19" Motorcycle Wheels vs 26" Bicycle Wheels (rim and tires)

markz said:
Best to go with double butted spokes, 12G would be the thickest to go. You actually want a bit thinner, so 13G/14G butted Sapims if possible on moto rim. Nipple holes on moto rim are quite wide. Spinning Magnets did an article on moto rims. Can use washers on nipples.

I'd go with 12g minimum on a rear. Front wheel can be anything.

Even for bicycles, depending on the power of course, for a bike going over 40mph one should use at least 13g and for 45+ 12g or heavier spokes (rear). For a long time I rode with a 48 spoke 14g rear wheel, and while it stayed true mostly, people behind me would say that it would twist and bend under acceleration. I never knew this of course, all I saw was that once in a while a spoke would break for no apparent reason.

I now have 26" wheels built with steel rims and 10g spokes which are complete overkill! but they were cheap.. two rims, two sets of spokes shipped for under $100.
 
The size of the stock motocross straight pull hub is 110 millimeters across....the same as the hubs ive been looking at modifying .And it takes I believe a 20 millimeter axle it may be a 22 this is a small problem compared to the width. A wheel off of a 250 motocross bike mounted on a 90 pound e bike will be almost indestructible. So now I am looking at machining an adapter that will allow me to put standard mountain bike discs directly on the Suzuki hub.. Even better if I could use the hydraulic Magura brakes that come on Suzuki, Kawasaki and Honda, etc bikes. Mounting the factory OEM disk caliper will be the issue. It would be nice to have a 250 millimeter disc up front. IMO the front brakes on suzuki rm 250s and 125s are second to none.
 
Pictured is a Kawasaki hub. I have a complete wheel here. The 4 mounting holes would take an adapter plate going to the 6 bolt mountain bike discs, I was looking at machining the mountain bike hubs. To accept larger spokes. I think this is a better way to go and stronger with the 10 gauge stock straight pull spokes. I have been looking at forks the Marzocchi 888 was one of my first choices. An inverted fork may be my only choice. Because of clearance on the hub i'm going to have to do quite a bit of research. And fitting
 
How much this hub weights?

I'm considering 32H pit bike alum hub with alum 17'' 1,6 rim.

price of such wheel is 80usd. Without axle, brake rotor and sprocket. Adapters needed if used with other than pit bike SDG sprockets.

What's your opinion about his hub?
 

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It would depend on what fork you're putting it on. It would not have enough room for a disk break on some forks, . The other consideration is how fast are you going to be riding and how cheap of a hub do you want to head down the road at 60 miles an hour on?? I'm not sure why I was trying to put a bicycle hub on this in the first place to run at that speed I have access to a lathe I could make my own, and that still isn't off the table, but if I can run an OEM motocross rim on this lightweight bike, it's a no brainer.. I am going to take another front hub and lace it to a rear wheel for a mid drive set up that will have a free wheel and maybe a heavier chain.. I have several mid drive designs on the drawing board, one is a dual drive. I have to build an opposite hand free wheel and the bottom bracket will have dual drive sprockets and the bike will have foot pegs. But that's for another area of this forum. For whatever application you want that hub for. I am a big fan of straight pull spokes for sure.
 
chaindrive said:
Pictured is a Kawasaki hub. I have a complete wheel here. The 4 mounting holes would take an adapter plate going to the 6 bolt mountain bike discs, I was looking at machining the mountain bike hubs. To accept larger spokes. I think this is a better way to go and stronger with the 10 gauge stock straight pull spokes. I have been looking at forks the Marzocchi 888 was one of my first choices. An inverted fork may be my only choice. Because of clearance on the hub i'm going to have to do quite a bit of research. And fitting

I looked into doing this a while back. I concluded it would be easier to run a complete MC fork and front wheel up front and modify the fork tube to fit the frame. When I say modify, I mean building a jig around the frame, then cutting out the head tube and welding a new head tube into place. The jig would make it possible by keeping the head tube angle in check with the OEM.
 
The problem is trying to use a push bike as a motorcycle there's always compromise if you want a 60mph bike that can handle abuse then convert a trials or motocross or what ever your taste, Converting a bike to be strong enough will cost more and still be compromised in strength compared to a purpose built the China ebike frames are dangerous in my eyes and people have seriously hurt them self's when they fail, I'm modding an a2b metro to do 45mph and that's mental in my eyes it's more than twice stock power just really not designed for it and it's cost an arm and a leg to get it where it's only half safe I still wouldn't rag it hard over demanding roads if it fails I got no one to blame but myself so I best hope I hurt no one in the process but myself.
 
