CrowSeph

I had the Deore M591On my first mountain bike i had the old Deore M591 from 2005-2006 (The worst derailleur of the history).
One year ago i made an hybrid bike (more like a gravel type) with the deore lx M550 a derailleur from 1989 , and that derailleur perform better (even with friction shifter haha) than the newest M591.
But if i had to compare all the older version with the new M4100 the differences are a lot , is more stiff , more stable with chain tension and also more quiet and precise.
But the main fact is not about a single part , is about the little difference of improvement a new bike can offer. Don't waste money on upgrade into an old bike (as i did) just find your type a buy a new one.

Ironfish653

Have there been improvements? Yes, but not so much at the bottom end of the market. Functionally, the last big shift was the Suntour Slant Parallelogram in the 1970s.
There is some ‘trickledown’ from the high end groups, like Di2/eTap, and clutched MTB derailleurs, but nothing you’re really going to see at the Alivio level the OP is asking about.

A $500 bike is a ‘price point’ bike, and at that level, the manufacturer and component suppliers are looking more at cost and a decent level of durability rather than performance, when they spec out a new design.
I’d venture to say, that if you examined a $500 hybrid bike (typical Alivio) from 2021, 2006, and 1991, you probably wouldn’t find a whole lot of differences; brakes would probably go canti > V-brake > disk, and the driveline would go from 3x7 to 2x9, but those are just details

Phil_gretz

I have been hands-on with derailleurs since the early 1970s. To answer the original question, yes, there have been significant improvements in derailleur performance in the last 16 years.

- Road group front shifting - the latest generation of Shimano's front derailleurs (105 -> DuraAce) have improved adjustment, ease of installation, and shifting. They are better.
- Shadow rear derailleurs - for mountain groups, this helped to get the derailleur out of the line of fire when riding through/between obstacles. It's an improvement. And the increased chain tension due to the clutch design all-but-eliminates routine chain slap. Maybe someone from the industry can comment on howwhen/why Shimano migrated the shadow mounting and mechanicals over to the road group, but my R8000 rear derailleur seems to have some commonality with earlier SLX and above mountain groups.

As for Alivio, no. Not so much. Would I use one on a flip? Sure.

As for SunTour Seven, it was a functional derailleur as were all of SunTour's offerings. But we didn't go out and replace with out Huret or Simplex derailleurs with steel SunTours (Honor, etc.), we went for the aluminum models to save weight on our 28-pound boom bikes.

L134 

I had one of those lying around that I naively put on my Atlantis before a 1 week trip on the GDMBR just to get the amazing chain wrap figuring I might accidentally cross chain too much when on my 19t chain-ring. Another rider laughed at my choice when inspecting my bike. I thought I would take it off when I got back home but it has performed so well it is still there around 3k miles later. Not mega miles but it is still doing a fine job.

cyccommute 

Shimano introduced shadow technology about 16 years ago. They introduced clutch technology a year or so later. Sure it was only available on higher end but it was available. Shimano is pretty good about trickling down technology to lower level components, however. The current Alivio is better in terms of fit and finish than the 2005 version but the 2005 unit wasn’t horrible. It worked well for a cheap unit.

DAC76 probably isn’t going to notice much shifting difference with new components of the same level. If DAC76 is looking at a new bicycle, a $500 bike now is going to be significantly worse. Instead of Alivio, it will have a Tourney which is far worse than even an old Alivio.

Phil_gretz

Yes. Exactly. Which is why many of us find and build up vintage bikes. For $500, you can have a pretty terrific vintage bike to ride, if you have the know how and the patience.

travbikeman

My first mountain bike a Trek think it was a 95, maybe 94 Mountain Track 830. It had the Alivio think the MC12. From what I remember to what I'm using now with the Alivio M4000, not a whole lot of difference in the shifting itself. More differences in the shifter, since back then I used the grip shifters instead of triggers. Have a few more gears now, but unsure if the lighter shifting I feel a bit now is due to the shifters or other factors.

What disappoints me on the new Alivio M4000, is how quickly it wears out. This past December I had to replace the then 6 year old Alivio on my prior bike because the plastic areas around the rivets or pivots on the body were far too loose to allow proper adjusting. The entire derailleur was wobbling all over. I don't remember that ever happening to me before. I had spent a long time attempting to adjust it and gave up and bought of course a new Alivio M4000 where the new one was easily installed and adjusted.

starchase

His link should start http and not https

cjenrick

which Suntour Superbe Pro rear derailleur model is he best? i am running a straight block and do not need the long cage Cyclone 2. thanks for any help.

