RSTrider

Can anyone help me choose new derailleurs (front and rear) for my bicycle? Details of the bike are below. I want to use the original shifters, but replace the broken derailleurs. I am not sure what will work given that everything modern is designated 10 or 11-speed and my freewheel is a 6-speed.
The bike is a mid ‘80s Raleigh road bicycle. It has a Shimano SIS shift lever and a friction lever on the down tube (that I want to keep). The rear wheel has a 6-speed freewheel with 28T largest sprocket and 14T smallest sprocket. My frame has a built-in derailleur mount on the right dropout. The original rear derailleur is a Shimano Light Action SIS one. The front derailleur is also a Shimano one, with friction lever. It clamps to a 31.8mm seat tube. It shifts a double chainring, with sprockets of 52T and 40T.
I would like to get the latest Shimano 105 series or Ultegra series derailleurs if they fill fit and function correctly. My research seems to indicate that a narrow range (SS cage) rear derailleur of either series will work correctly, even if they are designated as 11-speed. Is this true? Will the indexing be correct? My research came up empty on the front derailleur though. The front isn’t indexed, but are the latest 10 and 11-speed front derailleurs designed for narrower chain than I have? Will they work fine anyway? Any help would be greatly appreciated.

Kevin

Bill Kapaun

The way I see it-
For the front, the narrower the cage, the fussier the trim will be. Since it's friction, the only advantage to a "high zoot" FDER is that you might save a couple grams. Who wants to trim after every shift or 2?

I'm too ignorant about 11 speed RDER's, but I thought they had a different pull ratio.
Somebody else can chime in about that.

SkyDog75

Any SIS (Shimano Index System) compatible road rear derailleur up through 10-speed would match your shifter's cable pull and be able to index properly. The potential catch is that a 10-speed derailleur is designed for a chain that might be up to 1.5 mm narrower than a chain for a 6-speed drivetrain. That difference in width could possibly present a problem. It's typically not an issue if the parts are close enough, like 7-speed and 8-speed, but 6 to 10 is a big jump.

Shimano 11-speed road derailleurs use a different cable pull ratio, so those wouldn't work. Shimano 10-11 speed 'DynaSys' mountain bike derailleurs also use this different cable pull ratio.

As is the case with the rear, new front derailleurs are also designed for a narrower chain than you'd be using with a 6-speed freewheel. The cage width is narrower, so you'd probably find yourself trimming the shift lever more often to minimize chain rub on the derailleur cage.

Personally, I wouldn't recommend going with modern 10+ speed derailleurs if you're running an otherwise 6-speed drivetrain. Especially when used components that should work better for you are plentiful and inexpensive.

dedhed

I've had no problem running 9 speed 105 RD on 6 speed SIS systems both with the indexing and the chain width working fine.

due ruote 

+1 I don't know beans about the new stuff, but you won't have to look hard to find a 105, 600 or Deore series RD that will shift beautifully with the gear you have, and it won't cost you very much.

RoadGuy

Personally I don't see any reason to pay top dollar for the latest derailleurs if you are going to keep your 6-speed shifters.

I've updated several bikes with 6, and 7 speed drivetrains, and I never go past 8-speeds. 8-speed derailleurs and shifters don't cost much (typically I pay $10-$15 a piece for them), and 8-speed downtube shifters are available for between $20-$40. Nice thing about going 8-speeds is that 8-speed drivetrains use the same chains and cranksets as 6-speed drivetrains with the same cog/cassette and chainring spacing.

Theoretically 9-speed and higher drivetrains have their own cassette and chainring spacing, their own chains (which will not last as long as 6,7,8 chains and cost more). Many people mix components from different generations (one generation newer or older) without bad consequences, but people seldom try to go to say 11-speeds from 6-speeds.

RSTrider

Thank you for your responses. Here is my dilemma: based on prices of used vs new parts, and my intention to keep using this bike for the long term, I don’t see as much value in the used parts. My rear derailleur lasted through approx. 30 years of use. I bought this bike (slightly used) in ’87 and do not intend to replace it any time soon as it still meets my needs. It seems that any used 6,7,or 8 speed road bike derailleurs will be close to the same age as mine (maybe a few years newer) and have an unknown amount of life left in them. Also, using ebay listings for the Shimano 105 series (rear) as an example, the 6/7 speed RD-1050 seems to be selling for $36-$40 used. The 9-speed RD-5500/5501 has a similar sell price. A new 10-speed RD-5701 is less than $50. If the 10-speed will work correctly, it seems a better value to me as it will likely last longer than I will have the bike. The used ones might last well too, but that is less certain and the difference in price (used to new) isn't enough for me to warrant the risk. Obviously however, if I need the 6/7 speed for proper function, that is what I will get. Too bad the 11-speed won’t work as the price on amazon for a new RD-5800 is $45.99.

