Bike Forums

Bike Forums (https://www.bikeforums.net/forum.php)
-   Classic & Vintage (https://www.bikeforums.net/classic-vintage/)
-   -   Short Cage RD NOT for triples? Really? (https://www.bikeforums.net/classic-vintage/1245025-short-cage-rd-not-triples-really.html)

mrv 01-12-22 08:16 PM


Originally Posted by Drillium Dude;[url=tel:22371876
22371876[/url]]After taking a detailed look at the rest of the bike, it seems the rider came up with a novel way of turning a rigid seatpost into a shock-absorbing one by removing the binder bolt and installing that V-shaped spring unit. If that makes sense; there doesn't seem to be any other reason for it.

Also like the brake reinforcing plate on the rear brake vice the front.

DD

i thought those seats spring things were an early iteration of version of a dropper post. The spring returns the seat to itís up position.
- not sure. Just thought that was what it did.
I mean, you can laugh at me if Iím way off hereÖ

Drillium Dude 01-12-22 08:20 PM


Originally Posted by mrv (Post 22371891)
i thought those seats spring things were an early iteration of version of a dropper post. The spring returns the seat to itís up position.
- not sure. Just thought that was what it did.
I mean, you can laugh at me if Iím way off hereÖ

I'm not sure myself - can't really tell what's going on there. Looks like a cobble, but I'm not well-versed in MTB stuff, vintage or otherwise. Surely someone with more knowledge will be along soon to school us :)

DD

jingy2 01-12-22 08:22 PM


Originally Posted by Drillium Dude (Post 22371876)
After taking a detailed look at the rest of the bike, it seems the rider came up with a novel way of turning a rigid seatpost into a shock-absorbing one by removing the binder bolt and installing that V-shaped spring unit. If that makes sense; there doesn't seem to be any other reason for it.


DD

Uhhh, that's a Hite-Rite. The precurser to the modern dropper post. Possibly invented by, certainly marketed by Joe Breeze back in the day.
Jim

Drillium Dude 01-12-22 08:23 PM


Originally Posted by jingy2 (Post 22371896)
Uhhh, that's a Hite-Rite. The precurser to the modern dropper post. Possibly invented by, certainly marketed by Joe Breeze back in the day.
Jim

How does it work?

DD

seypat 01-12-22 08:33 PM


Originally Posted by Road Fan (Post 22371264)
Its all a matter of whether the largest rear sprocket can be handled by the rear derailleur, and the total change in the number of links that must be wrapped by the derailleur cage are within its design capability. The rear derailleur only cares about those two parameters, not how many rings are on the chainset. The sizes of the rings, yes, but the number of the rings no. Master how all of that works and you, too, will be a master gear finagler! I'm pretty sure Sheldon Brown covers all of that, it's not so obscure or hard to find.

This right here. It's easy to figure out what size sprocket the RD will take. The upper jockey wheel will start hitting the sprocket when you've reached the limit. Now you have to fiddle with the chain length until you get something that works on both ends. Also of importance is the cage length of the FD. If it's too short, the chain will drag on the cage plates bolt while on the small ring.

thook 01-12-22 08:59 PM


Originally Posted by Drillium Dude (Post 22371839)
If the biggest cog out back on that Salsa is a 28, a short-cage RD would prolly work just fine. If an old-school NR RD can handle a 28, why not a modern slant?

I think many people might think a long cage is needed to get all the gears, but really, who would use the smallest cogs out back with the smallest ring in front? Or big/big? Cross-chaining extremes would likely not work with this setup, but gear-smart riders know the limitations inherent in their drivetrains.

Every time I see a photo of a bike on the Forum in the big/big combination I wince a little and think "those components are going to have a shorter life than normal..."

Of course, YMMV.

