Upgrade Peugeot 5-speed to indexed flat bar shifters

Question

My girlfriend got a vintage Peugeot with original 5-speed cassette (2 front gears) and friction stem-shifters (with a flat bar). She's struggling with the shifting. I'm considering the following upgrades:

1. Replace the stem shifters with 5-speed twist shifters. Would I need to also replace the rear derailer in that case?
2. Replace only the rear derailer (and maybe the cables) and see if that makes it easy enough for her to learn friction shifting.
3. Alternatively, I could go with new 6-speed parts: shifter and derailer. But would that mess up the shifting since the cassette is still 5-speed?
4. Replace the front derailer as well, but not the front shifters. So I'd have twist (indexed) rear shifters and stem (friction) front shifters. Is there any reason that wouldn't work?

Which of these would you recommend? Are there any important things I should be aware of/look out for (I've not done a bike project like this before)?

Answer 1

If the goal is to make it easy and work well, for sure get a modern freewheel, like a Shimano 6-speed hyperglide one. Hyperglide style ramping is the glue that holds indexed shifting together. Even if you jumped through all the hoops needed to try to make it index with the freewheel you've got, it wouldn't work.

A lot of gripshifts threaten to take up too much room on the sort of bar it probably has, so good idea to measure that ahead of time (adding in the length of the grip you'll use).

If it can fit them, then a good cheap approach would be getting 6-speed MRX comps with the semi-index aka non-index left (lots of small clicks) plus almost any cheap MTB/hybridy rear derailleur and the aforementioned freewheel, plus a new chain. You could even get the rear gearing lower this way, which is good because that sort of bike didn't come with very thoughtful gears. You could do the same thing with similar thumbshifter sets, where the left is friction and the right is 6.

Making the front index is a whole other ballgame and usually would require replacing the crank before it works smoothly, which isn't necessarily bad depending on how hard you want to commit to the bike.

Answer 2

Are the shifters mounted on the stem? Those were a terrible 70's design.

A 5 speed bike is almost certainly a freewheel and is not going to have the right tooth profile to work well with indexed shifting. You can get upgraded freewheels that have the hyperglide tooth profile needed to work with indexed shifting, that does lead down a rathole of upgraded parts. French and Italian bikes of that era often had different threading standards, so upgrading them can get complicated and expensive quickly.

Definitely replace the cable and housing. That's relatively cheap and will make the best of a bad design.

What I would suggest next is to upgrade the bike to friction thumb shifters with a high quality micro-index. Rivendell Bicycles silver shifters with thumb mounts or Paul Thumbie's are the high priced gold standard, but Microshift makes a lower priced solution that can be switched to friction.

https://www.microshift.com/en/product/sl-a09-sl-t09/

If you can find older Deore SIS MTB shifters on ebay, those work really well also. However, people interested in this stuff tend to snap them up pretty quick. Another source for good thumb shifters is often found on used MTB's from the 90's.

Sheldon Brown's website is a really good resource for working on older bikes. www.sheldonbrown.com