The Shimano RD-TX800 Tourney Rear Derailleur (7/8-speed, black) is an entry-level mountain/trekking rear derailleur designed for simple, reliable shifting on low to mid-range bikes.
Shimano Tourney RD-TX800 Rear Derailleur 7/8 Speed Black
What it is
This is:
- a rear derailleur for 7 or 8-speed drivetrains
- part of Shimano’s Tourney TX series
- designed for MTB, hybrid, and commuter bikes
It is Shimano’s most basic indexed MTB derailleur tier.
Key features
- Compatible with 7/8-speed SIS shifting
- Works with Shimano HG 6/7/8-speed chains
-
Double Servo-Panta mechanism
- improves chain tracking across the cassette
-
13T/13T pulleys
- larger jockey wheels reduce noise and wear
- Supports up to:
- 34T largest sprocket
- 43T total capacity
What “capacity” means
Total capacity (43T) is how much chain slack the derailleur can handle across:
- front chainring differences
- rear cassette range
Total Capacity=(Largest front−Smallest front)+(Largest rear−Smallest rear)
If exceeded, you may get:
- chain slap
- poor shifting
- inability to reach all gears safely
Ride feel
- Simple and predictable shifting
- Not very fast under load
- Designed for casual riding and commuting
- More tolerant of misadjustment than higher-end derailleurs
Best suited for
- commuter bikes
- school/utility bikes
- entry-level MTBs
- budget 7/8-speed setups
Pros
- very affordable
- easy to set up and maintain
- widely compatible with Shimano 7/8-speed systems
- durable enough for everyday riding
Trade-offs
- heavier and less precise than Altus/Acera/Deore
- slower shifting under pressure
- limited gearing range support
- basic bushings (not high-end bearings)
Bottom line
The Shimano RD-TX800 Tourney is a basic but reliable 7/8-speed rear derailleur built for simple bikes and casual riding, offering dependable shifting at low cost but without the precision, speed, or durability of Shimano’s higher-tier MTB groupsets.