Bike Gremlin

Hope these three articles will help:

Rear derailleur

Front derailleur

How many speeds? - Bike Gremlin

FastJake

My recommendation: Shimano Claris. Cheap, effective, and designed for 8-speed so the front derailer will have a cage width appropriate for 6/7/8 speed chain.

Newer 9/10 speed rear derailers will work fine for you, but 9/10 speed front derailers will not. The cages are too narrow and will require nearly impossible trimming and you'll have lots of chain rubbing.

Claris FD, $22 shipped: Shimano Claris 2400 8 Speed Double 28 6 31 8mm Front Derailleur | eBay

Claris RD, $26 shipped: Shimano Claris 8 Speed Medium Rear Derailleur RD 2400 GS Road Hybrid Commuter | eBay

RSTrider

Thank you. I was just looking at the Claris. For the rear, if you were to choose, would you choose a used 105 series RD-1050 (approx. 25 years old) or a new Claris RD-2400? The 105 series would be a higher level component, but obviously a lot older and worn, whereas the Claris would be new, but part of a lower level groupset.

AnkleWork

See the first two words of post #9 .
Really, if you want bling just buy whatever you want. Function hardly matters.

FastJake

I have used both and I can tell you that the Claris stuff works great.

I've also bought more than my share of used stuff ranging from bottom end to Dura Ace/XTR. It's hit or miss. Sometimes it works beautifully while other times you get a part that's mostly worn out, or has partially stripped screw heads, worn pulleys, etc. My choice from now on is lower-end new stuff (I have gotten over the snob appeal of top-shelf stuff) or used stuff where you KNOW that it has very low miles and isn't trashed.

Long story short, shelling out $30 for a used Dura Ace derailer that's been to hell and back is not a good purchase.

RSTrider

Thanks FastJake and everybody else. It looks like I will be getting the Claris stuff. I was a bit worried about how well it would work but it sounds like a good choice.

Dave Mayer

I almost exclusively use second-hand bike componentry, because I am cheap.

But get the Claris.

Why? you have to be careful with used stuff; in my experience about half of the derailleurs for sale at swap meets and Craigslist are compromised in some way. The usual fault is that the pivots are worn out from thousands of shifts, and so the derailleurs are loose and provide sloppy shifting. Or that the bike simply fell over, and the derailleur is subtly bent. Or the pulleys are worn out, either the teeth or bushings or both.

These problems are frustrating, in that the derailleur may look OK, but you may spend unsuccessful hours trying to sort out shifting issues.

Finally, there are incompatibility issues. Old 7 and 8 speed Dura-Ace may be very nice stuff, but it is basically incompatible with all other Shimano product.

bikemig 

I'm running claris 8 speed stuff on one of my vintage bikes. The stuff works great.

RoadGuy

The age of a component has little to do with how much wear it has, that's more a function of who owned it previously, how it was used, and how wel it was cared for.

I've seen lots of 30 year old components that still look like new, because the bike they were on was never ridden much. And I've seen lots of 10 year old or newer bikes that have worn-out shifting components.

Some less expensive groups were not made of the best materials, or using the best manufacturing methods, so the age faster than higher quality parts of the same age or older.

Shimano STX comes to mind. Good looking when new, and heavily advertised by Shimano when introduced, many of the bikes I've seen carry STX components need derailleur and shifter replacement. STX derailleurs and shifters just didn't turn-out to be that durable, even though they were advertised as a upgraded group from the bottom, many bottom level Shimano components aged better than them.

The price of used Shimano 7 and 8 speed components (RX100, 105, and Ultegra) has remained higher than many newer groups simply because Shimano built them well. They are attractive, durable, and serviceable components. Many newer components are not supported by Shimano with service parts, meaning that when they break, that's the end of them, because replacement parts are not offered (and they have more plastic and pot metal than the earlier components).

I'm staying with RX100 and Ultegra 7 (I have 105 1055 components was well, but I don't like the paint color) and 8 speed components, because they work, and can be worked on if they ever need attention.

There's a reason that used RX100, 105, Ultegra components often sell for more than new Sora, and Claris components.

RoadGuy

I would get Tiagra at the lowest. The Tiagra derailleurs (8-9 speed) that I have appear to be rebranded 105 derailleurs and work great. The newer Claris derailleurs that I have are more like the 2300 Sora, which are made from bent sheet metal, and not nearly and rigid as cast alloy parts like the 105/Tiagra feature.

ramzilla

My favorite vintage Shimano derailleur is the Sora. Espcially if you can find them in the old brushed silver alloy version. Otherwise, I've used ordinary brand new Shimano whatever 6 speed derailleurs on old bikes. They work just fine.