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Shimano Altus RD-M310 7/8-Speed Rear Derailleur

Name: Shimano Altus RD-M310 7/8-Speed Rear Derailleur
Brand: Shimano

The Altus M310 is a step up from Tourney and the common derailleur on 8-speed e-bikes; it also works with 7-speed shifters, which makes it a popular upgrade when a TY300 dies. It mounts to a standard derailleur hanger (no claw version), handles up to a 34T cog, and shifts noticeably crisper than Tourney. It is still inexpensive. If your bike uses a direct-mount claw bracket, you will need an adapter or to stay with Tourney. Replace the shift cable at the same time and check the hanger alignment.

8-speed e-bikes needing a replacement derailleur7-speed bikes with a standard hanger that want crisper shiftingRiders running a 34T low cog

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Key considerations

Standard hanger mount only
7/8-speed; not for 9-speed and up
Check the hanger is straight
Replace cable and housing while you are at it

Pros

Crisper than Tourney
Handles 34T cogs
Good value

Considerations

No claw-mount version
Plastic parts in places

Features & specifications

Speeds	7/8

Specifications are manufacturer-published figures or our own notes; confirm on the current listing before purchase.

Compatibility notes

Shimano 7/8-speed shifters on frames with a standard derailleur hanger

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Similar alternatives

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Derailleurs

Shimano Tourney RD-TY300 6/7-Speed Rear Derailleur

The Tourney TY300 is the derailleur on an enormous number of 7-speed e-bikes, and it is what you buy when the original gets bent by a fall or a stick. It is cheap, easy to set up, and available in a few mounting styles: a direct-mount version with a bracket (claw) for bikes without a hanger and a standard-hanger version. Before ordering, look at how your old derailleur attaches. It shifts fine for a 7-speed hub-motor bike and pairs with the stock thumb or trigger shifters; just expect to replace the cable at the same time.

Best for: 7-speed hub-motor e-bikes with a bent or broken derailleur · Budget like-for-like replacements · Riders who want a part that matches the stock shifter

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E-Bike Chains

KMC e8 E-Bike Chain (8-Speed)

KMC's e-series chains are built for the extra torque a mid-drive motor puts through the drivetrain, with thicker, stronger plates and pins than a standard chain of the same speed. The e8 is the 8-speed version and also works on most 7-speed systems with 7-speed cog spacing. If you have a Bafang BBS02, BBSHD or a production mid-drive bike (Bosch, Shimano STEPS, Bafang M-series) with an 8-speed cassette, this is the chain to buy when the old one measures worn. It will not make a hub-motor bike faster, but it will not hurt either.

Best for: Mid-drive e-bikes with 8-speed cassettes · BBS02/BBSHD conversions · Heavy riders who break standard chains

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Cassettes

Shimano CS-HG400-9 9-Speed Cassette 11-34T

Mid-priced e-bikes frequently ship with a 9-speed Shimano Alivio or Acera drivetrain, and the HG400-9 in 11-34 is the standard replacement cassette. The 34-tooth low gear is a real help on hills if you prefer to keep the assist low, and the 11-tooth top is enough for fast flats. It is an inexpensive, durable cassette and the right partner for an e-bike-rated 9-speed chain. As with any cassette swap, confirm you have a freehub body, and budget for a lockring tool and chain whip if you do not have them.

Best for: 9-speed Shimano-equipped e-bikes · Riders who want a lower climbing gear than stock · Drivetrain refreshes with a new chain

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