somegeek

I'd like to swap my wife's stock cassette for a 12-32 on her (92 I think) Trek 1200 however I need to replace the derailleur. It has the stock RX100 derailleur on it at the moment and it won't work for this cassette. Any derailleur recommendations?

Thanks in advance.

somegeek

HillRider

Any Shimano MTB derailleur from 7-speed up to 9-speed will work fine as the indexing is in the shifters and the derailleur just follows instructions. A Deore is a good mid-level component. You must avoid the newest 10-speed "Dyna-Sys" MTB derailleurs as their geometry is not compatible with earlier shifters.

somegeek

Thanks! Ordered a Shimano RD-M591.

fietsbob

N/m

somegeek

??

Al1943

I always thought that originated with my wife.

GeorgeBMac

From my experience, the RX100 is a road based (not MTB) derailer and the RX100 shifters are on the downtube.

If that is your setup, won't replacing the derailer require you to switch to newer shifters on the bars? And, once you go down that road, will you not have to replace both shifter and therefor both derailers?

Or, can you continue to use DT shifters on new derailers?

HillRider

Shimano's downtube, barend and brifters for a given "speed" all move the derailleur the same distance per "click". So if the OP substitutes a newer MTB rear derailleur for his current RX100 (and yes it was a road group) it will work with what ever shifters he has.

thirdgenbird

Not completely true. Derailleurs shove the chain sideways a prescribed distance based off a specific cable pull distance. A Campagnolo or SRAM 1:1 RD would not work with a shimano 7spd cassette and shifter.

Al1943

7-speed SIS downtube shifters are compatible with Shimano road derailleurs or mountain derailleurs except 10-speed mountain derailleurs. If the new derailleur has a narrower cage than the old derailleur an 8-speed chain may be a good compromise.

Of course if the shifters are indexed 7-speed the cassette needs to be 7-speed.

somegeek

I replaced the DT shifters with Shimano 7-speed RSX STI brifters on this bike.

Thanks for the replies.

jwilson220

Hello, I am new to the forums and need some experienced guidance in finding compatible parts for my new little project.


I have a late 80's Trek 1000 that I am about 90% complete on but I have one more piece of the puzzle that I cant quite find any definitive information about.


7 Speed Rear Derailleurs, Modern Ones


I have replaced every piece of hardware of my Trek except the derailleurs, which I wasnt planning on upgrading yet, but there seems to be a problem with the rear and Im just going to get a new one.


The problem is choosing the right one for my application and after sifting through posts all over the internet Im still not quite sure.


Let me give you my specs


1988ish Trek 1000
7 Speed Flywheel, 12-26
Double chainring Crankset which I changed from the stock Over Tech Rings to Shimano, 39/47
Stock Suntour Edge 4050 Derailleurs
Upgraded the Downtube Indexed Shifter to Shimano Stem Mounted Shifters
New Derailleur Lines and Housing
Grand Cru Bottom Bracket
Tektro Inline Brakes Levers
Cane Creek SR5 Standard Brake Levers
Tektro Dual Pivot Brakes Calipers
Velo Orange Brake Lines and Housings
SRAM PC850 Chain


Im having problems with the rear derailleur now that I have done all of this and am thinking that the rear is bent or broken


It has a dent in the front arm and is all scraped up, the original housing was busted and the cables were frayed and rusted.
They are like 25 years old so...


I set the high and low limits and have played around with the cable tension but I can get it to shift properly.
Its either the high end is right or the low end is right,
Adjust the cable tension to dial in one or the other and the other end is out.

Also, when on the work stand I can get it close but under load it skips in these areas also.


Maybe its compatibility with the shimano and suntour components ? Not sure


So I think that at this point I just want to upgrade the derailleur to something Shimano but am not sure which way to go.


The stock on is a medium cage but do I need a different cage style since I have changed the chain rings ?


I am comtemplating
Sora RD-3400
or
Tiagra RD-4500
Or a Used Ultegra RD-6600 off of Ebay.


I dont really want to spend more tha $50 on this.


Can anyone out there give me some educated advice on this ?


Thanks so much
J

Dave Mayer

Bingo.

