Condensed answer: If you have a 7-speed specific hub, you won’t be able to install a 10-speed cassette on it because the hub will be too short.
If the hub isn’t 7-speed specific, and actually designed for more speeds, you will be able to install a 10-speed cassette on it.
What Is a 7-speed Specific Hub?
7-speed specific hubs are made for a 7-speed cassette and are thus shorter than 8,9,10,11 and 12-speed hubs.
To know if you have a 7-speed specific hub, you will have to examine it and search for a spacer behind the largest cog/gear. A spacer is essentially a thick washer designed to fill space.
If you can see a spacer behind the 7-speed cassette, then the effective length of the hub is greater and thus it can accommodate 8+ speeds.
Shimano’s 8,9,10,11,12 cassette hubs have the same width and thus one can quickly upgrade to more speeds without having to change the hub.
This is accomplished by reducing the space between the cassette cogs and thinning out the chain with each gear jump. Hence why multi-speed chains are known to be weaker than single-speed chains.
The actual thickness of the sprockets, however, stays the same across all cassettes.
7-Speed Cassettes On an 8-12-speed Hub
If there’s a spacer behind the largest sprocket, then the hub is effectively wider and can therefore accept cassettes with more speeds including 10-speed models.
The spacer is there to fill the space created by the narrow 7-speed cassette and prevent movement of the cassette.
FAQ: Can I Replace My 7-speed Hub With a 10-speed One?
Technically, you can, but the procedure will require a new hub, spokes and labor.
You will need new spokes because the new hub will more than likely have flanges of different dimensions and will thus require slightly longer or shorter spokes.
You will also have to pay someone to build the new wheel if you don’t know how to do it yourself.
Once it’s all done, it may be cheaper and quicker to simply buy a new wheel.
Do You Have a Freewheel Or a Cassette?
If you have a 7-speed freewheel, your hub is not capable of taking a bicycle cassette.
Freewheels come with their own ratcheting mechanism and screw onto the hub. Therefore, hubs designed for a freewheel are incompatible with a standard cassette.
You can find out whether you have a freewheel or a cassette by examining the lock ring (the front of the cassette or freewheel).
A freewheel has two parallel dots on the front whereas a cassette does not.
The images below show both a 7-speed cassette and a 7-speed freewheel.
Parts Needed For a 7 to 10-speed Conversion
Conversion from 7 to 10-speeds will require the following parts:
A. No Hub Replacement
If the hub is 10-speed compatible, you will need:
- a 10-speed cassette
- a 10-speed chain (You can’t use a 7-speed chain because it’s too wide and will rub against the surrounding cogs.)
- a 10-speed shifter
- a new gear cable and housing
If you have to replace the hub, you will need the following parts:
- а 10-speed hub (You will have to buy a new wheel or rebuild the old one.)
- а 10-speed chain
- а 10-speed shifter
- а new gear cable and housing
If you plan on switching to a 1×10 drivetrain, you will also need a narrow-wide chainring to ensure decent chain retention. It’s also highly advisable to get a chain tensioner or use the existing front derailleur as one by positioning it via the limit screws.
The Benefits of a 7 to 10-speeds Conversion
Conversion from 7 to 10 speeds offers the following benefits:
- Smaller gear jumps
The greater the number of gears, the smaller the gap between them. As a result, the rider has an easier time maintaining high cadence.
Cadence is a term referring to the rotations of the cranks per minute. High cadence (e.g., 90RPM) is associated with greater average speed and minimal energy expenditure.
- Greater range
A 10-speed cassette can offer substantially lower gearing. Some 10-speed MTB cassettes have a large rear cog with over 40 teeth.
- 1x Drivetrain
Thanks to high-capacity cassettes, 1x drivetrains have become a lot more popular, especially in the world of MTB.
A 7-speed cassette, however, is too limited to make a 1x drivetrain viable. 10 or more speed cassettes solve that problem by offering extra cogs.
The Downsides of a 7 to 10-speeds Conversion
Conversion from 7 to 10 speeds has the following downsides:
10-speed components are more expensive, and you will have to buy many to make the conversion possible.
You will have to wait for the new parts to arrive (if you can’t find them locally) and then invest 1 or 2 days in mechanical work.
Of course, one can always pay a bike shop to perform the conversion, but very often the labor costs are quite high. Hence why most people end up doing it themselves.
Summary: What You Need To Know
- If you have a hub designed specifically for 7 speeds, it will be too short to accommodate a cassette with more gears. You can know whether you have a 7-speed specific hub by examining the cassette area. If there isn’t a spacer behind the largest cog, then the hub is 7-speed specific.
- If your 7-speed cassette is installed on a hub with a spacer, then the cassette can actually accommodate a cassette with more sprockets. In that case, you will be able to install a 10-speed cassette.
- If you have a 7-speed freewheel, you won’t be able to install any cassette on the rear hub due to incompatibility.