On 19 Oct, 14:02, Duncan Smith <
[email protected]> wrote:
> On Oct 19, 12:47 pm, [email protected]
>
> (D.M. Procida) wrote:
> > Following recent bike misadventures, I'm considering taking up a
> > friend's offer of an old frame, to turn it into a fixed-wheel bike.
Yeah, go for it. It's fun.
> > My main concern is that the bottom bracket will be too low and I'll keep
> > catching the pedals on the ground, something that I've done several
> > times lately on my old Raleigh hybrid.
Low profile pedals. I gather you're planning to use those new-fangled
clipless thingies- you should be fine with those as far a clearance
goes (though other fixie riders may laugh at you... or maybe that's
just me
.
> > What else do I need to consider?
What gear you want- personally I like a lowish one (~64"), most
people seem to prefer something nearer 70). Cogs are easiest to find
around 15-16t, so if you can get a chainring around 42t that can make
it easier to get a likely gear.
> > I konw it needs to have horizontal drop-outs. What about axle spacing?
This can usually be fettled fairly easily- if you're using a "track
hub" then you can buy to suit, otherwise you'll probably want to
redish the wheel anyway. A suitable combination of dish, spacers etc
can usually be arrived at.
> You can always fit shorter cranks (160mm?) if you're worried about
> pedal strikes.
These can be quite hard to find. 165mm "track" chainsets are quite
readily available at a price, standard road ones are usually 170mm and
will probably work fine. 175mm ATB cranks are probably best avoided
for this application...
> ... You might be allright with the drop-outs on an older
> frame as they tend to be more diagonal than vertical so you could get
> enough fore and aft positioning of the wheel to tension the chain - if
> not, you could pop on a tensioner like this one:
>
> http://www.on-one.co.uk/index.php?module=pagemaster&PAGE_user_op=view...
NO! Not for a fixie. It'll work on a single-speed (which is what On-
One are listing it for) but won't take the strain from a fixie.
> You'll also something like a Hozan C-205 Lockring spannerhttp://www.hubjub.co.uk/etc/etc.htmfor keeping the cog on - unless
> you never brake by pedaling backwards as pedaling forwards will only
> tighten the cog.
I prefer to use brakes to stop, as a general rule, though I sometimes
skid-stop the last bit to keep the cranks orientated for a good
launch. I, along with many others, havn't had any problems running
without a lockring. One of my fixies has a 22t cog (ie lots of
leverage) without a lockring and it doesn't unscrew. If not running a
back brake it might be worth ensuring you have one but otherwise I
wouldn't sweat it.
Cheers,
W.