Broken Spokes (On Going Problem)

[markz]

I currently have 8 broken spokes on a Leafbike laced 26" wheel, rear hub.

Have had it now for, 3-4 months I'd guess.

Same old problematic broken spokes I've always been having for years for 380lbs. This time though, its a new kind of damage I've never experienced.

Leafbike does 12G, the rim is brand name non-V-brake rim, disc only. Not sure what brand (if any) spokes they use.

Interesting spoke breakage (see pictures below) - Right at the top of the J-bend. In some circumstances right above the bend, so the entire spoke, plus a hair of the bend was intact.

Riding - I was babying it, not wanting broken spokes AGAIN! I would slow down for curbs, and sidewalk edges/buldges, wouldnt even do corners at 30kph, hardly ever want any sideways load.

I might as well go cast wheel, I do have a 19" motorcycle rim, requires purchase of 125mm spokes.

Quick and easy solution is the "18 inch casted hub with magnet" - Item ID #LBMP-18INCH - $95usd
The biggest downfall is if I hit the rim, or get a crack in the cast, then s.o.l.
https://www.leafbike.com/products/e-bike-hub-motor/18-inch-casted-hub-with-magnet-976.html

 

[markz]

No mention of the inside "wall-to-wall" width of the cast wheel.
The question for the cast wheel is, whats the tallest tire I can obtain?
Because the bicycle has 26" wheels, a 26" front wheel.
Only 2 out of four 18" tires available at Chain Reaction Cycle. 18x2.2 and 18x2.3 BMX tires.
Motorcycle tires is up for grabs.



That cast wheel states
Package Size: 46cm L x 46cm W x 10cm H
Detail:
Hub: Ø372mm Casted Alloy (Hub Fit For: 18 × 2.125" / 2.5" tire)
Material: aluminium
Magnet quantity: 46pcs
Magnet height: 30mm
Magnet thickness: 3mm
Used for: 36V 750W & 48V 1000W
Net weight: 2.8 kg / 6.2 lbs
Gross weight: 3.2Kg ( after packing )

 

[markz]

https://www.kimpex.com/en-ca/products/motorcycle/tires-tubes-and-repairs/tires/mitas-mc11-moped-sport-tire
Mitas MC11 18 x 2.5 $61cdn

https://www.kimpex.com/en-ca/products/motorcycle/tires-tubes-and-repairs/tires/mitas-b3-moped-classic-tire-reinforced
Mitas B3 18 x 2.5 $40cdn is more reasonable price

https://www.kimpex.com/en-ca/products/motorcycle/tires-tubes-and-repairs/tires/duro-trail-tire-hf307a-hf307
Duro Trail Tire (HF307A/HF307) 18 x 2.75 $49cdn out of stock

 

[speedmd]

It does look like maybe the hole is a bit too big and or thick flange is helping ripping the caps off. All look like that? Is there room for washer?

You want the spoke to start load transferring at the spoke bend and not bend and load at the cap base. Your healthy spokes and hole dents should lend some clues on fails. If you can fit washers, I would add them on both ends and find a good wheel mechanic to evenly tension them firm. Min 110kg. Make sure it stays there. If that does not hold or you pop one, then you go up in gauge.

BTW, the cast wheels in this class are mainly permanent mold alloys that are much weaker and crack prone than good hard extrusion alloys. I wish they could- would be made with hard strong alloy.

 

[goatman]

https://www.kimpex.com/en-ca/products/motorcycle/tires-tubes-and-repairs/tires/mitas-mc11-moped-sport-tire
Mitas MC11 18 x 2.5 $61cdn

https://www.kimpex.com/en-ca/products/motorcycle/tires-tubes-and-repairs/tires/mitas-b3-moped-classic-tire-reinforced
Mitas B3 18 x 2.5 $40cdn is more reasonable price

https://www.kimpex.com/en-ca/products/motorcycle/tires-tubes-and-repairs/tires/duro-trail-tire-hf307a-hf307
Duro Trail Tire (HF307A/HF307) 18 x 2.75 $49cdn out of stock

one of my bikes had that problem, went to grin and got their dual gauge? sapim spokes, they've been awesome. wheels stay true on my 24x3.0 at 2500 watts and on my trike same spokes at 2200 watts and haven't had to true my wheels. I just had to buy a new tire for the 24 because the sidewalls are about to let go

 

[markz]

one of my bikes had that problem, went to grin and got their dual gauge? sapim spokes, they've been awesome. wheels stay true on my 24x3.0 at 2500 watts and on my trike same spokes at 2200 watts and haven't had to true my wheels. I just had to buy a new tire for the 24 because the sidewalls are about to let go

Gosh what a dream that would be for me. Yes I had sapim double butted spokes from Grintech, sapims from local store, even tried generic ebay spokes because I'm cheap, did washers on the mxus 4503, dunno what brand spokes on the current leaf. Laced wheel with boiled linseed oil, regular oil. Tightened them up over time.

