what about the mechanical (small) advantage
of crank length?
2011-04-09 12:48:28
5
Gear ratio vs. gear inches
I just want to have my thinking confirmed. If one were to ride a "boneshaker" bike, direct drive fixed gear, with a 52" wheel ( http://worksmancycles.aitrk.com/shopsite_sc/store/html/page38.html ), when I go to Sheldon Brown's gear calculator ( http://www.sheldonbrown.com/gears/ ) and punch in 700 x 28 wheel with 48 chainring with 25 t cog, it gives me 51.4 gear inches, which comes out close to the 52" direct drive wheel, is that right?
So, a person of reasonable fitness could reasonably ride a 48 x 25 fixed gear all around the hills of Pittsburgh, therefore, a 52" boneshaker as well, right?
I think I might need to start liquidating some non-essential items to Craigslist.
2011-04-09 12:06:56
Yeah, the chart has an input for that, too.
2011-04-09 12:54:58
Yes, that is the whole meaning of gear inches, equating your "safety" bike's gear ratio and smaller rear wheel to that of a high wheeler.
52" is really small for a fixed gear though, even with the hills here in town. I ride between 68 and 72 gear inches, lower for my more distance oriented fixed road bike, 72 for shorter, faster rides.
2011-04-09 13:47:18
Even if a boneshaker was available in something larger than a 52", I don't think my 30" inseam would allow me to go to a higher "gear". Ha, ha!
2011-04-09 13:51:21