any given rim, the thinner the spokes must be to yield a reliable wheel. That's because the spokes must remain tight as the wheel distorts under load-- the greater the load, the more the rim distorts, and the more elastic the spokes must be to follow along without going slack.

Moral of the story is, use a rim as strong and stiff as your application demands, and use the customary gauge spokes for that rim, or thinner if you're concerned about the wheel's durability.

For e-bikes, 14-15ga (2.0-1.8mm) butted spokes represent probably the optimum compromise between elasticity, strength, and ease of building and maintenance. They might need washers under the spoke heads to work properly with hubs that are drilled for thicker spokes.

 

[FluxZoom]

I seem to have to repeat it again and again: The higher the loads you put on any given rim, the thinner the spokes must be to yield a reliable wheel. That's because the spokes must remain tight as the wheel distorts under load-- the greater the load, the more the rim distorts, and the more elastic the spokes must be to follow along without going slack.

Moral of the story is, use a rim as strong and stiff as your application demands, and use the customary gauge spokes for that rim, or thinner if you're concerned about the wheel's durability.

For e-bikes, 14-15ga (2.0-1.8mm) butted spokes represent probably the optimum compromise between elasticity, strength, and ease of building and maintenance. They might need washers under the spoke heads to work properly with hubs that are drilled for thicker spokes.

So spoked wheel is strong until spokes come loose. How 'strong', dunno, need science, rims are an infinite variable.

How do you make it so spokes never come loose?

I've considered red loctite, solder, brazing, and welding (blast with a TIG torch). If the wheel gets kinda beat up, to the point where the spokes are loose enough to need re-tightening I'd be glad to either replace the rim and/or cut the spokes. Just can't have nipples turning after the wheel is set.

Have anything that scientifically illustrates the strength of various wheels? Ever test this idea or have ideas on how?

 

[Chalo]

The rim determines how strong the wheel will be. Spokes have very little to do with that. However, if the spokes don't stay tight under load, two things happen: The length of rim spans that are unsupported by spokes that are tight enough to keep them braced gets longer, and the nipples gradually unscrew as tension is repeatedly removed and reapplied.

The center part of a 14-15ga spoke has a cross-sectional area less than half that of a 12ga spoke. So under the 1000N of tension that's recommended for most bicycle rims, the butted spoke stretches more than twice as much, and will remain tight while the wheel bears loads more than twice as heavy as those that allow the 12ga spoke to stay tight.

Thicker spokes make sense for rims that can tolerate proportionally higher spoke tension, like motorcycle rims.

Bicycle manufacturers have mostly settled on straight gauge 14ga spokes because they're very cheap and easy to build with. Most custom wheelbuilders default to 14-15ga butted spokes because they're almost as easy, widely available, and compatible with any hubs and rims that will take 14ga spokes.

For some challenging applications, I'll always use thinner spokes (like 15-16ga or 14-17ga) if they're available to me. These gauges are a little harder to build with because they tend to wind up by variable amounts as they approach full tension. But the reward is a wheel that can carry heavier loads, requires less maintenance, and weighs slightly less despite being more robust.

 

[Chalo]

It's a Very Bad Idea to try to keep spoke nipples from turning freely. Tightening and loosening spokes is your only way to keep a wheel straight when minor damage or wear and tear causes the rim to go out of true. At most, a mild threadlocker like linseed oil should be used, so that it's easy to break the bond later for servicing.

 

[FluxZoom]

Ignore the idea of rim brakes, they do not apply to the question.

Which wheel will last longer, one with locked nipples or one without locked nipples?

 

[MadRhino]

Nipple threadlock is meant to prevent seizure, much more important than locking the thread. When a wheel is laced tight, nipples don't come loose by themselves. If there is a loss of tension after a while, it is because of spoke stretch and placement. Once this is corrected, the wheel will stay stiff until a hard hit. If there is a long time before the wheel hits enough to require the next correction, nipples might be seized if they were not installed with threadlock. I use linseed oil like many old wheel builders do, but any brand of nipple threadlock, blue Locktite or ski wax will do as well.

 

[FluxZoom]

the wheel will stay stiff until a hard hit

Which wheel will last longer, one with locked nipples or one without locked nipples?

