<\/p>\n
With the added drag of the trailer, and the additional weight of two kids, I found myself doing the walk of shame up steep hills more often than not. I needed another gear, but I’m fond of my good ol’ Redline 29er.<\/p>\n
There were a couple of options:<\/p>\n
- \n
- Nuvinci N360<\/a> (which I still might get if I save my duckets)<\/li>\n
- Sturmey Archer 2-speed hub like the S2<\/a><\/li>\n
- SRAM Automatix<\/li>\n<\/ul>\n
I chose the SRAM Automatix because it’s inexpensive, and it’s hackable. There are a few articles out there outlining how to change the shift point on the SRAM Automatix, so I won’t go into the mechanical detail on how to do it. You can read those<\/a> articles<\/a> for instructions.<\/p>\n
Regular Gear + High Gear<\/h2>\n
Most people are “unwinding” the shift spring to give the Automatix a shift point at a greater speed. This allows them to have a “normal” gear and then a “high gear” for puttin’ the spurs to it.<\/p>\n
I actually wanted to do the opposite.<\/p>\n
Low Gear + Regular Gear<\/h2>\n
I wanted the shift point to be lower, so that I can use the low gear under 10mph\u00a0for climbing and the high (regular) gear for “normal” cruising.<\/p>\n
Trying to get a comfortable shift-point on the Automatix can be tricky because there are a number of factors that determine which speed it shifts at. First is wheel size – the shift point is based on rotation speed, so it will shift at a much faster moving speed on a small-wheeled folding bike than on a 29er. The larger wheel will take you farther per rotation.<\/p>\n
You also want it to jive with your cadence. On my 29er with the stock 34t crankset, it shifted at about 14mph. My cadence was ridiculously high at that point.<\/p>\n
To get the low-speed gearing right, I switched from\u00a0the stock 19 tooth to a 20 tooth gear. This gave me the stock mountain bike, low-gear ratio that my Redline came with. Great for going up hills.<\/p>\n
I needed to “wind” the shift spring just a tiny bit to bring the shift point down. It doesn’t take much when winding, as winding the spring actually loosens<\/em> the pressure it puts on the shifting mechanism. Less than 45\u00b0 did it for me<\/p>\n
![\"automattix_wind\"](\"https:\/\/www.foell.org\/justin\/files\/2015\/09\/automattix_wind.png\")
<\/a><\/p>\nThat change was enough to put the shift point\u00a0at about 10.5MPH on by bike, which is a good balance for slogging up hills, and just cruisin’. Now I only have to do the walk of shame on the steepest inclines.<\/p>\n
<\/p>\n
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Send to Kindle<\/span><\/div>","protected":false},"excerpt":{"rendered":"I have a single speed bike. I chose a single speed for it’s simplicity. I just get on it and pedal. It has suited me well for about 6 years. The only thing that has changed is kids. These darn kids, they start at 6 or 7 pounds and eat and grow, and grow and… Continue reading
- Sturmey Archer 2-speed hub like the S2<\/a><\/li>\n