Schwinn le tour upgrades

[Cooper S.]

I picked up a 73-74 ish schwinn le tour and I want to upgrade it a little bit. I’ve got a few ideas but I’d like some second opinions.
First off: does anyone know if there’s a sealed bearing replacement for the bottom bracket
Second: I plan on converting the rear to a 6 or 7 speed; should I use a vintage suntour derailleur or a modern one?
Third: does anyone know how wide of tires I can fit on the arayas that came with the bike or the iso numbers for the rims?
Thank you and I’ll keep the build updated here.

 

[Iverider]

1 - There are lots of options for cartridge bottom brackets for your bike. None of them are necessary unless you just want that and your current unit is shot. I like the rebuildability of a caged ball and axle bottom bracket on road bikes. Mountain bikes are more prone to seeing mud and dust so sealed bb is nice.

2 - Suntour Derailleurs are great. Use it if you have it and it works with your gear range. If you're running a double chainring up front and the rear is 28 teeth or less you should be fine with a short cage or medium cage length derailleur.

3 - Your rims won't be the deciding factor on the width you can fit in your Letour as they are already pretty wide and could probably fit a 1.75" wide tire if they existed in 27". The distance between the chainstays will limit the tire size. If you're considering upgrading things, you might look at a wheelset with Alloy rims. changing sizes at this time is also an option. You could go with 700c and probably fit a bit wider tire still. You'll want to measure your axle spacing out back before deciding this route and either buy a wheelset with a hub that matches the axle spacing, or cold set the rear end to match your new axle spacing. If you don't know what axle spacing is, consult https://www.sheldonbrown.com/ He also has a lot of good articles on bike tech in general.