A seller told me the Ryde Andra 40 is not a suitable rim for a 1000w hub motor. Is that true?

P

Planet Indigo

100 mW
Joined
Sep 22, 2018
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I was interested in buying a Ryde Andra 40 to replace the rim of my 1000w rear hub motor because I had read on this forum that it was one of the strongest rims available.
After contacting an online seller (bike24 website) to ask a few questions, I was told that that rim was not suitable for 1000w motors but only for 250w motors going up to 25kph.
Is that true or is the seller mistaken?
The official website talks about it being compatible with e bikes but doesn't specify max wattage.
Given that it's being advertised as a very strong rim and that it seems to be the feature most discussed when that rim is reviewed, I was a little surprised to hear this from the seller.
 
That's 'i don't know' from someone who has never built an ebike in their lives. There's no such thing as a wattage limitation for a rim.

This Ryde Andra 40 is a stronger rim than what i'd normally use on a bikes that do up to 35mph.

Hub motors don't require anything stronger than a mountain bike rim. Chose a double walled rim ( standard for MTBs ), and you're good. The Ryde Andra 40 is double walled and fairly thick already.

The tire choice is a lot more crucial; ebike wheels, due to their increased speed vs a bike, will have stronger forces hitting them as they smack bumps and such. Protecting against damage to the rim is the function of the tire. If you previously destroyed a rim after hitting a pothole, the reason was because you didn't have enough air volume to absorb the impact. So what you really needed was a bigger tire or increased PSI before.

How big of a tire you need depends on your speed and wheel diameter. What were you dealing with before?
 
Ryde Andra 40 is an excellent rim for a powerful hub motor. I've built a few of them, and I have only one caveat: do not drill them out for thick spokes if they weren't made that way originally.

Most (oddly not all) examples of Andra 40 have countersinks on the inner surface of the drilled holes. This is because the spoke bed of the rim is extra thick, and without the countersink, the depth of the hole might restrict the nipples' ability to tilt in line with the spokes to a normal degree. If you enlarge the holes so you can use spokes thicker than 14ga, you'll lose some of the countersink depth. If you try to enlarge the countersinks yourself, you'll have a very hard time getting consistent depth, and you may harm the rim's structural integrity.

So if you use Ryde Andra 40, use 14ga, 14-15ga double butted, or 13-14ga single butted spokes, with washers at the hub if necessary to mitigate oversized holes in the hub. Incidentally, that will give you the best possible combination for high static and dynamic loads on a bicycle wheel: a strong stiff rim combined with relatively thin elastic spokes.
 
neptronix said:
That's 'i don't know' from someone who has never built an ebike in their lives. There's no such thing as a wattage limitation for a rim.

This Ryde Andra 40 is a stronger rim than what i'd normally use on a bikes that do up to 35mph.

Hub motors don't require anything stronger than a mountain bike rim. Chose a double walled rim ( standard for MTBs ), and you're good. The Ryde Andra 40 is double walled and fairly thick already.

The tire choice is a lot more crucial; ebike wheels, due to their increased speed vs a bike, will have stronger forces hitting them as they smack bumps and such. Protecting against damage to the rim is the function of the tire. If you previously destroyed a rim after hitting a pothole, the reason was because you didn't have enough air volume to absorb the impact. So what you really needed was a bigger tire or increased PSI before.

How big of a tire you need depends on your speed and wheel diameter. What were you dealing with before?
Click to expand...

Thanks, I kinda figured the seller was mistaken but I wanted to make sure.
I originally had a rear rim and tire that came with my 1000w motor kit. A chinese silver rim 31mm external width (25mm internal) with 25mm height profile, double walled, and a 26" 1.75" wide road tire. I was running about 40 psi when I hit that pothole at about 20-25mph (it bottomed out my rear shock). I am planning to use wider tires when the thread on those tires is gone. The pothole was a bit of a freak incident but I still would like to go stronger in the rim replacement. Do you know about any rim/brand model of disc brake rims that would be at or near the strenght and price of the Ryde Andra 40 but would be sold by some sellers in the US? (trying to save money on high shipping costs from european sellers, and I can't find any US seller that carries the Andra 40).
Also, out of curiosity, were you running 12g spokes on that 6000w motor hub you talked about in my last thread?
 
Chalo said:
Ryde Andra 40 is an excellent rim for a powerful hub motor. I've built a few of them, and I have only one caveat: do not drill them out for thick spokes if they weren't made that way originally.

Most (oddly not all) examples of Andra 40 have countersinks on the inner surface of the drilled holes. This is because the spoke bed of the rim is extra thick, and without the countersink, the depth of the hole might restrict the nipples' ability to tilt in line with the spokes to a normal degree. If you enlarge the holes so you can use spokes thicker than 14ga, you'll lose some of the countersink depth. If you try to enlarge the countersinks yourself, you'll have a very hard time getting consistent depth, and you may harm the rim's structural integrity.

