Updating drive gear... never-ending headache

[mr_grumble]

A bit of a long drawn out story I know but as of two days ago, I had no idea of what the mechanicals of a MTB's drive gear were.

I have an Avanti Montari MTB
- 24sp
- 1999-2000 vintage
- Shimano Acera Shifters, Front / Rear Derailleur, chainrings, hubs etc

It all started when recently, one of my shifters shat itself, so I found a supplier on ebay that I purchased a set of new Shimano Alvio shifters from.

Along with the shifters, I also picked up the matching set of Shimano Alvio Front and Rear Derraileurs as the current Shimano Acera gear was beginning to show their age.

I began to dismantle yesterday and found inscriptions on the chain IG NARROW. As I had no idea what this was I began to google and soon found out that my old Interactive Glide (IG) chain/rear derailleur and cassette were not suited to my new Hyperglide (HG) derailleur.

I am now looking at additionally purchasing to suit the new HG setup;
- Shimano Alvio Crankset & BB
- Cassette
- Chain

My problem is now with the replacement of the Crankset / BB and the Cassette.
Crankset & BB - my existing BB is what appears to be the older Tappered Square spindle which I assume is the older 'internal' bearing variant. Can I still get a Shimano Alvio Crankset with this style of BB or will I have to move to the newer Hollowtech variants.

Cassette - The existing IG Cassette Cluster (which is starting to look aged) is the older Threaded Freewheel Hub style. Can I still purchase a new 8-cog HG Cassette that is a Freewheel style or am I going to have to replace the hub to suit ?

I know the Shimano Alvio range is certainly not high-end gear, but I don't wish to spend big $$$ on an older MTB. If anyone can enlighten me on the points that I haven't been able to research, it will make my life just that little easier, my daughter is on my case to get my bike together again so we can ride.

Cheers,

Steve

[cyclerUK]

Ignore the fact IG versus HG.
I have found no problems mixing either. (chains/cogs etc.)
Alivio cranksets are available in square drive version as are other makes.

The rear sprocket cluster is NOT a "cassette", it is a "freewheel".
If you use the term "cassette" when ordering you may end up with the wrong part.
8 speed "freewheels " are still available but make sure they are SHIMANO compatible if a different make.