Singlespeed & Fixed Gear - One-piece

I've ridden BMX for a few years, and I'm now really getting into fixed gear. I am converting my road bike to fixed gear and I was wondering it it would be a problem to keep the one-piece thats allready on there on there for now? I will be getting a 3-piece eventually, but I can't afford it until after Iactually buy the fixed gear wheel and all of that. Thanks alot. My name is Rob by the way.

3 piece suit

I definitely prefer a 1-piece. A 2-piece is way too revealing.

Yes, glomarduck! I want to play tablas!

Tambien yo queiro jugar las tablas...

Tablas!

I.M. me for march of the tablas track from my band


Also I have no clue what the hell is being talked about here but if you want an audio track be my guest

I definitely prefer a 1-piece. A 2-piece is way too revealing.

Yes, glomarduck! I want to play tablas!
I was just wondering if the one I have on there is cool, like the one allready attached to the sproket.. on a bmx bike, its not attached..

OK, I'll take a stab at this one. I am assuming that you are referring to a one piece crankset as opposed to a three piece crank. You might try stating these minor details in the future since our forum mindreader made the mistake of reading the Advocacy Fourm a while back and developed migraines.

Anyway, you MAY be able to use your current one-piece crankset for a fixed gear. It's going to depend on the chainline you get with whatever hub you pick. The chainline is how well the chainring and the rear cog line up. www.sheldonbrown.com has a very good description of this that is far more elegant than I can do here.

If you have chainline problems, you may be able to fix them by spacing the rear cog over and redishing the wheel. I suspect the chainwheel cannot be moved with spacers on a one-piece crank so you are limited to aligning the rear hub.

I would also be concerned about the strength of a one-piece crank when it comes to skidding. Since a one-piece crank is used on low end bikes, the material used is probably not the strongest alloys. I guess that's the risk you take.

Yea, sorry for not stating that, but in bmx if you say 3 piece, its understood you meen 3 piece cranks.. I'm incredibally new to road bikes and fixed gear bikes. I'll learn the minor differenecs in terminology the more I learn about fixed gear, but for now I'm stuck just knowing about bmx bikes.. What you said cleared up what i was wondering.. I have no choice but to run the one piece crank set for now, I was just wondering if it would be at all possible. I will get a 3 piece crank set eventually, when i can afford it. Thanks alot.

A one-piece crank will be plenty strong, just not all that light. If you can get a good chainline, you'll be fine.

i dunno if a one-piece cranks set-up will do the job. yes, the 1 piece crank will be strong enough, but the BB will take a beating. i rode a BMX with a one-piece for a while and would go through BB's like they were candy. i can only imagine have a one-piece on a fixie would need constant BB adjustment.

any road bike that came with one-piece cranks is generally very low end, and probably not the best idea for a fixed conversion. you should hold out for a frame with a threaded BB shell.

building a singlespeed or coaster brake would be the better choice for a 1piece crank, and much easier on the wallet.

Mine's got a 1-piece crank, its obviously not a really classy bike or anything, but my BB is holding up fine, and I have great chainline. My next frame will probably be a 3-piece crank, just because I worry that people won't take me seriously with a 1-piece, but whatevs.

you dont have any problems with the BB loosening up? on my BMX it seemed like i was adjusting it everyweek! what kind of frame is it?

I've been riding it for a couple months, but its about time to tighten up the BB again... but another thing I like about 1-pieces is that you can field-strip them in a couple minutes with a couple basic hand tools, very simple. My bike is a 79 Schwinn Continental, fixed.

a friend of mine messengered on a little 500 for about a year, and in the last 3 months before gettin the espresso and wreking it he rode it fixed. i had to adjust his bb all the time. i think bb's are the big problem issue unless you find a phil 1 piece bb :-D

Just watnted to get some things clear: There is a big differacne between road/mtb three piece cranks and BMX three piece cranks. Obvisously road 3pc are alloy with threaded BB and tapered spindles. BMX three piece are typically unthreaded american bmx style BB wth cartrage bearings and splined spindels. The crank arms are usually hollow co-Moly steel and attach via bolt through the crank face and bolts that tighten perpnedicular to the spindle that clamp the arm tight to the spindle like a seat post clamp. Chain line is adjusted on bmx cranks via spacers placed between the BB, chain ring(which does not attach to the arm via 5 bolts) and crank arm. Many racing bmx's are going to a euro crank bb set up but most are still the old american style. I would reccomend for
sxe fbm rider's schwinn to go with an adaptor that bolts into the BB shell and allows a modern eruo BB to bolt in its place, and of course go with road style cranks and chain rings. I know they sell some at Danscomp.com

I dont have a schwinn... I dont know what it is.. I'll look into all that. the thing is, I have no choice but to go with the 1 piece cranks that are on there now.. just cant afford anything.. I just wanted to know if it was allright for now..