 

[MadRhino]

It will last longer with lesser maintenance if you build with threadlock. The difference can be important if you ride in wet and salty conditions, simply because seized nipples are forcing spoke replacement and eventually, a complete rebuild.

Then, nipples are not locked when you are using threadlock. It is the other way around, threadlock is keeping them from locking (seize).

 

[Chalo]

I use only oil, grease, or dry lubricant on the threads of my own spokes, and I never have any problems with spokes loosening despite my body weight of something close to 340 pounds.

I use thin spokes and I get them nice and tight to begin with. That's really all it takes, once you pick a rim that's fit for purpose. But use a rim that's too flexible or spokes that are too thick, and then you have to glue the nipples in place to keep them from backing off.

 

[amberwolf]

Ditto to that, and my wheels have to tolerate heavy loads and potholes, and on the trike there are also heavy sideloads in turns.

So spoked wheel is strong until spokes come loose.

Spokes won't come loose if you use thin enough spokes so they can be tensioned properly on that rim without destroying / deforming the rim itself.

Use a motorcycle rim, then use that gauge range of spokes.

Use a moped rim, use that range.

Use a bicycle rim, use that range--usually 14 or 15g. 13 if you have to and the rim is strong enough (all of the OEM hubmotor wheels I've had come with rims that don't handle those thicker spokes very well; they crack when the spokes are tensioned correctly, so the spokes are then no longer tensioned, so the nipples then start coming loose. Wouldnt' happen if the right gauge was used).

Which wheel will last longer, one with locked nipples or one without locked nipples?

If you mean nipples that cannot turn at all, even to retrue the wheel, then the unlocked nipples will "last longer" because you can fix it when it gets bent a little from an impact, sideload, etc.

But it is not a simple question, because it has to do with spoke tension and rim strength (using it with the right size spokes for that rim).

If you use spokes too thick for hte rim, and solidly lock the nipples so they can no longer be moved at all after tensioning, then when the rim breaks from the overtension required to make those spokes at their correct tension, you won't be able to retension the spokes, so the wheel will not last as long as if the right spokes were used for the rim.

If you use the right spokes for the rim, and solidly lock the nipples so they can no longer be moved at all after tensioning, then the rim won't break from that, and then the only limitation is if you need to retrue the wheel for any reason, in which case you'd have to build a new wheel.

If the locking is not so solid you can't move the nipples yourself, then you can still retrue it, so it will last just fine.

But you generally wouldn't need to lock the nipples if the wheel is tensioned right for the spokes and rim chosen.



Best I can recommend is to get a few old bike wheels of various kinds, and experiment with them to see how this works, without compromising your own regular wheels. Sometimes bike shops have old wheels off bikes that they are tossing out, or else you can check out thrifstores or curbside collection piles (even junk little-kids bikes are good for this).

 

[cycleops612]

seems to me the topic isnt about the best way to spoke a wheel, but I am sure many are elsewhere.

Its more about a strong wheel for big commuters, w/o the hassles your posts so amply demonstrate.

Advances have altered the paradigm. Large diameter light wheels were the preserve of spokes despite the hassle, but now there is an option at an acceptable incremental weight penalty, especially to a heavy rider.

Just a topic. Debate seems a bit quiet on ES ATM. I am not big, so not my problem.

I guess on further reflection, a geared hub & a heavy rider may not be such a good idea, but i still think a 26" cast wheel (assuming its as strong or stronger, & ideally ok for wider tires) well worth considering for a big guyS mid driveS rear wheel - noting that it precludes an IGH (of which, arguably, only the $1500-$2k rolloff would be robust enough for a big rider).

The usual solution is big heavy powerful, but that has its downsides as we know - unliftable, ~wont pedal, as hard as a motorbike to transport e.g. .

I imagine w/ most big riders, there is a get fit element to their proposed bike also, so they are buying with an eye to a bike that also suits when they get fitter - which they will.

Even sub 100kg folk going fast w/ 1kw+ motors have problems with fiddly spokes on comfortable wheel sizes.

