Condensed Answer: Shimano Alivio represents a mid-tier series of bike components designed for MTB and trekking bicycles. Some of the parts (e.g., rear derailleur, cassettes, hubs…etc.) can be integrated into a road system. However, other units such as the brake levers will not operate properly on a road bike.
Modern shifters are indexed. Each click of the shifter pulls or releases a pre-determined amount of cable that cannot be changed.
Meanwhile, rear derailleurs have a rear shift ratio. The rear shift ratio of a derailleur shows how much the derailleur moves per 1mm of cable pulled or released by the shifter.
For example, if the derailleur has a 1.7:1 rear shift ratio, it moves 1.7mm per 1mm pulled or released by the shifter.
If a unit with a different rear shift ratio replaces the original derailleur, it will not integrate properly into the system because it will move either too much or too little for a proper shift to occur.
Shimano Alivio rear derailleurs are designed for 9-speed MTB drivetrains and have a 1.7 rear shift ratio.
Consequently, the derailleurs are compatible with 10-speed Shimano road systems which also rely on a 1.7 rear shift ratio. However, the derailleur cannot be integrated into a non-Shimano indexed system.
A front MTB derailleur can work somewhat acceptably on a road bike, but it’s not an ideal solution for two reasons:
- MTB front derailleurs have a different shift ratio than road versions and offer less than ideal shifting experience with indexed gearing.
- Road bikes use larger chainrings. Thus, road derailleurs have longer cages for easier shifting.
In custom scenarios, one may be able to come up with a usable combination with the help of an MTB shifter, but in that case, the user will have to give up drop bars because MTB shifters are designed for flat, risers and city handlebars.
In general, it’s best to get a front road derailleur.
For an MTB cassette to work on a road bike, it has to have the same cog pitch as its road equivalent.
The cog pitch is the center to center distance between two adjacent cogs on the cassette. If that distance is not accurate, the indexed shifting system will not provide the smoothest and most accurate performance because the cogs will not be positioned at their expected places.
The formula for calculating the cog pitch of a cassette is:
Cog Pitch = Cable Pull x Rear Shift Ratio
(The cable pull is the amount of cable that the indexed shifter pulls or releases; the term rear shift ratio is explained at the beginning of this article.)
Shimano Alivio cassettes are 9-speed. 9-speed Shimano shifters have a 2.5mm cable pull. Thus, the cog pitch of a 9-speed Alivio cassette is 2.5mm x 1.7 = 4.25mm.
Since the cable pull of non-9-speed shifters is different, non-9-speed cassettes have a different cog pitch too.
Consequently, an Alivio cassette can only be used with 9-speed Shimano shifters. In all other cases, the cassette will not play nicely in an indexed system.
For more information on installing an MTB cassette on a road bike, consider reading the full post.
Whether a Shimano Alivio crank can be installed on a road bike ride away depends on the bottom bracket.
If the bike in question has a square taper bottom bracket, it should readily accept Alivio cranks designed for that bottom bracket model.
If the cranks are designed for a bottom bracket with external bearings, then the user will have to install an MTB bottom bracket on the bicycle.
The new bottom bracket is needed because MTB cranks designed for outboard bottom brackets come with a spindle attached to one of the cranks. The spindle of MTB cranks is longer than that of road models. MTB bottom brackets reflect that and are wider too.
However, the bottom bracket shells (the place of the frame where the bottom bracket goes) of road bikes are narrower than those of MTBs. Thus, road bottom brackets are narrower than MTB bottom brackets.
If an MTB crank is installed on a road bike with a road bottom bracket, the cranks won’t be stable due to the two gaps that form.
To avoid that, the user will have to install an MTB bottom bracket with spacers to make up for the narrowness of the road frame and then mount the cranks.
For more information, consider reading the full post on the topic.
Alivio shifters are designed for flat bars, risers, and different trekking bars (e.g., butterfly). To use Alivio shifters, one will have to transition from drop bars to flat bars, for example.
Furthermore, the shifters should be compatible with the current transmission of the bicycle. The following requirements will have to be met:
- For best performance, the number of gears/cassette cogs should match the number of speeds that the shifters are designed for. In the case of Alivio, this means that only 9-speed cassettes can be used.
Since the cable pull of 9-speed shifters is different from that of 8 and 10-speed shifters, combining Alivio shifters with non-9-speed cassettes will result in inaccurate shifting.
Also, the front shifter isn’t compatible with road front derailleurs due to shift ratio dissimilarities.
In short, the only option is Alivio Shifters + 9-speed cassettes.
Note: The cassette shouldn’t exceed the total capacity of the derailleur. For example, if the derailleur is designed for a large cog with 36 teeth maximum, it will be unwise to use a cassette with 43-teeth.
All Alivio brake levers aren’t compatible with a road system.
The disc brake levers cannot be used on a road bike because road disc models are flat mount whereas most MTB disc brakes are post mount.
The terms flat and post mount refer to the way the disc brake attaches to the frame or fork. Flat mount calipers lie flat on the bike whereas post mounts stick out a bit.
Trying to make an MTB disc brake system work on a road bike will be quite difficult and can result in frustration and no positive results.
Alivio’s mechanical brake levers aren’t compatible with road brakes either because of dissimilar cable pulls.
Road rim brakes have a smaller mechanical advantage than V-brakes (the standard MTB rim brake.) Consequently, road levers pull less cable than V-brake levers. Switching between the two will result in poor performance. (read more)
The spacing of a front MTB hub is 100mm and matches that of road hubs. Thus, a basic MTB front hub can be installed on a road bike.
Meanwhile, rear MTB hubs are wider than rear Road hubs designed for bikes with rim brakes. Thus, rear road wheels built around MTB hubs won’t fit on a modern rim brake frame.
However, disc-brake-ready road frames have a 135mm rear O.L.D. and can therefore accept a wheel with an MTB hub.
For more information on that topic, consider reading the dedicated full post.
Summary: What You Need To Know
- Shimano Alivio rear derailleurs are 9-speed MTB units. As such, they can be combined with 10-speed road drivetrains thanks to the matching rear shift ratios.
- Front Alivio derailleurs will not offer top performance on a road bike.
- An Alivio cassette can be used on a road bike.
- Alivio cranks can be installed on a road bike, but if the bottom bracket uses outboard bearings it will have to be replaced with an MTB one.
- Alivio 9-speed shifters can be used if the bike is converted to flat/risers/townie bars and the bike uses a 9-speed drivetrain.
- Alivio’s brake levers cannot be used with road brakes.
- Front MTB hubs can be used on a road bike.
- Rear MTB hubs can be used only on road bikes designed for disc brakes.