1970s Peugeot PX10 - from traditional to restomod
 

I recently picked up what appears to be a 1972 PX10 via a three Peugeot, three Brooks Pro saddle deal. The PX10 came from the original owner, but some time ago the owner's wife had converted it to an upright commuter.

The front wheel appears to be original: Normandy hub, Simplex skewer, Mavic wheel.
The rear wheel, however, certainly is not: Schwinn hub, no-name skewer, Chromalux steel wheel, Maillard 5-speed freewheel. So the freewheel may be original.

As I will be keeping the PX10 for myself, I will initially be simply returning it to something resembling it's original form from available parts, which I will hopefully be riding for the likes of the 2021 Cino Heroica.

Over the long term, however, I intend to convert it into a restomod, as I won't be concerned with resale value. This will probably include repainting and new decals, along with an updated drivetrain and aero levers.

Currently, I have it stripped down almost completely for cleaning, except for the crankset; my J.A. Stein Stronglight/TA crank puller comes today.

Pics are here.

Interesting things of note, and questions:
1) Both crankarms have "9/16" on them. Does this indicate that the pedals are threaded for 9/16", rather than French-threaded? If so, that certainly makes my life easier for choosing pedals!
2) Given that it's Reynolds 531 and French, what is the proper seatpost size? The original Simplex steel seatpost does not indicate size.
3) For quill stems, is there anything I need to know specifically for size, or does any 1" quill stem work?
4) Any other thoughts/concerns/ideas regarding either the short-term (build it back up and ride it!), or long-term (restomod) plans are appreciated.

I've owned four PX-10s through the years and they all took a 26.4 mm seatpost. The stock unit is a steel Simplex micro-adjust unit, though I have also run SR LaPrades in 26.4 with success. It never hurts to gently clean out the interior of the seat tube with a brake cylinder hone to remove any corrosion - I've had to do that with the last few 531-tubed Raleighs that have come through my hands.

If you choose to use a Nitto Technomic or similar stem, you won't have an issues running a standard unit in that bike. If memory serves, Peugeot used the same Nervor (not be be confused with Nervex or Nervar!) metric butted steerer with a 25.0 mm exterior and a 22.0 interior. The Nitto stems are usually actually around 21.9 mm. Again, it may be helpful to run a brake cylinder hone just to clean up any corrosion, and some headset lock rings may need to be opened up a touch to permit the stem to go through - some of the top lockrings have lips that overhang the actual steerer aperture. I've done that with Motobecane O.E.M. headsets, but it may not be necessary with the stock Stronglight - I think they used the V4 for the PX-10 all the way through this era. This way you don't need to sand down the stem.

Stronglight sold cranks with 9/16 pedal threads as well as metric 14 mm, and it would make sense for them to have fitted those for U.S. market bikes.

I still think you have a 1973 PX-10, based on the more upright angles and straighter fork and the hand-stamped serial number. I don't think your bike EVER had a number plate on it, and someday I hope to learn WHY Peugeot used that numbering style on PX-10s c.1973-74 with the steeper angles.

1. If the cranks say 9/16, you're good to go. If you ever end up with a French-threaded crank, that can always be retapped 9/16"-20.

2. Typically a PX-10, and any frame with metric-sized Reynolds 531 tubing (whose seat tube is unbutted at the top) should* take a 26.6 mm seat post. (EDIT: Sheldon Brown's seat post database has a 1973 PX-10 with 26.4, a 1976 with 26.6; Peter Kohler reports having a 26.6 post in a 1969 PX-10 -- so caveat emptor. This thread has a couple different reliable sources [[utag=86268]retyred] advising 26.4, and another [[utag=27118]Grand Bois] saying you need to know the year to determine correct seat post diameter! I have a 1972-1974 PX-10 frame [not sure which] hanging on my wall that I've never put a seat post in, but the opening is 26.6 wide thwart-wise, though a bit less measured front to back; I concluded that a 26.4 post should probably fit well.)

3. Quill stem for French is 22.0 mm. Most of the time one that's nominally 22.2 mm (7/8") will not fit -- you do want some clearance for a bit of grease. It's fairly easy to sand and polish 0.1 mm off a non-anodized stem, to get down to 22.0, though it's easy to overdo it too.

*A typical classic Reynolds 531 seat tube is an 0.8/0.6 mm wall-thickness affair (though Reynolds at that time used "21/24 gauge", the gauge being Imperial Standard Wire Gauge [SWG]), with the thicker-walled butt only at the bottom bracket. Thus, an English-sized tube, being 28.6 mm outside diameter, minus 1.2 mm, plus a bit of clearance, takes a 27.2 mm seat post; and a French tube is 28.0 mm diameter, with the same wall thickness, so takes a 26.6 mm seat post, nominally -- unless the seat tube is butted at the top too. See this thread for more, especially post #13 by Scooper. Why, and under what conditions in which years, a Peugeot PX-10 would take a slightly smaller seat post, I can't tell you.