So if you use Ryde Andra 40, use 14ga, 14-15ga double butted, or 13-14ga single butted spokes, with washers at the hub if necessary to mitigate oversized holes in the hub. Incidentally, that will give you the best possible combination for high static and dynamic loads on a bicycle wheel: a strong stiff rim combined with relatively thin elastic spokes.
Click to expand...
Interesting, are you saying that by default none of the Andra 40 rims that you have seen (and they seem to vary since you said they were not all the same) could accommodate 12g spokes with their default drilled holes? I was kinda trying to stick with overengineered 12g spokes since that's what came with it and my hub has the holes drilled for 12g.
 
Ahh, 1.75" wide tire is kinda weak compared to a 2.0 or larger.

12g spokes have extremely bad road feel, a hub motor doesn't really need them in practice, they're used because they are cheap, not because they're good.

I would follow Chalo's advice, he knows what he's doing in this arena
 
Planet Indigo said:
Interesting, are you saying that by default none of the Andra 40 rims that you have seen (and they seem to vary since you said they were not all the same) could accommodate 12g spokes with their default drilled holes? I was kinda trying to stick with overengineered 12g spokes since that's what came with it and my hub has the holes drilled for 12g.
Click to expand...
There are versions of Ryde rims that are drilled for oversized spokes. But it would be a mistake to use one of those if you have a 14ga version available.

Thick spokes make weaker, less reliable wheels. I've discussed this in detail here many times.
 
Yeah, ~14 gauge spokes is the way to go. The wheel will have a couple millimeter of give when you are hitting a bump, which helps contribute to the wheel's suspension and contributes to protecting the rim - nowhere near as much as the tire does, but every bit counts.

The 12 gauge spokes you had previously have close to zero give and didn't help soak up that large impact to the wheel. The rider quality is also poorer with ultra stiff spokes.

I would not use those again.
 
neptronix said:
The 12 gauge spokes you had previously have close to zero give and didn't help soak up that large impact to the wheel. The rider quality is also poorer with ultra stiff spokes.
Click to expand...

Beyond any effect on ride quality (which would be a result of rim flex anyway), the thinner and more elastic spoke has an easier time remaining taut when the rim deflects from load or impact. A thick spoke goes slack momentarily when loaded, which creates periodic opportunities for the nipple to unscrew and for the spoke and nipple to chafe the rim and hub. Then when the rim flexes back to its original shape, the contact between nipple and rim is more abrupt and hammer-like, which promotes cracking at the rim hole.
 
If you really want to use 12 guage spokes you will need a really stiff rim. Think moto rim.

With a moto rim you will not get faster fatigue of the spokes at the elbow like you would with a flexy bicycle rim. The moto rim eliminates the need for 14 guage spokes and such in order to build a "durable wheel".
 
Almost nobody choses to go that route because the rotating weight is much higher and this will have an adverse effect on acceleration. maybe a good idea if you're doing hardcore motorsports.

Ideally the tire does the job of preventing contact from ground to rim.
 
neptronix said:
Yeah, ~14 gauge spokes is the way to go. The wheel will have a couple millimeter of give when you are hitting a bump, which helps contribute to the wheel's suspension and contributes to protecting the rim - nowhere near as much as the tire does, but every bit counts.

The 12 gauge spokes you had previously have close to zero give and didn't help soak up that large impact to the wheel. The rider quality is also poorer with ultra stiff spokes.

I would not use those again.
Click to expand...

Using rim flex as suspension is a really bad idea when suspension and/or increasing tire size are options. Even having a steel frame with a bit of give would be a much better idea than having the rim flex.
 
It'd be useful when crashing into a pothole to have a few millimeters of motion instead of snapping at the weakest part ( now the hub itself since the spokes and wheel are super strong. )

a little bit of flex is how bike wheels were designed to work and when we have a very tall hub ( DD motor ), we have half the spoke length, so the spoke doesn't need to be as strong, 14 gauge is totally good.
 
neptronix said:
It'd be useful when crashing into a pothole to have a few millimeters of motion instead of snapping at the weakest part ( now the hub itself since the spokes and wheel are super strong. )
Click to expand...

Thing is, hubs don't hang from the spokes. The forces being traded are concentrated between ground and hub, and they subtract from spoke tension rather than adding to it.

From Ian's Bicycle Wheel Analysis

3c_spoke_values.png

The late Jobst Brandt used to say "the wheel stands on its spokes", and he was correct inasmuch as the hub is being supported by the static preload in the spokes being "stood" upon.
 
neptronix said:
a little bit of flex is how bike wheels were designed to work
Click to expand...

Wire motorcycle wheels flex too; they just do it at motorcycle weights and speeds. That why they need tightening from time to time.
 
neptronix said:
It'd be useful when crashing into a pothole to have a few millimeters of motion instead of snapping at the weakest part ( now the hub itself since the spokes and wheel are super strong. )
Click to expand...

A few millimeters of deflection at the part of the rim over the tire contact patch would be way way too much deflection. Certainly well before that level of rim deflection the spokes at the part of the rim above (and around) the tire contact patch have gone completely slack. This even more so because with a 232mm PCD hub motor the spokes don't have that much length to begin with.