Further, hoping am not breaching any confidences, am chatting privately w/ fluxzoom (will get bak to u soon - sorry) re his real tho unclear such situation, & best he could find in cast integrated DD motor wheels was 20". they look great cost aside.

I am sure he will share link later if not already.

Same result w/ my imperfect searches of alibaba etc., but i suspect bigger may be out there somewhere.

meh, druthers aside, it would be the last thing on the bike to break, not the first, as now. It sounds immensely strong and trouble free.

To me its engineering poetry vs archaic spokes. The rim (weakened by spoke holes)/~40 fiddly spokes &hub motor, is all reduced to one piece of precision designed and cast metal, with one moving part. Awesome.

I notice ~20" cast wheels seem almost the norm now on the pervasive petrol and electric step thru scooters of asia. I also notice those things get hammered weight wise, by a whole family on board, which seems a good test.

 

[amberwolf]

It might not have started out as about spokes, but the questions were asked/brought up, so the answers mgiht as well be posted, too.


As for the topic itself, spokeless wheels (like car wheels, etc generally are made) are plenty strong too--they're just likely to be significantly heavier, and not re-true-able if something happens to them. (at least, not at roadside).

It's also not easily possible to swap out motors within the same wheel should one choose to do so (I've done this easily twice with a spoked wheel, even being able to reuse the same spokes as well as rim/tire/etc), to upgrade torque/power). Probably not something most would ever want to do, but it is a "minus" to the spokeless-integrated hubmotor type.


Whether they are more durable than spoked wheels, I can't say, as I haven't used them--but the spoked wheels I built and use every day for commuting don't have any problems caused by the spokes. The only problem I have had in use was a rim edge failure that would have happened regardless of method of connection to the hub. :/

Given the weight of my ride and myself, and my more-than-occasional live cargo, and the potholes/debris I've been unable to avoid, that havent' damaged the wheels, it shows that the spoked versions can work just fine if they're built right, with no "hassles" of any kind (other than just doing it right to start with, which is not a hassle in and of itself, unless the person simply doesn't want to learn about how to build a wheel, or to have someone else that does know how to do it build it for them).


Nothing is bulletproof, unfortunately.

 

[MadRhino]

seems to me the topic isnt about the best way to spoke a wheel...

The discussion about cast wheels, can't avoid comparison with spoked wheels. Best way to spoke a wheel, is the answer to those who believe that a cast wheel is the best and only solution. Well it is not. It is for most heavy vehicles, inluding many motorcycles, but not for light weight motorcycles or the vast majority of ebikes. Then, they are a good compromise on scooters, and some specific ebikes with very small wheels.

Ebike cast wheel motors are easy to find, for most are obsolete and sold for peanuts. Buy one and try it for yourself if you find easier to buy a cast, than learn to lace a wheel properly.

 

[Chalo]

meh, druthers aside, it would be the last thing on the bike to break, not the first, as now. It sounds immensely strong and trouble free.

To me its engineering poetry vs archaic spokes. The rim (weakened by spoke holes)/~40 fiddly spokes &hub motor, is all reduced to one piece of precision designed and cast metal, with one moving part. Awesome.

You're simply demonstrating that you don't understand tension speed wheels. I recommend that you check out a copy of Jobst Brandt's The Bicycle Wheel from your local library, and read it. A bicycle wheel is a tensegrity structure, far more sophisticated and efficient than an equal amount of equally strong material used in an unstressed chunk.

A decade ago, Aerospoke fiberglass wheels were faddish among the fixed gear crowd, mostly for reasons of style and color choice. But even those folks have left Aerospokes behind. Though they're more than adequately strong under normal conditions, the wheels are heavy, less stiff than wire spoked wheels, and not repairable after even minor damage. Their superficial appeal didn't last, even to the folks who were predisposed to like them. The same goes for Skyway glass reinforced nylon mag wheels for BMX bikes, which were very popular thirty years ago.

I notice ~20" cast wheels seem almost the norm now on the pervasive petrol and electric step thru scooters of asia. I also notice those things get hammered weight wise, by a whole family on board, which seems a good test.

All that tells me is that one piece casting is the cheapest possible way to make a wheel that does the job. Since when have Chinese domestic market manufacturers done things any other way?