While the above statement is true for some metric gauge 531 bikes, the 1970, 1973 and 1974 PX-10s, as well as the 1975 PR-10L (531 db mainframe) I owned all took 26.4. Same for the the three Gitane TdFs I have owned.

There ARE metric-gauge 531 bike that take a 26.6, but those are usually just a wee bit nicer than the PX-10. I have a Swiss Allegro that takes a 26.6, but that's because it takes a slightly thinner-walled .9.6.9 rather than the 1.0-.7-1.0 used on most French production bikes.

Valuable info on seatpost/stem sizing, thanks!

Another question: Given my hub spacing in the rear being 123mm, am I limited to a 5-speed hub, as is? Anybody spreading to 126mm or larger? Would love at least 6-speed in the short term, but is 8-speed possible? I see possible Gugificazione! in my future...

I run an "ultra-spaced" 6-speed Shimano 13-26 freewheel on my UO8, which now also measures 123mm overlock. Perfect fit with the right selection of axle spacers, which you may already have.
The big caveat is that your rear hub may be French-threaded, and I have never seen an ultra-6 French-threaded hub -- it seemed to be a Japanese thing.
A standard-spaced 6-speed needs 126mm, but you can easily cold-set a steel frame from 120 to 123 or to 126. Been there ... done that, running 6-speed standard on my 1959 Capo.

This is good info. My two Reynolds 531 DB French bikes (a '73 Motobecane Grand Record and a 70s Mercier 300) both take a 26.4 seatpost.

I thought--perhaps incorrectly--that the Atom 77 compact 6 spd freewheels would work on a 120 OLD rear wheel.

VeloBase.com - Component: Atom 77 Compact (6 speed)

I like my px-10 very much but the simplex dropouts, metric steer tube and French bottom bracket threads do make it more difficult to modernize it.

That PX 10 looks to be in awfully good shape for a repaint. That said, it is your bike.

The resto mod makes sense particularly given that you would like to ride it on an eroica ride. The bottom line is that the bike needs to work for your intended purpose.

I'm doing something along those lines with a 70s Mercier 300 I am rebuilding. I want it to have better gearing than came on the bike originally so I'll make changes but I'll still run vintage gear.

Three things you may want to think about.

(1) It is really easy to run a compact French crank if you are looking for better gearing. A stronglight 99 can go as small as 28 on the inside. For my Mercier 300, for example, I'll likely run a 50/34 Stronglight 99 with a 13-28 ultra 6 freewheel.
(2) That's a simplex criterium rear derailleur, right? According to the specs, that can take a pretty big freewheel and has a lot of chainwrap:
VeloBase.com - Component: Simplex Criterium
(3) The clearance for large tires is pretty decent by and large on older French bikes which is perfect for an eroica type ride.

I think for those reasons, French bikes are terrific for eroica builds. They tick a lot of boxes, IMO, in terms of gearing and tire size.

With a 123 OLD, you can run a 126 OLD rear wheel there easily. That means you can run a 7 speed freewheel. You'd have to spread the frame to 128-130 to run 8.

Personally I'd hunt around for a quality 126 OLD wheelset (or build a wheelset around a pair of campy nuovo record hubs) and call it a day. 2 x 7 will give you all the gearing you need if you run a "compact" crank like a Stronglight 99. Assuming your existing bottom bracket and spindle are in good shape, that should work fine with a stronglight 99. Alternatively the 93 can be triplized but finding the right BB for that will be a challenge. You're best bet would likely be to look on eBay France for the right length spindle.

https://www.redclovercomponents.com/..._42_Teeth.html

I may not repaint it, it's definitely not a priority yet. It seems I usually end up changing my mind about repaints anyway, haha.

1) Seems like I could grab a Stronglight 99 triple like this 47/42/28, and I'd be set. Spread the rear to 126mm, add a 6-speed, and I'd be golden. Does this seem likely?
2) I'm ditching the Simplex Criterium for either an SX610 (on the low end), or up to SLJ6600 (on the high end).
3) Yup, I think I can easily get some 38s in there!

I think I'll avoid going beyond 126 and a 7-speed. This wheelset, or similar, would work nicely.

Yeah but look around locally for a wheel. It will be cheaper and you can check to see if the wheels are true. There are plenty of good quality 126 OLD wheels out there. Plus if you have a choice, I'd get mavic rims rather than rigida.

That is the crank though I think you can buy one for less than a $100 if you shop around. You might want to put up a WTB on the CV for sale forum.

But first you have to make a decision whether you want to run a compact double or a triple. I'm a fan of triples but the right length stronglight spindle will be hard to track down. Your existing spindle should work with a 99 double. Plus spindles in the right length for a double are readily available. I think you're better off running a 99 as a compact double.

This stronglight 99 for example will run around a $100 shipped from the UK but the 44/32 chainrings will give you very useful climbing gears. You can track down a 47 or a 48 to replace that 44 and sell the 44.

