Hybrid Bicycles - Changing a derailleur

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View Full Version : Changing a derailleur


MJH
03-19-10, 12:24 PM
I have an '97 GT Virage that I just love. Still can't find anything that I want to replace it with.

However, I wouldn't mind doing some upgrades. It currently has a Shimano Alivio rear derailleur. It shifts fine, but not as crisp as I would like. Would I get a lot better performance from a Deore XT? What else would I have to replace? Would I want to do the front, the shifters/brakes? I just don't know enough.

Thanks in advance.


Panthers007
03-19-10, 01:05 PM
How about a real Shimano Ultegra for $39.96 + shipping?

http://www.cambriabike.com/shopexd.asp?id=68265&page=SHIMANO+ULTEGRA+RD-6500+REAR+DERAILLEUR

MJH
03-19-10, 02:20 PM
How about a real Shimano Ultegra for $39.96 + shipping?

http://www.cambriabike.com/shopexd.asp?id=68265&page=SHIMANO+ULTEGRA+RD-6500+REAR+DERAILLEUR

Price is great and I know that is a great derailleur. My cluster is an 8 speed, so I assume that would have to be changed. And then the shifters, right? Is there just a derailleur that will just fit in?


khutch
03-19-10, 02:53 PM
I think the derailleur would work fine with an 8 speed system, the indexing is in the shifter not the derailleur. I'd be more worried that the chain wrap and largest cog capacities would be in sufficient. You don't say which Alivio you have. The current long cage model has 45T chain wrap and 34T largest cog where the Ultegra is only 39T and 28T respectively. The short cage Alivio is 33T and 34T so even if you have that your bike could be incompatible with the Ultegra.

The Deore XT is three grades up from what you have so I would think it would be capable of excellent performance. My new Fuji has a 105 transmission which likewise is three grades up from the entry level and it is very, very nice. However, it is a complete 105 system and I rather doubt that just slapping a 105 rear derailleur on a bike with 2200 grade components would produce the same result. I'm hardly an expert on this but I think you could be looking at changing out shifters, both derailleurs, cogs, chainrings, and while you are at it the chain, to get the full benefit from a Deore XT rear derailleur. If you like your bike it may be worth it and you don't have to do it all at once. I would definitely do the chain and gears at the same time to prevent worn components from prematurely wearing out new components.

Ken

Wanderer
03-20-10, 08:25 AM
If you do a really good job of cleaning up that Alivio, and oiling it well, you might be very surprised at it's smooth shifting capabilities. When I clean and lube my grandchildrens Alivio stuff, it works like a dream....

Clean the cables real well, and oil them lightly - as many shifting problems can be traced back to poor cable movement. If questionable, replace them - they're cheap.

Nothing like something working properly - and helped considerably by good lubrication.

Much, much, cheaper than replacing a part that still works well. When it's worn out, and can't be adjusted properly, is the time to upgrade.

p.s. don't forget to clean and oil the chain, while you are doing the derailleurs. A clean, oiled, and smooth running chain, can have a significant impact on shifting .....

Surfindixon
03-20-10, 02:07 PM
I got 6000+ out of the jockey wheels that came with my XT RD but I did clean them and grease them up regularly. It was better performance than expected. So on that basis the XT was good value.

Wanderer's advice is bang on and I have always isolated really poor shifting performance (where no adjustment makes any difference) to the cables. I absolutely recommend the Shimano Deore/105 gear cable set. The outers are good and they're pre greased as well (silicon grease I think) and are also good value. I swear by them.

In adition to Wanderer's comments regarding a clean chain I would aslo recommend cleaning the rear cassette if it's cruddy. I take the edge of a thickish cloth to the gaps between the sprockets after a wet cruddy ride. Once in the gap move the cloth side to side to clean each sprocket (I'll post a piccy of the technique if you want...a picture is worth a thousand etc). My pals think I'm a bit anal but I hate it when shifting is crappy. Just can't tollerate it.

MJH
03-21-10, 09:22 AM
Thanks for the great advice. I do keep my drivetrain clean. I was just hoping for a little better shift. Maybe I shouldn't be so picky. I ride pretty easy and don't get into too many situations where the shift doesn't happen fast enough.

I think maybe I just want to do something nice for the old bike. :)

khutch
03-22-10, 06:57 AM
I think maybe I just want to do something nice for the old bike. :)

Have you ever replaced the chain or checked it for "stretch"? If not then read Sheldon Brown's comments on chains HERE (http://sheldonbrown.com/chains.html). Scroll all the way to the bottom to see how to measure the chain wear (which is what chain stretch really is). If your chain is badly worn after 13 years of use then you would have to replace the gears, front and back, along with the chain but that isn't so expensive and it would make the bike shift like new. If you have been keeping up with this all along then everything is likely to be fine as it is.

Ken