Wiswell

I seem to have not the greatest quality derailleur (hey, the bike was $300, but do you expect): Shimano TX50 7spd. The shifting is often choppy. It's typically good for a while (especially after a tuneup), but after 100 miles or so it gets sluggish (as in, shift, and wait 5-6 cranks for it to happen, or trim the shifter to get it to go) when shifting to the smaller rings. Does anyone have a recommendation for the next level of quality (or something I can do to improve the shifting smoothness - I have adjusted the screws in the past, but it's typically a short-term fix). I have no idea of the price, either: can someone give me a general idea? I'd have the LBS install it.

Thanks

Hunter

I would reccomend at least Acera or Alivio from shimaNO. However a higher reccomendation would go to SRAM and get 3 or 4.0. Of course this entails a SRAM ESP der. as well but that IMO.

Don Cook

Since there's no commomly accepted definition of a tuneup, I have no idea what was done to your rear derailluer. So, here's what I'd do: Sluggish shifting from larger gears to smaller ones, is most frequently caused by excessive friction that prevents the rear derailleur from returning to it's relaxed position, which is all the way to the outside towards your smallest rear cog. This movement is permitted by the shift cable becoming slack, and the derailleur return spring returning the deraileur to the relaxed position. If it is sluggish, first look at the overall cleanliness and lubrication of the derailleur itself, next remove the shift cable from the rear derailleur. Remove the outer cable housing. Spray a degreasing chemical into the inside of the cable housing. You'll see all kinds of nasty looking gunk run out of the cable housing. Clean this thoroughly and then clean and lube the shift cable itself. With the cable still disconnected from the derailleur, push the derailleur all the way towards the center of the bike (under the biggest cog). Quickly slide your fingures or hand off the derailleur to allow it to spring back to the outer position. Does it quickly snap to the outer position? Work the deraileur back and forth and try to detect any binding or sluggish behaviour. If not sure, degrease, clean and lubricate the derailleur. Check for any possible source of binding in the cable guide that is mounted to the underside of your bottom bracket. Lastly, either replace the derailleur return spring or replace the derailleur.

sydney

Why do you do ShimaNO? There are sram RD that are shimano shifter compatible.

Avalanche325

Why not just use a Shimano der? They work fine. It is usually much better than mixing equipment.

Go with Alivio or better. It will be fine. Don't listen to people that hate Shimano just to hate the big guy.

sydney

Nothing wrong with mixing if it's compatible, and some absolutely are.

Retro Grouch 

I suspect that you have at least two separate problems, maybe more.

The first has to do with the condition of your shift cables and housing. As a general rule, a fresh set of cables and housings will do wonders for a bike's shifting expecially from the big cogs to smaller cogs in the back.

Next I'd look to the overall cleanliness of your rear derailleur. Do the best job of cleaning it that you can and go real real real easy on the lubricants. I can't remember the last time that I used ANY lubricant on the derailleurs of any of my personal bikes.

Third, you mentioned adjusting the screws on your derailleur. That's a bad thing. The limit adjustment screws on your derailleur virtually never need adjusting. Most derailleur adjustments are made with the shift cable tension.

Finally, shift into a gear combination that makes your derailleur cage point straight down and look at it from the back of your bike. When your bike is vertical, your derailleur cage should be vertical too. If it's not, try to bend your dropout until it is.

AndrewP

Advice above is good but you can also look for further info and diagrams etc in Sheldon Brown's site which is very useful.

https://www.sheldonbrown.com/articles.html

Rev.Chuck

Do you have twist shifters(Sram)? If so have your shop replace the housings with fresh ones and replace the stock cables with 1.1 mm cables. It will make quite a change.

Chi

LX is always affordable.

Wiswell

So I went to Sheldon Brown for some confidence,as well as read up more on ensuring good maintenance on my derailleur. I cleaned up as best I could with a toothbrush to clean out the gunk and relubed everything, checked the spring, and turned out the cable tension adjuster slightly. Now the gears run through smoothly except when I am on the middle chainring, it won't go into the fourth smallest cog, or if I am in the large chainring, the third smallest cog. Instead it stays in the smaller cog (going up is ok, it's going down that it doesn't work). When I want to move onto to the next cog, it simply skips over (3 or 4 whatever the case may be). Any reason why it does this and what I can do to correct? The derailleur doesn't seem to be bent. I imagine, though I didn't check, that if I was on the smallest chainring it would probably not want to go into the 2nd smallest cog, but that was too close to the crossover that I would bother with, anyhow. Why would it not work in just those two combinations, if they are right in the middle of cassette? I can see if it wouldn't do several, or wouldn't go to an end, but this confounds me.