Shedding the derailleur!

Erich, you are a master of finding bikes, I guess you know how to search and what terms to search for. Nothing will happen this month due to other expenditures. I really like the idea of buying a frame and building it up from there. Love that Rockhopper in the last link. I'll be begging for your assistance in finding a frame after we close on the house.

So the ghetto single has some issues. 10 miles last night and the chain came off three times. one time both ends came off and got seriously jammed up. The last time when I got it back on it went to the next larger rear ring (19T Vs 17T) As I had no tools with me I couldn't slack off the rear wheel, but it was so so tight on there I couldn't move it and had to ride that way. Instead of being easier to ride it was much harder. The chain was so tight and at such and angle there was significant resistance to turning the crank even when off the ground.

When the chain first popped off I thought the wheel was loose, but no, it was on tight. I'm not sure why it kept coming off as I had it as straight as I could on the gears. It always happened when I was really putting torque through it either on a hill or leaving a stop light. Could I be flexing the ubber E36 M3ty one piece crank and thin crappy chainring? Lesson for tomorrow, take a 15mm spanner with me.

The chainring and sprocket on multispeed bikes are kinda designed to have the chain slip off. It makes it easier to shift gears. If you can get sprockets designed for a single-speed you will see that the teeth are deeper, more like the sprockets on a kid's bike or a motorcycle.

That's one of the reasons that it is difficult to make a "ghetto" single-speed out of a multi-speed bike. If you leave enough slack on the chain you run the risk of the chain coming off during hard pedaling.

If you get the chainline and tension just right you can get it pretty good, but to have it perfect you may need to get the right parts. Another option is to use one of those chain tensioner devices, or even just leave the derailleur and use a short piece of cable to fix it into the right "gear."

SEADave's right. The easiest way to make a derailleur shifted bike into a single speed is just don't shift it, but you lose any advantage of weight loss or simplicity gained by a SS bike. Second best way is one of the Surly Singleator or Nashbar type chain tensioners. SS rings and cogs are fantastic and can be expensive but don't have to be. My experience with a built-to-be-SS mountain bike is that i still occasionally dropped the chain but it was rare and on rough terrain.

The cheap cogs and gears are usually okay unless you are doing some kind of stupid human tricks with torque levels. One bit of advice - for the rear cog you want one that's thicker material where it interfaces with the hub. Some cheap ones are thin all the way down to the hub and they can cut into the aluminum hubs over time. Look for cogs with the thicker interface.

Stay away from the gear clamp style SS kits, the spacers are better. I've actually never seen anyone use the clamp style (which says something) but the spacers let you dial in your chainline without worrying about slippage.

The chain often slips due to the chain line being off. On a single speed it needs to be pretty much dead straight. That's one reason to use the clamps conversion in lieu of the shims - assemble the parts loosely, get the chain line right, then cinch down the clamps. If the chain line is right, there should be little to no forces trying to move those clamps.

Otherwise, I agree with keeping an eye on CL. You should be able to find somethign you're looking for in the <$200 range.

being in the flat midwest i normally ride a 20inch with 43/12 gearing but when im feeling lazy i have a cheapo mountain bike converted to 6 speed. never really understood the reason for going to single speed aside from trying to ditch weight but it seems like your going to use the bike to cruise and not urban trial rides?

Guys thought on this one?

http://detroit.craigslist.org/okl/bop/4693675235.html

That like looks just about ideal. Jump on it. It is a larger frame but as long as it fits, that's a steal.

texted the guy, if it's still available and is straight I'll get it. I'm 6' with a 32" inseam so I hope it's the right size for me.

I'd jump on that..

Ball monkeys. No reply from the CL seller

Adrian, Try the local police or university auctions. I picked up 20 bikes for around $150 dollars total. Gave a few away after some basic maintenance. Worked out great for those kids. Sold a couple, made most of my money back. The ones from the university auction are usually of the more expensive bikes. The kids here just leave them when they go home for the summer, and the school cleans up the dorm bikes racks around the end of June. All of these bikes sit outside until they deceide to have a property sale. Last year saw a $1500 (forget brand) bike go for $418 cause 2 people knew what it was worth. That was high for the day, I usually look for steel frame bikes ($30 or less)to hack. Check out AtomicZombie.com for bike ideas.

I worked the MSU bike auction a few years back when I was in school. Most of the bikes were extremely lousy, with lots of repairs needed. Only a handful were worth buying, and you really had to know what you were looking at to spot the diamonds in the rough.

Too bad your budget isn't a bit (lot) higher Adrian. A bike I've always wanted just popped up on Craigslist. But I'd have to sell my touring bike to fund it.

LOL, I just picked up the same bike from craigslist to do the exact same thing Adrian wanted to do. I'm way more stubborn than he is though so I'm going to go through with it. My only goal is to just putter around the neighborhood with my 8yo in the evenings. It really is a crappy bike but it was also the cheapest one in the area that fit me. I was googling info on the Columbia ATB and found this thread, I remember reading it back when it was posted. I may start my own thread when I get into it. This is too funny.

So I road the old pos around with the ghetto single speed for months then bought a new single speed with a flip flop hin. I got a Pyxle Fyxation. I'm on my phone now but will post pics later. It was instantly 10 mins faster over 12 miles. Great comfortable bike with quick steering

Does the new bike have the same gearing and tire height?

I don't recall the old bikes gearing in the end, it may be up thread

The new bike is

Frameset: Fyxation Pixel 4130 main triangle
Wheelset: Forged flip/flop 32h hubs with 30mm alloy rims
Stem: 3D Forged alloy stem
Bars: Alloy narrow rise bar
Brakes: Alloy dual pivot caliper
Bottom Bracket: Sealed cartridge bearing
Cranks: Forged Alloy track cranks
Flip flop hub so the bike can be run single speed or fixed
Fender/rack mounts on frame and fork dropouts
Clearance for 700x32c tires (700x28c with fenders)
Complete bike weight: 23lbs
Gear Ratio: 46x17
Made in Taiwan
Frame size: 49, 52, 55, 58cm

In reply to Adrian_Thompson:

That should treat you very well for a long time.

I run a 46x20 on my singlespeed, but I'm more of a spinner than a masher.

My dad gave me an old 10 speed Nishiki that was kicking around. Just for fun I dropped it off at the bike shop and had them go over it. Its around 30 years old. They converted it to upright bars and replaced the tubes (not the tires which they said were indestructible on older bikes) and tuned up the gears. It is just a fabulous bike to ride and every time I get on it I wonder why we went away from good tires and simple derailleurs (do we need 20 gears to get across town?). I really haven't got on my very expensive mountain bike since I got the old one back. The bike shop charged me around $120.00.