BUCKLOS 8/9/10/11/12 Speed Cassette Ultra-Light 11-25/28/32/34/36/40/42/46/50/52T Bike Cassette Fit Mountain Bike/Road Bike/XC/DH/AM,Compatible with Shimano Sram HG Hub Driver…

Addressing the drivetrain might be better to make this your first upgrade. It's not going to be CHEAP cheap, but it should be affordable, and in the end you will get a BIG, BIG upgrade with a step up to the "modern" era of vintage mountain bikes. You have a few things that really limit customization and performance right now that we can address all at once. Those cantilever brakes and your wheel is a freewheel. Both can be bolt-on upgraded and are worth doing now. I do 100% recommend you do them, they'll unlock some seriously fun customization and make maintenance easier later on. If you really love the cantilever look, DM me and I can make replacing that part cheaper with pads and a different shifter, but it'll still need cables, which will eat into that cost. There are used parts that will work, but I wouldn't bother unless you have access to a good used bike parts shop. Firstly, you need to either re-lace that wheel for a modern hub, or for about $75, I'd just get a new wheel with one already in it. It'd have a fresh braking surface that will last forever, and this one has a proper shimano hub in it. This will convert your bike from the freewheel to an 8 speed cassette, which unlocks tons of fun. That means you can also upgrade your very antiquated cantilever brakes to v brakes with fresh cables and way more braking power. This wheel will fit directly. They're usually dead true, so all you do is put some grease on the cassette splines and slide a new cassette on. Just need a cassette lockring tool (and they do have torque specs but "good and tight" is fine. If you want a torque wrench, you need a big one and a small fine one. I'd get a small fine one in inch-pounds first, but neither are REALLY necessary unless you're adding carbon parts or have a habit of way overtightening things) https://www.amazon.com/Wheel-Master-Weinmann-Rear-Release/dp/B0040DNJ88/ref=sr_1_8?sr=8-8 That wheel https://a.co/d/0gjnutk2 That cassette. You now have a behemoth climbing gear that will make any hill on earth insanely easy. You will maybe need a derailleur if your 7 speed can't reach, but you could try getting away with it first. If it doesn't reach all the way, this is what I put on EVERYTHING because it's smooth, easy to adjust, it will easily do a 7 speed (I have it on my classic road bike too lol) and with a clutch, means it won't chain slap! https://a.co/d/03XAaotL (I'd wait to do this one until you try your current derailleur unless you really want an upgrade, it's a nice upgrade but may not be necessary for this. And if you need cheaper, there are plenty of other choices without a clutch, which again isn't mandatory, just noticeably nice to have) It's $50, so I'd wait to see unless you want another fun upgrade that will make a noticeable difference on bumps. You could get something cheaper, as long as it's proper shimano or microshift branded and advertised for 8-11 speed, itll work. no SRAM Your front derailleur is fine. But if you do this, you'll need an 8 speed shifter. And while that's about $20, you can spend $40 on brand new shifters/brake levers AND upgrade your brakes HUGELY. https://a.co/d/0axiVEia These combo shifter/brake levers will be a big upgrade. I think they come with full cables and housing. If not, you shouldn't reuse the old cable. New shimano cable and housing kits are $20 for both brakes and $20 for both deraileurs, make sure you use the short one for the front and long for the rear, lol. CNC also makes some nice ones that come in colors!. Don't go cheap, those two brands are reliable and smooth. And they then let you convert those cantilever brakes to V brakes (which while both are cable, they have different pulls so need different levers). Big upgrade in feel and performance and safety. That change requires the new brake levers, so doing this all together now will save you about $80 in new levers later. V brakes are a big, big upgrade V brakes are you get what you pay for in ease of adjustment. These will bolt straight into where your brakes are now, and give you a MASSIVE boost to feel and power. About $50 for the pair. You could do kool stop pads now too, they WILL be a big upgrade, but for now, the included ones will work. KS pads are just another level and worth the $50 initial investment later on. https://a.co/d/05J5adkL https://a.co/d/07YFaf1L So now we've got you a new wheel that is a modern standard, new brakes, a modern rear cassette that will be way more fun and easily changed later, and new shifter/levers to control them all very comfortably. It should come with all the cable and housing you need. A chain, you need to make sure it's an 8 speed chain. The widthof the chain switches for 9 speed and up https://a.co/d/02RF73Pb Bucklos is solid and cheap. Gold for bling, silver for simple. Lastly, we need cranks. This is either a cheap thing or an upgrade opportunity. You have a 5 bolt crank which makes finding new chain rings annoying. Switching to a 4 bolt crank with NON RIVETED chain rings means replacement rings will be cheap and easy to get later. https://a.co/d/03eYe2hc That will bolt right on. You WILL need a crank puller tool, you will NEVER get them off without one. That said, since you got that $13 pawfly crank puller and BB tool, let's do your bottom bracket since it's a wear item. A new shimano square taper bottom bracket is another $25 Or, for $45, you can upgrade to a WAY stiffer external bottom bracket and hollowtech crank set all in one! https://a.co/d/0cCvZVun So use that pawfly tool to remove the cranks and the bottom bracket (the right side with the pulleys is reverse threaded, so you turn it right to loosen. That and pedals are the only reverse thread items on the bike to worry about. You will need this tool to install the new external BB since I'm not sure what size cups it uses, this will do ANY of them. It's $25 instead of $12. https://a.co/d/04JBo9te Either one will work for you and the bike. I would do the hollow upgrade since overall it's cheaper, stiffer, and if the BB fails a nice replacement shimano hollow BB is cheap. Just make sure you use one of the included 2 spacers on either side. There is a torque setting technically, but anti-seize on the threads and "as tight as I can reasonably get it without trying to break it with the handle on that tool" is A-OK. So. We've put a modern rear wheel on. Now you've got a modern easy to upgrade and replace cassette with a modern climbing gear that will transform the bike on climbs, and another gear! We're gonna probably try to keep the original rear deraileur, the front is 100% fine, and we've got a new chain, and a new external BB and hollowtech cranks that will make the whole bike feel stiffer and better. We've got bigtime upgraded brakes too. Check your headset bearings. park tool video for that. If you need to replace them, get a cheap $10 kit and replace just the bearings + cages, using some of that moly grease.

First make sure if it is a cassette or a freewheel. https://youtu.be/iTJ3taJHOn8?si=ydHhtw5ySFQV25kq You don’t have to buy the Mercedes Benz quality Park tools. Oumers are Ford of bike tools and work fine. https://a.co/d/09Au526C I’ve had good luck with these Bucklos cassettes. https://a.co/d/03FRzl5p Keep the range at 11-40T and it is under $30. If you do go for a wider range cassette you will need a longer chain. OR Stick with the same range and just use the existing chain. YouTube university is your friend.