Double check spoke lengths

[oldie1982]

Hi Everyone

Can someone please be so kind just to confirm my spoke calculations are correct.

ERD 593mm - checked 4-5 times around the rim.
Single cross pattern
Spoke size 245mm

 

[Benjahmin]

Here's a link to e-bike.ca site that gives you everything you need. Demo vids on how to do it and how to use their calculators.

Wheel Building - Learn

There are many good print and online references for lacing bicycle wheels. Many will defer to Sheldon Brown, Brandt's Bicycle Wheel Book, and others. However, a lot of the points and details with a conventional bicycle hubs don't necessarily apply to hub motors with their much larger flange...

ebikes.ca

 

[saneagle]

My spoke calculator gives 245.7mm. The centre is offset by 7mm, so you will have to build in an offset, which means longer spokes on one side than the other. If your frame is symmetrical, that would mean 245.2 and 246.4mm would be ideal, though you can accommodate that on the thread if you get the longer ones. If the spokes are a couple of mm too long, they're normally still OK, but if they're 2mm too short, it can be very difficult to build the wheel.

What's more important is how you got the ERD. How exactly did you come to 593mm because you can't measure it directly? You said that you measured it, but how did you measure it and what did you add to the measurement?

 

[oldie1982]

Here's a link to e-bike.ca site that gives you everything you need. Demo vids on how to do it and how to use their calculators.

Wheel Building - Learn

There are many good print and online references for lacing bicycle wheels. Many will defer to Sheldon Brown, Brandt's Bicycle Wheel Book, and others. However, a lot of the points and details with a conventional bicycle hubs don't necessarily apply to hub motors with their much larger flange...

ebikes.ca

Cheers , did check that site, just wanted to make sure.

My spoke calculator gives 245.7mm. The centre is offset by 7mm, so you will have to build in an offset, which means longer spokes on one side than the other. If your frame is symmetrical, that would mean 245.2 and 246.4mm would be ideal, though you can accommodate that on the thread if you get the longer ones. If the spokes are a couple of mm too long, they're normally still OK, but if they're 2mm too short, it can be very difficult to build the wheel.

What's more important is how you got the ERD. How exactly did you come to 593mm because you can't measure it directly? You said that you measured it, but how did you measure it and what did you add to the measurement?

245 or 246mm? What do you suggest? i want to just get one size.

ERD, 2 spokes opposite to each other, measure the gap using a digital gauge and then added 2 x spoke lengths. It was on the park tool website.

many thanks

 

[saneagle]

Cheers , did check that site, just wanted to make sure.



245 or 246mm? What do you suggest? i want to just get one size.

ERD, 2 spokes opposite to each other, measure the gap using a digital gauge and then added 2 x spoke lengths. It was on the park tool website.

many thanks

If I were doing it and my frame was symmetrical, and I was using a double-walled rim, I'd be ordering 247mm; however; I always measure the rim I/D, add on 3mm and use that as the ERD, then round everything upwards. As I said, you can normally deal with too long, but not too short.

 

[oldie1982]

The rim is double walled. I think i will try your measuring method to and see what ERD it comes to.

 

[saneagle]

My method is very much " back of a fag packet" method that works for me. Other members have used other methods that presumably worked for them.

 

[thelarkbox]

I have built ONE wheel, and as i replaced a damaged rim with one with a significantly different profile and therefore spoke length, i found amazon prime free delivery and no problem distance selling returns a modern day cheat code on zeroing in on the correct size spokes..

Edit - the side effect bonus is any wrong sized spokes are a free practice runs, by my 3rd and final set the initial spoke fitting took 10 mins or so.. ok perhaps 20 mins.. I wasnt checking but i steamed through it.