Since you're planning on using a 126 OLD wheel, you can run 6 or 7 in the back. You can find a new 7 speed 14-28 Shimano freewheel for under $30. The tooth profile is good for shifting. Another good choice would be one of the suntour winners in a 13-28.

The criterium is a good derailleur. I wouldn't be in a hurry to ditch it if it is working. Simplex derailleurs are available but pricey. If doing a resto mod, you can also think abouit whether you want to mod the drop out.

This is a useful thread:
https://www.bikeforums.net/classic-v...-dropouts.html

The stock Stronglight spindle for a double was usually a 118 mm asymmetric unit. They also made 113 spindles for single-ring use. For a triple you’ll probably want the 125, the same spindle Raleigh used with the model 93s kitted out with a cyclo-cross styled chain guard where the big ring usually goes and spacers and extra long chainring bolts. They’re out there, but the compact double has the virtue of simplicity.

I've looked for a 125 on and off for a while. They're hard to find. There is a decent supply of Stronglight spindles for doubles and there are sealed units available from Velo Orange and IRD that will also work with doubles. There are more expensive options that will work with a triple from Phil Wood and Rene Herse.

Stronglight 99 triples can be reconfigured as doubles with the right crank bolts; a double can be made into a triple.

The triple currently on eBay at around a $100 with a 47/42/28 rings will give you great gear combinations with a 14-28 freewheel for an eroica bike but then you will need to sort out the spindle/bottom bracket situation.

https://www.ebay.com/sch/i.html?_fro...ht+99&_sacat=0

I think it may be possible to run a non-French spindle to make this work. I think Narhay did this.

Also older Stronglight cranks need a special puller.

A compact double in the Stronglight 99 makes more sense to me, such as that one in the UK with the 44/32. I'd like to move away from triples towards compact doubles, except for the Sugino GT on my Univega Alpina Uno, that stays. :D Swapping out the 44 for a 46-48 seems like a good bet. With a 13,14-28 freewheel in back, that would give me plenty of range. I could also search out a 28-30 chainring if I was going to do some serious hill climbing.

EDIT: Should have grabbed that Stronglight 99 in the UK last night when I was looking at it, someone snagged it!

I'd put up a WTB in the CV for sale forum. You are likely to get a better price than the US based seller on eBay who wants a $100 for the triple. Also keep your eye peeled for a local donor bike. Some bikes came stock with a Stronglight 99. You can simply swap out crankset and sell the donor bike. That may end up costing you only your labor. I recently picked up a Peugeot UO 9 for $49 mainly because I wanted the stronglight 99 on the bike.

Also the wheels on the blue Peugeot you picked up with the cottered crank are good quality with deore hubs and sun cr 18 rims. Is that a 130 OLD or 135? Likely the latter with a deore hub but I'd be tempted to keep those wheels for a project. They're strong wheels.

Yeah, I'll be on the lookout, and also put up a WTB in C&V sales.

I did keep the Sun CR18/Deore wheels, they are nice. Exactly as you said, they will surely come in handy for a future project. Haven't measured them yet to see whether they are 130 or 135.

I gave the frame a bath today, even though I haven't been able to remove the BB yet. Got some penetrating oil working on that...

It cleaned up very nicely. All the rust stains from the cable guides, etc., came off easily. I'm really appreciating that this bike had one owner, and it was always stored inside. I'm kinda on the fence about removing the remnants of the 531 stickers on the fork and down tube. On the one hand, I don't care about resale value, so they can go; on the other hand, it's "beausage" and should stay. I could remove the remnants and replace with reproductions, but again, not concerned with resale value. Meh, I'll see how I feel about that later.

Something interesting about the stickers: the down tube and seat tube decals are under the clear coat, whereas the headbadge sticker and 531 stickers are outside the clear coat. I would think at least the headbadge sticker would be under the clear coat.

Added more pics to the gallery, but here's a shot of the cleaned frame:

https://cimg1.ibsrv.net/gimg/bikefor...085bf8156e.jpg

They will - that’s what they’re designed for.

Maillard’s answer to SunTour’s ultra-spaced freewheels. Been using one on my Bertin for decades.

After letting the BB soak in some penetrating oil for a while, I was able to remove the lock ring and get it off (still working on the drive side). I don't think this was ever serviced, so about 50 years of grease and gunk, and what are those strange shapes I see?

https://cimg4.ibsrv.net/gimg/bikefor...82b80cbf17.jpg
About 50 years of crud

https://cimg3.ibsrv.net/gimg/bikefor...0720288afc.jpg
I see the drive side bearings, but what are those other things?

https://cimg5.ibsrv.net/gimg/bikefor...86579a192b.jpg
Talk about debugging your bottom bracket!

I love the bugs -- they take us right back to Admiral Grace Hopper's coining of the word computer bug when she found a dead moth in a mechanical relay switch. :)