DD

Well, the whole reason I started the thread was kind of in light of that. You can read all over the BF subforums about never using a short cage with a triple...or simply never exceed the total capacity. Which I get. There are inherent issues....one of them being potentially injurious. But, I never make big/big or small/small combo's. In fact, the '86 Ross Mt Hood I'm modeling after that white Salsa has had a weird issue since I've had it. I can only use the two largest cogs while on the the granny gear or the chain rubs the tail end of the FD cage. I dunno how to fix it. I've tried. I even went to using 46t outer ring instead of the original 48t so I could get the FD mounted lower. Helped a little. Anyway, point is, I can't make small/small combos before the chain rattle on the FD, anyway. So, I may just try using a short or medium cage cyclone RD on it. Curious to see if it will shift any snappier

thook 01-12-22 09:15 PM


Originally Posted by Drillium Dude (Post 22371897)
How does it work?

DD

It works in conjunction with the quick release. While riding and approaching a descent, for example, flip the quick release open and the saddle drops down from your weight all the while the hite-rite clamp keep the saddle center. Saddle drops and close the release. When you're ready for the saddle to be at normal height, flip the quick release, saddle pops up, and close the release, again. Here's an article I found....

https://mbaction.com/sept-hardtales/

thook 01-12-22 09:16 PM


Originally Posted by mrv (Post 22371891)
i thought those seats spring things were an early iteration of version of a dropper post. The spring returns the seat to itís up position.
- not sure. Just thought that was what it did.
I mean, you can laugh at me if Iím way off hereÖ

No, you're right.

tyrion 01-12-22 09:16 PM


Originally Posted by sincos (Post 22371889)
Is making a big deal of this a new thing? Who actually rides fully cross-chained like that?

No idea.

Drillium Dude 01-12-22 09:29 PM


Originally Posted by thook (Post 22371935)
It works in conjunction with the quick release. While riding and approaching a descent, for example, flip the quick release open and the saddle drops down from your weight all the while the hite-rite clamp keep the saddle center. Saddle drops and close the release. When you're ready for the saddle to be at normal height, flip the quick release, saddle pops up, and close the release, again. Here's an article I found....

https://mbaction.com/sept-hardtales/

Ah, thank you! I was thinking suspension post vice an early version of a drop post - no wonder I was confused. The other thing on the Salsa that had me scratching my head was that it appears the binder bolt ears are located in front of the seat lug, and that there wasn't a bolt installed. Funky old-school setup! I actually used a modern saddle dropper on a borrowed MTB this past summer and quickly appreciated - and got used to - the technology.

DD

Road Fan 01-13-22 07:21 AM

In all of this, I'm figuring out why I don't agree with a lot of the builds, as great as the bikes are. It's just my prejudices, dating back to the late i960s.

1. I don't like the chain to be slack, ever. I understand it's a choice and I did try it, but it always felt odd and was distracting.

2. I don't like to have to remember to have to avoid certain chain position combinations, such as cross-chaining. I have trouble keeping track of what gear I'm in, and my eyes haven't let me look down quickly and scope out the status when I'm beating like crazy trying not to lose too much speed on the uphill. So it's too distracting to have to worry about crossing.

3. Different makers may have different design margins relative to their stated limits. Most of us agree Campy application margins are tighter than those observed by Shimano. I have mostly Campy setups, since I've never warmed up to Shimano brifters compared to Ergopowers. But, I get really upset if I break a derailleur!

Campy's can be manipulated somewhat: a lot of us have used 13/28s with Campy NR which at least in early releases seemed to have 26 limits, and a local shop here tweaked one of my setups to accept a Campy 12/30 10v cassette when it was stated only to run over their 13/29 range, I think they added a link pair and increased wheel setback in the dropout. But they got it done with no looseness. Expensive frame and I was reluctant to risk the chainstay integrity.

So I need to focus on the riding and matching my pedaling to the road/wind conditions. Rather than learn to worry about geari system limitations other than range, I like to set up my shifting systems, downtube friction or Campy Ergopower 10s triples, to go where I tell them right away no matter what. Then I can just maintain the flow as well as my meager muscles will let me!

That's why I never advocate over-limit derailleur systems, because I don't like to deal with the effect of the limits or worry about breaking my stuff. But it is your choice to accept limits in your shifting systems, if it turns out they have any. I've seen all the "textbook" ones and I don't want to accommodate them.

