PX-10 gearing
 

It’s very hilly where I live in the Western Catskills, with many of the secondary and seasonal roads I ride on having quite steep grades. When I got back into cycling last spring I had to rework the gearing on my Cannondale so I could handle the hills (while a touring model, a PO had put a road-triple 30/42/52 and not-very-wide cassette on it- I replaced with 26/38/48 chainrings and an 11-34 7sp cassette). 2k of riding this past season has helped immensely and I find I’m almost never using the granny now, though I’ll want it if I carry panniers, etc, and no doubt I’ll lose a lot of strength over the winter (no trainer, no space for one….). I do pretty regularly end up on 38x34 on longer, steeper climbs, though. So, I’m trying to decide on a gearing arrangement (friction, btw) for my PX-10 build/rebuild now… I’m not really concerned about higher gearing and spinning out on descents- I’m quite happy to coast, because there’s always a steep climb up ahead. It’s the lower end I want to be OK on.

I need ‘new’ wheels for the bike (it came with crappy, steel 27”)- I’m not having luck finding some more-or-less period-correct 700c wheels locally/cheaply, and if I’m going with new wheels I may as well cold-set the frame to 126mm and go with either a 6 or 7 speed freewheel. I’ve got an SLJ long-cage RD (5500, I think). Also have an SLJ FD to replace the original delrin FD which is cracked.

So my choices seem to be-

1) triple-ize the crank and add a 28t granny and run with a 28t large-cog freewheel. I’ve already got a longer spindle for the BB. 6 and 7sp 28t freewheels seem reasonably common… Research indicates the SLJ FD will handle the triple and the SLJ GT RD has the total capacity).

2) Keep the crank as a double and get the smallest chainring I can (37t) and find a freewheel with a 32 or 34t large cog. 34t gives me about the same lowest ratio I’m able to get away with on my Cannondale, and I think I’d do OK with 32t- though it seems like finding a 6 or 7sp freewheel with a 32 or 34t large cog might be a bit harder than 26t large…

3) Cold-set to 130mm, and get a wheel set that takes cassettes… Still leaves me with the double vs triple question and, really, I’m disinclined to cold-set from 120mm to 130mm….. but possibly more availability with cassette gearing?

$-wise, triplizing will cost me a little bit more (triplizer middle chainring + granny ring) than just getting a 37t ring for a double, though maybe that would get offset by being able to use a more common freewheel.

Yeah, sure, there’s the option of gearing the bike as original, but… no. I live on a dead-end road with something like a half-mile of 12% grade…. and then there’s my long, uphill, dirt driveway after that! Original gearing means an unusable bike for me!

Recommendations? Things I’m missing?

For what it's worth, I favor a 126 to 128 OLD with a 6- or 7-speed freewheel, although a 7-speed cassette would be better for loaded touring because of the rear axle breakage potential with a freewheel. A 38/32 low gear should get you up most grades.

I do suggest using the smallest outer chaining you can stand -- if you are happy with something like 49/14, 50/14, 46/13 for a top gear, as I am, see if a smaller outer ring will give you a better set of ratios.

I am partial to 46-38 / 13-15-17-19-22-25-30 or 13-15-17-20-23-26-32.

I assume it has its original Stronglight mod. 93 crank? If so, I’d suggest swapping in a Stronglight 99 or 49D, and run as a compact double with something like 46/30t rings. You can keep that French vibe but not have to suffer terribly on those hills!

I'm sure there are variations in the different available hubs, but if you had a 126mm 6-7 speed freewheel hub, it might be respace-able to 120mm and used with a 5 speed freewheel. The wheel will probably need re-dishing. I've got a 8 speed free wheel 135 mm hub reduced to 126mm and 6 speeds that survived the test ride.

Next project is converting a 135mm 8 speed freewheel wheel set to 126mm single speed. I'm thinking that I might get close to zero dish on that one.

