Inside392

Hello,
Long time browser first time poster here.

I have a 75-80 Peugeot I have no idea what the model is. The shifters and derailleurs are simplex, the shifters are mounted on the stem. Maybe that helps.

My questions is this.

I want to get smaller chain rings or just get a smaller inside chain ring if that's possible. my problem is I have no idea what will work or not. Ive read on Sheldonbrowns website and other places online and I just find myself confused.
I have a newer 6 speed cassette and currently old 52t and 42t front chain rings.

My reason for wanting smaller chain rings is that I have a lot of hills in my area and it would be nice to not have to totally grind it out every time I ride. I do love hitting the hills but it gets to be a bit much.
Oh also its friction shifting, but I am sure you vintage geniuses already guessed that.

Thanks!!

upthywazzoo 

Read up on Sheldon's site on how to measure crank BCD. With that knowledge, you can do some research on what chainrings will fit your crank. Depending on how low you want to go--you may be required to find a new crank entirely.

icepick_trotsky 

Your other option would be to install a tripelizer. Google red clover components.

John E

As suggested above, the late great Sheldon Brown's website holds a wealth of information for you.

Do you have steel (usually cottered) cranks or aluminum? Are your chainrings secured to the spider with 3 bolts or with 5 (or perhaps 6)? What brand are your cranks and chainrings? Does your inner chainring bolt directly to the outer, or do both bolt independently to the spider?

Shoot us a picture, if at all possible. The attached are pictures of cottered steel with 3-6 bolt adapter (circa 1960) and cotterless aluminum with 144mm BCD (42T minimum). Does yours resemble either of these?

Attached example is a cottered steel crankset, typical of lots of 1950s and 1960s bikes and of lower-end 1970s bikes

due ruote 

Is this what you were looking at? Can you tell us what crankset you have, or post a picture?

Also, a) you probably have a freewheel, not a cassette; b) what are the cog teeth numbers on it?

Finally, have you been riding long? Sometimes beginning riders think they need lower gears, then discover that the initial part of the development curve is pretty steep. Ie. you might find that you get into better shape pretty quickly and your current setup is adequate.

Rocky Gravol

Chances are it's a 122 mm bcd. Stronglight.

Depends on how low do you want to go.

I went through this. Check out this thread.

https://www.bikeforums.net/classic-vi...eugeot-uo.html

Inside392

Thanks for the replies.

It is a steal cotter and the spider has a 5 bolt pattern that is 110MM BCD. The inner chainring is on the back side of the spider with the outter chainring on the front with a bolt basically clamping them on. The image below should clarify with I am trying to say.

I do not know the teeth count on the rear cogs, I will give it a count when I get home.
I have been riding for about 2 years. I road all of 2013 took 2014 to train for a marathon and am back on the bike this year.
I would normally agree that I may just need to suck it up and get stronger, but I dont think I will ever be able to comfortably spin up the hills I like to ride with my current gearing.

I am not sure of the make of the crank, If i remember correctly it is something like doteck? It is casted into the back side of the crank arm. The current chainrings have no clear markings of a make on them.

Oh, also, I don't want to go super low in gearing. Currently as I said above the small ring is a 42t. I think going to something around a 39 or 36t would be good enough.

Here is a link to a picture of what my crank looks like. Please note this is not my bike specifically just one to show the crank style.
https://djcatnap.com/wp-content/uploa...eot_uo8_06.jpg

rhm

I don't believe I've ever seen a Dotek cottered steel crank; but if it looks like the one in the photo you linked, I can well believe you have a Dotek cotterless aluminum crank, which would indeed have a 110 bcd chain ring size. You can get those chain rings as small as 34 teeth. Changing the chain ring is not a big deal; take out the five bolts that hold on both rings, take off both rings, then put on the rings you want to use. You'll need a 5 mm allen wrench.

Rocky Gravol

Now I'm curious.

What year did Peugeot switch to cotterless cranks?
And can the year and model be identified by the crank it has?

My late 70's 1980? Peugeots have stronglight 104's

Inside392

But how do I know what chainring to buy, besides the 110bcd and the teeth?
On these websites it tells you its for a 8, 9, 10 or 11 speed. I don't know what they mean by that and if it even matters to what I need.
That is what is confusing me, the way the websites.Components > Drivetrain, Brakes and Pedals > Chainrings | Jenson USA as an exmple, filter stuff.
Can i get a smaller chainring and then put my current small ring on the outside?

Im sorry if these are silly questions, sometimes I over complicate things for myself.

rhm

You would want an 8 speed ring, but it really doesn't matter.

You can go to a triple setup, putting three 110 mm bcd rings side by side; you'd have to get new chain ring bolts. Triple chain ring bolts are sold in sets of five, complete with spacers. So the longer bolts would go through your small ring, spacers, middle ring, crank arm spider, and large ring respectively. BUT you would also need a longer bottom bracket spindle and possibly a new front derailleur, all for very little benefit.

I'd suggest you count the teeth on your existing setup and enter them into Sheldon Brown's Gear Calculator:

Sheldon Brown's Bicycle Gear Calculator

then play with different options. As you'll see, your existing setup probably has a lot of redundant gears since there's little difference between the two chain rings. By putting a smaller chain ring on the inner position you will reduce that overlap and get some lower gears.

For simple purchases like one chain ring, the best selection is often ebay.

BluesDaddy

Hey @Inside392 ... I'm also in the Granite State. Maybe if you're near me (Lakes Region) I can help out in person.

Rocky Gravol

Not necessarily,

a 47 tooth inside, or middle ring.
Note the indent for the chainring bolt, and the ramps next to the teeth
to help the chain engage.


Opposite side note the lack of both.

A 48 tooth big ring.
Note the indent for the chain ring bolt, but no ramps.

Same ring, note no bolt indent but it has the ramps.


Now not all rings have those ramps, so yours might be different.

Inside392

Thanks a lot for the information thus had been very helpful. I feel better about my search for New rings. @BluesDaddy thank you for the offer, I do however live in manchester and work down in Massachusetts so I'm not sure how feasible it may be. I will keep the thought in mind even if to just join you on a ride some day

busdriver1959

Don't overlook the option of going with a new freewheel. Unless I missed it, you haven't said yet what you have back there. People here can tell you the max number of teeth you can use with the Simplex RD. The right freewheel might be an easier find.