The same five bullets as the CS-HG50, and $5.24 cheaper
SHIMANO CS-HG51, 8-speed, 11–32T, 300 g (10.6 oz)
A Shimano CS-HG51 8-speed cassette in 11-32T at 300 g (10.6 oz), with nickel-plated Hyperglide sprockets.
What you are getting
A Shimano CS-HG51 cassette: 8-speed, 11-32T, 300 g (10.6 oz), with cogs of 11-13-15-18-21-24-28-32, a nickel-plated finish and sprockets cut away to save weight. $25.26.
And its twin on this page costs five dollars more
The CS-HG50 reviewed on this page is also 8-speed, also 11-32T, also 300 g (10.6 oz) — and carries the same five bullets, word for word:
High quality 8-speed cassette. Hyper glide sprockets have a computer designed tooth configuration with contoured shift gates. Close ratio gearing allows a more efficient use of energy through finer cadence control. Sprockets are cut away to further reduce weight without reducing rigidity. Nickel-plated finish offers hard wearing resistance to corrosion.
| this one | the CS-HG50 |
|---|
| Model | CS-HG51 | CS-HG50 |
| Speeds | 8 | 8 |
| Range | 11–32T | 11–32T |
| Weight | 300 g (10.6 oz) | 300 g (10.6 oz) |
| Bullets | identical | identical |
| Price | $25.26 | $30.50 |
Nothing published separates them except the reference and $5.24. The CS-HG50 listing does add one line in its description that this one does not — “corrosion-resistant steel cassette lockring” and “for narrow 8-speed HG chains” — so if a lock ring matters, that is where it is mentioned.
Otherwise, this is the cheaper of two identical descriptions.
The cog list is the specification, and it is published
11-13-15-18-21-24-28-32. Two-tooth steps at the top, then threes and fours.
Eight sprockets across a 2.91× spread means coarse gaps by modern standards — the 12-speed 105 on this page covers 3.09× in twelve steps. That is what eight-speed is: wide range, few gears, and a chain cheap enough to replace often.
The chains page on this site has the matching part: this needs a narrow 8-speed HG chain, and the SRAM PC-830 published there is a 6/7/8-speed chain at 7.1 mm (0.28 in).
Hyperglide, and what the shift gates do
“Hyper glide sprockets have a computer designed tooth configuration with contoured shift gates.”
Shift gates are the ramps and cut-away teeth that let a chain climb from one sprocket to the next under load instead of waiting for a gap. It is the oldest of Shimano’s cassette technologies and it is why an 8-speed Hyperglide cassette shifts better than a 1980s freewheel.
Nickel plating, named as corrosion protection
“Nickel-plated finish offers hard wearing resistance to corrosion.”
The description adds “chrome-plated steel gears”, which is a different plating — two metals named for the same part on one page. Either way the point is that these are plated steel sprockets rather than bare, which on a winter bike is the difference between a cassette that lasts and one that rusts into the chain.
What is not published
No freehub body — an 8-speed Shimano cassette takes the Shimano 8/9/10 and SRAM 8-10 body — no lock ring, no ratio spread as a figure, and no explanation of what separates it from the CS-HG50. The description names the group as Alivio.
Availability
Read on the day this page was built: $25 at the American Amazon shop.
Read from Keepa on the day this page was last revised; stock and price both move without notice.
Prices quoted in this text were read on 2026-10-06. The live price is at the top of the page.
