tag:blogger.com,1999:blog-18676999.post2405237950864922129..comments2024-02-27T01:52:06.519-08:00Comments on Kent's Bike Blog: Retro-Direction Perfection?Kent Petersonhttp://www.blogger.com/profile/12906603746565831689noreply@blogger.comBlogger12125tag:blogger.com,1999:blog-18676999.post-67097143043126160362013-10-27T17:25:24.694-07:002013-10-27T17:25:24.694-07:00Hi Daks,
If my previous posts (follow the links i...Hi Daks,<br /><br />If my previous posts (follow the links in this post or use the blog search function) don't answer your questions, drop me an email at kentsbike@gmail.com.<br /><br />KentKent Petersonhttps://www.blogger.com/profile/01607372827627527450noreply@blogger.comtag:blogger.com,1999:blog-18676999.post-6078630252528842712013-10-27T15:44:56.257-07:002013-10-27T15:44:56.257-07:00Hi Kent,
I am becoming a Tech Ed teacher (shop tea...Hi Kent,<br />I am becoming a Tech Ed teacher (shop teacher) in Vancouver, Canada and I am very interested in building a retro-direct bike as a project. I would love to ask you a couple of logistical questions, mostly about the two independent freewheels on the wheel. Dakshttps://www.blogger.com/profile/15885697859985765709noreply@blogger.comtag:blogger.com,1999:blog-18676999.post-36328893911286234722009-02-03T23:39:00.000-08:002009-02-03T23:39:00.000-08:00Hi Kent, I may soon become the third(?) retro-dire...Hi Kent, I may soon become the third(?) retro-direct rider in Seattle. I'm hoping to make it a 2x(-2) with 2 chainrings (this bike I'm using came with a 40-50 crankset) and a sprung tensioner. I kept running the numbers and the most sensible gear spread for me looks like 16 small and 24 big freewheels, but of course no 24t freewheels are to be found. But! I found some freewheels made for electric scooters that use bolt on sprockets:<BR/><BR/>http://www.electricscooterparts.com/SPR-SB4H.htm<BR/><BR/>And if I'm measuring the picture right, that is (or is nearly) a 4x64mm BCD just like MTB granny rings! This might be the solution to the big freewheel problem. I have one on order and will let you know how it turns out.zzyzx_xyzzyhttps://www.blogger.com/profile/10247462614273990943noreply@blogger.comtag:blogger.com,1999:blog-18676999.post-62513620101666887982008-12-12T07:28:00.000-08:002008-12-12T07:28:00.000-08:00Cafn8,Yep, the long idler arm does a couple of thi...Cafn8,<BR/><BR/>Yep, the long idler arm does a couple of things. Having the idler pulley close to the crankset lets the chainline to the back freewheels be pretty straight. When the idler was further back the angles going into the freewheels wound up being more laterally extreme and things were noisy and tended to derail. The other trick with the idler arm is that it attached to the bike with bands cut from old inner tubes. It actually pivots slightly (with the bottom bracket shell as the fulcrum) so the chain tension stays constant, even though the inexpensive Dicta freewheels don't spin perfectly round. Since the outer freewheel is attached to the inner one, the out-of-roundness effect is kind of additive. The arm pulls up the slack in the system.Kent Petersonhttps://www.blogger.com/profile/01607372827627527450noreply@blogger.comtag:blogger.com,1999:blog-18676999.post-36896364402531400292008-12-12T05:26:00.000-08:002008-12-12T05:26:00.000-08:00Cool project.I'm curious about the long idler arm....Cool project.<BR/><BR/>I'm curious about the long idler arm. Is it there to reduce the lateral angle of the chain as it comes around the bottom of one cog and back over the other? I'm wondering since the retro direct XO2 looks more like your original setup (although apparently the iteration that looks most like your original setup wasn't quite perfect either.) Is it for length, angle or both?<BR/><BR/>I love odd bikes.Cafn8https://www.blogger.com/profile/12823570445012150263noreply@blogger.comtag:blogger.com,1999:blog-18676999.post-21997089388766958582008-12-11T04:48:00.000-08:002008-12-11T04:48:00.000-08:00Kent,you're messing with the laws of nature. This ...Kent,<BR/><BR/>you're messing with the laws of nature. This ain't right, nice or moral. Pedals are meant to turn in one direction, and one direction only. Please leave things as they are and don't try to push the envelope too far. Just because things are possible don't mean that you gota try them.<BR/><BR/>My prayers be with you.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-18676999.post-21619849376983314352008-12-10T09:27:00.000-08:002008-12-10T09:27:00.000-08:00Sounds like that Wikipedia page could use a bit of...Sounds like that Wikipedia page could use a bit of updating, then, regarding the benefits of low-forward high-reverse gearing, from somebody who has (retro-)direct first-hand experience... :-)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-18676999.post-54317347498906535852008-12-09T08:24:00.000-08:002008-12-09T08:24:00.000-08:00Erik,The arm is held to the bike with straps cut f...Erik,<BR/><BR/>The arm is held to the bike with straps cut from an old inner tube. I haven't bashed it yet, but in theory the arm will flex rather than snap off. In fact it does flex a bit because the cheap Dicta freewheels aren't perfectly round.<BR/><BR/>The pulley does pick up a fair bit of grit and after yesterday's trip that involved a lot of muddy trails I've fashioned a coroplast mud shield to keep the worst of the crud off the front pulley.<BR/><BR/>Larry, the bars are flat mountain bike bars with Newk bar-ends. Newks aren't made any more, but I scored a set at Bike Works. I use the lower drops while back pedaling in the high gear and the upper bar-ends with the low gear for climbing.<BR/><BR/>KentKent Petersonhttps://www.blogger.com/profile/01607372827627527450noreply@blogger.comtag:blogger.com,1999:blog-18676999.post-18561581267951183932008-12-08T21:19:00.000-08:002008-12-08T21:19:00.000-08:00Kent, I happy to learn that this is working out. S...Kent, I happy to learn that this is working out. Sounds like big fun. By the way, what kind of handlebars are those?<BR/>Best,<BR/>LarryLawrence Fiemanhttps://www.blogger.com/profile/18199687567601070049noreply@blogger.comtag:blogger.com,1999:blog-18676999.post-30017565520336351732008-12-08T16:03:00.000-08:002008-12-08T16:03:00.000-08:00Nice job man.Nice job man.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-18676999.post-27513721456600517582008-12-07T16:13:00.000-08:002008-12-07T16:13:00.000-08:00Perhaps, after a few months of retraining your neu...Perhaps, after a few months of retraining your neuro-muscular system on the current gearing, try reversing it again.Vincent Muonekehttps://www.blogger.com/profile/15652019997091119820noreply@blogger.comtag:blogger.com,1999:blog-18676999.post-14658480180750441762008-12-07T15:16:00.000-08:002008-12-07T15:16:00.000-08:00This has been a really interesting series and I'm ...This has been a really interesting series and I'm definitely going to post another link to this update from my NorCal Bikers blog. One question for you, how fragile a set up is this? It looks like the arm with the cog hanging low could get destroyed by a curb jump or something in the road.<BR/><BR/>Still, a very cool project!Fenhttps://www.blogger.com/profile/02175572083582286145noreply@blogger.com