What to look for in a donor frame?
 

I'm set that I'm going to build a fixed gear (Flip/flop fixed/free). I haven't selected gear ratio or the like yet..

But, frames? Are there prefered frames, (road, MTB)? I have an old cromoly MTB frame that I could convert, or should I stick to finding a road frame? The fixed gear bike is to help me improve on my roadbike I ride now, so I'm thinking a fixed gear road bike would be preferable. But I"m open to opinions.

Do I select a slightly smaller size than normal?

Would steel be preferable?

Are there certainthings to watch out for?

Etc?

it's got to have horizontal dropouts. other than that the sky is the limit.

The unwritten credo is to use old spare parts or to salvage a frame from the curbside trash pile.

Although that could take FOREVER.

I just recently bought a steel mtb frame from Nashbar for only $32, plus shipping. When I got it, it was damaged in shipping, so I'm currently waiting for a replacement. But, the welds were decent, the paint job was mediocre, but for $32.00 what do you expect.

The also had a real cheap road frame as well. It didn't have horiz dropout, but you can always use a retention device if using a free hub, or there are some programs avail where you measure the chain stay lenght and it'll provide you with what gear combinations to use for a fixie.

L8R

For me, let me ask, you mean the rear portion of the bike where wheel is placed can not be anything but horizontal, correct?

This would be because of torque pulling issues?

As well as the drop-outs, remember to use a long wheelbase frame. You really don't want your feet or clips, if you use them, fouling the front wheel.

If you have no strong preference either way, a light road frame will build up into an easier ride for a new fixed user to experiment with- especially when you get tired or try a gentle hill for the first time.

Gearing: think what you use most often on your current bike and work from that. For most people on the flat- and traditionally in the hey day of fixed wheel racing and club riding, you're looking at 60 or 65 inches as a starting point.

eric

Eric,

Can you elaborate on this?

William,

I'm expressing this idea in the old formula (U.S./U.K.) which you and your buddies might have discarded....multiply chainring tooth number by wheel size, then divide by rear sprocket size.

for example:- 40 tooth chainring multiplied by 27" wheel, divided by 18 tooth sprocket , equals exactly 60 inches.

I use the old Stronglight 49D cranks, which take T.A.Cyclotouriste rings- good quality and lots of choice. I also use 27x1 1/4 rims and tyres, which fit the frame I'm using. The calculations are slightly different, of course, if you use 700c or 26" rims.

hope this helps -sometimes I confuse myself:)

eric

We allways use 27 as a standard in that calculation rather than change it for different tire sizes.

One more thing to look for that hasn't been mentioned is a high (relatively) bottom bracket shell. This will help keep you from scraping your pedals when going around turns because you have more clearance. Of course, you usually don't have much choice in this matter when scrounging for a used frame so you can always use short crank arms. I am going with 165s on my Miele build up.

On a side note, I finished tearing the bike apart and cleaning it and I noticed what a beautiful white paint job I have. It has a beautiful pearlescent shine to it when the light hits it just right. Guess I never noticed before under all the dirt and grime :). she is getting new cranks, chainring, BB and headset. The conversion will cost me a total of near $200 with the new wheel and cog. Not too bad.

Victor

This fixed gear bike is going to be an interesting learning experience for me. It's a lot more complicated than I thought, but not so that it's daunting, more so that it's pretty interesting.

I never considered crank length an issue until now. Hmm..