apologies for the non drive side photo and the awful front wheel.
i have this old peugeot 501 that was converted to a fixed gear some time ago. i want to convert into a geared gravel bike. i know very little about bikes but there’s a local cycle project i hope to spend some time at to help me build, but i have a few questions here first about components. i basically need new everything? please be patient with me and talk to me like a 5yo. for reference i’m 5”4, beginner and based in the UK.
1) pretty sure i want to go to 650b and bigger tyres but i’ve heard about cold setting but i have no idea why i might need to do it 🙃 no idea
2) do i need a new bottom bracket or would i be able to just replace the crankset?
3) what is a beginner friendly gear setup? this is where i have absolutely no idea about bikes. don’t intend on climbing massive hills but i no doubt encounter and don’t mind walking. i have jelly thighs. does having 650 wheels change what i go for? probably just wanting a double crankset and a 10 cassette but no idea how many teeth!? would i need to get a smaller crank arm?
4) top tube is lacking cable guides but i’m pretty sure i can get clamp ons? and add some boss stops to the downtube.
5) i read that disc brakes on bikes that aren’t made for it isn’t ideal, so v brakes it is. i assume i’ll need long reach ones with smaller wheels. do the brakes all have to be the same brand?
6) the forks aren’t original and i’ve no idea what size they are but i’m planning on keeping them if that’s possible?
7) i want to keep the stem but i want to change the bars (i am not a dropbar kinda gal) – i quite like the idea of the nitro baby bosco or some other kind of riser cruiser type bar so i’m more upright.
8) seat post can stay, and thats the height i need it.
9) why are thumb shifters so expensive? i like this setup but don’t want to spend a fortune on the mounts and shifters and paul brake levers. https://thewoodscyclery.co.uk/products/rivendell-thumbshifter-mount-handlebar-clamp-for-silver-shifters
10) is there anything i’ve missed? :’)
by alivingdiary
4 Comments
any help at all would be helpful 🙂
someone in /xbiking said screw the build if i plan on having my seat that low but as a noob i don’t know why sooo…
There is a lot going on here. I assume you want to go 650b so you can running bigger tiers for comfort or gravel. I’ll address a few things, but generally would dissuade you from going down this path unless you have a parts bin, a lot of time, or want a BIG project. If you’re trying to save money converting this fixed bike to a geared 650b bike you are going to spend way more than just buying another geared bike. It would probably be cheaper and easier to buy another frame and start there if you are set on building a 650b bike. A few notes below.
650b wheels will may not fit on this frame with wider tiers. There will not be clearance for wide tires in a frame down where the rear wheel is closest to the bottom bracket. The front fork also looks to have limited clearance. Looking at pictures online of this frame it looks to have clearance for 700cx25mm ish.
Cold setting would be used to change the hub spacing so you could fit modern wider hubs (the hub is the part where the fork and rear drop outs connect to the frame) but that would not increase tire clearance. Old road bikes have 126mm rear hub spacing and moder are 130/135. If you want to use modern 650b wheels you will have to stretch the frame clearance to fit.
You will also have issues with break caliper adapting. This frame was designed for 700c road brake calipers. With 650b wheels the rim is smaller so it’s further away from the caliper. There are some adapters out there or long reach calipers to go from 700 to 650B but it would be another challenge to overcome and cost.
So lots to unpack here, and its a huge undertaking.
1. So since this is a road bike from the 80s, the rear stays (where the rear wheel bolts on) are either 126 or 130 mm apart, cold spreading is the act of pulling those stays further apart (typically to 135mm, which was the mountain standard for awhile)(DONT DO THIS ON ANYTHING OTHER THAN STEEL). You are looking for a quick release 135mm rear hub
2. The bottom bracket might be fine, but a new square taper crank is dependent on a specific spindle length, so its a bit of a crapshoot.
3. A 2×10 is a very solid setup for most situations, a 50/34 compact double up front can get you most places and you should be able to find a square taper crank that could support that (110mm 5 bolt BCD being very common). The 10 speed cassette would need to be 11- low 40s as high 40 tooth and 50+ are typically 1x drivetrains.
4. Several companies make cable guide clamps for the top tube (origin8 for one), they also make cable guides with adjustment for where the downtube shifters would have gone.
5. I would not put disk brakes on that bike, too much torque on the headtube is sketchy, and you would need some solid welding skills to make rear disks happen. They do make single bolt canti brakes that fit what you need the Tektro R559 long reach being the cheapest option.
6. Since you would need to basically strip this bike down to the frame to do most of what you want, I would have an LBS give that fork a once over, since its carbon and you don’t know the life its had.
7. For the stem you will have to measure the clamp diameter of the current bars and find something that will fit (its probably 25.4 mm, but measure for sure).
8. Your seat being that low would tell me that the frame might be slightly too large for you, You could alleviate this a little bit by getting shorter cranks (see if you can get 165mm or shorter)
9. Paul components are the most you can possibly pay for old school looking bike parts. Thumb shifters don’t have a huge market these days, so more cost (supply/demand). Microshift thumbies are the way, they cost less and work great. They just aren’t as “sexy” as paul and rivendell stuff.
10. 650b wheels will need to be a 8-10 Shimano HG hub for cheaper cost, availability, and selection of cassettes that work. Make sure they are rim brake compatible! It will be a guessing game on what tires will fit on that frame with 650b, get friendly with your local bike shop, so you can try a couple different tire sizes without having to buy them. Canti brakes require short pull break levers. Overall if you pull the trigger on this, it will be a really cool project when its done.
Don’t bother with converting that fixed gear. If I were you I’d just buy a retro mountain bike instead and upgrade that. You’ll spent a lot more money, time and effort doing it with that fixed gear and it won’t be half as good as you’d like it to be because parts won’t be compatible etc.
I recently bought a 90’s Specialized rockhopper and converted it to a 1x gravel bike and it’s great fun but ultimately it was a money pit (£90 for the frame and then close to £1000 for all the parts I needed to replace, repairs I needed to do and mistakes I made along the way). I could have bought one someone else had done up for a lot less but I enjoyed what I learnt along the way… wouldn’t be in a rush to do it again though!