Spoke length for Edge on a 27.5 MTB

[Steveohlhaber]

I have a 27.5 rim with 3 inch wide tires that have 36 spokes.  Does anyone know of a rim that is 27.5 by maybe 50mm wide that has 36 spoke holes?

I suppose I can spoke only 32 of the holes into the hub, but that seems weird.  It would be nice to have a 27.5 option.  I realize MTB isn't ideal for a DD, but I am running a mid fat just as a beach cruiser.  I wont be doing hills, I just want bigger tires for the sand and suspension aspect of it, which I love.  I am amazed that there is no a single ebike hub kit for 27.5 either, nowhere.  I couldn't find a single one.  Probably due to the 32 holes in all the 27.5 rims.  Any info would help.

[Bikemad]

Hi Steve andto the forum.

I could only find one 50mm wide, 27.5" (650b) rim with 36 spoke holes but it is carbon fibre and costs $200 plus $68 shipping from China 

The only other rim I could find with 36 holes that would safely accommodate a 3" wide tyre was a Mavic EX630 27.5", 584 MTB Disc Rim in Black.

You would need to enter custom measurements for both the rim and the MP Edge hub into the ebikes.ca spoke calculator to determine the length of the spokes.

I would suggest that you use 13/14g Sapim Strong butted spokes if possible:



Alan
 

[Steveohlhaber]

Its incredible that 36 hole rims on 27.5 don't really exist in the aftermarket.  For an ebike, it makes a lot of sense because you get a bigger tire with more rubber between the rim and the road.  With the electric assist, you probably will be going faster and need more rubber down there to avoid breaking the rim on curbs and bumps.  If you break a rim on this bike, you buy another bike I guess, because your not going to replace that wheel.

I guess I will use my stock rim, which will work, but I wanted to be able to swap the rim back in there.  I don't think I want to try to lace 32 spokes of a 36 hole hub.  .

[Steveohlhaber]

Also, I can't use that hub spoke calculator because it doesn't have 27.5 inch rims as an option.

[Bikemad]

I can't use that hub spoke calculator because it doesn't have 27.5 inch rims as an option.

You would need to enter custom measurements for both the rim and the MP Edge hub into the ebikes.ca spoke calculator to determine the length of the spokes.

Select "Custom Rim" from the dropdown menu in the Rim Settings section and then select "650B (584)" from the Nominal Diameter.
(650B is just another name for a 27.5" rim and therefore has the same 584mm bead seat diameter)

If you know the ERD for your particular rim you can simply enter the correct measurement, otherwise you will need to measure the ERD before you can enter it. 



My MP Edge has a "Flange Diameter" of ~231 mm with a "Flange Spacing" of 22 mm.



The above screenshot shows the results obtained using the measurements for the carbon rim mentioned in my previous post, and shows that this particular rim would require 173 mm long spokes to assemble it onto a MP Edge hub.

Alan
 

[Steveohlhaber]

Nice, thanks for the info.  I will take a shot at doing this myself.