I want to convert my PX10 to a fixed gear. What do you think?

No, it isn't as horrible as it sounds, at least I don't think it is. Bear with me!



I bought this bike off Craigslist. It is a '74 (guess) PX10 with the fancy Nervar lugs. It has nice wheels with wired and soldered spokes, and the small chainring was almost unused while the big chainring was completely worn out - a nice touch, I thought. But I don't like the plastic Simplex derailleurs and shifters, and the bike needed a complete overhaul, so I tore it completely down and set it aside for a someday Nuovo Record kit.

Time passed. I am trying hard to back off from excessive buying and building of bikes, from the n+1 ward. I'm not yet beyond hope, and I want to pull myself back to health. Therefore I have not bought the NR bits, and won't. So the PX10 frame hangs lonely in the garage.

Well, I happened to visit a BF'er last weekend and took a two block ride on his track bike. Conditions were not ideal. I was wearing running shoes on clipless pedals, it was snowing, I was on a slick white New York street and I'd never ridden a fixed gear bike before. Still, it was - intriguing. I think, I think I, umm, want one. Okay, I get it, the fixie thing is passé and all the hipsters are into gravel grinders and fat bikes now. Well, I'm always uncool anyway.

My thought is, suppose I remove the small chainring, fit the new large chainring that I bought, and install a fixed cog on the rear hub, is that all I will need to make this old road racer into a fixed gear bike? I'd reinstall the brakes and overhaul the wheels. The derailleur hanger shall be un-drewed, of course. There will be no irreversible changes. Most of this city is not hilly, I can do almost all my daily riding in 53 x 18 which is similar to the gearinches I see lots of fixed gear riders use.

I never rode the PX10 before tearing it down. It wasn't really in a fit state. So I don't know how it rides, or will ride as a fixed gear. I assume the geometry is different from any track bike but I'm planning to ride it on the street anyway.

What do you advise?
1. Convert the PX10 to fixed gear
2. Restore it to stock
3. Rebuild it with NR
4. Sell it and buy a Pista

I don't see what's wrong with the bike in the picture. What was unworthy about it?

But with that said, I think it would make a very good fixie.

Seconded, fix it. You'll have so much fun riding it and it will be very different than any of your other bikes.

No, you can't just install a fixed cog and turn it into a fixed gear... at least get a fixed rear wheel.

But it's not a bad idea, and you'll probably like the end result.

Tom, the tires were rotted and I didn't want to glue new tubulars just to ride w/o regreasing bearings etc. And I was in kind of a frenzy of bike strip down. The n+1 illness was running deep then. I'm better now.

whatwolf, I was assuming I could thread on a fixed cog with a lock ring and respace / redish the axle / wheel? Per Saint Sheldon? https://sheldonbrown.com/fixed-conversion.html I would prefer not to use a different rear wheel, because then the front and rear wheels won't match, and at that point I might as well install purple aero rims, colored tires, a coffee cup holder, and a plastic seatpost fender to complete my dissolution.

If that's the original wheel, the rear hub is likely metric thread and you won't easily find a fixed cog to fit on that hub.

A fixed wheel doesn't have to look ridiculous...

so do you mean a fixed cog plus a bottom bracket lock ring? I guess that would work, unless the threads are metric. Still not ideal... personally, I'd just get a hub designed for the purpose I'm using it for. I wish you luck with the build!

Maybe be another option is an affordable used wheelset, since you are just wanting to try out riding fixed. You could always sell it if you end up not liking the ride or upgrade if you do.

Also re-dishing the tied and soldered wheel might be problematic; not sure as I never tried it.

I have done many fixed gear bikes as you suggest, using a road hub per Sheldon's page. I've never had a problem with it. Brakes are a must though.

53 x 18 sounds pretty stout, at least it would be for me, and it's flatter where I live, I promise you that. I like around a 70 in. gear eg. a 42 x 16 or 53 x 20. Spinning is good.

Hipsters didn't invent fixed gear and they won't be the last to ride them. I see nothing wrong with using your bike that way.

Ah - that sounds like a problem. Yes, it is the original wheel. Maillard hubs? I think.

These frames make a nice looking fixie - Keep the original paint - Don't knock off any lugs...

Now are you going to make a Fixie Fixie or a poser fixie???

I would recommend a different wheel set with proper dish and another crank set...

I experimented with a fixed gear bike last year, and sold it after a few months. Truth be told, I miss it and plan on building another one someday.

