from Rookie’s keyboard,
Hello, friends
Another day, another post on rookie journal.
Today, I’ll talk about one of my favorite Shimano series, namely – Alivio. Why do I like that little monster so much?
Three reasons: 1) it’s robust 2) it’s cheap 3) it’s universal.
Most people get the first two, but the third one is a bit more…”niche”.
It’s simple. Alivio represents a mid-tier series of bike components designed for MTB and trekking bicycles. However, some of the parts (e.g., rear derailleur, cassettes, hubs…etc.) can be integrated into a road system.
This makes Alivio – a universal warrior for people who don’t care about having a maximum number of speeds on their cassette. That would be me…as you can already guess.
The Rear Derailleur
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.
Front Derailleur
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.
Cassette
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.
Cranks
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.
Shifters
Alivio shifters are designed for flat bars, risers, and different trekking bars (e.g., butterfly). To use Alivio shifters on a road machine, you 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.
Brake Levers
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.
Until next time,
– Rookie
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