At the same time the other spokes in the wheel which are trying to resist the circular rim becoming an oval will be under extreme tension and thus pulling very hard on the spoke flange which, of course, stresses the hub flange.
 
neptronix said:
a little bit of flex is how bike wheels were designed to work
Click to expand...
A bicycle wheel is a tensioned structure unlike a wooden wagon wheel (or a bicycle "mag wheel") which does not support itself through tension but rather by resisting compressive forces between the hub and the tire contact patch.

The flex that occurs in a tensioned bicycle wheel is not purposely designed in it is merely a undesirable but accepted consequence of pursuing high strength to weight ratio and aerodynamics.
 
The reason that wire wheels are still with us after 150 years is because of their built-in resilience and repairability. People keep trying to make bike wheels stiffer and more monolithic, and they keep failing to achieve anything worthwhile that way.
 
Chalo said:
The reason that wire wheels are still with us after 150 years is because of their built-in resilience and repairability. People keep trying to make bike wheels stiffer and more monolithic, and they keep failing to achieve anything worthwhile that way.
Click to expand...
You can also make a wheel stiffer by adding more spokes.

A wheel with 48 spokes instead of 36 spokes will be more resilient for hitting potholes and yet at the same time it will also be stiffer.
 
ebike4healthandfitness said:
You can also make a wheel stiffer by adding more spokes.

A wheel with 48 spokes instead of 36 spokes will be more resilient for hitting potholes and yet at the same time it will also be stiffer.
Click to expand...
It will only be stiffer laterally; in-plane stiffness is a function of rim material and geometry alone.

I have ratholed 48 spoke parts for decades. I even got a custom run of 72 hole rims made. Anymore, you can get better structural integrity from 36 spoke and even 32 spoke equipment because the available rims are better optimized.
 
Fingers crossed that we're not over OP's head already.. 😅
 
Chalo said:
It will only be stiffer laterally; in-plane stiffness is a function of rim material and geometry alone.
Click to expand...

No, a wheel using the same rim will increase its radial stiffness by increasing its spoke count.

Everything I have read over the last few decades has always said this and it makes sense. Why and how could this not be true?

The only time a stiff rim will always be radially stiffer than a more flexy rim is when there are no spokes in the equation.

Push down on the flexy rim (without any spokes) and it will obviously go from circular to slightly oval much easier than the stiffer rim (without any spokes). However, once spokes are added to the rim via a hub it becomes a tensioned structure and the spokes work to prevent the shape changing from a circle to one that is slightly oval.
 
Some links to back up what I wrote:

www.declinemagazine.com

Do More Spokes Make a Wheel Stronger? | Decline Magazine

Do More Spokes Make a Wheel Stronger? A bike wheel with more spokes is stronger than a bike wheel with fewer spokes. However, different spokes offer differing levels of strength and durability.
www.declinemagazine.com www.declinemagazine.com

"The spokes number determines your bike’s lateral stiffness as well as its radial stiffness in that it will enable you to control the bike with better speed and traction.

So, the more spokes your bike has, the better it is in terms of lateral stiffness and radial stiffness."

Rim Strength And Lacing

More charts and graphs today! I finally figured out how to illustrate a point that's been banging around in my head for a long time, which is how rim strength affects lacing. We've talked about lateral stiffness in rims a bunch of times (enough to earn ourselves the clearly affectionate...
novemberbicycles.com novemberbicycles.com

The above link has an experiment demonstrating how adding spokes to a rim increases its radial stiffness.

How Bicycle Wheels Work – Spinning True

spinningtrue.com spinningtrue.com

"different spoke counts and lacing patterns also have a theoretical effect on radial stiffness"

"radial stiffness can be affected by the design of the rim, with deeper section rims being more resistant to bending than shallow rims, as well as by the spokes, with more or thicker spokes being more resistant to slackening or lengthening."

elevationwheelcompany.com

What is a radially compliant rim? - Elevation Wheel Company

elevationwheelcompany.com elevationwheelcompany.com

"Spokes play another major role in how a wheel rides, both with radial and lateral stiffness. Spoke type, spoke lacing pattern and spoke count all play a big role here. In general, the thicker the spoke and the more spokes you use, the stiffer the wheel will feel both radially and laterally."
 
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Spokes can only pull. The more of them there are, the more they can support and stabilize the arc of the rim, but the in-plane rigidity of the wheel is still primarily a function of the beam stiffness of the rim. For spokes to contribute more than very slightly in that regard they'd have to carry compressive loads, and they can't do that. The only way they can contribute to in-plane stiffness is to resist the rim's tendency to deflect outward on either side of the loaded section (those couple of spokes in the diagram above that show positive values around 40 on the scale), when that's only a tiny fraction of the deflection that's happening.

It's the same reason why thick spokes don't stiffen a wheel radially. They can't affect the bending stiffness of the rim, so when it flexes inward under load they just slacken.
 
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