This ultralight cassette offers significant weight savings and decent shifting at a low cost, but durability varies by model and size, with larger cassettes having critical design flaws that risk catastrophic failure.
Pros
- Significantly lighter than equivalent Shimano cassettes (e.g., 117g vs. 260g for 105)
- Good initial shifting performance (90-95% as good as OEM)
- Low cost (approximately £60-£66)
- Durable all-steel teeth on some models
Cons
- Shifting performance doesn't match Shimano's latest hyperglide technology
- Wears out faster than OEM cassettes (approximately 2,500 miles)
- Cannot replace individual sprockets due to monoblock design
- Critical design flaw in larger sizes: thin supports create weak points that can shear off
Key Facts
- Monoblock steel construction with all-steel teeth
- Weight ranges from 117g (11-28T) to 200g depending on model
- Black oxide coating (less durable than nickel plating)
Reviews & Ratings
The reviewer analyzes the ZTTO SLR Gen 3 ultralight cassette, focusing on a specific failure case where the top two sprockets sheared off. They describe the cassette's construction: the top three sprockets are milled from a single aluminum block, with the rest being monolock steel, resulting in significant weight savings (117g vs. 260g for Shimano 105). The reviewer has personally used smaller versions (11-28T) for thousands of miles without issue but identifies a critical design flaw in larger sizes (11-30T and above). In these larger cassettes, the top two sprockets are connected to the third by a thin ring of supports, creating a potential cantilever beam effect and stress risers at sharp internal corners. This design, combined with spiky power delivery (e.g., in cyclocross) and the increased flexibility of larger sprockets, increases the risk of failure. The reviewer concludes that these cassettes prioritize minimal weight and low cost over structural safety margin and long-term durability. They advise caution, particularly for the 11-36T and 11-34T versions, and suggest stronger alternatives like ZTTO's all-steel or Gen 2 cassettes. They also note the shifting performance is decent but not as good as OEM, the cassettes are noisier, and aluminum teeth can snap if shifting under load.
AI Summary
Pros
- Incredibly lightweight (e.g., 117g for 11-28T vs. 260g for Shimano 105)
- Great looking and available in funky colors
- Low cost (about 60 quid)
- The reviewer has run smaller versions (11-28T) for thousands of miles/years without problems
- Shifting performance is described as 'really decent', about 90-95% as good as Shimano/SRAM
Cons
- Design flaw in larger sizes (11-30T, 11-32T, 11-34T, 11-36T): top two sprockets connected by thin supports, creating a weak point
- Risk of sprockets shearing off, as evidenced by a viewer's cassette failing after ~150km
- Sharp internal edges (90° corners) act as stress risers
- Prioritizes weight saving over safety margin and long-term durability
- Built to a low price point, which compromises robustness
- Larger sprockets are more flexible, increasing failure risk
- Noisier than official Shimano cassettes during normal running
- Aluminum teeth on the upper sprockets can snap if shifting under load, as aluminum is softer than steel chain
- Not suitable for abuse like shifting under heavy load
- The reviewer questions how much safety margin, if any, is built in
Key Points
- Brand: ZTTO, model referenced is SLR Gen 3
- Construction: Top three sprockets milled from single aluminum block, rest is monolock steel
- Weight: 117g for 11-28T size
- Price: About 60 quid
- Failure case: Top two sprockets sheared off as one piece on an 11-36T cassette after ~150km while climbing
- Design analysis: Thin support arms create a cantilever beam effect; sharp internal corners are stress concentrators
- Size matters: Only the 11-28T version has a different, safer web structure where only the largest sprocket uses thin supports. All larger sizes have the risky 'double stack' layout for the top two sprockets.
- Use case matters: Spiky power delivery (e.g., cyclocross, out-of-saddle climbing) increases stress
- Alternatives suggested: ZTTO cassettes milled from a single block of steel with a chunky aluminum spider, or ZTTO SLR Gen 2 cassettes where only the largest sprocket is aluminum.
- Shifting: 90-95% as good as Shimano/SRAM, but noisier
The reviewer discusses their experience with a ZTTO monoblock cassette, which appears to be the ZTTO Ultimate 11/12 Speed Road Bike Cassette, though the exact model name isn't explicitly stated. They mention purchasing it for £66 and highlight its lightweight design at 200g, comparable to Shimano Dura-Ace. The cassette initially shifted well but wore out after approximately 2,500 miles, with the eighth gear becoming completely unusable. The reviewer conducted a hardness test comparing it to Shimano cassettes, finding the ZTTO's steel hardness relatively good but less uniform in hardening. They note the cassette has a basic black oxide coating rather than the more durable nickel plating found on Shimano products. The reviewer replaced it with a newer ZTTO SLR Gen 3 model but expects even lower durability due to aluminum teeth on the smaller cogs.
AI Summary
Pros
- Lightweight at 200g
- Good initial shifting performance
- Price of £66 is much cheaper than equivalent Shimano Dura-Ace
- Steel hardness is relatively good in testing
- Comparable weight to high-end Shimano cassettes
Cons
- Wore out after approximately 2,500 miles
- Eighth gear became completely unusable
- Hardening less uniform than Shimano cassettes
- Basic black oxide coating less durable than nickel plating
- Cannot replace individual sprockets due to monoblock design
- Newer ZTTO model expected to have even worse durability with aluminum teeth
Key Points
- 200g weight
- Monoblock steel construction
- Black oxide coating
- Approximately 2,500 mile lifespan
- Purchased for £66 on AliExpress
- Comparable weight to Shimano Dura-Ace 9100
- Hardness testing showed good but inconsistent results
- Replaced with newer ZTTO SLR Gen 3 model
The reviewer discusses the ZTTO Ultimate 11/12 Speed Road Bike Cassette, highlighting its performance and value for money. They mention using it on multiple group sets and finding the shifting to be consistently good.
AI Summary
Pros
- Good shifting performance across different group sets
- Lightweight (200g)
- Affordable (60 quid)
- Durable with all-steel teeth
- No issues reported after extensive use (over 1500 miles)
Cons
- Shifting performance may not match Shimano's latest hyperglide cassettes
Key Points
- 11-speed 11-28T monoblock cassette
- Compatible with HG freehub
- All-steel teeth for durability
- Weighs 200g
Where to Buy
ZTTO Ultimate 11/12 Speed Road Bike Cassette Ultralight 11s 12s 11-28/30/32/34/36T Gravel Cassette 11V 12V Black Freewheel HG K7
Questions about ZTTO Ultimate 11/12 Speed Road Bike Cassette Ultralight 11s 12s 11-28/30/32/34/36T Gravel Cassette 11V 12V Black Freewheel HG K7
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