I will be building a 20" freestyle wheel soon using a SUZU cotterless 36hole hub and a BSD “NASA” BMX rim (ERD 388mm)
According to the UDC UK spoke calculator I will need 181.13mm spokes. Now the holes are slightly off centre and usually, you need to add a little for this. About how much would you typically add? Image below shows how off center the holes are. TIA
-Philip
That’s a pretty tiny deviation, even on a small wheel. Way less than 1mm. I’m not an expert, but I think most rims have offset spokes, so the measurement offered by the calculator is probably very close to what you need, well within the margin of error. I will defer to any wheel-building experts who may follow.
BTW, where did you get your SUZUE hub? Is it an old Miyata hub? I’m looking for a replacement…
If the spokes were 10" long for a 20" wheel and ran radially, the change in spoke length required for a 5mm hole offset from center is 0.05mm. This is incredibly negligible. For a 1cm offset the change in spoke length is 0.2mm. Still pretty much nothing.
It is stamped “SUZU”. Darren Bedford Still has some, got it from him last week. It is NOS for sure, never built up. He said he had 48 spoke as well though 48 spoke rims are getting hard to come by.
-Philip
Many thanks! So, in other words, there is more than enough thread there to make this tiny bit up. 
-Philip
I think the spokes will be too long, not too short. Imperceptibly, though. They would only be too short if they crossed the center line of the rim to go into a hole.
I missed the fact that you already selected 181.13mm spokes. Including a 5mm offset, the required length would be either 181.07mm to 181.20mm so you can see there is really no difference. I don’t even know if you can buy spokes in anything other than 1mm increments.
I thought that too, but if you look at the rim closely, it appears that the spokes are meant to be crossing the center on this rim. Apparently that gives you better spoke support at the hub.
The difference is going to be tiny either way, and I am still uncertain whether or not I should believe in these tiny details having a significant impact on wheel strength. In my experience, as long as your spoke tensions are even and at the right level, your wheel is going to last, if you neglect maintenance, it doesn’t.
Noted :). I have a local builder who has a spoke roller so they can cut any size within 1mm. When I ordered the spokes this morning I left the full measurements I got from the calculator and asked them to cut +/- appropriately to their professional opinion.
-Philip
Huh. I wonder if it’s the same company, or something completely different? My older Miyatas have no branding at all on the hubs, but later ones (like from the 90s or 00s) say SUZUE.
I think these have been in his little shop for about 10 years?
Here is a photo of the one I aquired last week. Its getting built on Sunday.
-Philip
Nice. But that one does say SUZUE on it. Is Darren still active in unicycling? I just sent him an email through his website…
I see Darren about once a week for unicycle basketball. The Toronto club turned 30 this year.
Yes! I heard back from him also. Great! When are you guys going to host NAUCC again?
I will have to bring that up with some of the brass. Would you visit if we did?
-Philip
I would do everything in my power. I used to go to all the USA conventions (starting in 1980) but in recent years I have missed too many due to work, family and conflicting travel situations. My wife and I both think Toronto is pretty cool, and I’m big on promoting large unicycle events in Canada so we would definitely do our best to be there!
Canada has been great at the large events; 3 Unicons, 2 USA conventions (currently called NAUCC) and even one “California” Muni Weekend. But still no national unicycling organization… 
I know the work, family conflict all too well. If you decide to visit ever aside from regular unicycle activities please do get in touch.
-Philip