I just wanted to know if it was allright for now..

The answer is YES. Especially on a budget! I'm just using Wellgo bmx-ish pedals (not a lot w/ 1/2" threads) with clips and straps from my geared bike. I just re-checked my BB today because I was replacing my chain (easier to check the way the crank spins) and it is as good as the day I repacked it a couple months ago, or so my perception is telling me. Regardless, even if you have to adjust it occasionally, it isn't the end of the world.

There is a big differacne between road/mtb three piece cranks and BMX three piece cranks. Obvisously road 3pc are alloy with threaded BB and tapered spindles. BMX three piece are typically unthreaded american bmx style BB wth cartrage bearings and splined spindels.
...
I would reccomend for sxe fbm rider's schwinn to go with an adaptor that bolts into the BB shell and allows a modern eruo BB to bolt in its place, and of course go with road style cranks and chain rings. I know they sell some at Danscomp.com

I was quite confused over the reference for 1-piece and 3-piece cranks but thankfully "Boss_Hogg"
explained it quite clearly.

However, I am not clear over the suggestion on "road style cranks and chain rings".

1) Does it mean it is better to road cranks (e.g. Sugino, Miche, Campy...)
rather than tough bmx cranks with Euro BB (e.g. Profile, wethepeople, DMR...)?

2) When we install 3-piece BMX cranks for fixie riding, does it still suffer from bb adjustment problems?

There is a big differacne between road/mtb three piece cranks and BMX three piece cranks. Obvisously road 3pc are alloy with threaded BB and tapered spindles. BMX three piece are typically unthreaded american bmx style BB wth cartrage bearings and splined spindels.
...
I would reccomend for sxe fbm rider's schwinn to go with an adaptor that bolts into the BB shell and allows a modern eruo BB to bolt in its place, and of course go with road style cranks and chain rings. I know they sell some at Danscomp.com

I was quite confused over the reference for 1-piece and 3-piece cranks but thankfully "Boss_Hogg"
explained it quite clearly.

However, I am not clear over the suggestion on "road style cranks and chain rings".

1) Is it is better to use road cranks (e.g. Sugino, Miche, Campy...) rather than
tough bmx cranks with Euro BB (e.g. Profile, wethepeople, DMR...)?
If so, why? other than less weight.

2) When we install 3-piece BMX cranks for fixie riding, does it still suffer from bb adjustment problems?

YumYum, I was refering to using alloy road/mtb style cranks. I know profile and some other brands make BMX cranks that fit euro BB's, but these are expensive heavy and not too many people use them, but they are an option. As far as your second question goes I'm not sure. I do know that 3 pc BMX cranks and BB are stiff and rock hard, considering that they are made to be pounded on I'm sure they would work OK. I haven't used a set up like this, I'm currious if bmx BB would hold up to fixie use or if the crank mounting system would put unneccesary stress on the inner race of the bearings. Anybody ever used this set up???

Boss_Hogg, thanks for the clarification.


I understand my question has a cross-discipline slant...
but just a desperate toss.

:-)

If your road bike already has a one piece crank, it's probably good enough to use. And probably not really worth upgrading to a aluminum three piece crank, as most bikes using one piece cranks were low end. There are a few exceptions, IIRC, Schwinn made a couple nice brazed chrome moly frames with "American" BB shells (larger BB shells that will accomodate one piece cranks).

One piece cranks are often generically called "Ashtabula" cranks, after a company that used to manufacture such things (kinda like cellophane tape being called "Scotch" tape even if it's made by a different company). I believe the Ashtabula company has been defunct for at least twenty years, so it's unlikely you'll actually come across "real" Ashtabula cranks.

Sheldon Brown has a nice page on them here: http://www.sheldonbrown.com/opc.html

Just about any one piece crank will be strong enough. Just heavy. I've never had problems with BBs for one piece cranks. Cheap ones can be found for about $5. Nice ones under $20. Most likely, the one you have can be made servicable.

There's some speculation that a one piece will not hold up to the rigors of fixed gear. I think that's nonsense, since the rigors of fixed gear are at least as bad as the rigors of coaster brakes (where one piece cranks are common), and vary from rider to rider. There may be a little concern if the chainwheel pin is sloppy, allowing it to slip a small amount when changing pedalling direction. The resulting slop is annoying but probably not harmful.

You will be limited in pedal choice, since one piece cranks use 1/2" threads. I've never seen clipless 1/2" pedals. But there are many nice 1/2" pedals out there that will accomodate toe clips.

With few exceptions, I would probably not sink too much money in a one piece crank equipped road bike. Just make it run with what you've got and have fun with it.