Recommended Free Tools
A bike hub is the wheel’s central assembly, but replacing one is not a matter of matching only the number of cassette speeds. Fit depends on the bicycle’s axle and frame spacing, brake and rotor interface, cassette/freehub pairing, and—if you are replacing only the hub—spoke count and wheel-building dimensions. This guide explains what the parts do and how to check compatibility before ordering.
What a bike wheel hub does
The hub sits at the center of the wheel and connects it to the bicycle. Its axle attaches to the frame or fork, while bearings let the wheel rotate around that axle. A rear hub may also carry the cassette on a freehub body and house the mechanism that lets the wheel turn while you coast.
These terms describe different components: the hub is the central wheel assembly; the freehub body is the cassette-mounting part of many rear hubs; and the cassette is the set of sprockets that mounts on the freehub. A parts diagram for SHIMANO’s FH-MT400 rear hub, for example, identifies an axle, steel balls, ball retainer, cone, locknut, freewheel body, washer, seal ring and fixing nut. SHIMANO FH-MT400 parts diagram (PDF).
How the bearings and other parts work
Bearings, cones and seals
In a cup-and-cone arrangement, steel balls run between a cup in the hub shell and a cone fitted to the axle. A locknut holds the adjustment in place; seals help keep contamination away from the bearing area. SHIMANO describes its cup-and-cone design this way: “Shimano cup & cone bearings use angular contact to effectively displace lateral and vertical loads for smooth rotation and excellent durability.” This is the manufacturer’s description, not an independent durability comparison. SHIMANO cup-and-cone bearing technology.
#1 Best Overall
- Smooth cam action lever. Durable deep color 5 micron finish in a wide color range. Extruded CNC machined alloy hub nut with large flange.
- Axle diameter: about 4.5 mm. Front Skewer Size: 145 mm. Front Skewer Weight: 46 grams. Rear Skewer Size: 180 mm,Rear Skewer Weight:51 grams.
- Material: Steel and aluminum alloy; Durable and compatible with most road bikes, mountain bikes, MTB, BMX.
- Easy to set up and quick installation, perfect for replacement, as soon as installed, you can use your bicycle like new.
- APPLICATION - The axles fit for the majority of 20" 22" 24" 26" 28" bike, work on a 6 7 8 speed road bike.
Freehub body and coasting mechanism
On many rear wheels, the cassette mounts to a freehub body. A ratcheting mechanism allows the wheel to keep turning when the rider stops pedaling and engages again when power is applied. The freehub body is not the cassette, and the whole hub is not interchangeable just because its freehub looks similar to another one.
Check these details before buying a replacement hub
Identify the existing wheel and bicycle first. A replacement must match the frame or fork, brake setup and drivetrain; a hub-only replacement must also work with the rim and wheel build. A product page for one hub is evidence only about that model, not a general standard.
Rank #2
- Front Wheelset: 27.5 inch front wheelset，suitable for repairing the front wheels of 27.5 inch bicycles, MTB
- Front Open File: 100mm. Before purchasing, please measure the distance between the open position of the front fork of your bicycle（like the picture）
- Suits for DISC Brake：this wheelsets only Suits for 6 bolts DISC brake, Please confirm that your disc brake is a 6 bolts disc brake
- The hub:the front hub is 2 bearings, which turns more smoothly and quietly without adjustment and maintenance, with higher waterproof and dust-proof performance
- Aluminium Alloy Double Wall Rim: Made from strong aluminum alloy with a double-wall build, it resists impacts and stays true on rough roads for a long-lasting, stable ride
- Axle fixing and dimensions. Determine whether the wheel uses a quick-release skewer, thru-axle or another fixing method. Verify the axle specification and the hub’s over-locknut dimension (the distance between the outer locknut faces). As one model-specific example, SHIMANO lists the FH-QC300-HM as quick-release with a 135 mm over-locknut dimension. SHIMANO FH-QC300-HM specifications.
- Brake and rotor interface. Confirm whether the wheel is for rim brakes or disc brakes. For a disc hub, match the rotor attachment standard as well as the rotor and brake system. SHIMANO’s FH-QC300-HM is specified for Center Lock; that does not make Center Lock universal across hubs. FH-QC300-HM product information.
- Cassette and freehub spline. Match the cassette to the freehub body’s spline standard and supported cassette range. SHIMANO’s FH-QC300-HM page specifies HG spline M and a 7-to-11-speed range, but those details cannot be applied to another hub. Check the manufacturer’s compatibility information for the exact cassette and freehub combination. SHIMANO freehub and cassette compatibility.
- Speed label and cassette family. “11-speed” or “12-speed” by itself may not settle fit: cassette and freehub compatibility can depend on the specific road or mountain-bike system and model. SHIMANO says its Dura-Ace 9200 road wheels support only Shimano 12-speed road cassettes, while specified Ultegra 8100 and RS710 wheels support both 11- and 12-speed road cassettes. Treat these as model-specific examples and verify the exact pairing in the manufacturer’s documentation. SHIMANO road-wheel cassette compatibility explainer.
