The cause of poor loading performance from the +2 range of Spectrums is often due to stretching and wear of the tape mechanism drive belt.
The old belts perished over time, particularly when stood unused for many years when they would often develop a "kink" where the belt rested unmoved over the capstan. This kink becomes a permanent feature in the belt causing it to jump when the drive is used again.
These replacement square section belts are made from modern, more resilient materials than the originals.
This is a replacement for the larger belt on the Spectrum +2 (grey model) and for the single belt on the Spectrum +2A and +2B (black models).
The Spectrum +2 (grey model) has two belts, a large and a small one. The small belt rarely needs changing, but if you need this as well, both belts are available as a set.