I plan to replace the broken spokes with 12G custom cut sapim's from either a local store, if their open and have their wheelguy there, I guess everyone else cant cut spokes.... or just go to grintech and get them mailed.
Still baby it while riding.
Order cast rim from leafbike.
Order 125mm 12g spokes for motorcycle 19" rim.

 

[amberwolf]

The j-bend break is the same thing you get with any of these too-thick-spoke-for-the-rim wheels; thicker spokes don't make a better wheel. Don't ever expect a premade hubmotor wheel to be built correctly or of the correct parts.

It's been discussed in so many threads that you can just look thru my posts for "spokes" or "spoke" and find a bunch of detailed info.

Comes down to: don't use spokes that are thicker than the rim was designed for. First use a rim designed for the load being put on it, and then use spokes that can be fully and correctly tensioned for that rim, and then do that. Ride the wheel a dozen miles, retension if necessary, then ride a hundred miles, and retension if necessary. After that it shouldn't have to be touched if it's built right.

 

[Drunkskunk]

2 things will cause that kind of failure. First, too thick of spoke causing the spoke to not be properly tightened. this leads to the spoke being able to move, and eventually fatigue.
Second, the cross is wrong on those spokes. on a single cross lace pattern, the spoke should cross behind it's opposite spoke. that puts pressure on both spokes, forcing the elbow against the hub, and releaving all pressure on the spoke head. On a properly built wheel, you could cut the spoke heads off and the spokes would never come out because of that cross.

I know you've been fighting this problem for a while, what about throwing in the towel, and building a motorcycle wheel instead?

 

[MadRhino]

We had discussed this long ago Mark. Maybe you didn’t believe me then, so I see that you are still with the same big spokes.

You have three options:

Going cast wheel and buy spare cast wheels instead of spare spokes.

Going motorcycle wheel to reduce maintenance at the cost of extra weight and performance loss.

Learn to build a good bicycle wheel and, to maintain it true and tight. This does start with quality spokes of the proper gauge, flange washers, nipple washers, long nipples. Completes with proper lacing pattern, proper tension, and regular maintenance.

 

[markz]

Second, the cross is wrong on those spokes. on a single cross lace pattern, the spoke should cross behind it's opposite spoke. that puts pressure on both spokes, forcing the elbow against the hub, and releaving all pressure on the spoke head. On a properly built wheel, you could cut the spoke heads off and the spokes would never come out because of that cross.

I know you've been fighting this problem for a while, what about throwing in the towel, and building a motorcycle wheel instead?

12G is too much, I agree, but shoulda lasted babying it. I'll have to look at it tomorrow to see if the spokes are elbows in, then next one on same flange is elbows out. Then there wont be pressure where they touch. There is a rubbing spot where the two spokes overlap on a 1 cross. I've seen some builds with alternating eblows in elbows out, but seen other builds where their all the same, whether all elbows in or all elbows out. Depends on dish I guess, which I never cared about.

Alternate the elbows in and elbows out on same flange, rather then doing it all the same.

 

[speedmd]

When your tension comes out of the wheel, you end up with one or two of the tighter spokes taking huge loads rather than spreading the loads out about the wheel through many spokes. As most here now understand, the thicker spokes allow for much less stretch and easier to become unsprung with minimal strain in the wheel. 12 gauge (2.6mm) may be a bit too thick depending on how sturdy your rim is. Washers will greatly help even weaker rims hold spoke tension by reducing the dent the knipples will induce on them.

+1 on the sapim, lacing- cross- weave and moto rims. Sapim do make a 14-13 (2.0-2.3mm) gauge with the thicker end at the j bend. Spoke Tension is the critical factor here. Soon as you knock out the rim at all with the thick spokes, most of them will go slack because they have only a tiny amount of stretch in them to begin with.

 

[MadRhino]

14 gauge is the size for bicycle rims. Can be playing between 13 to 15 gauge when using butted spokes, but standard spokes must be 14. I prefer standard because they are available locally. My favorites are DT Swiss standard SS spokes, that many bike shops have in stock. Long brass nipples 16 or 18 mm, brass oval rim washers, soft alu conic flange washers. Favorite rims are old school DH racing, trial, and some wide chopper rims.