- Spoke count and wheel-building dimensions. If replacing the hub rather than the complete wheel, check the rim’s spoke-hole count and confirm the dimensions needed to build the wheel. SHIMANO lists 32- and 36-hole versions of the FH-QC300-HM; that specification does not establish which version fits a particular rim. FH-QC300-HM specifications.
- Exact service parts. Use the technical document for the exact hub model before ordering cones, seals, freehub bodies or other parts. The FH-MT400 diagram lists component parts and warns that parts without an interchangeability mark are not interchangeable. Similar appearance is not proof of fit. The diagram is marked January 2019 and notes that specifications may change, so check the current documentation for the model. FH-MT400 technical document.
Choosing between hub options
There is no universally best hub established by these specifications. Compare candidates against the needs of the actual bicycle and wheel rather than relying on a broad ranking.
| What to compare | What to verify |
|---|---|
| Axle and spacing | Fixing method, axle specification and over-locknut dimension must suit the frame or fork. |
| Brake interface | Rim-brake use or disc-brake rotor attachment standard must match the wheel and brake setup. |
| Cassette fit | Freehub spline standard and supported cassette combination; a speed count alone may not be enough. |
| Bearing and service design | Identify the bearing arrangement and whether the correct service parts and instructions are available for that model. |
| Wheel-building fit | Spoke-hole count and the dimensions required for the intended rim and build. |
The FH-QC300-HM is one documented rear-hub example, not a general recommendation: whether it suits a bicycle depends on all of the fit checks above. Its product information gives the model-specific details, but does not establish availability or price. SHIMANO FH-QC300-HM.
Quick Recap
Best Value
- Easy to install:the wheel set equipped with 2 quick releases for easy to install, You could install the tire on the bicycle with a press
- Suits for DISC Brake：this wheelsets only Suits for 6 bolts DISC brake, Please confirm that your disc brake is a 6 bolts disc brake.
- Suits for Cassette Freewheel: This wheelsets only compatible with 7/8/9/10/11 cassette speeds mountain bike, Please confirm that your freewheel is cassette
- The hub:the front and rear hub is 2 bearings,which turns more smoothly and quietly without adjustment and maintenance, with higher waterproof and dust-proof performance
- Open File:Front :100mm Rear :135mm
Rank #4
- The exquisite technology makes the bike axle look delicate, the surface is smooth without burrs, the thread end is complete and deep, the force is uniform, not easy to slip, light and practical, wear-resistant and firm, suitable for long-term riding. The lightweight, quick-release bicycle axle bar is removable, making it easier to use and very strong.
- The weight of the bicycle wheel hub axle is light, and it will not increase the training amount in your training, which is suitable for long-term riding. Precision machining, high strength, fine process and design, do not require other tools, it also has a long service life. Quick release strings, practical bike parts that are a good alternative to old or damaged parts.
- The bicycle hub axle is made of high quality steel and can be used for a long time. You can use it to quickly repair your mountain bike. Perfect for cyclists. Quick release bike string helps you remove bike wheels quickly and is easy and fast to use. Can be used for bicycle axle wheel frame bearing replacement and seamlessly integrates into your bike's drivetrain components.
- A pair of quick-release hubs and hollow axles for both front and rear wheels. In addition, the front wheels are equipped with shorter hollow shafts and hub quick-release rods, while the rear wheels have a longer setup. These quick release forks are suitable for 6, 7 and 8 speed road bikes. Bicycle rear wheel bearings are used for moving parts of a bicycle, such as wheels, cranks, and steering tubes. They are designed to reduce friction and allow these parts to rotate smoothly.
- This bike part is suitable for most length matching bikes, mountain bikes, variable speed bikes, training bikes, etc. The best choice for bike lovers, you can use it to quickly repair your mountain bike. Very suitable for cycling enthusiasts, your best choice, sufficient quantity can meet your diverse needs of replacement bicycle parts.
Rank #3
- The new updated Road Mountain Cycling parts are made of Steel 1045, the quick release are made of alum, durable and practical for most bikes.
- Usually the axels fit 20" 22" 24" 26" 28" bike, work on a 6 7 8 speed road bike, durable and extra hard dustproof cap, the thickness: 65 degrees, 2.4mm / 0.09inch. (the important measurement is the axle diameter and length. Measure your axles and compare with the measurements in the description, thank you ! )
- The long release lever for the rear wheel, hollow shaft size: approx. 145mm / 5.7", diameter: approx. 9.2mm / 0.36", quick release: approx. 190mm / 7.48"
- The short release lever for front wheel, hollow shaft size: approx. 110mm / 4.33", quick release: approx. 155mm / 6.1"
- The quick release skewer weight: approx. 270g / 9.2oz, color: black
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