Ianhill said:
The problem is trying to use a push bike as a motorcycle there's always compromise if you want a 60mph bike that can handle abuse then convert a trials or motocross or what ever your taste, Converting a bike to be strong enough will cost more and still be compromised in strength compared to a purpose built the China ebike frames are dangerous in my eyes and people have seriously hurt them self's when they fail, I'm modding an a2b metro to do 45mph and that's mental in my eyes it's more than twice stock power just really not designed for it and it's cost an arm and a leg to get it where it's only half safe I still wouldn't rag it hard over demanding roads if it fails I got no one to blame but myself so I best hope I hurt no one in the process but myself.

Thats a good point Ian. The toughest ebike isn't going to be as strong as the average MX Machine. It almost makes more sense to go to the local cycles savage, find an old YZ125 or bigwheel KX80 rolling chassis and start with that. Of course modding the frame to utilize a bottom bracket and pedals, and the swingarm to accept a hubmotor along with a brake tab to mount MTB Rear brake, would be equally challenging, however, the package would be tougher. I guess this is why I am such a fan of the DIY FUTR Alpha frame. Its tough and can accept the biggest, strongest dual crown Downhill MTB fork out there.

@Chainring,my apologies for deviating from your original post, less us know what you do and how you did it.
 
strong double crown bicycle front fork 3kg - 4 kg.
MX fork around 8kg - 10kg

bicycle wheel around 2,5kg
mx wheel 4kg - 5 kg

bicycle frame from 3kg up to 15kg.
don't know how much weights mx frames but must be over 10kg.

We always can use mx parts but the weight is the factor.


If you take rolling chases of light mx than your get around 50kg-60kg without battery and motor.
So you add motor 7kg-15kg, controller2kg-5kg, battery10kg-20kg

You end up in 80kg territory at least.

So heavier the rolling chassis, heavier other parts needs to be to do push whole weight.
Light bicycles about 50kg have their own territory.
 
Guys, please let me know your opinions - based on experience. What can I expect from a radially laced rear wheel at 16kW of power?
 

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I was skeptic of radial lacing and still am little bit. I would prefer cross lacing. I had an opportunity to try mxus (45mm magnets) radial laced in 17'' mc alum rim with 7kw and does not look like there would be any strength issues due to radial lacing.
Also I see radially laced rims with 273 hubs in the internet and nobody says that they are having some issues due radial lacing. Anyways, I would say if you have option to choose than cross lacing and if no - radial.
 
for me as a mechanical engineer it feels a very bad idea.
at heavy loading, jumping, or cornering.. i do not see a real issue, but a spoke is made and basically can only bear a force along its axis.
and in the rear there are torques in two directions (braking and accelleration) that must be transferred from hub to rim. with there being no or a very small lever due to the radial lacing there will be some rotation of rim against wheel when torque is applied.
...and the worst case is when this stress is changing not only frequently but also changing direction (going down to 0N). as in going from accelleration to decelleration to accelleration.. this is theory, if it matters - especially with this power (and the possibility to go >120kph...) i don't know. just feels dangerous...?! the wheel is a given like that :(
should i give it a try and buy the bike?
 
I too understand forces in the wheel theoretically, I too think that radial wheel should fall apart much much sooner than cross spoked, nevertheless people are happily riding radial spoked wheels. Also you can consider respoking in the future. Price may be 20usd spokes plus work whatever they take for it in your place. If it's 273 and 17rim than maybe it's hard due angle to cross spoke. Maybe that's why they choose to spoke radially.
For example, QS company offer few types of spoking, one of them is radial. If radial is very weak than they might offer if because there is no option to spoke it otherwise without bending spokes which does not look esthetically. Customers would run away seeing slightly bent spokes. Maybe they offer whatever customers want.
I can't say about 273 but if it was some 205 than I would not be afraid to buy a radially spoked 17'' or 18'' mc wheel.
 
it is a 273 in 19" wheel.
i guess there is no other way to lace it (or they could't find the right length spokes? :| )..
actually, i looks like they bent the spokes to force them in radial position.. :roll:
 
joe81 said:
Guys, please let me know your opinions - based on experience. What can I expect from a radially laced rear wheel at 16kW of power?

