Here are all the specs for the Diamondback Axis from 1991.
Tires: Schwalbe Hurricane 26 x 2.0 (mostly road profile tires)
Crankset: Shimano Deore XT, 110 BcD, 5 screws, 3 rings.
Rear and front derailleurs: Shimano Deore XT, 7 / 3 speed.
Cassette: Shimano Deore XT, 7 speed.
Frame and fork: true temper ox, steel.
Front rim: Avenir Duro 17 (made in USA), 26 inches, 32 holes, rim brakes.
Rear rim: Mavic 217 SUP Ceramic (made in France), 26 inches, 36 holes, rim brakes.
Front and rear wheel hubs: Shimano Deore XT.
Stem: Tioga Avenger TT Bone (quill stem).
Handlebar: Avenir, flat style, 565 mm.
Seatpost: Avenir.
Combo brakes and shifters: Shimano Deore XT, cantilever brakes.
Probably Shimano Deore XT pedals.
Usually the bicycle had retro bar ends.
Overall, a very outdated bicycle by the standards of 2022.
If you plan to restore this model, it will not be easy, mostly for the crankset bottom bracket as it requires some special tools to take it out.
Modern tools are not compatible.
This bicycle was sold in 1991 for about 600 pounds, around 750 US dollars.
Probably fully restored it’s worth these days around 300$ at best.
The position is not very comfortable, outside of collecting, this model is not great for every day ride, compared to modern bicycles.
Regarding other models, Diamondback has released a few other models in 1991, like Diamondback Axis Team (the top of the line, very rare), Shimano Deore XT + XTR, Axis (the one from the article), full Shimano Deore XT.
Then we have: “Apex”, full Shimano Deore DX.
“Ascent EX”, full Shimano Deore LX.
“Ascent”, this was the entry level model, having a combination of Shimano 400 LX and other parts like “Araya RX-7”.
Overall, a classic bicycle, amazing for 1991, using high quality parts.
As we can see today, companies are finding hard to add even the most entry level Shimano parts, like “Altus” or “Acera”.
These were all the Diamondback Axis 1991 specs that I could find, hopefully they are useful for you.