MXUS 36V 350W rear hub motor spoke size

[billriv]

High guys. I am starting an ebike conversion on a 20 inch wheel Tern A7 Link folding bike. This is my first DIY ebike conversion, because as has been said, "necessity is the mother of invention". In other words, I don't have a whole lot of money!

I am going to start with the wheel build and hope you guys can help me out with your experience with ebike conversion kits.

I bought a 36V 500W MXUS XF15 rear hub motor from PSWPOWER, which is a China based company. The motor specs show a spoke specification of 36H*13G, but I don't know what that means. I know 13G is a reference to spoke gauge, but what does 36H represent? Does anyone know what spoke size I would need for my 20 inch rear wheel? Below is the link to the motor.

Thanks,

Bill

http://www.pswpower.com/ven.php?cargo.2019-bu-bfer

 

[2old]

36H means the hub has 36 holes and you need to use a rim with 36 holes. Look at ebikesca for a spoke length calculation, but read sheldon smith on wheel building before you order spokes; you don't need to be a Rhodes Scholar to build a wheel, but it helps to know a little before you start.

 

[billriv]

Hi Guys. I am a newbie that is doing a DIY ebike conversion using a Tern A7 Link folding bike. I have no experience doing an ebike conversion.

I want to build a rear wheel with an MXUS XF15 rear motor using my bike's 20 inch rear rim. My bike's 20 inch rim has 28 spoke holes and the MXUS XF15 rear motor has 36 spoke holes. Do I have to get a rim with 36 spoke holes, or can I use my bike's 20 inch rim with 28 spoke holes?

Bill

 

[dogman dan]

You need a 36 hole rim for the motor. Or buy one laced into one. Some folding bikes have very skinny frames.. Most motors come in 135 mm wide axle, for the standard bike frame. Measure your frame before you buy a 135 mm wide motor.

 

[billriv]

Hi guys. I am going to use the online spoke calculator found at the Grin Technologies ebikes.ca website in order to find out what spoke sizes I need for my rear hub motor on my 20 inch folding bike. The calculator requires some measurements for the hub motor and I understand most, but don't know how to get the dishing offset number. The number is to be in mm. Does anyone know how to get the dishing offset number?

Bill

 

[amberwolf]

sheldon brown's site among many others shows how to lace mismatched hubs and rims.
https://www.google.com/search?q=lace+mismatched+hubs+and+rims
there's even threads here on es about them. one start is here
https://endless-sphere.com/forums/viewtopic.php?f=2&t=64324
others are buried in this list, most of which is not relevant
https://endless-sphere.com/forums/search.php?keywords=mismatch*+hub*+rim*&terms=all&author=&sc=1&sf=all&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

 

[dogman dan]

So easy to just buy a 36 hole rim. Set aside your old wheel, in case you ever sell the bike. no need to use that original rim.

 

[billriv]

You need a 36 hole rim for the motor. Or buy one laced into one. Some folding bikes have very skinny frames.. Most motors come in 135 mm wide axle, for the standard bike frame. Measure your frame before you buy a 135 mm wide motor.

Thanks for the information dogmas-dan. I will buy a rim with the 36 spoke holes. I think it will be easier than trying to figure out how to lace a 28 spoke hole rim with a 36 spoke hole motor.

 

[billriv]

sheldon brown's site among many others shows how to lace mismatched hubs and rims.
https://www.google.com/search?q=lace+mismatched+hubs+and+rims
there's even threads here on es about them. one start is here
https://endless-sphere.com/forums/viewtopic.php?f=2&t=64324
others are buried in this list, most of which is not relevant
https://endless-sphere.com/forums/search.php?keywords=mismatch*+hub*+rim*&terms=all&author=&sc=1&sf=all&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

Thanks for the info amberwolf.

 

[billriv]

So easy to just buy a 36 hole rim. Set aside your old wheel, in case you ever sell the bike. no need to use that original rim.

Thanks dogman dan. I will follow your advice.

 

[billriv]

Hi guys. I have attached a pdf file with a diagram of the MXUS XF15 rear hub motor. This is my first wheel build and I don't know what the measurements in the diagram show. I think the measurements may show the information I need to input into bikes.ca online spoke calculator, but they are not labeled so I don't know what they are measuring. Some of the measurements seem obvious, but I want to be sure to avoid any costly mistakes. I have not received the motor yet and will, of course, double check any measurement information I get by measuring the motor itself.

Can anyone find the following measurements in the attached pdf file:

Flange Diam. mm

Flange Spacing mm

Dishing Offset mm

Axle Length mm

Hole Diam. mmView attachment MXUS hub motor specs.pdf

 

[E-HP]

Why two threads?

 

[amberwolf]

he actually has at least four about this wheel.

 

[mark5]

All merged.

billriv, please keep wheel/spoke-related questions in this topic.