Singlespeed & Fixed Gear - Another conversion question
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07-11-05, 06:14 PM
Hey, I am trying to convert one of my old roadies to a fixed gear and have a couple specific questions about the process. i have read sheldon brown's article several times through and have tried to search the older posts, but still have some questions.
This being a pretty low-budget build-up, i'm looking for a cheap rear wheel to use on this conversion. NYCbikes sells a budget track wheel with cog and lockring for $60, have any of you guys had experience with this wheel specifically? http://www.nycbikes.com/item.php?item_id=442
Also both the bikes i am thinking of converting both have 3piece cranks with double chainrings. in the conversion process, i want to get rid of one of those chainrings - will i need to replace the bottom bracket? one of the bikes is a peugeot from the 80's - will that have the french threading problems? or was that just earlier french bikes? The entire front chainring subject of fixed gear bikes is in the dark for me. what are my options?
Thanks for entertaining all my silly questions
Since this question probably comes up alot, let this newbie jump in and test my understanding so the old pro's don't have a fit about "here we go again..."
Since you already decided to go with a new hub instead of living without a lockring and redishing and respacing your original hub you should probably go with one of these hubs, an IRO or a cogswell,
they're sightly more expensive than the Suzue basic hub that NYCBikes sells with that offer. The better hubs will come with sealed bearings and a higher quality threading for the cogs. Also make a note of your rear dropout spacing (distance between the dropouts) before buy your hubs, you should be able to respace (if the axle is long enough...) later if you happened to buy 120mm spaced hubs and your frame turns out to have 130mm spacing between the dropouts.
As far as which chainring to get rid of...it depends on the gear set you choose for your self. Here's one chart. Most people pick something around 70 gearinches, I think, to begin with (42x16 or 52x20 or 39x15).
The chainline (measurement from center of the bike out to the chain, or chainring) is the important thing here, you want your chain to travel in a straight line between the front and rear gears other wise it'll have a tendency to jump off. So which ever chainring gives you the straightest shot back to the rear cog is the one you'll want to keep. You shouldn't have to replace the bb, unless it'll help you get a more straighter chainline.
good luck and have fun
07-11-05, 07:14 PM
I think the best way to figure out what gear you need is by riding around on your geared bike and find the highest gear you can still crank over the hills.
Then punch in those gear numbers (53x23 for me on 700cx23 tires, I live in a really hilly area) in sheldon brown's gear calculator for gear inches, then find a corresponding gear for your fixie. I'd go a little higher than your actual gear inch because on your geared bike, you know you can shift to an easier gear and it holds you back from cranking over the gear.
07-11-05, 07:30 PM
so the small chainring on my crankset is a 44 tooth. so a 17t cog will probably ideal, yes? and with this set-up i wont have the one lockup location problem from what i've gathered, is this correct?
I realize there are much better hubs/wheelsets out there for fixies, but i'm mainly lookin for a safe, cheap alternative to dumping all my money in the hubs. and a suicide hub definately doesn't seem safe to me, so the cheap NYCBikes wheelset looked to be the best option. Unless anyone has had a bad experience with that wheel/hub, that is.
The IRO wheelset was the other one i was considering, but its $40 more with no cog or lockring for the rear wheel - though i wouldnt mind having these quality wheels. does the sealed bearing make a big difference for a commuter bike?
A lot of people seem to be happily riding around on the Suzue basic hub. You'll get all kinds of opinions on which hub to buy. Wish we could all justify a set of Phil's...
Maybe you won't even like riding with a fixed gear.
I think there's a few threads on here about stripping hubs and the joys of cheap cogs as well.
The wheelset is probably one of those things that you'll depend on the most, especially for a commuter.
Anyway, you get what you pay for.
Go for the sealed bearing hub, especially if its for your commuter. Not sure if you are planning on riding in the rain, but if you are, a sealed hub will save you the trouble of tearing apart hub and cleaning and repacking it.
If you were to use the non-sealed vs the sealed hubs, you would definately notice the difference (at least witht low end non-sealed).
07-11-05, 08:36 PM
Thank you all for your input. I'm leaning towards a more expensive wheel, might as well get it right the first time.
For the front chainring though, with a 3piece ring can i just remove the bigger ring and keep the smaller (44t) ring on there? will i need spacers? I think i can get them frm harris cyclery...
07-11-05, 10:24 PM
You probably won't need spacers for the chainring. On most conversions, the spacing seems better if you have the ring on the inside of the spider (where the small one is usually), so you should be fine.
As for your decision on the wheel, I think its a smart one. Cheap hubs have bad bearings and won't ride smooth and will need to be replaced all too quickly. Also, I have no idea what kind of cog and lockring they use, but remember, this wheel is also your brake. You will put your life in its hand and its not the place to skimp. The IRO is as low as I'd go quality-wise.
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