But I prefer to stay within my criteria - observe the limits that derailleurs are made to operate within: maxcog and chain wrap capacity.

Road Fan 01-13-22 07:44 AM


Originally Posted by seypat (Post 22371901)
This right here. It's easy to figure out what size sprocket the RD will take. The upper jockey wheel will start hitting the sprocket when you've reached the limit. Now you have to fiddle with the chain length until you get something that works on both ends. Also of importance is the cage length of the FD. If it's too short, the chain will drag on the cage plates bolt while on the small ring.

True dat! The front derailleur also needs to match the chainset range, as well as being designed to work with the chosen gearset and chainring shifting aids to get the smooth reliable shifter response we paid for.

With an extreme front spread like 40/20, some experimenters like Jan Heine have designed short, stout cages to push the chain around and stay free of the chainstay (big chainstays, wide tires >42 mm and low, 8 cm BB drops) and achieve very low Q-factor for his randonneur bikes. So it's also a choice to go back to such 80-year old designs (Herse, Alex Singer, and other French constructeurs in the 1940s, plus innovators like Hirose), relying on modern chainrings and chains to assist shifting the wide range.

But this is pretty costly, being nearly 100% custom and shop-made.

jonwvara 01-13-22 08:37 AM


Originally Posted by Drillium Dude (Post 22371839)
...but really, who would use the smallest cogs out back with the smallest ring in front? Or big/big?

DD

No one rides around in the big-big on purpose, but even smart people make mistakes sometimes. If you shift onto the big-big without meaning to and the chain is too short, you're going to break something, and maybe hurt yourself. A slack chain in the low-low combinations is not ideal, but it's not really a safety issue. I cheat that way all the time, but learned the hard way about making sure the chain can handle the big-big. Even though, you know, you're never going to use the big-big. Except maybe that one time.

squirtdad 01-13-22 12:09 PM


Originally Posted by jonwvara (Post 22372217)
No one rides around in the big-big on purpose, but even smart people make mistakes sometimes. If you shift onto the big-big without meaning to and the chain is too short, you're going to break something, and maybe hurt yourself. A slack chain in the low-low combinations is not ideal, but it's not really a safety issue. I cheat that way all the time, but learned the hard way about making sure the chain can handle the big-big. Even though, you know, you're never going to use the big-big. Except maybe that one time.

+1 on this. I did a new build and did the chain a bit too small and too late to get another chain, but was excited to try the build.... so I went out knowing big/big did not work and was sure I would not go there.

Sure enough end of ride on a MUP and had to deal with uphill and combo of clueless adult, kid, animal and oncoming idiot on an electric fat tire bike, and slammed it into big/big without thinking.
Immediate stop, but was going so slow I was able to reach out, and grab lean on a fence and clipout. at speed it would not have been pretty

Germany_chris 01-13-22 12:16 PM


Originally Posted by thook (Post 22371274)
Oh, I know about all that. The max cog for those short cage XT's is 28 and the total capacity is 30. Either of the bikes' capacity is at least 39t, though

So the whole thread is disingenuous and snarky...I kinda thought it was

thook 01-13-22 01:03 PM


Originally Posted by Germany_chris (Post 22372569)
So the whole thread is disingenuous and snarky...I kinda thought it was

Snarky? Yeah...somewhat. But, I mean no real harm. ;) Disingenuous.....not really. I'd read some blog and participated in a few threads over the years about the idea of running a short cage with a triple. It made sense to me theoretically, at least, why it could be a good idea and how to get away with it. But, by and large others's opinions were it was stupid idea and served no real benefit. Well, that may all be true, but I had no idea there was a time pro's were actually doing it and that it had been an industry trend...even if only for a short time...and was surprised to find out. I was under the impression it was a more recent hack idea going around to try and eke out a little more performance. So, was is it just an expirement that was appropriately short lived? Does it really make a difference? I don't know. I"ve never tried running the set up...yet. I'm considering it once again. It does look pretty slick, too.

