cmherrmann

My son needs a new rear derailleur on his Trek 1500 triple. Currently it has an Ultegra, the bike shop wants $125.00 for the Ultegra and he cannot afford that kind of price. I can get a new Ultegra 6600 off of Ebay for $65.00 or a used Dura Ace 7800 for around the same price or less.

What would you choose?

Would a 105 be almost as good as the Ultegra or would he be better off with the Ultegra/Dura Ace?

dstrong 

If he rides recreationally and doesn't race, 105 is more than enough. Shimano defines 105 as "entry level race" and there are plenty of people who ride 105. If you buy off eBay, make sure you figure shipping into the final price and make sure they're not shipping from your state which requires them to charge sales tax.

Jed19

I have the Ultegra, and it is good stuff. If the used 7800 is not really beat up, I'll opt for that. In my view, 7800, save the rear hub, is gonna become a classic. Shimano really hit it out of the ballpark with the 7800. The weak point is the 10-Speed only rear hub.

cmherrmann

Thanks, if it makes a difference he has a 3X9 and I believe the Dura Ace will do 8, 9, or 10?

cmherrmann

Are there any good references on how to adjust the rear derailleur or would he be better of letting the LBS do that?

dperreno

105 5500, Ultegra 6500, and Dura Ace 7700 are the 9-speed versions and those can be had for under $50 on ebay. If he has a triple front chainwheel, you should probably be looking at the GS (long cage) versions. I don't believe that there is a GS version for the Dura Ace, so that would suggest 105 or Ultegra. The derailleurs referenced previously in this thread are all 10 speed versions, and I don't know if they use the same cable pull, someone else will have to chime in on that.

dstrong 

https://www.parktool.com/repair/byregion.asp?catid=53

and

https://www.sheldonbrown.com/derailer-adjustment.html

You'll need to be able to take your chain apart, either using a chain-breaker and then a replacement pin or using a "quick link" if the chain has one.

You'll need a 5mm allen wrench to remove/install the derailleur and a 4mm to take off/replace the cable.

If this sounds like too much, then the LBS is the way to go.

What happened to the current derailleur?

Tabor

105 is fine. If I had an Ultegra equipped bike I would probably keep it Ultegra... but if you can get DuraAce for the same price...

DMF 

Tiagra is fine, too.

Why does his RD need to be replaced? Is it broken? RDs last nearly forever. Most of the time I see someone wanting to replace one it's because they can't get it adjusted correctly, but that's not the fault of the RD...

Camilo

I have a dura ace long cage rear der. on my 9 speed triple set up. Don't know the model number, but it's ca. 2003 or 2004 original (this a bike with all components being Ultegra 6503 bike except that it came originally equipped with the above mentioned GS (long cage) Dura Ace RD) .

9 or 10 speed rear derailleurs will work fine. The cable pull is determined by the shifter, not the derailleur.

DMF 

I'd stick with 9-speed. 10-speed stuff tends to be tailored for the narrower chain (and it's likely more expensive).

Shifter and derailleur pull ratios need to match. Fortunately they do with all Shimano 9 and 10 speed road components.

Al1943

+1
Any 8, 9, or 10-speed long cage (GS) derailleur will work. Stay away from 8-speed Dura-Ace, but there was never an 8-speed D-A long cage RD anyway.

mobike_moexcite

+1 Why is it being replaced again?

valrulez

+2 on why

Jeff Wills

Well... I've worn out a Shimano Deore XT rear derailleur, but that was after about 10,000 miles of use. The pivots were worn enough that it sometimes shifted the chain into the spokes. Other than that, it worked fine.

I'd also want to know why it needs to be replaced.

cmherrmann

He crashed the bike last year and the LBS straightened the cage/hanger at that time and said that eventually it should be replaced. He is having some shifting problems now. Could the derailleur be repaired instead of being replaced? Or could it be a different problem altogether?

gitarzan

Check this site out...

https://www.bikesportmichigan.com/fea...-ultegra.shtml

rogerstg

Check the RD hanger again first. Straightened aluminum RD hangers often do not stay straightened. It may need to be replaced.

cmherrmann

So just the hanger can be replaced?

Wanderer

Yes

joejack951

On bikes with bent rear derailler hangers, I've seen the castings for the derailler crack at the pivots where they are the thinnest. If this is the problem, the derailler is junk (though good for scavenging small parts off still) and needs to be replaced.

cyccommute 

Sometimes. Depends on whether the hanger is replaceable or not. Since the shop tried to straighten it, it might not be replaceable.

cmherrmann

I will see what the LBS says, I recently bought a 1997 Trek 2300 with Shimano 600 group on it and the shifting was not working well at all. I took it to the same LBS and they told me it needed new shifters. I got a real good deal on the bike so I figured it was worth the cost of the new shifters. I will see if they are just out to make quick money by replacing the entire derailleur or not.

I was stupid and did not ask to get the old shifters back, should I have asked for the old shifters back when they were replaced? It was only a month ago should I go back and see if they still have them? I see where someone had posted that it is possible to rebuild them but it looked like a lot of work.

Where would a person get the hanger other than having the LBS do it?

dedhed

https://www.universalcycles.com/shopp...s.php?id=21919

cmherrmann

Thanks for the link to a really good price on the derailleur, but I was looking for just the hanger or cage if possible. Might just be easier to get the entire thing. LBS wanted $125.00 plus install!!!!! :-(