What I would do to that PX10 would be to simply redo the brake cables/housing/bar tape, and buy a cheap fixie wheelset online. Save those tied/soldered jobs for when you do a complete restoration. Something like these wouldn't break the bank: https://www.ebay.com/itm/New-Weinmann...item3f2a0c153d

I disagree. Cleaning and overhauling the PX10 can bring you $500 or more. You can buy a decent fixie for $300.

But it would not be a PX10.

I'd buy a set of fixed wheels and Portland is not a bad place to find some deals, City Bikes often has some nice fixed wheel sets at a good price or you could buy a set off the peg from many shops.

The chain line might require you to run the chain ring to the inside of the spider... for Portland I'd be looking for a gearing around 72 GI so if you have to stomp it up Clinton your knees won't hate you.

Keep all the original bits and leave the brakes on... you might want a flip flop hub with an SS / FG combo.

Yes, use the inside, not the outside, chainring position on the spider for best chainline. The stock 45T is probably a good choice for single speed use.

I would keep the gears, but then I love my gears too much to go the fixie route -- I'm the guy who converted a Swedish Avanti track bike to a 4-speed freewheel system by machining a SunTour derailleur hanging claw to work backward on a track dropout.

I get your reasoning so why not? I'd go with 1. Box the rest for another day. That PX10 is no minty but has soul and character. Do the fixie and enjoy it.

I say go for it. It's your bike, and you know how best it should be set up to make you ride it the most.

Fix that puppy!

You might have an issue with a French headset - but no problem if the one that's on there is good.
You might have an issue with a French BB - same as above.
And you might have plain old English threads on your rear hub so you could just put on a track cog if you don't mind keeping the sewups for a while.

Okay. In the "active project" queue she goes!

I'll take a look at the hub threads. Worst case, I see various not-crazy-costly track hubsets on eBay and I have some extra rims laying around. (Any excuse to build wheels, you know.)

It doesn't matter what gear setup you choose to use, a fixie is just fine. Just make sure you hold on to the original stuff, or make sure you pass them on in some way to someone who can put them to good use.

I was looking at an old BSA that was partially converted to a fixed gear, but I passed on it because the seat post was rusted to heck and I figured the inside of the frame must be too.

In another time a bike like this might have been converted to a fixed wheel set for spring training... it would save the derailleurs and get the legs in shape for the main riding season.

I have the luxury of owning a good number of bikes and have some dedicated fixed gear bicycles so the geared bikes stay that way and don't see too much crap weather... but if I didn't I'd probably be riding my Ron Cooper as a fixed gear and figure that without the shifting hardware and a decent set of fixed wheels and tyres it would be a sub 20 pound bike.

My 531 Raleigh Gran Sport was a 531 frame and hit the curb at 19 pounds when it was a fixed gear... that was sweet.

The world has enough fixed gear bikes, but nowhere near enough PX-10s in good, ridable condition.

If this were my bike I'd swap out the derailleurs for Simplex Super LJ types, then locate some new sew-ups (preferably fat ones by Challenge, Dugast or Conti) and mount those. Chainrings are still available for the Stronglight, so you can replace those easily enough. Other upgrades you could do here would be to mount the Simplex ratcheting shifters, or (better yet) try to locate some Suntour barcons or Campagnolo bar-end shifters.

Lastly, a Brooks Professional in place of the original ass-hatchet Unicantor would be a nice touch.

A decent fixed gear wheelset with low silver rims, high flange novatec hubs and SS (but not DB) spokes can easily be had for under 150$. I've run one for years without problems. I'd say go for it, you can always return the bike back to it's original state and sell the wheels. I've had loads of fun on my 60's/70's 531 frame converted to FG: it does feel distinctly different from a 300$ gaspipe job in flashy colors, and worlds apart from converting a tight Italian crit racer to FG. I'd say frames like these lend themselves very well for conversions.

Chainline, as Tom pointed out, will be important. Use the inner chainring position on the spider. Also, 77+ gear inches would be too high for daily knocking around. You might want to start with lower gearing until your confidence increases. I've found that ~72 GI is a good place for varied up/down conditions. That's about a 19 mph bike at 90 rpms. The PX-10 will be a sharp looking conversion.

+1 to this, it's not hurting anything, just keep the parts. It's far better to enjoy a bike on the road then to have another bike just hanging around the garage. It'll make a fine fixed gear ride

I think it would make a cool fixed gear or single speed trainer like some guys used to use back in the old days before everyone got rollers.

as long as you don't drew it or repaint it some gaudy fluorescent color and put contrasting neon wheels and tires on it I won't petition to get you kicked out the BF forum.