Lacing in or out of the flange is a matter of the following factors: flange width and shape, rim holes offset width, rim diameter size, dishing. When none of those factors interferes, I prefer standard single cross alternate (one in, next out). Flange washers are letting us extra freedom of pattern and tension, would it be necessary because of some of the factor(s) interfering with proper alignment.

 

[DogDipstick]

I never had this problem in 1000 miles of abuse. I agree the wheel leading spokes should be behind the trailing. Hope I aint speaking to soon, but yeah I beat on mine. 12g Spokes in a Suron rim. All leading behid trailing, and all spoke heads in.

8Kw. Jumping and landing spinning fast. Linelocks. Endo witha spinning wheel then slam the wheel bac down and hear the "Zfffft" of the wheel skidding from unloaded to loaded. Holding the front brake and pushing as many amps through the rear as I can. Going as faast as I can onlly to do the "j-skid" every kid loves with the back tire.

Hell you guys know I cooked the Halls in 720 miles, so it has gotta be at least a little abused, right? Lol. I tried thicker cheaper spokes but they never tensed. 12G and the Suron rim never let me down.

Went with 25$ of custom Sapim from Yojimbos Garage on eBay. I know you guys are trying to save 4-6 lbs for using a bicycle wheel.. but.... if they fail regularly, it is either something wrong and cannot handle it, or the wheel is build to light... and she is gonnna make you sit someday waiting for repairs.

On a properly built wheel, you could cut the spoke heads off and the spokes would never come out because of that cross.

 

[MadRhino]

I never had this problem in 1000 miles of abuse. I agree the wheel leading spokes should be behind the trailing. Hope I aint speaking to soon...

Yes and no

Yes, you are speaking too soon. There are some nice summer weeks that I ride close to 1000 miles.

But no, you are not as likely to have wheel problems as one big guy who is riding a hard tail hub motor build on bicycle rim. Heavy wheel and short spokes, you know...

 

[serious_sam]

Lacing in or out of the flange is a matter of the following factors: flange width and shape, rim holes offset width, rim diameter size, dishing. When none of those factors interferes, I prefer standard single cross alternate (one in, next out).

+1

On a properly built wheel, you could cut the spoke heads off and the spokes would never come out because of that cross.

Cut all of your spoke heads off and tell us how you go then...

 

[markz]

The spokes on the Leaf 1500W are alternating elbows in then elbows out on same flange.

Did 36km today with 11 spokes broken today, to get some custom spokes. I felt maybe 2 break on the ride.

 

[markz]

Also remember I am 380lbs of weight on the rear hub wheel, motorcycle weight needs likewise.

 

[spinningmagnets]

This is one area where Chalo was a certified expert who converted more than a few ebikers. I would ask if you are willing to convert over to using a moped rim with angled nipple-holes?

If no...purchase spokes of a known quality from a respected vendor. I have had good luck from Dans Comp, and they will provide custom spoke orders that are not listed on their website. 1-844-970-4269

Switching to a frame with rear-suspension will dramatically reduce the peak shock-loads from hitting a pothole, as will switching to a fatter tire (which may also require a slightly smaller-diameter rim).

The rim is more flexible than most people would assume. When you hit a bump, the rim attempts to take on an egg-shape. A thick spoke is not flexible. If one or two nipples become looser, the remaining nipples take on more load.

In the pic below, washers were added under the spoke-heads, in order to move the "loading" closer to the spoke-head elbow, instead of farther out (moving the pull-load farther out would give it more leverage). washers = good.

 

[goatman]

if youre mixing spokes it wont work. they all need to be the same or youll just keep popping the heads off.

 

[MadRhino]

if youre mixing spokes it wont work. they all need to be the same or youll just keep popping the heads off.

Yep. But I would not replace 11 spokes, other than a temporary emergency solution. I mean, when so many spokes had broken on a wheel, many of the remaining spokes had suffered damage already, and likely to break soon. It is a case for a new lacing job, with a complete set of identical, quality spokes of the proper gauge. That is why I like lacing with spokes that are commonly used in the bicycle industry, for I can buy them at the corner shop, cut and thread them in half an hour, lace the wheel and ride.

 

[amberwolf]

Also remember I am 380lbs of weight on the rear hub wheel, motorcycle weight needs likewise.

Nope.

