Spoke Strentgh (My spokes are breaking like mad...)

[spinningmagnets]

I found the graphic posted by Chalo to be very educational, I had previously assumed a bike rim would be more rigid and the majority of the force of a pothole hit would be transferred to spokes on the opposite end away from the pothole. (imagine a bicycle traveling from left to right, pothole strike is at 5:00 O'Clock on the wheel). I hadn't considered that the force would try to pull the rim into an oval shape, and this would transfer some of the forces to other spokes that are far from the opposite end of the hit.

I can't help but to suspect that there are a couple/three methods of fixing the "broken spoke" problem at play here.

The LFP/Chalo method [picture shown] was for a non-hub, (20-inch wheel/moped tire?...on a hardtail, street use).

When researching the Raptor using a Cromotor, found this:

"...You should really only use a 19″ prowheel [motorcycle] rim in the rear...If you insist on using small spokes, go 12-Ga minimum. High quality 12-Ga will be adequate, but 8-Ga to 10-Ga is better, though…”

This advice was for a heavy Cromotor, heavy Shinko motorcycle tire, 2-cross spokes, on a frame with a long rear suspension travel.

It has been my understanding that one of the benefits of the Cromotor was that its diameter being smaller than the Crystalyte 5-series made the spokes just longer enough to dramatically improve the broken spokes issue. (is the large-diameter 5-series/extra short spokes combo the worst offender?)

Maybe the non-hub LFP/Chalo method (taken from the pedal bicycle world) uses flex to its benefit, but...the Raptor/Cromotor method overcomes the issue with a very heavy non-flexy method that is only useful for a specific user-profile? I'm trying to learn...my mind is open...

 

[cal3thousand]

If you use quality spokes (14ga or 14-15ga),.

thanks for the other tips but just want to focus on the above.

The 4065 hub flange usually takes 12 gauge and some even put 11/12 ones with the 11 at the flange. Are you saying that 14 gauge is the best to lace a 19" bicycle rim into a 4065 (will be 2.8-2.5k of torque mostly) for the high torque parts.

To me, 12Ga are moped spokes and should be used with Moped rims.

14-15Ga are perfect for most bicycle rims.

 

[zener]

If you use quality spokes (14ga or 14-15ga),.

thanks for the other tips but just want to focus on the above.

The 4065 hub flange usually takes 12 gauge and some even put 11/12 ones with the 11 at the flange. Are you saying that 14 gauge is the best to lace a 19" bicycle rim into a 4065 (will be 2.8-2.5k of torque mostly) for the high torque parts.

To me, 12Ga are moped spokes and should be used with Moped rims.

14-15Ga are perfect for most bicycle rims.

Even for DH bicycle rims?

 

[cal3thousand]

Yes. Even DH bike rims

 

[John Bozi]

If you use quality spokes (14ga or 14-15ga),.

thanks for the other tips but just want to focus on the above.

The 4065 hub flange usually takes 12 gauge and some even put 11/12 ones with the 11 at the flange. Are you saying that 14 gauge is the best to lace a 19" bicycle rim into a 4065 (will be 2.8-2.5k of torque mostly) for the high torque parts.

To me, 12Ga are moped spokes and should be used with Moped rims.

14-15Ga are perfect for most bicycle rims.

Isnt there any problem with the twisting around in the holes on the motor though? My 12 gauge already have enough of movement.

 

[cal3thousand]

thanks for the other tips but just want to focus on the above.

The 4065 hub flange usually takes 12 gauge and some even put 11/12 ones with the 11 at the flange. Are you saying that 14 gauge is the best to lace a 19" bicycle rim into a 4065 (will be 2.8-2.5k of torque mostly) for the high torque parts.

To me, 12Ga are moped spokes and should be used with Moped rims.

14-15Ga are perfect for most bicycle rims.

Isnt there any problem with the twisting around in the holes on the motor though? My 12 gauge already have enough of movement.

Not if you lace the motor correctly. I've only ran into slight issue when the hub is drilled with reliefs for both outbound and inbound spokes, where the spoke head is too small for the counter sink. Washers can help in those situations. Hub drilling differences are not what should determine what spoke gauge to use.

 

[the12be]

Hey guys, it seems like everytime I hit the throttle/go over a bump a spoke breaks...!

It's annoying as hell, and I want it to stop !

What are the solutions, is my wheel just built like crap or is this something everyone experiences with their ebikes?

Are there any one piece solid wheels with hub motors built in availible? (No spokes)

Yes but the 16 inch are the biggest I have seen on Aliexpress for a 150mm dropout


Are there heavier duty wheels that wont do this?

Help! Thanks

 

[Chalo]

For best results:

Use top quality round stainless steel spokes. Sapim, DT Swiss, Wheelsmith, Union/Marwi are all excellent brands.

Use the thinnest spokes available to you. It's OK if the ends are thicker, the center thickness is what counts. Thinner than 15ga (1.8mm), spokes become twisty enough to complicate tensioning and truing. Also, thinner than 14-15ga spokes become increasingly difficult to find in odd lengths. Use washers at the hub holes if they are too big for the spoke heads.

Use at least 30 kgf/mm^2 of spoke cross-section, if your rim can tolerate it. That's about 100kgf of a 14ga spoke, about 175kgf for a 12ga spoke. Only about 55kgf for a 17ga spoke.

Stress-relieve your spokes once they are up to full tension, by squeezing pairs or prying them near their crossings. This is vital to long spoke life.

Make sure the spoke enters the nipple in line, not at an angle. This means limiting spoke crosses to one or even zero as the hub diameter gets bigger, or the rim smaller.

AND, bigger stiffer rim cross-sections make it less likely to break spokes, because they distribute forces more broadly across more spokes.

 

[DrkAngel]

I went 12ga w/washers at the hub to pull the elbow close to the hub flange.

And I knew the rim would be sorely stressed by the 12ga nipples ... so I added washers there too.
Nipples set nicely in the concave side of the washers.
Wrapped a couple turns of duct tape to isolate galvanized washers from aluminum rim.

14ga to 12ga Spoke Upgrade