About this guide
A 7-speed rear derailleur is one of the cheapest, highest-impact upgrades on a hybrid, mountain, or commuter bike with sloppy or worn-out shifting — most direct-fit replacements run under $30. Here are seven real, currently sold 7-speed derailleurs across Shimano’s budget lineup plus the two most common third-party alternatives, with cage length and speed compatibility noted for each.
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The picks, in detail
Shimano Tourney RD-TY300
Shimano's entry-level direct-attach derailleur for 6/7-speed SIS Index Shifting drivetrains — the most common budget OEM replacement on hybrid and mountain bikes.
- 6/7-speed SIS compatible
- Direct-attach mounting
- Aluminum alloy cage
- Cheapest reliable option in this lineup
- Widely stocked, easy direct-fit replacement
- Basic finish/durability versus the Acera step-up
Shimano Tourney RD-TY500
A step up from the TY300 within the same Tourney line, still built for 6/7-speed drivetrains, commonly specced on entry-level mountain and hybrid bikes.
- 6/7-speed compatible
- Long or short cage options
- Tourney-line construction
- Reliable, well-reviewed budget shifting
- Easy compatibility with Shimano 6/7-speed shifters
- Marginal upgrade over the TY300 for the price difference
Shimano Altus RD-M310
A long-cage 7/8-speed derailleur one tier above Tourney, a common upgrade pick for riders who also want compatibility with 8-speed setups down the line.
- 7/8-speed compatible
- Long cage
- Altus-tier construction
- Cross-compatible if you later move to 8-speed
- Sturdier than the Tourney tier
- Pricier than the Tourney options for a 7-speed-only build
Shimano Acera RD-M360 (SGS)
A long-cage 7/8-speed derailleur with a 34-tooth largest-cog capacity and 43-tooth total chain wrap — suited to mountain, gravel, and hybrid bikes with wider-range cassettes.
- 7/8-speed compatible
- SGS long cage
- 34T max cog / 43T total capacity
- Handles wider-range cassettes than the Tourney/Altus tier
- Solid mid-range durability
- Overkill if your cassette range is narrow
microSHIFT RD-M21SA
A short-cage 7-speed derailleur compatible with 6/7/8-speed Shimano-pattern shifters, at one of the lowest prices in this category.
- 6/7/8-speed Shimano-pattern compatible
- Short cage
- Budget aluminum construction
- Lowest price point of any option here
- Direct Shimano shifter compatibility
- Short cage limits it to narrower-range cassettes
microSHIFT RD-M46L
microSHIFT's long-cage 7-speed derailleur, for riders who need the wider chain-wrap capacity a short cage can't handle.
- 7-speed compatible
- Long cage
- Shimano-pattern shifter compatible
- Wider capacity than the short-cage RD-M21SA
- Still priced well below Shimano’s own lineup
- Less brand recognition than Shimano for resale/warranty
SunRace M2T (RDM2T)
A 6/7-speed SGS long-cage derailleur built as a direct Shimano-compatible replacement, sold with its own mounting bracket.
- 6/7-speed compatible
- SGS long cage
- Includes mounting bracket
- Includes hardware other budget options sell separately
- Shimano shifter-compatible
- Smaller aftermarket parts availability than Shimano
What each one costs
Typical price, cheapest first. Tap a name to jump to that pick and its buy link.
Compare any three
| Shimano Tourney RD-TY300 | Shimano Tourney RD-TY500 | Shimano Altus RD-M310 | |
|---|---|---|---|
| Price | $15-$20 | $15-$22 | $25-$31 |
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Buying tips
- Match cage length to your cassette’s total tooth-count range, not just the number of speeds — a short-cage derailleur (like the microSHIFT RD-M21SA) can’t take up enough chain slack for a wide-range 7-speed cassette.
- Shimano’s own tiers (Tourney < Altus < Acera) are also compatible with each other’s shifters as long as the speed count matches, so you can mix a cheaper derailleur with an existing higher-tier shifter.
- Direct-attach vs. bracket-mount matters at install: check whether your frame’s derailleur hanger needs a direct-attach model (TY300/TY500) or one that includes its own mounting bracket (SunRace M2T).
As an Amazon Associate and eBay Partner, toptenpick.com earns from qualifying purchases. Prices and availability are subject to change.