Hi, I have my dad’s old 1970’s road bike that I’d like to do up. I’m wondering if I could put my Mavic Cosmic Elite wheels on it if I get a 6 speed rear cassette fitted so that the wheel fits the rear forks spacing as currently it’s 9 speed cassette on a road bike with 130mm rear spacing. If I can do this with a smaller rear cassette wil the chain line up with the original 2 cog front chainset or will it be out of line and a nightmare? Could I also replace the front cogs for more modern ones? Bike has all the original derailleur/brakes etc. It’s just the Mavic wheels I’d like to stick on it if possible. Any help much appreciated!