26/28 cassette

[Mustang]

I have a 126 rear space, it runs a current Sant'e rear derailler with a hyperglide seven speed 12/ 25 tooth cassette. Works fine.

To keep it period correct (& make for easier climbing) it should run a "uniglide" cassette, which I have in a 12/26. Trying to run the larger cassette with the Sant'e causes the derailler body to run into the large sprocket. (no "B" adjustment screw.)

I have tried a modern long cage 105 shimano derailler & it did not track. I can keep the min/max adjustment within the required 7 x speed width but it will not index correctly. Perhaps the current chain is too short?

Question: When going on a ride with hard climbs I would like to be able to change to a larger cassette say 13/28 even on a different wheel. Using a derailler that would handle both in 7 x speed. ( Or I would be happy to leave the larger cassette on permantly)

There is a long cage SIS derailler on ebay but owner dosn't know the speed? Is the speed utmost or can you use say an 8 speed on a 7 speed cassettte?
Sheldon Brown does not appear to go into this with deraillers?
Cheers Brent

[ldrcycles]

I would try measuring the derailleur hanger, if it is a short one that might be the cause of the Sante not handling the 26. I've got a SunTour derailleur with a very short cage running a 28t on my Mercier, but the hanger on that frame is ~33mm (i'm just guessing but i measured that from the centre of the dropout, or centre of the axle if that makes more sense, to the centre of the threaded hole for the derailleur).

Disraeli Gears (http://www.disraeligears.co.uk/Site/Shi ... LS%29.html) quote Shimano as saying the Sante will take a 28t but doesn't mention hanger length. Could be chain length too.

[Mustang]

I would try measuring the derailleur hanger, if it is a short one that might be the cause of the Sante not handling the 26. I've got a SunTour derailleur with a very short cage running a 28t on my Mercier, but the hanger on that frame is ~33mm (i'm just guessing but i measured that from the centre of the dropout, or centre of the axle if that makes more sense, to the centre of the threaded hole for the derailleur).

Disraeli Gears (http://www.disraeligears.co.uk/Site/Shi ... LS%29.html) quote Shimano as saying the Sante will take a 28t but doesn't mention hanger length. Could be chain length too.

Hi Idr,
Hope your injuries are feeling better.
Just measured the length at 30mm, didnt know where to look before. When you get time PM me the model or number of your Suntour. Interesting that disraeligears give a max of 28. That would be great.
EDIT:Info
This offering is for a new-old-stock (NOS) Suntour Alpha 5000 rear derailleur from the late 80's. It's a legitimate (Japanese made) Suntour rear derailleur that incorporates first generation index shifting technology (or as Suntour used to call it, "Accushift" indexing technology). With respect to the shifting capacities and other notable specifications, we have included the following...


Index shifting compatibility: 6/7 speed (with Suntour branded or compatible index shifters and freewheels/cassettes)

Friction shifting compatibility: Several options (most 5/6/7 speed freewheels/cassettes)

Front capacity: Double chainring w/12T (max) difference

Rear capacity: 28T

Total capacity: 28T (combined front chainring and rear sprocket difference...also known as chain wrap)

Weight: 277 grams (per our digital postal scale)

Other notes: The pulley cage length, is the technical specification having the most direct impact on rear derailleur capacity limits. This particular model has a relatively short cage length...measuring 56 mm from the center of the jockey/guide (top) pulley to the center of the tension (bottom) pulley. The cage length is slightly longer than Shimano's designated "short cage" length of 50 mm, so this Suntour rear derailleur should compare favorably (in terms of capacity limits) to similar Shimano branded models with the short pulley cage. The primary benefit to a shorter pulley cage is less weight (although, in all honesty we are only talking about grams here, so probably not a noticeable savings for most of us). The downside, as most already know, to a shorter pulley cage is lower capacity limits, which limits these derailleurs to double crankset road bikes with a relatively narrow gear range on the freewheel/cassette.

We've identified a few different Suntour Alpha model derailleurs from this late 80's period and it appears they

[spirito]

...if it is a short one that might be the cause of the Sante not handling the 26.