Erzulis Boat 01-13-22 01:06 PM


Originally Posted by Drillium Dude (Post 22371876)
After taking a detailed look at the rest of the bike, it seems the rider came up with a novel way of turning a rigid seatpost into a shock-absorbing one by removing the binder bolt and installing that V-shaped spring unit. If that makes sense; there doesn't seem to be any other reason for it.

Also like the brake reinforcing plate on the rear brake vice the front.

DD

I used to race MTB in that era. That is the predecessor to the modern dropper post. The spring (under control-rider "weight") would limit the travel upwards. You popped the quick release, and your weight would push post down for descents, and then a re-lock. Once back on flat/climb, you would loosen QR, and allow seat to rise under control to the designated stop (spring limit).

As the brakes became more powerful, sometimes the reinforcing bridge became necessary on the rear as well. You could plainly see the seat stays flex (some frames) out under braking and get this horrible squeal.

ETA- Got beat on the explanation

Erzulis Boat 01-13-22 01:14 PM


Originally Posted by dddd (Post 22371813)
The short cage on a mtb derailer is longer than on a similar road derailer. I've swapped them and the difference was there.
They are intended for use with triples, just not combined with the x-32t cassette in most cases.

Correct. I had the XT setup, and the box it came in specified "Medium". You had a very narrow window to get the wrap/capacity right, and I recall seeing what happened with too much/little chain for the setup. I wore mine out, and then went to a long cage XTR.

thook 01-13-22 01:50 PM

For funsies...a couple more short cagers...

https://cimg6.ibsrv.net/gimg/bikefor...1bee494aa9.jpg

https://cimg8.ibsrv.net/gimg/bikefor...d607799cba.jpg

Miele Man 01-13-22 03:18 PM

Isn't this why Suntour came out with their triple-pulley rear derailleurs design? The two upper pulleys acted as a short cage rear derailleur and then when in the lower gears the forward lowest pulley would take up the chain slack.

https://cimg8.ibsrv.net/gimg/bikefor...5d4fd008ac.jpg
Cheers

thook 01-13-22 03:51 PM


Originally Posted by Miele Man (Post 22372827)
Isn't this why Suntour came out with their triple-pulley rear derailleurs design? The two upper pulleys acted as a short cage rear derailleur and then when in the lower gears the forward lowest pulley would take up the chain slack.

https://cimg8.ibsrv.net/gimg/bikefor...5d4fd008ac.jpg
Cheers

I do believe it is the reason. And, of course, the design makes sense. I'm wondering about the whole idea of larger than normal pulleys within all this. I think it's a good idea for short/med cage RD's. I have Suntour 6000 series "med" cage RD with a larger than normal bottom pulley. It won't clear more than a 28t cog (that I know of), but I"m pretty sure it's supposed to be able to handle a triple within reason on total capacity vs the double the bike came with. There's another version of this 6000 that has both pulleys of the same size.
Anyway, probably this will bore anyone here reading this thread, but my Ross mtb started getting me to thinking about doing some mod's on it. It has Suntour XC Sport derailleurs, and I've mentioned this above, but the front derailleur cage drags the chain, so I had to use a smaller outer ring to enable me to lower the front derailleur. Originally when I acquired the bike, I couldn't use any of the cogs except the largest when in the granny before the chain would drag. So, I'm thinking if I can use a 42t ring as the outer ring, I could drop the FD even lower and have a chainset of 42/34/24 and a tighter freewheel or cassette cluster in the back. Like 13-26/28 or 12/26...something like that. Or, cutting things up even further. 42/28 and 13/30 freewheel.Then, I thought after running across the Salsa website maybe I could use that 6000 medium cage because the total capacity would have dropped closer to the 6000's factory range. <<<blah, blah, blah>>>....lol! I don't know. Just messin' around, but it'd clean up the drivetrain removing some redundant gears and give smoother shifting

ThermionicScott 01-13-22 04:08 PM


Originally Posted by thook (Post 22371920)
Well, the whole reason I started the thread was kind of in light of that. You can read all over the BF subforums about never using a short cage with a triple...or simply never exceed the total capacity. Which I get. There are inherent issues....one of them being potentially injurious. But, I never make big/big or small/small combo's.

