Hi all. I plan on making (or having my bike guy make) a 26" wheel with an existing MAC 7t motor. The motor is mounted in a 29er wheel. I have done a search and read several posts and I get the impression that I cant use the spokes on the motor already as they are too long and I have to order the exact correct length of spoke? Can someone help with selecting the correct spokes? The MAC hub is 36 spoke type. Any help is appreciated.
Confused about spoke length
- Thread starter olemetry
- Start date
shenzhen_ex
100 W
I recently had a question on here about spoke length. I was pointed to a spoke length calculator: http://www.ebikes.ca/SpokeCalc.shtml
It was helpful but did not directly account for my bracing angle.
It was helpful but did not directly account for my bracing angle.
cal3thousand
10 MW
Here are the 2 best spoke calcs that i know of:
http://leonard.io/edd/
http://wheelspoking.com/Build.aspx?Mode=Advanced
I've used the first one with much success after putting in my measure values for the hub motors.
http://leonard.io/edd/
http://wheelspoking.com/Build.aspx?Mode=Advanced
I've used the first one with much success after putting in my measure values for the hub motors.
Supertux1
100 W
I had to re-lace my mac 10t into a 26" Alex rim recently (see bike in sig) and these are the numbers I used in the ebikes.ca SpokeCalc.
It's all going to depend on your new wheel's ERD. (effective rim diameter)
For my Alex 26" rims it was:
Effective Rim Diameter 544mm <-- your rim's ERD, depends, check your rim documentation.
Hub Flange Diameter 172mm
Flange Spacing 54mm
Diameter of a spoke hole 2.3mm
Cross pattern 1
Number of spokes 36
Calculated Spoke Length: 194.2 mm.
You will have to order two different sized spokes because rear wheels are typically dished to account for gear cluster. Also depends on your frame, sometimes the right chainstay is offset so no dishing is required (unlikely.)
The gear side / drive side spokes happen to be 2mm shorter than these calculations, so 194mm and 192mm are the spokes for my rim @ 544mm.
Some people prefer not to dish their wheels and do okay as well, but you may have a problem with your tire rubbing the left chainstay depending on how thick it is.
As for which spokes to use, I highly recommend the Sapim single butted spokes. These spokes are 13 gauge at the elbow, the exact size of the mac flange holes (2.3mm), and taper down to standard 14 gauge after a few inches.
They will fit into standard nipples, use standard spoke wrench, and you can tension them properly.
There are lots of threads out there on how to build wheels and confusing spoke placement diagrams, videos etc... it looks scary but e-bike wheels are easy; they are the cross 1 pattern.
You'll have to learn to lace a wheel eventually if you play with bikes long enough.
Here's a good article: http://www.electricbike.com/lace-hub-motor/
It's all going to depend on your new wheel's ERD. (effective rim diameter)
For my Alex 26" rims it was:
Effective Rim Diameter 544mm <-- your rim's ERD, depends, check your rim documentation.
Hub Flange Diameter 172mm
Flange Spacing 54mm
Diameter of a spoke hole 2.3mm
Cross pattern 1
Number of spokes 36
Calculated Spoke Length: 194.2 mm.
You will have to order two different sized spokes because rear wheels are typically dished to account for gear cluster. Also depends on your frame, sometimes the right chainstay is offset so no dishing is required (unlikely.)
The gear side / drive side spokes happen to be 2mm shorter than these calculations, so 194mm and 192mm are the spokes for my rim @ 544mm.
Some people prefer not to dish their wheels and do okay as well, but you may have a problem with your tire rubbing the left chainstay depending on how thick it is.
As for which spokes to use, I highly recommend the Sapim single butted spokes. These spokes are 13 gauge at the elbow, the exact size of the mac flange holes (2.3mm), and taper down to standard 14 gauge after a few inches.
They will fit into standard nipples, use standard spoke wrench, and you can tension them properly.
There are lots of threads out there on how to build wheels and confusing spoke placement diagrams, videos etc... it looks scary but e-bike wheels are easy; they are the cross 1 pattern.
You'll have to learn to lace a wheel eventually if you play with bikes long enough.
Here's a good article: http://www.electricbike.com/lace-hub-motor/Similar threads
