I have a 1987 Peugeot Versailles. I want upgrade the wheel set. It has a 7 speed shimano freewheel cassette. I have a used set of Mavic Open Pro 32 spoke with Ultegra 6500 Freehub. The bike has Shimano 600 down tube shifters. What do I need to purchase to make this conversion happen? Any help would be great.

7 speed cassette (you may (probably will) need a spacer for this as well), and possibly you will need to bend / cold set the stays from 126mm to 130mm. If everything else on the bike is 7 speed, and the cassette is 7 speed, you should be OK with the shifters. dérailleurs you have.

Before you start bending anything or buying anything, take a cheap plastic
vernier caliper (or a better one if you have it),and measure the rear dropout
width in your frame.. .. Then measure the over lock nut distance for your current
wheel and that for your replacement wheel.

In theory, the old for the wheel that goes in should match the dropout width
for the frame, but you can get away with a few cm difference either way.

Your bike might require a little resetting, or none at all.

If you do decide to cold set it bigger or have someone do it, read up on the
proper way to set up a string from the drops around the head tube so you get
the stays to go out equally on each side. Otherwise your alignment suffers.

What size spacer would I need?

"you can get away with a few cm"

Watch your units, a few mm is more like it.

It depends. If you have 600 "Tricolor" 7-speed (assuming I'm not hallucinating) indexing DT shifters, and you want to use indexing, you'll need an 8-speed cassette spacer. You'll put the spacer on, then the 7-speed cassette, then the lockring. If you don't have indexing then you don't have to care: just use an 8 or 9 speed cassette and chain, and be happy (after verifying/modifying your drop-out spacing). Some people don't care for friction shifting on 9-speed; I'm not one of them. I find that it works well as long as you shift just as we did back before dirt was invented: ease of on the pedals whenever you shift.

Good luck, and enjoy your new/old bike. Updating drive trains does wonders for these old machines.

If you use a 9-speed cassette and use the shifter in friction mode, you won't need any spacers at all.

Yes, it's a very specific 4.5mm for putting a 7 speed cassette on to a 8/9/10 speed Shimano hub. Here is a link to one at Harris Cyclery, any good LBS should have / be able to get them https://harriscyclery.net/itemdetails.cfm?ID=2127 & https://sheldonbrown.com/harris/parts.html

If you have friction shifting now, I'd go ahead and get a 8 speed HG50 cassette with a suitable gear range, like 13-26. you'll undoubtably need to readjust your rear derailleur a bit if you're going from old school 7 freewheel to 7 speed on a 8/9/10 freehub anyways.

if you do have index shifting, well, stick with 7 + the spacer, but yeah, you'll likely need to completely readjust the rear shifting as the new sprocket will likely be about 1/2 cog farther to the right. your old wheel is probably 126mm nut-to-nut, and the new one will undoubtedly be 130mm. a 4mm spread is trivial on a steel frame.

also, with the 7-speed on the freehub, your chain line might be just a hair too 'in' ... this just means when you're in the small front chain ring, you'll find it will be more likely to scrape the back of the big chain ring when you use the smaller half of the rear cassette. simple solution is, just don't do that. shift to the big ring in front before you get down to the taller/smaller 3-4 cogs in back, and everything will be much happier.

I have indexing shifters.

k, are you familiar with adjusting them from scratch?

first, make sure the derailleur is completely square to the cogs.. tweak the hangar if not.

its easiest if you have a work stand. if its a 3x7, put the chain on the middle chainring in front, otherwise the big chainring. shift to the highest gear (smallest cog), and adjust the 'H" set screw on the derailleur so the idle wheels on the derailleur are centered on the outside edge of that small cog. now put the chain on the largest rear cog (if its a 2x, also shift the front to the small, otherwise 3x leave in middle), and adjjust the "L" screw so the chain is square with that socket when the derailleur is against the stop. you'll probably have to adjust the cable takeup, whever that is on your bike, to reach both extremes. now put the chain on the middle cog, and adjust the cable takeup so the derailleur wheels are centered on that cog. now ride the bike, middle gear, and shift up 1, down 1. if its slow going up 1, then tighten the cable a 1/4 turn. if its slow going down 1, loosen. repeat until perfect.

(thats all from memory sitting at my keyboard.... you can probably find better instructions with pictures at the Park Tools site)

Thanks everyone for all of that awesome information. Ill order the parts and give it a go.

.............................oopsie.

the worst case stretch is from 120mm old 2x5 10 speeds to 135mm hybrid/mountain... thats a 1.5cm (15mm) stretch, which is 7.5mm on each side if you will. if you stick with road axles, its 120->130mm wihc is a 10mm/1cm stretch, 5cm per side. either of these will let you run 8/9/10 speed cassettes.

I bought the HG50 8 speed cassette and put on it on the upgraded wheel. After a few adjustments it works great! Ill put it to the test this weekend. Thanks everyone for the fantastic input.

How do you know what's suitable for the OP?

Maybe he's like me, and would almost never use a 26t, but can't live without a 16t.

width of cassette body minus thickness of 7 speed cassette.. but wait.. the way the 7 speed era
cassettes were held on, is, by screwing on the small cog outside, thread on the freehub..

now the 8 speed and more use a lockring, that screws into an inside thread..

...only if you're talking about Uniglide hubs. There's plenty of 7-speed Hyperglide (with lockrings) stuff out there.

a 1987 Peugeot might be freewheel rather than cassette, no?

that totally changes everything.



EDIT: oh geez, learn to read, P. (me). he's switching wheels, NEVER mind.

The 1989 Versailles came with a 6-speed freewheel, so I doubt the wheels are original.