It's one of those things where it's fine if you know what you're doing. But sometimes we can tell a poster is in over their head and doesn't really appreciate derailleur capacity, or remembering not to use certain gear combinations, so the simplest and I'd argue most responsible thing is to say "no, don't do that." :)

Because I do club rides and long brevets that impair my cognitive abilities, I include myself in both the "clever" and "idiot" categories. ;) Toward the end of a 1200k, I don't want to have to remember not to use the extreme gear positions, because that's when I'd accidentally shift into them and blow up my bike. So my drivetrains are set up so that any gear combination works (chain rubbing on the FD cage is non-fatal, so counts as "working" here.) If I need wide enough range, I'll suck it up and install a long-cage rear derailleur. My Deore 7-speed ones shift just fine.

One idea that comes to mind for squeezing more capacity out of a short-cage RD is to install larger pulleys. After all, that's how the big 3 are doing it. You might have to bend derailleur cage tabs out of the way -- or remove them entirely. (EDIT: in the long time it took me to compose this post, you already got to the larger pulleys idea. :lol: )

thook 01-13-22 05:28 PM


Originally Posted by ThermionicScott (Post 22372892)
It's one of those things where it's fine if you know what you're doing. But sometimes we can tell a poster is in over their head and doesn't really appreciate derailleur capacity, or remembering not to use certain gear combinations, so the simplest and I'd argue most responsible thing is to say "no, don't do that." :)

Because I do club rides and long brevets that impair my cognitive abilities, I include myself in both the "clever" and "idiot" categories. ;) Toward the end of a 1200k, I don't want to have to remember not to use the extreme gear positions, because that's when I'd accidentally shift into them and blow up my bike. So my drivetrains are set up so that any gear combination works (chain rubbing on the FD cage is non-fatal, so counts as "working" here.) If I need wide enough range, I'll suck it up and install a long-cage rear derailleur. My Deore 7-speed ones shift just fine.

One idea that comes to mind for squeezing more capacity out of a short-cage RD is to install larger pulleys. After all, that's how the big 3 are doing it. You might have to bend derailleur cage tabs out of the way -- or remove them entirely. (EDIT: in the long time it took me to compose this post, you already got to the larger pulleys idea. :lol: )

Together we stand....lol!!
Yeah, I do know that's the responsible thing to tell "no..don't". Again, I was just surprised to find pro's were actually doing it. Question is, does a short cage really even shift different enough to justify using one instead? I wouldn't know since I've never actually used one on any of my bikes

steelbikeguy 01-13-22 05:57 PM


Originally Posted by squirtdad (Post 22372553)
+1 on this. I did a new build and did the chain a bit too small and too late to get another chain, but was excited to try the build.... so I went out knowing big/big did not work and was sure I would not go there.

Sure enough end of ride on a MUP and had to deal with uphill and combo of clueless adult, kid, animal and oncoming idiot on an electric fat tire bike, and slammed it into big/big without thinking.
Immediate stop, but was going so slow I was able to reach out, and grab lean on a fence and clipout. at speed it would not have been pretty

I can identify with that! :)

Like anyone, I hope that I'm a rational person at least 90% of the time. However, I also know that my brain gets distracted now and then, or just starts shutting down due to environmental stresses (heat, hunger, etc) and that is when I'll do something stupid. Better to plan on that "stupid" happening now and then, and making stuff as stupid-proof as possible than to expect myself to be smart all of the time. We all know how that works out!

Steve in Peoria

Drillium Dude 01-13-22 07:03 PM


Originally Posted by jonwvara (Post 22372217)
No one rides around in the big-big on purpose...

In my experience I've seen it quite often. I notice it because the drivetrain is quite noisy and when taking a look to determine the cause: big/big. Often it's a rider who should know better :)

YMMV. Just calling it as I've seen it.

DD


All times are GMT -6. The time now is 12:50 AM.


Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.