"I was trying to think about how to better quantify it but I was not sure how to. I would like it a little easier but don't want to be spinning too hard!"
The way I do exactly this is I decide what my comfort-range is for pedal RPM. I've ridden enough miles with a cadence RPM cyclometer that I know this range pretty well. I have a MAX and MIN comfortable RPM in my pocket. So, for a particular gear, I calculate how fast I'm going at my MIN and at my MAX RPM and if that range of speed makes sense, that's a decent gear. For some environments, maybe 8-14 MPH would be a decent range. For other environments, maybe 13-22 MPH might be a more appropriate target. Let's say for example you decided your comfortable RPM range was 60-120RPM. At 60RPM in a 70.5 inch gear, you would be traveling 13,300 inches per minute or about 12.5MPH. That means you NEVER plan to ride comfortably below 12.5MPH. At 120RPM you are going 25MPH. That means you expect to spend a significant amount of time cruising along at 25MPH. If those were my numbers for my RoadUno, I'd want to shift them way down. I'm never comfortably cruising at 25MPH on my RoadUno. I go 25MPH on my fixed gear in Michigan but only on the downhill side of an undulation, and that's just for a moment at WAY over my max comfortable RPM. For something like a city-bike application I may shoot for 9-18MPH which is a gear in the low 50s. A gear around 60 inches would be more like that 11MPH to 22MPH range. FWIW, my RoadUno is a two-speed drivetrain with a 38/26 in front and a 16T freewheel, giving me a "high" gear of 66 inches and a "low" of 45. Your comfortable RPM range depends entirely on you. I know some mashers that are perfectly content at 30RPM for long periods. Some spinners can easily spin up to 140RPM and maintain it. Bill Lindsay El Cerrito, CA On Wednesday, December 18, 2024 at 3:16:05 PM UTC-8 Edwin W wrote: > I am running my Roaduno with 49/19, 40mm (or so) tires, 165mm crank, which > works out to 70.5 (fixed) gear inches. > > I was thinking of making it a slightly easier gear. For those that have > experience in small changes in fixed gear gearing: > > I would love to hear about your experiences in changing gearing. How "big" > is a jump from 70.5 to 69 (48 tooth)? to 67.6 (47 tooth)? > Or to 66.9 (20 tooth rear cog) or 63.7 (21 tooth cog)? > > I know these are subjective differences,. I was trying to think about how > to better quantify it but I was not sure how to. I would like it a little > easier but don't want to be spinning too hard! > > Let me know what you think, > > Edwin > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/rbw-owners-bunch/37511bff-64b2-4274-b40e-036793050ad4n%40googlegroups.com.
