Large rim offsets

[yooper2001]

Due to peer pressure from this forum, I am going to attempt to build my new rear wheel. There is one thing I can't find the answer or wrap my brain around without help.
The reason I need to build a wheel is because there is a lack of hub motors available 20x3 with a 135mm offset. This is an extremely common folding ebike size, so I don't know why I can't find them.
Since you guys convinced me to try, I needed to find a rim. When I finally found a 3 inch (60mm) rim, i noticed that the spoke holes on it are evenly offset from center on both sides, but to the extreme, near the outer wall of the bottom of the rim. My current Bike is also evenly offset on both sides of center , but only like 1/2 inch .

What is this greater distance from center called, and is it a problem? What is it for?


Thank you in advance for edu-micating me.

Yoop

 

[yooper2001]

 

[yooper2001]

My current rims

 

[RunForTheHills]

Maybe to reduce the spoke angle when lacing it to a fat hub?

 

[yooper2001]

I'm sure the rims are made for lacing to a hub with a 170-190mm offset. I'm wondering if it's OK to use them with a 135mm offset (narrower hub)

 

[yooper2001]

Ok...since I didn't know what to call it....I couldn't find an answer.. but EVENTUALLY Google came through...and the answer was here....(good thing too...the rims havnt shipped)

 

[RunForTheHills]

Yeah, that could be a problem. Are you also planning to use a radial lacing pattern because of the small 20" rims?

 

[yooper2001]

My current rims and hub are the same size....and have a double offset x... same pattern on Grins calculator as number 1. I'm just going from a 500w motor to a 1000w. Both geared...so no gear less or 5000w crazy sizes.

 

[RunForTheHills]

Well, it could work, but I don't have any experience lacing that kind of rim. It might end up sketchy. I have laced rims, but only 26" and larger with a standard 3 cross pattern. They all turned out strong and reliable. If you try it and it doesn't work, you will be out the cost of the rim. Or you could try to find a different rim. FWIW, I don't think 60mm is the right rim width for a 3" tire. You should be using a 40-50mm rim: Tire Size Chart For Bicycle Rims

 

[yooper2001]

The stock rim in the picture as you can see is 60mm and I am happy with the way 3 inch tires fit on it.
I am happy with my bike except the 40nm of torque for my Xtra large ass. The new hub has twice the watts and over twice the torque from 500w/44nm to 1000w/90nm. In the same size (but different configured) hub....so I can't just switch cores.

 

[yooper2001]

Ok....The supplier ended up giving me the correct rim. It is considered a 60mm rim, because the flanges are 60mm, but it is tapered. The bottom of the rim is 40mm. This is how my original rim in the picture is. The new rim has the holes in the bottom portion of the rim so less than 40mm wide, and the flanges on the hub motor are 55.. so I am good.

. It does hold the tires steady, as my son slid into a curb hard, sideways, and the tire stayed on fine, (although I had to deflate and reset the bead so it wouldn't wobble)

 

[yooper2001]

I got my rims, and they are sweet! I also bought a micrometer...and the old rims are 63mm wide...the new ones are 58 wide....now waiting for the hub...