Monday, August 24, 2020

Gravel Bus In 650B Mode

 The Gravel Bus with Irwin Aon GX 35 Carbon wheels in 650B.
 My Saturday plans were laid waste by duties having to do with my son's participation in football and rain. Basically, it was a double whammy, as I wasn't going to get to do what I had intended either way. Sometimes somethings weren't meant to happen. 

So, I had a lot of time on my hands Saturday and I used that to get some things done I had intended on doing. I had just purchased a Surly single speed spacer kit, a Surly 20T cog, and I had picked up a box of super-secret stuff for RidingGravel.com at Andy's Bike Shop as well. I decided to get cracking on the 650B wheel set up for the Gravel Bus. I had already set the tires up tubeless and all I needed was to match up the gearing so I wouldn't have to do any chain tensioning when I switched back and forth between the 700c and 650B set-ups. The box? Nunya. You'll have to wait for a little over a month to find out what's up there. 

I ended up running the first Standard Rando I had in 650B mode pretty much on a permanent basis until I sold it. That was because it was the only way to get any decent volume tires on that frame and fork. The clearances were tight on that design. With v2, Twin Six has allowed for a bigger tire to be fitted, so I can run 700 X 43mm tires with no issues. But that still allows for 650B as an option, so now this Standard Rando is actually more versatile, at least for my uses and intentions. 

So, how does it ride? Stiffer with smaller diameter wheels......maybe. The caveat here is that I had been riding Spinergy wheels on this which do ride pretty darn smoothly, so switching out to a deeper section carbon wheel with steel spokes and in a smaller diameter? Probably no surprise that the bigger hits are more sharply felt there, even with the cushy tires. One thing a lot of people do not take into account is that the 650B diameter- even with a 47mm wide tire- effectively lowers your gearing range. You can most acutely feel this when switching from 700c and keeping the cog size and chain ring size the same, as I have done here. 

The smaller diameter wheel/tire combo effectively lowered the gain ratio on the Gravel Bus.

This will come in handy when conditions are worse, in hillier areas, or on really windy days when I want to use a single speed. It's kind of a round-a-bout way to change ratios without changing anything on the cog/chain/chain ring front. Plus, it looks like I could squeeze in some fenders. That might be nice in muckier, transitional weather. 

So, this will end up being the dedicated 650B wheel set and my matching 700c Irwin Aon GX 35 Carbon wheels will end up becoming the alternate wheel set for the Gravel Bus. This will bring the Project Gravel Bus to a close. I doubt I will be doing anything major, in as far as changes go, to this rig anytime soon.

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