Magnesium rims for ebikes

[johnrobholmes]

Chalo is the same guy that argues with me that rim brakes are just as good for a E bike as disc s

And Chalo is correct about this in many ways. Even with rubber based compounds the leverage and brake surface area favors rim brakes. If you don't believe Chalo, then ask a trials rider why they use rim brakes on the rear. The only two advantages that disc brakes have is that you can ride through deeper water before they get wet, and the wheel trueness doesn't affect the brake surface. In some cases disc brakes can also have less fade, but that is typically the fault of the rim brake compound being the wrong type. If we used a sintered metallic pad on a rim brake (or disc at the rims diameter for sake of argument) it would have far far less fade than a regular disc brake.

 

[recumpence]

Chalo is the same guy that argues with me that rim brakes are just as good for a E bike as disc s

And Chalo is correct about this in many ways. Even with rubber based compounds the leverage and brake surface area favors rim brakes. If you don't believe Chalo, then ask a trials rider why they use rim brakes on the rear. The only two advantages that disc brakes have is that you can ride through deeper water before they get wet, and the wheel trueness doesn't affect the brake surface. In some cases disc brakes can also have less fade, but that is typically the fault of the rim brake compound being the wrong type. If we used a sintered metallic pad on a rim brake (or disc at the rims diameter for sake of argument) it would have far far less fade than a regular disc brake.

Also high speeds tends to wear out rim brakes and make them screech. For me, I love the lever feel and progressive consistency of hydraulic disks. My wife's bike has rim brakes and does great with the 25mph it runs at.

Matt

 

[rider95]

LOL funny stuff no rim brakes are not just as good as dics for e bikes no matter what, yes if you ride slow and in the dry sure you can get away with them but using rim brakes for E bikes should be discouraged. Some are over analyzing every thing and assuming that they are right just because they are always right and never let real world experience get in there way . The guy just needed a stronger wheel build no need to reinvent the wheel just lace the hub to a downhill rim from a good wheel builder .

 

[wesnewell]

The problem with all these hub motor wheel builds is the rim spoke holes are drilled at 90 degrees , while with a 10" hub motor in a 26" wheel the angle is about 60 degrees. It has nothing to do with the size of the spokes. Every time power is applied the spoke is put under tremendous pressure at the nipple and the spoke is bent because it's not in a straight line between the hub spoke hole and the rim spoke hole. That and loose spokes are why you are breaking them.Has anyone, other than me, drilled their bicycle rim spoke holes at an angle to line up with the spoke hole of the hub motor spoke hole they are going to. Do so, and torque them properly and I doubt you'll ever break another one.

 

[liveforphysics]

The problem with all these hub motor wheel builds is the rim spoke holes are drilled at 90 degrees , while with a 10" hub motor in a 26" wheel the angle is about 60 degrees. It has nothing to do with the size of the spokes. Every time power is applied the spoke is put under tremendous pressure at the nipple and the spoke is bent because it's not in a straight line between the hub spoke hole and the rim spoke hole. That and loose spokes are why you are breaking them.Has anyone, other than me, drilled their bicycle rim spoke holes at an angle to line up with the spoke hole of the hub motor spoke hole they are going to. Do so, and torque them properly and I doubt you'll ever break another one.

I tried the proper angled rim spoke holes. No improvement for my application.

A spoked wheel is strong when it can distribute stress over a wide area.

If your spokes don't have adequate stretching on them, the wheel can't share the stress, and instead focus it on individual spokes breaking them. (Or deforming the rim so the spoke loses tension, which also results in spoke breakage).

If you want it to survive huge power and huge impacts, don't go bigger than 14-15awg, and tension the spokes to be as even as you can get, at a tension so high it's actually yielding the spoke to set it.

 

[liveforphysics]

I should add, whilst that method makes the most durable robust wheel, it does change the failure mode to something generally more exciting.

Wheels built that way tend to fail completely and catastrophically when they fail. They hardly even get out of true for the life of the wheel in my experience, but when some impact/event occurs with the energy to fail, they fail essentially everything at once and you're left with a hub that once had a rim around it instead of the wadded up mess of aluminum and steel.

 

[friendly1uk]

For what it's worth, I work with a fleet of more than 50 pedicab trikes. They side load the heck out of their wheels, which are 26" or 29" in diameter, and which sometimes carry 1000 pound loads among three wheels. The trikes in the fleet have wheels with 14ga, 13ga, and 12ga spokes. Of these, the thinner spokes have proven to be the most reliable, with the thickest spokes being the least reliable.

The latest wheels I've been building are 29", with custom spec 1000g, 42mm wide rims and forty-eight 14ga spokes each. That's what we have determined works best after years of observation-- use a stout rim but normal thickness spokes.

The qualities of a hub motor wheel with less than 40mm between the spoke flanges are very different from, and less rugged than, those of a pedicab wheel with close to 100mm between the flanges, but the prescription for reliability is the same.

So you can respond without being a asshole ? Im impressed.

You may not of liked the tone he used while helping you, but I don't see where he posts purely to insult you.

This is not a playground or twitter or facebook. There are no children here. Nobody is giggling. In years to come you may have your children get hold of your user name and look about to see who their dad is. Or maybe your mum will pop your name in google and find this. Who do you think will read such posts and be glad your family? This is an ebike discussion forum. Stop swinging your handbag at people only interested in helping you.

 

[ebikedelight]

For what it's worth, I work with a fleet of more than 50 pedicab trikes. They side load the heck out of their wheels, which are 26" or 29" in diameter, and which sometimes carry 1000 pound loads among three wheels. The trikes in the fleet have wheels with 14ga, 13ga, and 12ga spokes. Of these, the thinner spokes have proven to be the most reliable, with the thickest spokes being the least reliable.

