Jeff, you can make this dead simple if you know 2 things:
1. How fast you *can *comfortable go now without spinning 2. How fast you *want *to go without spinning out It can be in whatever units you want: miles per hour, meters per seconds, megaparsec per millennia. Once you know that, take the ratio of item two vs item 1 (2/1). This is how much you need to increase your front chainring by. For example: 1. How fast you *can *currently comfortable go 15 mph 2. How fast you *want *to go 20 mph 3. 20/15 = 1.33; that how much bigger your chainring needs to be 4. In this case, you'd need to increase your chainring from 38T to 50T (That's big, but this is just an example! Obviously need to round up or down to nearest whole size, they don't make fractional teeth :) Since everything else is constant (crank length, wheelsize, cassette, etc) you don't actually need to account for them. If you don't know 1 & 2 for you, maybe you can estimate it from previous ride's data. Or go on a typical ride and just note those speeds approximately. Ben On Tuesday, March 25, 2025 at 4:17:41 PM UTC-7 [email protected] wrote: > Yes, any 110bcd compatible ring will work for your cranks in the middle > (and outer) positions. > > On Tuesday, March 25, 2025 at 6:13:27 PM UTC-5 [email protected] wrote: > >> Ok! As Al Pacino said "the inches we need are everywhere around us." >> >> Would a 42 from this page >> <https://www.rivbike.com/products/chainring-110mm-130mm?variant=39827677151343>be >> >> what I'm after? >> >> Thanks again, the "10" further per revolution" explanation resonates with >> me. >> >> Jeff >> On Tuesday, March 25, 2025 at 7:08:52 PM UTC-4 [email protected] >> wrote: >> >>> With the numbers i gave you, with every pedal revolution you'll go about >>> 10 inches further. Crank arm length doesn't make much of a difference, >>> more leverage in theory, all things equal, it may take you a little longer >>> to spin up but once your at your natural cadence expect 10 inches more per >>> pedal revolution (80 to 100 rpm) will equal 800 to 100 inches more so 60 to >>> 80 feet more per min. so on and so on...... >>> >>> On Tuesday, March 25, 2025 at 4:02:37 PM UTC-7 [email protected] >>> wrote: >>> >>>> Thanks for the replies and the explanations for the layman! Crank arms >>>> are 173mm. >>>> >>>> I will spend some time with the Sheldon Brown calculator. I have been >>>> trying to wrap my head around the info on the page on the Riv site but >>>> somehow how it's still confusing to me. >>>> >>>> Jeff >>>> >>>> On Tuesday, March 25, 2025 at 6:55:18 PM UTC-4 [email protected] >>>> wrote: >>>> >>>>> Hi Jeff, >>>>> >>>>> I have the same gearing on my Homer (650B), I use Sheldon Browns Gear >>>>> Inch calculator (https://www.sheldonbrown.com/gear-calc.html). >>>>> >>>>> The highest being 89.8 gear inches (38x11) , bumping it up to 42x11 >>>>> you would get 99.3 gear inches. >>>>> >>>>> What does that mean....i think you would get that sweet spot in higher >>>>> speed, i also have the silver 2 crankset, you can just get the 42 tooth >>>>> ring, you would still keep the chain guard too. >>>>> >>>>> I don't recommend you go higher than 42, as an 18 tooth jump for your >>>>> front derailleur (42 to 24) is prob stretching it, doable, but stretching >>>>> it. >>>>> >>>>> I say go for it! >>>>> >>>>> On Tuesday, March 25, 2025 at 3:37:48 PM UTC-7 [email protected] >>>>> wrote: >>>>> >>>>>> I know this topic is addressed in countless ways online, so I'm >>>>>> looking for more of a real-life take on the concept of gear inches. >>>>>> >>>>>> I'm running the wide/low double 38x24 (with guard) and an 11-34 on >>>>>> the rear but feel like I am spinning out at the top end of the range >>>>>> on my Hillborne. I'm a heavy guy, riding a big heavy bike and, momentum >>>>>> being what it is, I can get up to a decent clip on flats and downhills. >>>>>> My >>>>>> Wahoo trainer has an 11-28 installed and even when grinding up a 10-12% >>>>>> grade in Watopia, I never use my 24 up front. I occasionally use it on >>>>>> the >>>>>> road, but mostly stay in the big ring...34 seems plenty low for me. >>>>>> >>>>>> I think I might enjoy having a bigger gear up front but am not sure >>>>>> how much of a difference it would make. I have a reasonable sense of >>>>>> what >>>>>> rear cluster gearing means, but less so up front. >>>>>> >>>>>> Is there any way to quantify or assess or describe what might be >>>>>> gained by going to a 42 or 44 over the 38? Can I just swap in the larger >>>>>> gear or will I lose the guard? >>>>>> >>>>>> Thanks to anyone who has read this far! >>>>>> >>>>> -- 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/09aea61b-82f5-414d-99e2-b55cd5614a12n%40googlegroups.com.
