Hi All,
Finished the wheel and got a question about it - I can't Private Message yet, so I thought I would post an update:
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Q: SRAM Automatix Hub - Did you ever build your wheel with the SRAM Automatix hub? If so, what sizes did you use for your front chainring and your rear sprocket? Has the hub worked well for you? - Thanks!
A: Yes I did - thanks for asking - it works well.
The rear sprocket that came with the SRAM Hub is a 19 tooth, which I am using.
There is a triple ring in the front, 48-38-30, and a rear derailleur in back to keep the tension on.
I live in Pittsburgh, so there is a lot of up and down hill riding, the 30 is good for moderate up-hill to stand-up riding. The 38 is good for general city riding and brief moments of stand-up riding. There is a long flat section of my commute to work, and I tend to use the 48 for that, but it also has a slightly downward grade....coming back I stick with the 38.
If I had to have just 1 front ring, I think I would go with something like a 38 or 40 tooth ring...2 reasons for this - 1 - I like easy pedaling and 2 - with a larger sprocket, like the 48, the wheel gets up to speed and shifts very quickly, so the first gear is shifted through almost immediately.
My wheel is 26" so that probably effects things somehow.
Someone had a post somewhere that said there was a way to adjust when the hub up-shifts. If I could control this, I would like to adjust it to up-shift at a higher rotation speed. Right now, if I use the 48 ring, it tends to upshift almost immediately, as the wheel is spinning so quickly...the 2 speeds are more distinct with the 38 ring. With a bigger ring, it is almost like a 1 speed hub.
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In case anyone is interested in doing a similar build, along with the SRAM Automatix hub, the wheel was built using a 36 spoke, Sun-CR 18 Rim (559mm), 256 mm length straight guage spokes (2mm), and I did use spoke washers, as Booger suggested. I probably could have skipped the washers, but they look really cool, and made me feel comfortable putting a lot of tension on the wheel, which does have large spoke holes.