bbbbbbb

hi,
i inherited my father's old px-10 from the early 70s and i put some 700x28 hybrid tires on there since i like to ride gravel trails sometimes. however, i'd like to get a wider tire on there and, since my father was taller than me, this bike is a little big. so if possible, i'd like to get the bike a little lower, which i understand you can do by putting 650b tires or the like on there. what about 26"? right now when i stand over the bike, i can put both feet flat on the ground, just barely, and it's not too comfy. any advice for me? i would like to keep this bike if it's possible and keep the conversion as cheap as possible. will include pics later, it's a bit of a beater. thanks!

Doug64

My PX-10 (1973) came with sew-up tires and rims. I'm assuming they are 700c. I built a set of 27 x1 1/4 wheels for training that worked well. The problem with 26" wheels might be the brakes. There may not be enough adjustment to accomodate 26" wheels. Wider tires also have trouble clearing the brake pads.




Asssuming a 26" wheel is really 1" smaller than a 27" wheel, there might be just enough adjustment to accomodate the smaller wheel. I just measured the adjustment I had left (assuming you still have the Mafac brakes) and it was about 1/2 inch. It would be close, but it might work.

mike

??? I have been riding a Peugeot PX 10 for nearly 30 years. As far as I know it always had and still has 27" wheels. I have gone through many wheels since then, of course. The common tire is 27" X 1.25", but you can get a slightly more narrow 1 1/8" tire.

27" wheels are plentiful. I can't see any advantage to going with 26" wheels.

Iowegian

You could do a 650B conversion but I doubt the Mafac Racers will still reach. You can find super long reach Tektro brakes that will work as well as the Mafac's and reach the 650B tires. 27" rims are 630cm in diameter, 700 are 622cm in diameter, 650B are 584cm in diameter and 26" mtb rims are 559cm in diameter IIRC, so it's a big jump from 650B to 26" and I wouldn't recommend that.

A 650B conversion won't be cheap as you'll need new rims, tires, tubes and probably brakes. There are lots of people who have done 650B conversions so search around for some discussion on it.

My advice would be to ask this question over at C+V or the mechanics forums. Or just search through there for 650B conversions. If it's already a beater bike it probably isn't worth the effort unless the bike has lots of sentimental value for you. You could also try to find another PX-10 in a smaller size and swap the parts over.

m750rider

If you can straddle the bike with your feet flat on the ground, even just barely, I would say the frame is not too large for you.

rhm

I think Iowegian's has covered it all correctly. Another option, by the way, would be 650 A, which is a little bigger than 650B; but 650B is probably better.

Bear in mind that smaller wheels will lower the whole frame, and necessitate shorter crank arms. I actually prefer shorter crank arms, so I put 26" (the MTB size) wheels on an early 70's Lambert (made for 27" wheels) which lowered the BB, which was the whole point of the exercise; but I couldn't find any rim brakes to fit it that way. I put drum brake hubs on it. It worked out very nicely.

markf

The PX-10 that I bought in '73 and the one I bought in '79 both came with (cheap) tubular tires, which have the same rim diameter as a 700C tire, 622mm bead seat diameter. Like Iowegian said, the Mafac Racer brakes are not going to adjust enough to reach a 650B rim or a 26" rim.

If it is uncomfortable to straddle the top tube of the bike with both feet flat on the ground then yes, the frame is probably too big for you. Take the bike to a good shop and have someone who understands bike fitting look at you on the bike, but my guess is that the frame will turn out to be too big.

If you want to keep the bike that's fine, but keep in mind that some repair/replacement parts are going to be difficult or impossible to find. The headset and bottom bracket are both French threaded, which is an odd sized thread that is no longer used. The original rear hub (if it still has the original) was also French threaded and was sized to take 5 speed freewheels, which may not be easy to find any more. I would suggest keeping the bike for occasional use without trying to modify it, and getting a modern bike that fits you and is designed with your intended use in mind for every day use.

bbbbbbb

thanks for the advice. yeah, i think the 650b conversion might be too expensive. maybe someday. maybe i'll see if i can live with wider 700 tires in the meantime, though it's not going to make it lower. here's a pic.

desconhecido 

That's not a bad looking bike though I'm not going to tell you what that front wuick release lever looks like.

In my opinion, which is worth exactly what you pay for it, just because you might be able to feel the top tube when you are standing flat footed doesn't mean the bike is too small. The important question is how it feels to you when you are riding it. The seat looks a tad low for my taste. but look at pictures of good riders from years back and you'll see that it's not low by historical standards. If you get a smaller frame, the top tube will be a little shorter, which might be a good thing (or not), but the bars will be lower (or not). The stem looks to be at about its height limit, but the relationship between the saddle and bars looks ok. Again, the important question is how it feels when you ride it, not how it feels when you are parked. If you have more than minimal biking experience, riding a frame of that size should not concern you -- if it fits in other respects.

LHT in Madison

A wider tire is also a bigger tire, which will make your standover height even worse. Maybe this is not the bike for gravel roads, as you may have reached the upper limit for tire width already.

Do you have any shoes with thicker soles that would work better for standover height but are not too absurdly thick soled like a hiking boot would be?

han123

Hi,

I have a pr10 1976 and am not sure what size the wheels are. I would like to replace the brakes but do not know which size to get.

There are two options: Tektro 559 55-73 millimeters vs. 539 47-57 millimeters

Any advice?

jefnvk

Start a new thread in the Classic and Vintage forum. There is a wealth of knowledge there

thumpism 

One other point to consider with smaller wheels like 650B to lower the bike is that the bottom bracket (and therefore the pedals on each downstroke) will be closer to the ground. This might affect handling or cornering.

Squeezebox

Like he said.

52telecaster

if that bike doesn't make you happy it will certainly make someone else very happy!

jefnvk

I've only been without a French bike for four days now, and I already NEED another!

52telecaster

yeah but its closer to my size!

jefnvk

Nice try, but I saw nothing in the post that indicated size

But seriously, not that interested in a TRUE oddball sized Frenchie, I want one that resembled my 85 PH10, in pearl white, art deco lettering, and with less rust and the tri-color red-orange-yellow stripes in a 54cm (or something a bit smaller than 57 depending on the year) with nicer than HLE tubing, and preferably nice vintage tubulars. Not to get too specific or anything!

52telecaster

you know you just bought a bike. sounds like intervention time to me.

jefnvk

Yeah, but I've since sold two and have a third on the chopping block. I deserve a reward

Plus didn't you just buy a much nicer bike than me?

52telecaster

it was only a frameset. that doesnt count.

jefnvk

Heh, that isn't what my fiancee says about that Trek 400 frame I've got lying around!

52telecaster

so now we are taking the word of significant others eh? i believe i will be in trouble if we do that.

jefnvk

Third bike just sold, so I am back at N. Turned a Peugeot PH10 into a bit nicer, lighter Univega road bike that fit better, a 1982 Miyata 610 into the Mazama, and a three speed Collegiate into a Miyata Cross bike, and an extra $45 into my pockets! I am back at getting to put dibs on bikes now (and really need to stop looking at a nice 105 equipped Centurion Ironman that just appeared on CL today)

52telecaster

wow, i never come out ahead on those deals. you should be doing all of my wheeling and dealing too.