Building up my beater.
 

Hello!

Sorry, I don't know if I should post this under the singlespeed section or the mechanical section - sorry if I made a mistake.

Story:

I have this old cheap bike that a friend gave to me. I needed a beater bike, so I accepted it. The frame of the bike is in good shape, but the components are really dirty and worn. I don't want to spend any money on a beater bike, but I don't mind putting in time to fix it up (I like fixing things :)).

Anyways, I have a wreck of my old "cheap" mountain bike. I crushed the fork in an accident and it isn't worth replacing/fixing. The frame is in really rough shape (that's why I don't take the fork off the beater), but the components are good (they've been replaced over the lifetime of the bike).

I am/was planning on swapping parts from one bike to the other, so the beater works properly. As I was swapping wheels (the wheels on the beater were heavy steel, rusted rims, mine were lighter aluminum + new), I noticed the beater had a five-ring cassette, and mine had a seven-ring cassette. My rim does fit in the beater and spin freely, but I think I might have trouble shifting into the smallest gear. As well, my Shimano Tourney RD can't be mounted on the beater's frame. Since the beater is heavy, and I don't plan on doing any serious riding on it, I thought: "hey, I don't need a RD - I don't need to shift gears."

Now I have a few questions before I start wasting my time.

Questions:

It's possible to ride around on a bike without a RD, as long as I don't shift at the front, and the chain isn't slack, right?

This means I can leave the FD on the front (to help keep the chain on the chain ring) and it'll all work out?

Would I be able to ride without the FD at all? Or, is that too risky (the chain will slip)?

I have three chain rings at the front. As I said, it's a really cheap bike. Is it possible to convert it to only a single chain ring at the front, or is it a chance sort-of-thing, or do I need to buy a proper crank for a true single speed?

I had to replace my back wheel over the lifetime of my wrecked bike. It went from the "old-tech" of the screw-on cassette to the "new-tech" of a cassette that slides on. I don't know if this is important to my question, but is it possible to turn that wheel into a single speed, or no? Do I need a special back wheel that supports only one gear?

These may all sound like really stupid questions, but I have little to no experience. I'm willing to learn, and I thought asking the more experienced people some questions first would be a good start.

Thanks!

Your best bet, in my opinion, would be to remove both derailleurs since you don't want to do any shifting. shorten your chain so you have a snug fit, and remove the unused chainrings up front. The tight fit of the chain around the ring/cog will keep the chain in place. a front derailleur in this instance is completely unnecessary and can be removed altogether (as can your shifters/cables). same goes for rear. While it's not likely, the chance of you dropping a chain is higher with the rd than without. Also, make sure you pick the cog in the back with as straight a chainline as the ring up front.

Does the bike have a RD (even if its crappy or non functioning?) because you can use a RD as a chain tensioner which would give you some flexibility with what your next move is.

The problem is keeping the chain from being slack if the bike has rear vertical drop-outs can be more trouble then it's worth.

You can take the FD off. All the FD does is push the chain from side to side when you shift. Other then that it shouldn't touch the chain, so no not having an FD won't effect the chain from slipping. If it falls off with a FD or without and FD you are still screwed :)

You could take the unused rings off. I'm not sure whether or not you would need any form of spacer then. You could also just keep them on and remove the FD for a manual geared bike? I.e. You can before you start riding put the chain on a different ring depending. If you keep the RD on and use it as a chain tensioner you can switch from ring to ring pretty easy.

Someone more qualified should answer this question. I think what you need to do if you want a true single-speed is redish the wheel or put spacers between the cog and hub?

You could also leave the rear cog on and just not shift.

Nah, this is actually in my opinion the model post of how good questions should be asked. You used paragraphs! Thank you!

