Bicycle Mechanics - Fixie project: Is filing drive-side dropouts necessary? Please help!

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Matterbator
05-28-08, 09:34 PM
Hey all. I just recently purchased a 1987 (I think) Schwinn World Sport frame on ebay in hopes of turning it into a little fixie side project. This will be my first attempt at building a bike. I recently found the exact (or so it looks) frame that was made into a fixed gear on Velospace.org. I was happy to see it can, and has, been done, however I read up that old school road bikes with drive-side dropouts like the one on this bike can be quite problematic for making a fixed gear.

http://i295.photobucket.com/albums/mm141/QcupVIPimp/4-22001.jpg
That's the bike I bought.

http://i295.photobucket.com/albums/mm141/QcupVIPimp/IMG_4090.gif
This is the fixed gear I found online. (He obviously made it work w/ the dropouts) I do not know if he cut them or just left it as is.

http://i295.photobucket.com/albums/mm141/QcupVIPimp/4-22014.jpg
Here is an example of the drive-side dropout.

http://i295.photobucket.com/albums/mm141/QcupVIPimp/rightd8fn.jpg
And here is another example from some other bike just to highlight what it looks like.

Now, I've heard some can manage without filing/cutting the dropout back (depending on gear ratio), although some have to shave it back and just kind of test it as they go. If I were to do this method, what tool would you recommend using to file it back? Any tips would be wonderful since I'm not familiar with either bicycle building or.. filling/cutting metal in general. Should I try to really convert this sucker? I'd like to get my hands a bit dirty and learn as much as possible since that's my main goal, aside from creating a sweet personalized ride. Thanks in advance!


MrCjolsen
05-28-08, 09:49 PM
My first fixed gear conversion was on an old Giant that had dropouts just like those.

Yes, I filed them.

The best way is to get a round file that is about the diameter of the dropout, hang the bike by a font wheel and just start filing. It will take some time, but progress will come faster than you might think.

The closer you get them to where the non-drive side is, the better.

However, if are able to get good chain tension with the whole axle nut on the dropout, and you don't want to change the gearing at all, then it's fine the way it is.

But if the chain is loose when the axle hits the rear dropout, or if any part of the nut is off the dropout, then you should file it a little so that you can get good tension.

Basically, the goal is good chain tension with a axle that is securely bolted to the dropout. What you don't want is your axle sliding off because the nut wasn't on the dropout enough or the chain derailing because it didn't have good tension.

It's also nice to be able to run different sized rings or cogs. But that's not essential.

Thumpic
05-28-08, 09:53 PM
Why would it be a problem? Just be sure the axle is well seated in the drive side and the wheel is centered and parallel to the center line.......make your chain the right length....and go for it........


Matterbator
05-28-08, 10:38 PM
Awesome, thanks guys =]. Guess I'll hit up a local hardware store and get to filling. Also, do you have any recommendations on gear ratios? I live in San Francisco which is kinda hilly. I'm leaning towards 48-16 but not sure yet. Thanks!

JiveTurkey
05-28-08, 10:43 PM
Don't skid much with that chainring/cog combo--you'll wind up with one bare spot (two if you're ambidextrous).

Matterbator
05-28-08, 11:07 PM
Don't skid much with that chainring/cog combo--you'll wind up with one bare spot (two if you're ambidextrous).

Ah yeah. What would you recommend? I know sheldon brown's site has a little calculator up so you can pick one that would allow for 3~ or so skid patches. Maybe I'll rethink it.

jgedwa
05-29-08, 06:46 AM
Grinding out that filler metal in there is not hard and can be done if needed.

But, are you sure it is needed. Especially if you have the option of using a half-link, you should be able to get the chain length close enough so that the small amount of latitude you have in the drop currently should work.

You really only need 1/2" of latitude (and a half-link) in order to do what you want. More is better, since it means no need for a half-link, and/or the use of several different cogs, and/or less precision in cutting the chain.

If it were me, I would try first with the drops as they are, and then grind it if necessary.

jim

Thumpic
05-29-08, 06:55 AM
Grinding out that filler metal in there is not hard and can be done if needed.

But, are you sure it is needed. Especially if you have the option of using a half-link, you should be able to get the chain length close enough so that the small amount of latitude you have in the drop currently should work.

You really only need 1/2" of latitude (and a half-link) in order to do what you want. More is better, since it means no need for a half-link, and/or the use of several different cogs, and/or less precision in cutting the chain.

If it were me, I would try first with the drops as they are, and then grind it if necessary.

jim

+1........like I said......... Grinding the drop out should be a last resort; you may want to put it back original later........or someone may offer you top dollar for an original Schwinn frame; who knows...

04jtb
05-29-08, 07:06 AM
Ah yeah. What would you recommend? I know sheldon brown's site has a little calculator up so you can pick one that would allow for 3~ or so skid patches. Maybe I'll rethink it.

something by 17

madman451
05-29-08, 08:41 AM
I have a Schwinn world sport fixie like this. I modified the dropouts. If you feel you have the finesse, an angle grinder will make 3 minutes of work of your dropout instead of 45 filing. 46/16 is tall, and I would especially think so for San Francisco. I run 46/19 in Minneapolis, which also has the advantage of 874 skid spots!

Good Riding.

dobber
05-29-08, 08:47 AM
Ah yeah. What would you recommend? I know sheldon brown's site has a little calculator up so you can pick one that would allow for 3~ or so skid patches. Maybe I'll rethink it.


Easiest thing to do is not skid. Mount a brake.

jgedwa
05-29-08, 09:04 AM
46x16 will make for pretty difficult skidding. Once you get the hang of it (mainly the art of unweighting the rear wheel), any ratio can be skidded. But it will seem impossible unless you are pretty adept at it already.

jim

Joshua A.C. New
05-29-08, 12:50 PM
Just change that ratio by 1 in either direction to prevent wear holes.

Also, SF with no brakes? Yikes.