The latest wheels I've been building are 29", with custom spec 1000g, 42mm wide rims and forty-eight 14ga spokes each. That's what we have determined works best after years of observation-- use a stout rim but normal thickness spokes.

The qualities of a hub motor wheel with less than 40mm between the spoke flanges are very different from, and less rugged than, those of a pedicab wheel with close to 100mm between the flanges, but the prescription for reliability is the same.

So you can respond without being a asshole ? Im impressed.

You may not of liked the tone he used while helping you, but I don't see where he posts purely to insult you.

This is not a playground or twitter or facebook. There are no children here. Nobody is giggling. In years to come you may have your children get hold of your user name and look about to see who their dad is. Or maybe your mum will pop your name in google and find this. Who do you think will read such posts and be glad your family? This is an ebike discussion forum. Stop swinging your handbag at people only interested in helping you.

Blow it out your ass

Theres ways to help people , without acting like a arrogant prick. Evidently a few people that responded, think they are gods gift of perfection, because they are knowledgable about ebikes. Fortunately several posters on this thread responded with good info, and did it respectably.

 

[Stevil_Knevil]

Is there any company where you can send your brushless hub motor and they can attach it to a bike rim using thick magnesium struts ?

We are very sorry to inform you that there are no companies or individuals currently offering that service.

Feeling better now?

 

[Miles]

Blow it out your ass

Theres ways to help people , without acting like a arrogant prick. Evidently a few people that responded, think they are gods gift of perfection, because they are knowledgable about ebikes. Fortunately several posters on this thread responded with good info, and did it respectably.

Cut out the personal comments, please.

 

[johnrobholmes]

Although rim brakes are great and all, anything above a 30mph or 60lb ebike I do use disc brakes too.


I drilled a rim at angles once. Marginally better. What actually solves the angle problem is to redrill the holes in the hub flange closer together for a 82 degree spoke insertion into the rim.

 

[dawrench]

Cars need massive rims and spokes because of the side loads on the wheels.

Motorcycle wheels are built the way they are because of the way they are used. Look closely at them. Then look at the wheels on a sidecar rig.

Chalo is in a perfect position to know what works for heavily loaded bike wheels and try new approaches. Just stop talking and listen. Then try what he says.

 

[bigsi]

Haha some guy

My local bike shop went with 12 ga spokes

The only 12ga spokes my wholesalers provide are no-name stuff. If you're breaking 12ga spokes, you can assume they are bad. Good 12ga spokes generally don't break in bicycle use. They loosen up chronically, they make noise, they crack your rims; but they don't break unless they're kinked at the threaded end.

A wheel is a tensegrity structure, meaning its structure depends on the taut members remaining taut. 12ga spokes are not elastic enough to stay taut under load in a bicycle wheel, so the wheel doesn't work as well or carry as much load as a wheel with thin spokes. If you want to beef up a wheel, beef up the rim. The spokes must be thin (in comparison to their static tension) to support the rim at all times.

but part of my problem may be that I went with airfree tires so I never have to worry about flats. I think if I had used normal pneumatic tires , spoke breakage may not be a problem at all.

What was that I told you about not assuming the whole world is doing it wrong? After decades on the market, foam tires are still a fringe product for very good reasons. And yes, one of those reasons is that they beat your wheels to pieces. Just for my amusement, I'd be curious to see how your rims are doing.

At this rate, the next thing we're likely to learn is that you ride a recumbent.

 

[rider95]

You and your personality are invisible due the anonymity that you hiding under it in this forum.
You can not use the word ..me.. when you are hiding.
And also driving an ebike does not need any expertize. lol what?? invisible ??

 

[rider95]

Kiriakos GR only clowns use cartoons and drive bikes we ride bikes over here

 

[markz]

For what it's worth, I work with a fleet of more than 50 pedicab trikes. They side load the heck out of their wheels, which are 26" or 29" in diameter, and which sometimes carry 1000 pound loads among three wheels. The trikes in the fleet have wheels with 14ga, 13ga, and 12ga spokes. Of these, the thinner spokes have proven to be the most reliable, with the thickest spokes being the least reliable.

The latest wheels I've been building are 29", with custom spec 1000g, 42mm wide rims and forty-eight 14ga spokes each. That's what we have determined works best after years of observation-- use a stout rim but normal thickness spokes.

The qualities of a hub motor wheel with less than 40mm between the spoke flanges are very different from, and less rugged than, those of a pedicab wheel with close to 100mm between the flanges, but the prescription for reliability is the same.

Good to know, against assumed logic. 14AWG (Thinner) is better then 12AWG (Thicker).

 

[Deafcat]

Not all spokes are equal; not all wheelbuilds are equal. If you're having problems breaking spokes, you have a deficiency in one or the other. Don't assume the whole world is doing it wrong just because you bought bottom-dollar Chinese junk.

My prescription is high quality 14 or 14-15ga spokes, laced to a good rim in a pattern that doesn't cause them to enter the nipple at an angle, plenty of tension (at least 100 kgf on the tighter side), and a careful assembly job including stress-relieving.

Totally.

thousands or maybe millions of motor vehicles are on spoked wheels, why on earth would anyone want to gamble with machined alloy wheel structure on a bike when spokes work so well? I would actually trust spokes more than most machined alloys, especially considering how much it would cost to build a better machined wheel than a spoked alternative. Not to mention, that one off wheel? only compatible with the hub it was designed for. terrible solution all around.