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...IMO, stretching to 130 is overkill. Anything more than 6 cogs in the back isn't going to get you more range, just closer steps in gearing. 8 is nice if you like gear freaking, but unnecessary to your stated purpose of getting up hills. You do need a rear derailleur that will handle both a larger cog and the additional chain slack in a wider range setup. The simplex rear derailleurs that will do this, with longer cages in the later SJ models, are simply beyond sanity in prices on e-bay now. A Shimano Crane from that time period comes in a long cage version, will work on a standard Simplex dropout (without a stop on it), is a durable and functional rear derailleur, and can still be had without mortgaging your house.

So that's the direction I would go, and I would probably focus mostly on finding that and a larger freewheel. I haven't priced freewheels lately, but they were also getting pricey in anything that was at all out of the ordinary, like something with five cogs and a 32 large. There's much greater availability in the 6 cog freewheels now. Or you could just build your wheels around a 126 OLD hub that uses a freehub and cog set. Sometimes you need to adapt whatever you can get for cog sets, buying a 7 or 8 and leaving off the smallest cog. which is not a problem because you're shifting with friction, not indexing.

The best cranks from that era that will take a small ring are the Sugino Mighty Tour, but those are also not French, and pretty pricey as well. Old triples are all over the place, but then you have to deal with the shifting of them.

Almost everything you do to accomplish a really wide range will make shifting a little bit less smooth and easy, so that's a good argument for more modern design cogs on your rear setup, whatever you decide to do.

I definitely won't be doing any loaded touring on this PX-10- at most I'll carry a bar/rando bag for my camera, snacks, etc. The 'small' ring on the Stronglight 93 crank is 45t- if I go the double with a 37t inner I'll put the 45 on the outside. My average cadence is generally pretty high so I don't mind losing the really high gears, though 37/45 might not give me the best spread, depending on the freewheel...But 37x32 does seem like it would be low enough for me (famous last words as I stare up the hills here....)

I love the way the 93 looks.... Though the 99 and 49D are also pretty classy, too. Still, if I can make things work with the 93 that's how I want to keep it.. I toyed with the idea of maybe converting this PX-10 to 650b, going for more of a 'rando' build, in which case a compact double would make perfect sense. But after choking when doing my year-end accounting over how much $$ I spent on bike stuff in 2021, I decided to keep the PX-10 somewhat more 'stock' and save up for a rando build down the line!

Learning wheel-building is something I'm interested in tackling, but not quite yet!

I’ve been helped on a similar issue in this thread Old 60s Mercier technical challenge, you’ll find a lot of valuable suggestions. I finally chose to go triple with a Stronglight 99 and also be able to use a large chainring, but if you don’t need it a compact double can do the trick, just make sure you can do that 12% grade with an appropriate freewheel.
On a PX I would stay all French and don’t think cold setting from 120 to 130 is a good idea. Please share some pictures if you have.

Luckily I have a nice SLJ GT that I got for a good price from someone here.
I'm not up to learning wheel-building (at the moment, eventually I probably will...), so buying a wheel set is where I am right now. Doesn't seem like there are a heck of a lot of new 126mm free hub wheels out there...

as bought-

https://cimg3.ibsrv.net/gimg/bikefor...881eed71a3.jpg

Now completely apart, cleaned up, polished, waiting for various bits, wheels, etc.....

My Lejeune is set up as a 49-37 Model 93 double, and six-speed freewheel. I can't remember the exact tooth counts--something like 15-16-19-22-28-32. Happy to go count the teeth and report, if you'd like. I was a little surprised to find that a short-cage Simplex derailleur (a 610, I think) can handle that full range without difficulty.

I like that setup. Most of my bikes have triples, but that gearing is just low enough for me. It sounds like the hills you're dealing with are similar to what I have around here.

Custom freewheels are easy enough. Get in touch with Pastor Bob and see if he can make you a 6-speed Suntour Perfect on a narrow-spaced body, which will let you use it on your PX-10 without respacing the dropouts. Not a French freewheel, but durable, well-made, and easy to find. That's good enough for me.

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...I don't have a good grasp of what's available in brand new, prebuilt wheels, because I make my own. Maybe someone else can advise on what's out there as replacements.

