Hello,

I’ve recently bought a cheap second hand bike that seems to be made up of a lot of different parts. It has an old giant rebel frame, gt bars and grips, Suntour epicon remote locking forks, Mismatched hydraulic disc brakes (the rear is a larger disc than the front?), a decent looking Mavic front wheel, and a Shimano rear with a missing spoke.
It looks like a previous owner converted it to a 1×8 or at least removed the front mech and levers. I had to put a new rear mech and cable on to get it to change gears. It still has the Three chainrings.
I’d quite like to make it a bit more useable, not for anything extreme, just gentle trails.
Do you think it’d be worth sticking an 11-40 cassette on as the current one has seen better days? And a narrow wide chainring? I’ll probably change the bb and headset bearings as I’m sure they’ve had their time.
Not looking to make anything competitive, but I quite enjoy tinkering. Thanks

If it’s old style geometry then may not be particularly comfy but am sure you’ll get more helpful replies than mine. Bumping your post anyway!

I also enjoy tinkering. Some points to consider, lacking full info:

You imply it’s currently on 8 speed rear shifter and a 7/8/9 speed rear mech. You can get 11-40 8 speed cassettes, apparently, but I suspect you’d need some sort of goatlink-type device to get it to work with the mech.

The mech won’t have a clutch, so a NW chainring is a good idea – how cheap is the crankset? Three chainrings riveted together, or bolted on separately? Latter case is easy, just a cheap eBay ring on the middle tabs with shorter single chainring bolts.

You’ll need a new chain with all that, too, unlikely the old one would mesh well.

What @Montgomery said

Personally with that age bike and 8 speed I would put the front mech and shifter back on. It’s the cheapest and easiest way to get more gears.

OP implied the front mech and shifter are AWOL; buying replacements will be cheaper than a 1x setup if the current drivetrain is worth keeping. Whether an old Giant Rebel (Revel?) is worth spending, what, £60? on a new drivetrain to keep trailworthy is up to the OP.