I think NitroPye's advice is excellent. I recently built up a single-speed form scratch, and I chose a wheelset with a single-speed hub for the rear wheel. If you want to reuse the old wheel from a geared bike, then the best way is to use spacers in the rear hub after removing the cassette. You could take the cassette apart and pick the cog you want, in terms of number of teeth, gear ratios, etc. Your LBS will help you do take the cassette apart if you have trouble with it. This will give you greater freedom to get the chainline really straight. It will also give you several cogs to use as spacers!

The front crankwheels give you much less room to play with, even if you remove rings, or change rings from one side to the other and add spacers, etc. A straight chainline is important for single-speeds because otherwise, the chain will wear unevenly and cause trouble later on. You could redish the wheel if you wanted to ( more work ) but it is not critical, I think. Sheldon Brown, as always, has fine advice at his site on this topic. Here it is:

http://sheldonbrown.com/singlespeed.html

I hope this advice is useful. I am not very experienced, but thought I would assist. My apologies if there is too much or too little information!

Sudevan

Thanks for all the advice so far. I find the flip-flop hub mentioned in the Sheldon Brown website interesting. Still, this is just a beater bike, and I'm not going to pay $$$ for one - I'm working on getting the money for my real bike!

I'm still working on the crankset (it's cold and dark out now - a bit harder to work!). I think I'll keep it relatively simple - I'll try to eliminate the unwanted chainrings and just leave the full cassette on the rear wheel. I don't have the proper tools to take apart a splined cassette (unless I can use common-found tools?). One chain ring in the front (in theory) and seven at the back - that's my plan.

I'm looking forward to the final product.

Thanks for the help so far!

I second that plan.

If your chainring bolt are too long you might have to buy a smaller/shorter set, but you shoul dbe able to get rid of the extra rings up front and ditch the FD, and use the rear as a chain tensioner.

I have a mtn bike that I use the same way. I use the RD and all the gears, but I removed the FD and granny gear, and replaced the big ring with a bash guard in the front.

Good luck!

I would keep the rear derailer as a tensioner/chain keeper on-er. I had a bad wreck once when my chain decided to shift on a set up where the cogs were left on but the derailer was removed. If you have access to a community bike shop or are willing to buy tools, you could remove all the extra cogs and replace them with spacers if it's a cassette or remove the multi speed freewheel and replace it with a single speed one.

Hey mate- Good show on going singlespeed. I've built up a couple and they're basically problem free once you get them going. Great fun for an around town or commuter bike.

For my first single speed, I wanted to have just a single cog in back. That would allow me to pick my gear ratio AND get my chain alignment spot on. I had the same problem you had. My rear wheel was the slide on cassette. I may just be slow, but I had the hardest time picturing what I was supposed to do to take apart a cassette and what these spacers were for. For this, you'll also need a cassette tool or the help of a friendly bike shop employee. The tool will just fit into the lockring that is holding your cassette in.

If you pull off your cassette, you can see that it is just pinned together with three metal pins. I was able to easily drive these out using a punch or old screwdriver and a hammer. In between each cog are the spacers you're looking for. You'll probably need two old cassettes to get the right number of spacers. I went to my local bike shop (Thanks again Budget!) and they hooked me up with some old cassettes from their bin.

Anyway, here are some pictures of the finished project. I just used the nicest cog from one of the old cassettes.

Today I didn't have much time to work on the bike. I've managed to get the brakes up and running, and sorted out the handlebar/stem/fork issues, as well as removing one of the cranks (the sucker was rusted on).

I told you it is a POS bike, but I like building things.

I don't think I need the RD. The bike is old and still uses horizontal dropouts. When I swapped the wheels, I kept the quick release mechanism on the axle. I figure if the chain ever did fall off, I'd be able to eject the back wheel and fix it up.

I plan on removing the large chain ring at the front, as well as the granny gear. I'll use the middle at the front and smallest ring at the back (no, I don't know the ratios). It'll be an easy ride, but I need it to get me on the trails, and a high-speed gear is not practical. As well, by removing the large chain ring, I'll have an inch or so more clearance for obstacles!

I can't continue to work on it until monday, though. I'll let you know how it goes, if you care.