jcarneytx Posted February 6, 2019 Share Posted February 6, 2019 Kill it with fire 2 Quote Link to comment Share on other sites More sharing options...
AustinBike Posted February 6, 2019 Share Posted February 6, 2019 I was promised there would be no math Quote Link to comment Share on other sites More sharing options...
AntonioGG Posted February 6, 2019 Share Posted February 6, 2019 38t chainring 28t cog 32t cog as 2nd chainring Looks like maybe standard 11-25 or 12-27 cassette There is no reason for that complexity. By my calculations (coffee still fully not kicked in) that gives them final ratio of 1.61 (assuming 27t cog) to 3.94 (assuming 11t cog). A road triple 53/39/30 would give them a bigger range. Shoot, even a compact 50/34 would be better. Quote Link to comment Share on other sites More sharing options...
jcarneytx Posted February 7, 2019 Author Share Posted February 7, 2019 13 hours ago, AntonioGG said: 38t chainring 28t cog 32t cog as 2nd chainring Looks like maybe standard 11-25 or 12-27 cassette There is no reason for that complexity. By my calculations (coffee still fully not kicked in) that gives them final ratio of 1.61 (assuming 27t cog) to 3.94 (assuming 11t cog). A road triple 53/39/30 would give them a bigger range. Shoot, even a compact 50/34 would be better. 2nd upper chainring has a derailleur, as does the actual crank/chainrings. The only "non-moving" chainring would be the upper to the back wheel (needs to stay where it is or interfere with adjustable chain. So you'd have (guessing) a possible 42 or 34 at crank, possible 12-28 upper gearing and say 12-32 on back wheel. At top end you'd have 42:12:12 ratio and at bottom 34:28:32. I'd say a bit more than just a normal trippel (final gear speed, anyway) 1 Quote Link to comment Share on other sites More sharing options...
AntonioGG Posted February 7, 2019 Share Posted February 7, 2019 I downloaded the picture really zoomed in and counted the teeth. It's a 38th big ring on the crank (weird size I know). I also counted the two cogs on that "idler" cassette. I'm pretty sure 28t and 32t are right. I hadn't realized there was a cable on that upper derraileur. I thought it was being used as a tensioner. The small gear looks to be a 15t by my count. The only one I couldn't count was the cassette on the wheel, but it doesn't look like a very large one. It looks like the one on my road bike (11-25). 38:15:12 for top speed 7.36:1 final ratio Not even a 60t chainring with 11t cog would compare. 28:28:? If it's a 25, that's a ~1.3:1 ratio. A 27 would be ~1.18:1. A 32 would be 1:1 ratio I want to see the cockpit on this thing! If they wanted low gearing, then a MTB triple would be way better with a <1 ratio possible with a 22t granny in a triple crankset. If they wanted high gearing, then, this is one way to do it I guess. But so is this 🙂 https://www.velonews.com/2016/09/news/ca-woman-rides-her-bicycle-147-mph-a-new-world-record_420507 Ultimately, it seems like an art bike and pretty cool if it works, but seems highly impractical. 1 Quote Link to comment Share on other sites More sharing options...
Ridenfool Posted February 7, 2019 Share Posted February 7, 2019 Perhaps it is a bike owned by a Semi-Tractor driver who enjoys having a ridiculous number of gear combinations with lots of shifters to fiddle with. 1 Quote Link to comment Share on other sites More sharing options...
Shinerider Posted February 7, 2019 Share Posted February 7, 2019 Holey shit the rain is driving ya'll bat shit crazy. 3 Quote Link to comment Share on other sites More sharing options...
AntonioGG Posted February 7, 2019 Share Posted February 7, 2019 10 hours ago, Shinerider said: Holey shit the rain is driving ya'll bat shit crazy. Better than arguing with certain people about inane things! At least we're discussing cool/weird bike things here and nerding out. 3 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.