SB Cruiser is 500lbs+ with me on it, and then I carry your weight in groceries in the back on top of that (or a wiggly St Bernard or two).

The rear wheels are 20" eyeletted doublewall wide rims, you could get good BMX rims that would probably be just like them. They use 13/14g single-butted Sapim spokes, radially laced no less, with the heavy MXUS 3K 450x hubmotors in them.

The trike is no suspension.

I don't get broken spokes, dpesite the road problems.

I have broken hubmotor axles...but not spokes.

I have dented rims, including crushing the bead seat area...but not broken spokes.


Really, you should try what I said, and look up my posts with "spoke" or "spokes" in them, for the many about this specific problem.

THen follow that advice.

Or look up Chalo's posts about the same thing.

Then follow his advice.


Otherwise I wouldn't even guarantee that motorcycle wheels will fix your problem, if you get those built like these wheels are.


FWIW, riding on a wheel with even a handful of broken spokes, especially when you know there is a problem with the wheel causing this breakage, is asking for a complete wheel collapse and a crash.

Don't do that.

If one or two nipples become looser, the remaining nipples take on more load

They also start unscrewing, loosening more, breaking more elbows, etc.

 

[Balmorhea]

Junk quality spokes are a problem. Too-thick spokes are a problem. Not stress-relieving the spokes at the time the wheel is built is a problem. Your wheel probably has all three problems.

I have some experience building trike wheels that are used to carry 700+ pounds per wheel, but rarely break spokes. The rims are massive but the spokes are thin. They aren’t 12ga spokes; they’re 14-15ga butted spokes. That’s because the heavier the load you put on a wheel, the thinner the spokes must be to reliably work with any given rim.

A thick spoke, even if it’s quite tight, goes slack easily when a load is placed on the wheel, because it doesn’t have enough stretch to stay taut in the rim as it flexes under load. A spoke that slackens once per rotation can gradually loosen. And a slack spoke is the same as a missing spoke, in its ability to support the wheel’s structure.

To generalize: A wheel’s strength is in its rim. A larger number of spokes makes a wheel stronger. But thicker spokes make a wheel weaker, at least in terms of being able to carry weight without falling apart.

If I were building a wheel for you? Origin8 DAT-PRO65 rim, Sapim Race 14-15ga spokes, Sapim brass nipples, stainless steel rim washers, 2mm or 2.5mm washers as necessary under the spoke heads to fill the oversized hub holes. Cross-1 lacing, angling the rim holes if necessary. Spoke tension not lower than 100 kgf nor higher than 140 kgf. No spoke thread locking compound, so that tension problems can be more easily found and maintenance more easily done. You would not have spoke breakage problems with a wheel like that.

 

[markz]

Balmorhea - https://www.modernbike.com/origin8-dat-pro-65-rim-559x57-nmsw-36h.-black
Thats quite wide for a normal cruiser 26" with ~2" tires, 57mm is 2.24" inside width. Tire size 2.8-3.1 from the tire charts.
I got a bottle of Boiled Linseed Oil I use on the spokes when I lace mine, I do stress relief
Leaf wouldnt be doing that now would they :lol:

Here is the list....
26" Alex rim DM24 36h 32mm Wide, Stainless Steel Spoke Eyelets, disc and rim brakes.
Sapim Strong 13-14g Butted Spoke, Silver
Not that far away for shipping neither

amberwolf - Thanks for the input.

 

[MadRhino]

That is OK, but I would buy a better rim. Anyway, if you lace an eyeleted rim, you have to drill them off in order to be able to align the nipples with the spoke angle. Don’t forget washers.

 

[speedmd]

+1 on the stronger / heavier rim. Glad to see your replacing all the spokes. Any of the ones not broken, would most likely have been compromised structurally.

The limiting factor to building the most stable wheels is the rim in most cases. It is what limits how tight you can string it also. It is also the component in the wheel that gets into plastic deformation soonest which is what causes the spoke tension to change. You want the stiffest - sturdiest rim and spoke it for the loads you normally see. For static loads heavier spokes will build a stiffer- and in theory a stronger wheel, but only if the rim can hold shape within elastic limits. If not, the thicker spokes will just pull the rim out of shape and soften the spoke tension.

As mentioned, many different ways, the opposite works out on the road - trail. You want to build a more "resilient" wheel that can flex, take bumps and impacts and spring back into shape. Dynamically, It is a much tougher (ability to absorb energy) wheel when the components stay in elastic deformation regions in a balanced fashion. Any over kill on one component just concentrates the effects on the weaker components.