OK. You have a 7-speed freewheel. You should tell us what maker.. Shimano? Suntour? Sachs or other? There are some small cog spacing differences between Suntour and others. If it were up to me, I would buy a new 7-speed Hyperglide freewheel and spin it on. Then you will have the super smooth-shifting Hyperglide cogs and no worries about incompatabilities.

Nevertheless, the root of your problems is a fundamental incompatability between the Shimano shifters and the Suntour Accushift derailleur - the derailleur will be traveling too far to line up properly with the cog spacing. An inexpensive Shimano derailleur, like the 8-speed SORAs, will work fine. Don't buy a 9 or 10-speed generation derailleur. It will cost more, and the narrow cage width may interfeare with the wider 7/8 speed chains that you will need to run. You should be able to find these derailleurs in the discount or discard parts bin in every bike shop on the planet. Last resort: Ebay for less than $20.

Finally, I cannot tell what type of Shimano 'stem mounted' shifters you've installed. Are they designed for 7-speed indexing? They need to be.

And to avoid a lot of grief with bike upgrades, please install new housings, cables and chains. It pains me to see how many problems folks have with trying to get proper shifting work with gunked-up and worn out parts. Chains and housing are throw-away consumables. I go through 4 chains per year, and at least one complete housing/cable kit. Makes a world of difference.

ThermionicScott 

Checking the Trek catalogs (god, I love VeloBase ), 1988 Trek 1000s came with Shimano indexed 6-speed, 1989s with SunTour indexed 7-speed. +1 to everything Dave posted.

fietsbob

Friction shifting I use 6 and 7 speeds interchangeably..

My Favorite RD: Campag Euclid

jwilson220

Hey guys, thanks for responding,

Ok, So yes it was in fact a Suntour set up, The Indexed Shifters were also Suntour Accushifts. All of this stuff was the original equipment which was ok but I hated the downtube shifters and wanted to move them up to the stem.
The Shimano Sy20A set I chose I really like.
So yes, after Installing the stem shifters, cables, housings, shift boss housing doodas, chain, etc. I didnt think Id have a problem and I actually got it somewhat dialed in on a workstand but once under load, No bueno.

So once I realized what the problem was I started searching for more info on the net and discovered I needed to go Shimano for the RD because of the pull ratio.

I didnt hear much so I went ahead and placed an order for a new RD last week.
I went with a Tiagra RD-4600gs which I thought was a good choice based on all of the research I did but from what Dave is saying this may pose a problem ????

Alot of threads and info on the web seem to say that this will work fine and that "Speeds" on RDs are more a marketing tool and dont really matter ??

I dont know

I had been looking at a bunch of RDs on Ebay before this but didnt really trust that I was buying a 3rd party item and couldnt return it or have a warranty so I bought new.

I was originally going to buy an Ultegra RD-6600 but again, some people have a no return policy.

this is what I bought but the GS model
https://www.amazon.com/Shimano-RD-460...agra+RD-4600gs

There also is a 105 on ebay for about the same price I was thinking about.

Thanks everyone

jwilson220

Oh an also, The cogs on the freehub are in decent shape but now that you mention maybe a new set would be in order.

Why again would there be compatibility issues ?
because the stock set were designed to sync with the suntour RD ?

Im really not sure of the maker but considering that every single other component that was on this bike was bine stock im assuming that it is suntour also.

There is a Hyperglide HG-50 on Amazon for $28 and free shipping
https://www.amazon.com/Shimano-CS-HG5...rglide+7+speed

Thanks

Dave Mayer

You need to run a 6/7/8 speed chain to match with your freewheel and the spacing of your chainrings. This width of chain may interfeare with the cage plates of a derailleur designed for 10 speeds. 10 speed chains are obviously narrower, and so are the the cages of matching derailleurs. The derailleur will be compatible in terms of pull ratio, but hopefully your chain will fit. I have run a 7-speed drivetrain with an unmodified Shimano 9-speed derailleur, so it may work.

