basic rear deraillleur replacement question

dsharp7th

I'm replacing a rear derailleur on my bog standard but otherwise sturdy Ridgeback Motion 08 hybrid bike. The derailleur spectacularly crunched, bent and snapped off this morning, probably wasn't cleaned enough. Other than adjustments, I've never dealt much with rear derailleurs before so don't know how specific I need to be when buying a replacement.

I believe the broken derailleur is a Shimano TX51 which is not available and presumably an old model. Halfords have a Shimano TX31 at £12.99 ready and waiting, is there any reason this wouldn't fit? (could probably get it cheaper online but need to be back on the saddle asap)

Should i be spending more on a higher spec part?

Any help much appreciated.

nicklouse

you need to look at how the mech fits to the frame.

most are a screw fitting to the drop out "ear" the TX31 is not that type. (or is available in both fittings).

Cladge

Alas, I note that this thread is about three weeks old so I'm guessing that you've already changed your derailleur, but if anyone else is stuck or interested...

The TX51 *should* be interchangeable with either the TX31 (mounts both ways) or TX71. The TX30, 50 and 70 are, I think, the Megarange versions and I don't know how compatible they are/n't. But Shimano have published brief compatibility tables for the Tourney range and these tables crop up in their various technical documents here...

http://techdocs.shimano.com/techdocs/bl ... ID=j6Wl5bp

I suggest you refer to document SI-6N9RA or SI-R917B (scroll down to rear derailleurs).

The Tourney series of components is large and bewildering, mainly because Shimano make it as a value one-stop-shop range for (mainly) trade use rather than retail, for manufacturers who want to produce relatively low cost bikes full of Shimano components. So it's the range that has everything from bottom brackets to roller brakes - it even has lights, computers, and (I believe) folder-specific derailleurs. Not all are marked as "Tourney", for instance, the Revoshift and low-end EZfire shifters live in the Tourney range, but aren't branded as such.

Thebigbee

dsharp7th wrote:

I'm replacing a rear derailleur on my bog standard but otherwise sturdy Ridgeback Motion 08 hybrid bike. The derailleur spectacularly crunched, bent and snapped off this morning, probably wasn't cleaned enough. Other than adjustments, I've never dealt much with rear derailleurs before so don't know how specific I need to be when buying a replacement.

I believe the broken derailleur is a Shimano TX51 which is not available and presumably an old model. Halfords have a Shimano TX31 at £12.99 ready and waiting, is there any reason this wouldn't fit? (could probably get it cheaper online but need to be back on the saddle asap)

Should i be spending more on a higher spec part?

Any help much appreciated.

Yes - I know this is quite an old thread now - Just reading what you wrote - are you sure it was the derailleur that snapped and not the hanger - which is actually designed to?

Just a thought

dsharp7th

Just revisited my query, thanks to those who responded. Needless to say I learned a lot about rear drivetrain systems that I didn't ever seem to need to know before. bigbee, derailleur was snapped, hanger was bent.

The damage was a lot worse than originally thought; in the end I needed a new derailleur, (went for the tx55), a new derailleur hanger (took ages to find the right one), new back wheel, new chain, so, in for a penny out for a pound, bought a new freewheel to complete the set. It was an almighty mechanical failure with no apparent cause.

Thanks nicklouse, prompt key info I may have gone wrong without.

And clasge, couldn't agree more - very difficult for mortals to know which of shimano's products will work together based on fiddly product codes and information available.