Fiber based spokes thread

[cst_jpr]

Since its been discussed in the ztto hub thread a few times its worth having a dedicated area here.

The massive MTBr thread: https://www.mtbr.com/threads/make-your-own-polymer-uhmwpe-spokes.1091276/
Avoid mentioning B3RD if possible, they stuck their noses in the thread above and tried to kill off any discussion.

Rope options:
Comparison list:


DM20 is the only possible option for Dyneema brand rope due to creep. If you use one of their formulations like SK99 it will stretch over a matter of days and the wheel will lose tension. The majority of "dyneema" for sale online is this SK type, DM20 is much harder to find.

Other options would be PBO, para-aramid, or vectran (LCP).


Sourcing:
Brand name       Diameter   Working strength   Breaking strength   Color   Weave
Marlow M-Rig max   2.5mm    839kg                   Black   
Liros D-Pro static    3mm       917kg                   Grey   
Mastrant M3           3.2mm   117kg   390kg   Twist
Mastrant M4           3.9mm    270kg   900kg   Sheath: Black Core: White    Twist
FL-32.NG               1.5mm     350daN (336kg)   White/Mix   Braid

Another sourcing option might be fishing line, as you can get Spectra line. But it would be necessary to weave multiple strands together.


Adhesion:
Apparently B3RD spokes are using simple cyanoacrylate to hold the DM20 to the threaded spoke portion. The weave also will grab providing friction.
Cyanoacrylate seems to be used in various places for bonding UHMWPE (what DM20 is made of).
Products are being sold as "surface prep" for plastics, as far as I can tell its just Heptane. Haven't investigated what it actually does to the plastic though. Then the other side of the spoke on the hub end is held in place with an eye splice.


Commercial brands:
- B3RD uses weaved DM20, 1.8mm thickness.
- Spinergy PBO uses sheathed PBO straight strands with end caps. Ends are epoxied into a conical end cap (link). I'm not sure if the same epoxy would work on DM20.
- PiRope uses weaved Vectran.

[cst_jpr]

Here is a photo of the Mastrant M3:



The full rope is 3.0mm and the core portion is about 1.9mm.

The advantage of Mastrant is its low cost and easy to purchase online. Downside is its many hundreds of thin strands twisted for its core, which means you'd have to use the Spinergy method of joining the ends. You could use it with the polyester sheath I suppose, but all the sheath does is protect from abrasion. I don't think there is a concern for abrasion other than at locations where the spoke attaches (eg some hub holes are quite sharp).

[bxcc]

These are really cool! The user MaineLotus in the MTBR thread has done an excellent job with this. I've ridden with him many times and the bike is impressive to say the least.

[Aliexpress Test Pilot]

I've sussed out how to build a wheel using this and have done it using sk75
I have come to the conclusion through trial and error that dm20 is the only option.
I'm just hunting for some dm20 in 1.5-1.8mm 12 strand braid or greater.


I have tried the fl 32NG lines, coincidentally some worn  kitesurfing equipment I had was from this era.
 as an 8 strand they are MISERABLE to eye splice and seem very fragile to cuts in that diameter at that age.

1.8mm is ideal 2.0 mm would be good   2.5mm will be too large for most spoke holes.

Marlow used to sell a 1.8mm dm20  I can't find it anywhere anymore and contacted marlow directly there were  out of stock with no plans to renew. 

If anyone finds some dm20 or convinces a manufacturer to make some, I'm in for a roll

[FullCarbonAlchemist]

These are really cool! The user MaineLotus in the MTBR thread has done an excellent job with this. I've ridden with him many times and the bike is impressive to say the least.

I just realized your profile pic is the classic Sugarloaf Outdoor Center pond shot, nice to see a fellow New Englander here. I build my mountain bikes first and foremost to ride in Carrabassett and Bethel!

[bxcc]

I just realized your profile pic is the classic Sugarloaf Outdoor Center pond shot, nice to see a fellow New Englander here. I build my mountain bikes first and foremost to ride in Carrabassett and Bethel!

Yes it is. Such a great place to ride. I used to be up there at least a couple times a month, not so much in the last few years. The amount of cars at the OC on any given Saturday is drastically different than it was 10 years ago.