Swapping axles and redishing is not that deep, and depending on your local Bike shop/co-op or even REI shouldn't cost to much to have done. I've bought a bunch of wheels from Velo Mine. They sell some cheap wheel sets with 126mm hubs. I know they also build wheels so it might be worth checking with them.

...oh yeah, I forgot to mention the venerable TA touring cranks, which are French, and were used on most of the early mountain bikes here in California. Those are findable, because they got used on so many of the first mountain bikes sold around here. Not sure about other places in the USA. Many of those bikes got crashed and busted, then stripped for parts.

What a nice bike, love the color and so well preserved, is it 1972?

Velomine is one of the vendors I'm looking at for a set of wheels. I wish there was a good, old-school bike shop anywhere near me, you know, the kind that has a back storage room filled with old stuff....

Actually the paint is pretty banged up, I believe almost entirely from being moved around in an over-filled storage space for a couple decades! Besides the front derailleur being completely mangled and the 52t chainring somewhat chewed up and bent (my suspicion is the delrin clamp cracked and the DR got sucked into the crankset!), it was/is in solid shape. It has cleaned up nicely, if a bit "patina'd"!
The RD cage is stamped 4/72... assuming supply-chain timing, importing, etc, the guess is it probably was sold in '73.

Interesting, and good to know, that a short cage can handle your 37x32!

Another good thing to know!

[MENTION=52458]jonwvara[/MENTION] (see post #10 above) is too modest (and too rule abiding) to toot his own horn, so I'll do it for him.. He makes a great triplizer for the Stronglight 93 crank, which lets you install any 74mm bcd small chainring you want (within the limits of your derailleurs, of course). I bought one from him and installed it on my brother-in-law's early 1970s Gitane TdF, and it works and looks great. Plus, he's a joy to deal with; I cannot recommend him highly enough. Follow the Red Clover link in his post.

The downside of this approach is that you will need a longer BB axle. I don't remember how much longer - sorry - but I think I was able to look it up on Sheldon Brown's website, may he rest in peace. You will almost certainly need a longer cage RD as well and probably a different FD, too, but there should be plenty of Suntour options out there for you (what I did for my BiL).

A fine option that works well. Probably not the cheapest way to go, but probably the most flexible in terms of getting the gears you want. As a bonus, you get to keep using that oh-so-cool looking Stronglight 93 . . . .

Here's an image of the drivetrain on my LeJeune, for whatever it might be worth

https://cimg1.ibsrv.net/gimg/bikefor...ddebad6a26.jpg

Red Clover is exactly where I'm looking for either the 37t inner ring, or the triplizer! I've got both the original (118mm, I think?) spindle and a 125mm spindle, so I think I'm ready-to-go with either approach (& yeah, keeping the 93 is key!).

If nothing else, a 45/37 ought to shift nicely. :thumb:

Yup, just about like the original 52-45. I would try for a 1.5-step setup, perhaps with a 6- or 7-speed freewheel and a large bailout low cog.

I did something similar when I built a bike for my wife in the mid-1970s. I had a TA Professional crankset with 52-42 rings and 120mm OLD, so I adapted the then-popular 52-42/14-16-18-21-24 to 52-42/16-18-21-24-32 for the hills above west Los Angeles. (I was duly amused when MegaRange freewheels began to show up on the market several years later.)

I did a deep dive into the Simplex threads, but somehow missed that one! Seems like I possibly could get away with a short-cage SLJ RD, but... I've got the long cage, so that's what I'm a gonna use!
That drillium 99 is fantastic looking.

IRD has a 6sp 13-32 freewheel that I think would get me low enough (I think.... after a particularly long/hard ride getting up that last hill home might be kinda miserable!), but they sure ain't cheap. Though maybe the above mentioned Pastor Bob would be able to make up something similar..

Craziest gearing I have ever seen was on a Peugeot I picked up. Stronglight double crankset, 51/49 tooth chain rings. Thats right, a drop of two teeth. It visually looked like the two chainrings were the same size....