Don't think about using a 9 or 10-speed chain on your current drivetrain - this will bring up more serious issues. First off, a 9-speed chain will cost double that of a 7-speed - for no apparent reason. The 10-speed chain will double that cost again. But the bigger issue is that the narrow chains may either skate on the top of the chainrings instead of engaging with the ring teeth, or worse, may find a way to get jammed between the rings.

jwilson220

Hey Dave, Yeah I wen with a SRAM PC850 Power Link chain, it is an 8speed chain.
Well, I dont want any compatibility issues and want this thing to get set up right the firs time so if there is even a possibility the I might just return the Tiagra.
Although alot of info, even articles like by Sheldon Brown seem to lean towards no issue.
The Sora 3400 was actually on my list of possible choices but I went with the Tiagra because in terms of quality and the Simano Hierarchy it technically would be a better derailleur.
But even so, the Sora also is marketed as a "9 Speed"
I looked for some Soras on the web, they are still about as much as the Tiagra price wise.
I can always return the Tiagra to Amazon if it wont work properly.

I also have a local bike guy, Sam Fitzsimmons that may have just what I need but it would be used so Im not sure.

Id have to ask him what he has laying around.

What should I be looking for ?

I really ideally would have an Ultegra

Thanks

Dave Mayer

Hmmm.. If it were me, I would reach in my derailleur bin to pull out a 90's vintage Shimano 600, or Shimano 105 or Shimano DX unit.

I am pretty sure that a 9-speed generation Shimano derailleur will take a 7/8 speed chain. Not so sure about 10-speed.

I would go for the Sora. There is no initial performance difference between this and the Ultegra. Since the Ultegra features stainless steel pins covered by brass bushings holding together the parallelogram cage, it will last considerably longer than the lesser derailleurs. As the pivots wear, the Sora will get sloppy in a few years time under regular use. However, in my experience, most derailleurs get torn off or pretzelized long before wear becomes an issue.

jwilson220

Wellllll, I unfortunately dont have a vintage derailleur box to choose from so Im a little SOL there.
A buddy of mine actually has a vintage 600 tricolor he said i could have but Im kind of looking at performance and aesthetics here. I wanted something that has a certain look and style.
The tri color is a little too old school for what i have going on here.

I live on the east coast and because of good old Sandy I still havent gotten the Tiagra.
When I do I think im going to compare cages and jockey wheels to see if there any noticeable size difference, then decide what to do.
I actually meant to order the RD-4500 when I ordered the Tiagra, which is confusing because there is no rd-4600 on the Shimano web site.
So Ill see what shows up.

Dave Mayer

I have a couple of the 600 Tricolour rear derailleurs. And I have a couple 9-speed era Ultegra units. They are completely cross compatible. In terms of shifting performance they are indistinguishable. As far as quality, they have identical features that includes 2 forged parallelogram plates, stainless pins, brass bushings, chrome in the right places - basically the 'good stuff'.

As long as the second-hand 600 unit is not sloppy & worn out, it is a perfectly fine choice.

jwilson220

Ok,
Thanks Dave, Like I said, I like the looks of the more current Tiagra, 105, Ultegra Units a bit better so I am going to play around with this Tiagra and see whats up, then decide.

Ill post how it goes

Thanks

jwilson220

UPDATE:
Well, I received the Tiagra RD-4600 GS today and unfortunately I was unimpressed.

First, I ordered this as a new unit from Amazon.com and the first thing I noticed is that it was covered in grease with all kinds of debris stuck to it. SO it looked like it was used and returned or something like that.
Secondly, the Shimano GS line is supposed to be a medium cage design, so I thought, but it is indeed a long cage measuring about 80mm between pulley centers. in my case is far to long and would look silly.

(I found it a bit cumbersome to find an actual length measurement of the cages, everyone only focuses on the capacity)

My stock Suntour 4050 is a medium cage according to Velobase.com but it is becoming harder to find these as these old 7 speeds are being phased out.

So, low and behold, after about an hour of searching the net I found a vendor on Amazon that actually listed the actual cage measurements on-line, 63mm, which is exactly the same as the Suntour.

So I ordered the Sora RD-3400 along with a new Shimano RG50 Hyperglide, 13-26, 7 Speed Freewheel with the difference in price.

Should probably be here this upcoming week.

RubberLegs

I have been running the Sora RD for the last couple years on a 10 yr old FELT I've been riding. Nothing fancy, but it does the job fairly well. Running it 8 speed with Sora STI shifters, and occasionally deal with stickiness up in the shift heads...clean, lube, works again.