The best cassette spacer depends on the cassette and freehub combination: a 1.85 mm spacer is commonly used when fitting a 8-, 9-, or 10-speed cassette to an 11-speed road freehub. The Shimano spacer is a focused choice for a 9- or 10-speed cassette, while the Juscycling single spacer suits standard HG-spline setups. For multiple thickness options, consider the Pawfly or Juscycling kit. Check the freehub type and cassette instructions before installation.
| Product | Best For | What’s Included |
|---|---|---|
| SHIMANO 1.85mm Low Spacer | 9- or 10-speed cassette on an 11-speed freehub | One 1.85 mm spacer |
| Juscycling 1.85mm Spacer | Standard HG-spline cassette setup | One 1.85 mm spacer |
| Pawfly Spacer Kit | Several cassette spacing adjustments | Nine spacers in six thicknesses |
| Juscycling 8-Piece Set | Multiple thickness options | Eight spacers in assorted sizes |
| Frienda 10-Piece Set | Several listed freehub conversions | Ten aluminum-alloy washers |
SHIMANO 11-Speed 1.85mm Low Spacer
Best for: Riders fitting a 9- or 10-speed cassette to an 11-speed freehub body. This Shimano spacer is a direct, single-size option when the needed thickness is 1.85 mm.
The product information specifies use with 9- or 10-speed cassettes on an 11-speed freehub. For a 10-speed cassette on an 11-speed freehub, it also calls for a 1.0 mm spacer. This makes it important to check the cassette and freehub instructions rather than assume the 1.85 mm ring is the only spacer required.
Limitation: It is one fixed thickness, not a multi-size kit. Choose another option if you need to compare or adjust several spacer sizes.
Juscycling 1.85mm HG Spacer
Best for: A rider who needs one 1.85 mm spacer for an 8-, 9-, or 10-speed cassette on an 11-speed road freehub. The listing says the spacer takes up extra freehub length so the cassette can lock down securely.
It is described as compatible with standard HG-spline cassettes, including Shimano, SRAM PG-series, SunRace, microSHIFT, and many aftermarket cassettes. Choose this single spacer if you know the required thickness and want an option identified for the common HG spline.
Limitation: The listing excludes Campagnolo and Shimano Micro Spline freehubs. It is also a single 1.85 mm piece, so it does not provide other thicknesses.
Pawfly Nine-Piece Spacer Kit
Best for: Home mechanics who need several spacer sizes for different cassette or hub adjustments. The kit has nine aluminum-alloy pieces in six thicknesses: 1, 1.5, 1.85, 2, 2.18, and 2.35 mm. It includes three 1.85 mm pieces and two 2 mm pieces.
The selection makes it more flexible than a single-size spacer when the required thickness is uncertain or more than one bike needs attention. The listing describes the spacers as intended for cassette setups from 7 to 11 speeds and notes an anodized finish.
Limitation: A range of sizes does not establish compatibility with every freehub standard. Confirm the hub type and the cassette manufacturer’s spacer requirements before fitting a ring.
Juscycling Eight-Piece Spacer Set
Best for: Buyers who want a range of sizes, including 1.85 mm, in one set. The eight-piece selection includes 1, 1.5, 1.85, two 2 mm, 2.18, 2.35, and 2.5 mm spacers.
The listing describes these as grooved spacers with machined tolerances and an optimized lightweight design. The assortment gives a mechanic more options than a single-thickness washer when working through a spacing adjustment, while the duplicate 2 mm piece may be useful when that thickness is needed.
Limitation: The product details do not specify a particular freehub standard or list cassette brands. Verify the fit and required thickness for your individual setup.
Frienda Ten-Piece Cassette Spacer Set
Best for: Buyers considering a set for several listed cassette and freehub conversions. The product information describes uses that include a 10-speed cassette on an 11-speed freehub, 7-, 8-, or 9-speed cassettes on 10- or 11-speed freehubs, and a 7-speed cassette on an 8- or 9-speed freehub.
The washers are made from anodized aluminum alloy and are described as having a no-groove design. This set may suit someone who wants multiple washers for different spacing tasks rather than one dedicated 1.85 mm spacer.
Limitation: The listing advises confirming the no-groove style before purchase. It does not provide a thickness breakdown in the supplied product details, so check the included sizes if a specific thickness is essential.
Buying Guide: How To Choose A Cassette Spacer
When do you need a 1.85 mm spacer?
A 1.85 mm spacer is commonly used when mounting a narrower 8-, 9-, or 10-speed cassette on an 11-speed road freehub body. The spacer fills extra freehub length so the cassette can sit correctly. Exact requirements can depend on the cassette and hub, so use the manufacturer’s directions for the specific parts.
Should you choose a single spacer or a kit?
Choose a single 1.85 mm spacer when you have identified the required thickness and need only that part. A multi-size kit is better for a workshop or for adjustments where the correct thickness is not yet known. Check the set contents carefully: kits vary in both size range and the number of each thickness.
How do you check freehub compatibility?
Identify the freehub spline standard before ordering. A standard HG-spline product may fit many common cassette types, but that does not mean it fits every hub standard. For example, the Juscycling single spacer listing excludes Campagnolo and Shimano Micro Spline freehubs.
What should you verify before installation?
- Confirm the cassette speed and freehub type.
- Check whether the cassette instructions call for one spacer or more than one.
- Match the spacer thickness to the specified setup.
- Make sure the cassette locks down securely after installation.
Frequently Asked Questions
Can I use an 11-speed cassette spacer with a 10-speed cassette?
It depends on the freehub. A 10-speed cassette on an 11-speed freehub may require a spacer; Shimano specifies a 1.85 mm spacer and an additional 1.0 mm spacer for the setup described in its product information.
Does every 11-speed freehub use a 1.85 mm spacer?
No. Spacer requirements depend on the cassette, freehub standard, and manufacturer instructions. Check the specific parts before installation.
Will an HG cassette spacer fit Shimano Micro Spline?
Not necessarily. The listed Juscycling 1.85 mm spacer specifically says it is not for Shimano Micro Spline or Campagnolo freehubs.
Is a spacer kit better than buying one washer?
A kit provides several thickness options for varied adjustments. A single spacer is more direct when you already know the required size and need no alternatives.