Radial lacing makes for some super stiff wheels. just keep your spoke tension checked, and true the wheel as soon as you notice it needs it. I suspect when the spokes take a set, you will not have to worry about it.
 
It might be he is after an ebike hub. This is more motorcycle hub. These heavy hubs are tempting. I tried one in bicycle. Never gets hot and rides like a tank.
Max Torque: 200N.M
Continious current:130A
Max current:190A ,Peak 260A
Rear Fork width for installation: 200mm
Cross Section of Phase wire: 16 mm2
N.W./ G..W. : 25kgs / 26kgs
 
I am looking for something that can take some beating offroad and fits the Enduro Ebike frame. The 17" looks nice and probably is a good choice on the road, but a cast wheel is not what I am after for this bike.

Thank you for your input I am more positive to try the radially laced option now.
 
joe81 said:
I am looking for something that can take some beating offroad and fits the Enduro Ebike frame. The 17" looks nice and probably is a good choice on the road, but a cast wheel is not what I am after for this bike.

Thank you for your input I am more positive to try the radially laced option now.

If you search the forum you will see the radial lacing has been a topic several times. It seems consensus is that radial laced wheels are much weaker then say 2 x pattern lacing. Worth thinking of. If you are getting a motor and a wheel from the same manufacturer they will lace the motor into a motowheel with your choice of lacing pattern if you press them a little. As I understand radial lacing is faster and easier work then 2 x lacing but result is a weaker wheel.
 
I tried in vain with CNebikes and evelbike.
they said they cannot offer the big motors with cross patterns. I also tried pushing them to do 3x or 4x on their front wheel... nope. seems I am the only one asking them
 
Personally I would find another source then. Especially because you already stated you will be giving your ride a good bashing.
I know that QS motor will lace to you need. If you got special hub in mind for front wheel that might add extra time but they will meet your needs.

As you are located in Berlin in EU your easiest purchase would likely be to order from Artur @ http://www.vectorebike.com he stocks QS motors and will do lacing as well. They are located in Munich, Germany.

For the front wheel I've been told it is even more important not to use radial lacing due to braking force etc.

I am sure there are other sources as well. You shouldn't part with your money if you end up with a product that does not meet your requirements.
 
Not all my thoughts relevant to this topic but anyway...

You can't bash 273 really hard, it is 20.5kg plus tyre & rim and you might end up with 23kg at least. It can work as cross-country type of bike, but certainly not as motocross. It goes as a tank but you will feel heaviness in rear suspension much more than 205 hub (16kg).

The smaller rim the more dynamic ebike gets from a standstill (of course less max speed). I'm sure you know it as an engineer, but I'm just saying that there is the difference between 17'' and 19''.
Considering qs 205. Starting 190Nm in 17'' rim is a lot torque. You can push through qs 205 hub up to 150A in peaks and an even little bit more if will some cooling method applied. Losses start to increase even more but who does not want few additional Nm.

I've tried few days to ride 273 V2 - old version (with 40mm magnets, 16'' moto alum cast rim) with 130A constant and 250 phase. It was not quicker/more dynamic than qs 205 with the same settings ie 130A / 250A. Just saying that if you get 273 it will need more amps justify additional weight. The good side is big sheer masss hub never got hot, but we got FF and hub sings already. Nevertheless, I adore 273 looks.

I've looked regarding 273 hub and I see in QS page they indeed do cross spoking.
Somehow mostly I see only radial spoking on 273.

I have seen many conversions and people are going following way:
first bike - basic hub 250w/500w (gets no fun in few days...)
next - MXUS (not enough starting torque and/or heating issues...), now it is solved with cooling.
next - QS 205 (what if I get more power)
next - qs 273 (omg that's fast and heavy, if it's in ebicycle frame)
next - midrive (engineering skills, top line)


I'm in qs 205 phase. Going to order qs 205 soon. I hope I'll be at least five years. I was planning middrive but sold PMS120 (Brammmo motorcycle motor) and other parts. There is nothing more bullet proof than a hub, it's like two cents, eh.. maybe little bit heavier.
 

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Yep, the QS really as a lot of "unsprung" mass... :roll:
I think I give the bike a try as it is on 19" front and rear and later maybe have it re-laced to 24"DH and 18"MX here in Germany.
Possibly downgrading to a lighter motor.
 
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