grimcow

So over the weekend I had my girlfriend look at an older Kuwahara road bike for me that I found on CL in a neighboring city. Knowing I wanted to attempt to build up a Fixie she went ahead and just bought it for me because shes a pretty awesome lady. I am super happy with the bike, it runs great, looks sexy with extremely little rust, basically just need to give it a good clean and maybe some new cables and she should absically be good to go i beleive. But now that iv begun researching into the conversion I am kind of unsure about some things. One of my bigger concerned is with the crank set. I believe this is a cottered crank? IT appears there is some kind of cap on it that i have yet to remove but underneath it looks like theres a pin in place. From reading i'v found this can be a bit of a hassle to work with, thats okay i have all winter to dick around with this thing so a little more work isnt to much of an issue (I am pretty new to all this stuff too.. the only mech stuff iv done is pretty basic repairs on my rockhopper.) I cant seem to find this crankset anywhere either, appears its a Singuno from 1985 (same year as the bike) and to me it looks like all the crank teeth wheel things (sorry im not 100% sure of the name for these things) are attached to the larger outer casing deal. I guess my question is can remove the outer casing and just buy new "teeth wheel things" or am i going to have to buy a whole new crank set (apparently a new BB seems to go along with these purchases?) Any help would be great, as i mentioned before im no seasoned bike mechanic and would also prefer to not have to spend a crap ton of money on a new crank set.. They look rather pricey. Also most everything on the bike seems to be original, which i think is kind of cool and would be cool to keep as much as possible.

^^Sorry for such a massive paragraph too

mihlbach

Looks to me like you can remove the inner chainring, but your are going to have to leave the outer chainring and chainguard. Nothing wrong with that. As long as you can get a reasonably straight chainline I wouldn't bother with a new crankset. Gear it appropriately. The bigger challenge will be the rear wheel. Are you going to redish and suicide or get a new wheel?

cobrabyte

If the large chainring is a 52T, a 19 or 20T cog will be a good size to use. That will give you a nice all around gearing.

LesterOfPuppets

I'd also use those cranks for now if on a budget. But to answer your question, they're not cottered. They're decent old square taper.

prooftheory

"Crank teeth wheel things casing" reminds me of today's xkcd. SheldonBrown.com might be a good place to pick up some of the lingo and get information about the conversion process.

grimcow

Thanks. I was kind thinking to try and redish it, not sure what suicide means. As i said iv never done this but honestly I kinda wanted to get into this more as a project and a way to learn a little more about the subject.. Im sure that will involve lots of fun old learning and a nights of screaming swear words but thats okay, i have a few months before the snow departs.

grimcow

Also thanks alot lester. That was kinda my big concern atm. And yes cobra they are 52t.. i just counted them. As far as the gearing goes theres some pretty decent hills where i live (Flagstaff, AZ.. like 7,300 ft up) i havent looked much into gearing at all yet but i will keep that mind

Thanks for all the help and to unconfirm my worries

grimcow

luls.. I'v been looking thru sheldon brown some.. guess i should continue.

grimcow

ah i see.. maybe im better off just buying a new wheel

mihlbach

A suicide hub just means there is no lockring. You are not going to be able to install a lockring on your hub because it is only intended for a freewheel. Its easy to thread the cog on tight enough that a lockring is unnecessary (google "rotafix"), although there is a possibility that the cog could unthread when backpedaling, hence the term "suicide". Its not really all that dangerous if you have brakes, though it is a bit janky. A new wheel (or rebuilding the old wheel with a track hub) is always better.

You need to decide what you want to do with the front of the drivetrain first...that will determine your chainline and what your options are for the back end.

Every conversion is a unique adventure!

EpicSchwinn

If you're thinking of getting a fixed gear wheelset on the super cheap, eighthinch makes one called Amelia which comes shipped with tubes, tires, 16t cog and lockring for $110.

I had them and they weren't bad. There was a slight wobble that nobody could seem to cure though.

If you're looking for something a little nicer check out velomine.com's selection of track wheelsets

grimcow

Ha..Epic I had just been looking through the Amelia's wondering how they would do as they seem relatively cheap. I think I might go with those for now unless my cheap boss decided to give me some kind of bonus for being a nice guy. Also frankly I dont enjoy doing anything much that has the word suicide in it.

mihl i think ill just keep that crankset.. If its really something that bugs me I assume I could always upgrade it at a far later date? Now my understanding is that I can replace the chainring though so long as I find something that will match will the bolts on current crank. Am I wrong in this thought?

mihlbach

Look correct to me...but I don't think you'll find a readily available modern chainring with a bolt circle diameter that large.

grimcow

oh well.. I suppose I could just use this one, saving money is always good anyways. Then to change the ratio I can simply adjust the back one correct?

So basically if i just replace the back with a new already fixed-hub wheel, then take off the extra chainring at the front, I technically would be good to go?(besides stripping extra parts) I feel like it should be more difficult then that.

EpicSchwinn

Only difficulty you might run into after that is chain line. It's something you're just going to have to see once you've got a wheel on there. With the weirdness of the crank you have, it would be hard to adjust it if your chain line is off. The good news is most local bike shops have all sorts of quality used road cranksets which can be had for cheap and used on your conversion.

If you were thinking of getting the Amelias anyway, Eighthinch has a conversion kit that includes a crankset, bottom bracket, chain, and that wheelset (incl. tires, tubes, cog and lockring).

That would probably be your cheap and easy solution.

https://ws-outlet.com/p-55657-eighthi...om-backet.aspx

Muffin Man

Haha I dont know too much about rockets, but that was amusing.

grimcow

I was kind of eyeballing those earlier.. I suppose that would be a good option. Should i be concerned about fitting the bottom bracket in or is that something that is generally a fit?

It will sadly prolly be a month or so before I have the spare time and money to put this all together so maybe ill look around some of the lbs to see if they have any said cranks at a good price. If not It sounds like the cheaper wheel/crank/everything package might be the way to go... Btw I appreciate all the help. Actually have learned alot here

seau grateau

Some bikes do have unusual sizes and threading for their bottom brackets, but I'd say this one will most likely fit the modern standard 68mm English threading. That's an educated guess, so don't quote me.

EpicSchwinn

make me, punk!

grimcow

Thanks again for all the help everyone. Going to go buy some tools tomarrow to get ready for the project.