Converting a freewheel hub to fixed

capt_slog

I received a gift of some "have a go sessions" at a velodrome. Before I use it I'd like to have a go on a fixed wheel bike, I don't know anyone who could lend me one, so I wondered about a lash-up.

I have sufficient bits hanging around: old frame with working hub, wheels and brakes, chain etc. I don't want to spend anything on this if possible, so i wondered if I can lock up the existing freewheel in the hub? (it doesn't matter if this is a one-way process, the wheel is close to scrap anyway).

Has anyone tried this?

I don't expect 100% reliable or effective, I won't be doing miles, and not on the highway. I just want to get the feel for it.

whyamihere

What hub is it?

Darius_Jedburgh

I did a jury rig once when my free hub jammed open and I was a long way from home. What I did was take the front mech gear cable and wrap that in and out of the spokes and in and out of the holes in the sprockets. Made the rear wheel effectively a fixie. I was atop Tan Hill at the time, and had to get back to Kendal, so it was that or a long walk!

It was a bit drastic but it did work. If you really, really wanted to you could wrap a gear or brake cable in similar fashion. All the stress went on my spokes - which showed no ill effects - but I was desperate. If your freehub is working then that should take a lot of the stress. If your wheel is close to scrap then you can't really harm it, can you?

capt_slog

Franco di Banco wrote:

I did a jury rig once when my free hub jammed open and I was a long way from home. What I did was take the front mech gear cable and wrap that in and out of the spokes and in and out of the holes in the sprockets. Made the rear wheel effectively a fixie. I was atop Tan Hill at the time, and had to get back to Kendal, so it was that or a long walk!

It was a bit drastic but it did work. If you really, really wanted to you could wrap a gear or brake cable in similar fashion. All the stress went on my spokes - which showed no ill effects - but I was desperate. If your freehub is working then that should take a lot of the stress. If your wheel is close to scrap then you can't really harm it, can you?

Like it! I can jam it by putting a few screws through if nothing else comes up, didn't think of that route.

Shimano 501 hub BTW. The wheel is my lads old one that has a rim too kinked to fix after an accident, the kink cathes on the rim brakes.

cycleclinic

You wont be allowed on the track with a bodged fixie. You can normally rent bikes at a velodrome.

964cup

I think the OP wants to try riding fixed (on the road) before going to the velodrome. I suspect doing this on a bodged roadbike is a bad idea, for a number of reasons. You won't learn much about riding fixed (from a velodrome perspective) if you use brakes - track bikes don't have any. I'd be very unkeen to see anyone trying to brake using a lashed-up freewheel as a fixed hub. It is relatively easy with most cheap hubs to bodge the freewheel to stop it coasting (e.g. wedge the pawls, add a spacer behind the freehub and then overtighten it onto the axle). You could also use a Mavic hub and just fail to oil the plastic bearing surface for long enough to get the "squeal of death" and it'll become a fixed wheel by magic. But I really, really wouldn't recommend it.

The velodrome session is a much safer space in which to try fixed for the first time. The bikes are set up properly and the coach/supervisor will take you through a set of drills to make sure you're safe and confident. If you like it enough then you might consider building a cheap fixie to ride on the roads (with a front brake at least, please), but you need at least either track ends/old-school adjustable dropouts or an eccentric BB to get enough chain tension, and a proper rear wheel with provision for a lock-ring (which won't fit in the 130mm rear spacing of your old frame; that's why most hipster conversions are single-speed, not fixed). You'll also need a front chainring of a) appropriate size and b) 1/2" chain compatibility. You can ride fixed on 3/8" chain, but I wouldn't - the chain certainly wouldn't last very long, I should think.

capt_slog

thecycleclinic wrote:

You wont be allowed on the track with a bodged fixie. You can normally rent bikes at a velodrome.

Yes, I know. And that's not the point of the build, read my original post.

@964Cup.
Thanks. I can see your reasoning, but I have the time, the bits and some know-how (even a lathe) so I'll have a go.
I realise track bikes have no front brake, but if I have one, i won't be breaking any laws (or by-laws in the local park) and won't be relying on the hub and lack of expertise should I really have to stop.

It's not a build i intend keeping.

cycleclinic

Erm I did read your post and thought why just why.

keef66

I got the hang of it pretty quickly when I had a go on the olympic velodrome as a birthday present. Only once when I needed a breather did I forget I couldn't freewheel; the bike soon reminds you to keep turning the pedals! The thing I hadn't anticipated was how dry the atmosphere was; I had to stop a couple of times for a drink - take a bottle and leave it trackside.

joe_totale-2

keef66 wrote:

I got the hang of it pretty quickly when I had a go on the olympic velodrome as a birthday present. Only once when I needed a breather did I forget I couldn't freewheel; the bike soon reminds you to keep turning the pedals! The thing I hadn't anticipated was how dry the atmosphere was; I had to stop a couple of times for a drink - take a bottle and leave it trackside.

What keef said. Remember to bring some shower stuff as you'll get pretty sweaty very quickly.
Riding fixed isn't madly different from a regular bike and the velodrome is a far safer environment to learn than a public road.

giropaul

If it is, as you say, a freewheel ( not a cassette) then all you need to do is unscrew the freewheel, a fixed sprocket should be the same thread. Use spacers to adjust the chain line if needed. A old fashioned bottom bracket lock ring, done up tight, should stop it unscrewing.