Correct, the normal (short) length hanger (which is what is most commonly availabl, especially here in Oz) has a 24t. max cog size and a total capacity of 24 teeth. The original poster is asking more than the derailleur can handle.

http://velobase.com/ViewComponent.aspx? ... &AbsPos=83

Keeping originality is one thing but hunting around for a Sante long cage rear derailleur is not something I'd opt for, especially when most any recent 7/8/9 speed long cage derailleur will work much, much better. Needn't be expensive either - $24, but you'll need to buy a new chain (or add some extra links to your existing one).

http://www.this link is broken/Mode ... elID=38673

[Mustang]

...if it is a short one that might be the cause of the Sante not handling the 26.

Correct, the normal (short) length hanger (which is what is most commonly availabl, especially here in Oz) has a 24t. max cog size and a total capacity of 24 teeth. The original poster is asking more than the derailleur can handle.

http://velobase.com/ViewComponent.aspx? ... &AbsPos=83

Keeping originality is one thing but hunting around for a Sante long cage rear derailleur is not something I'd opt for, especially when most any recent 7/8/9 speed long cage derailleur will work much, much better. Needn't be expensive either - $24, but you'll need to buy a new chain (or add some extra links to your existing one).

http://www.this link is broken/Mode ... elID=38673

Thanks for the lead Spirito, all starting to make sense.

[ldrcycles]

The Cyclone RD i have is identical to this one on Disraeli Gears, even down to the date code http://www.disraeligears.co.uk/Site/Sun ... 00%29.html.

If you're looking at a one of those later Alpha Accushift models i have a couple of those lying around that i haven't used as i don't like the look of them, from memory one of them is a long cage model too. I'll have a look when i get a chance and let you know, if you're keen you can have either or both, they're of no use to me. Neither is in the best cosmetic condition though.

Just out of interest i've heard a few people say that Accushift was hopeless, and there is a fascinating article on the net called "sunset for suntour" which attributes the collapse of the company in part to the failure of Accushift. I had an australian made ProTour for a while a couple of years ago though which had a full SunTour GPX group which had Accushift indexing and it was significantly better than Shimano downtube indexing, it shifted well with a very crisp, positive feel. That group had a relatively late production date though, so it may have been that they started off poorly and by the time they got things in order the reputation couldn't be fixed.

All of which is why i am a firm fan of SunTour stuff, apart from the fact they work well, the history of them is fascinating!

[Mustang]

The Cyclone RD i have is identical to this one on Disraeli Gears, even down to the date code http://www.disraeligears.co.uk/Site/Sun ... 00%29.html.

If you're looking at a one of those later Alpha Accushift models i have a couple of those lying around that i haven't used as i don't like the look of them, from memory one of them is a long cage model too. I'll have a look when i get a chance and let you know, if you're keen you can have either or both, they're of no use to me. Neither is in the best cosmetic condition though.

Just out of interest i've heard a few people say that Accushift was hopeless, and there is a fascinating article on the net called "sunset for suntour" which attributes the collapse of the company in part to the failure of Accushift. I had an australian made ProTour for a while a couple of years ago though which had a full SunTour GPX group which had Accushift indexing and it was significantly better than Shimano downtube indexing, it shifted well with a very crisp, positive feel. That group had a relatively late production date though, so it may have been that they started off poorly and by the time they got things in order the reputation couldn't be fixed.

All of which is why i am a firm fan of SunTour stuff, apart from the fact they work well, the history of them is fascinating!

Hi Idr,
I would appreciate that, I'm riding in the Conquer Cancer in two weeks on the old Vitus & would like that larger rear cassette fitted, otherwise the 25 will suffice, info has been great. i'll PM details.

[ldrcycles]

Stop the presses, i just remembered i have a long cage Shimano Light Action in stock, that would be much better than having a mismatched SunTour derailleur on there. That lovely Vitus deserves matching gears . I'll be able to get it from my farm on thursday.

[Mustang]

It works If only on the bench, index & friction, both chain rings, I,m excited!!!! will test ride tomorrow,
12/28 (modified) Hyperglide cassette, 105 long cage derailleur, my problem previously was using too short a chain, thanks to the forum for the valuable information.
( Thanks to Old Al)
"Idr" I will still take your derailleur, to keep somewhat period correct.
I also was able to run the 12/26 "Uniglide" cassette, which I will refit after the Conquer Cancer ride.

[spirito]

It works

Cool, good for you