Moisture

I've actually gotten my old Suntour replaced with a new condition Acera last week:



Great derailleur. I've used the Tourney, Altus, Acera, Alivio extensively (as well as the deore briefly.) Between all of them, I'd say the biggest step up in shifting quality was the altus. After that I didn't find any major difference in shifting performance. They are all good. I think acera strikes the best balance with cost to performance ratio.

Neither my old suntour nor the new acera was designed to be used for friction shifters- especially not with my 9 speed cassette. my suntour with its bent pulleys seemed to be a bit more reliable specifically when shifting in the bigger cogs. I get a bit of occasional ghost /funky shifts towards the inner part of the cassette. But for the most part shifts are a bit smoother and otherwise the same in terms of response under power.

The newer derailleurs are designed to tension the chain automatically based on body position whereas with the suntour you can tighten down the hex bolt holding the derailleur to the hangar to tension as you please. The newer design is better.

Biggest advancement here id say would be the pulley cage. It keeps the chain straight and in place to avoid skipping. Compared to the primitive design on my old unit where you can easily slip the chain off the pulleys...

Otherwise, no major differences between old or new, more or less expensive units. They all do the job properly. Id say the Suntour was more robust and resilient to abuse.

cyccommute 

Nope. The Suntour GT was a friction derailer because it was made about 20 years before indexed shifting was a thing. The Acera was designed for indexed shifting but there isn’t anything that prevents it from being used with a friction shifter. Are you trying to use the Suntour with indexing? If so, it may not work properly as the pull ratio may not be correct for indexing.

I’m not sure what you mean by the Suntour’s “bent pulleys”. Friction derailers need just as straight an alignment as indexed derailers do to work properly. If the cage is bent or if the hanger is bent, the derailer doesn’t work like it should.

Nope. The derailer hanger bolt on the Suntour was a step bolt that only allowed for a certain amount of tightening before the “step” hit against the hanger. The A knuckle on the Suntour needed to turn freely for the derailer to move correctly. I could be wrong but I don’t think the Suntour had a spring in the A knuckle like the more modern derailers does.

Again, nope. If your pulley cage was bent on the Suntour, the derailer was damaged. The Suntour did have an open design that is somewhat less stiff than modern derailers but that shouldn’t cause skipping in friction mode. The mismatch in derailer design is likely the cause of skipping.

MrWasabi

Great thread. If you don't mind I'm going to gravy train some advice. I have a 2014 Fuji Traverse with a Deore rear (model?) and Acera front derailleur that came stock. I was going to replace them both with Deore M591 derailleurs (2015ish) and at the same time the stock Shimano Acera Rapid Fire shifters with Deore 590 RapidFire Plus shifters. I already have the parts in my stash and my shop said it won't cost much to swap them as I'm getting new bars at the same time. Should I even bother with the new derailleurs and will I see any improvement? I like the 590 shifters better and thought why not just do them all at the same time.

Thanks for any input.

Road Fan

Discussions like this are usually so riddled with vagueness as to be not very useful. At the risk of shadowing Robert Pirsig, what is quality? Weight? Durability? Smooth shifting? Excellent untoothed shifting? More capability (more/bigger gears)? More little wheels? More pivots? More consistent free chain length?

what are “the old days”? For me it might be 1967. For Moisture it seems to be 2000, leaning into my idea of “modern.”

Or is quality from a time sensitive perspective? Are Nuovo Record mechs superb because they were the best of their day, or total trash because they are nearly unusable in a really modern machine? And is the arguably better shifting of a new Delrin Simplex a factor?

Or is it all about color?

It’s a decent discussion for a snowy winter, better than bar wrapping or chain lube. Gentlemen, start your engines!!!

sbarner 

Among the limitations of cheaper derailleurs is in the pivots and strength. It is counter-intuitive, but stamped steel parts are usually less able to resist unusual bending stress than aluminum parts. If there's a redeeming value, it's that you can sometimes bend the steel back, where aluminum would crack or snap. On a complex device like a derailleur, getting it to work well again after bending is likely going to be a potentially insurmountable challenge. In terms of pivots, most steel derailleurs I've seen have parallelogram arms made of flat steel, bent into a U cross-section with the pins simply going through holes punched in the arms. There's not much bearing surface there, and the resulting wear introduces slop which reduces shifting precision. Mid-range aluminum derailleurs may or may not be much better, but most people would both never notice, and never ride their bike enough for it to be a problem.

The reason why the Campagnolo Gran Sport / Record / Nuovo Record / Super Record series stayed popular over its 37-year lifespan was that its shifting didn't really change, no matter how many miles you put on it, as it used full-length brass bushings on the parallelogram pivots, and similar robustness in other places. It was true that Suntour and Shimano had much better shifting units by the mid-1970s, and the introduction of functional indexed shifting in the mid 1980s fully defined Campagnolo's design as anachronistic, leaving Campy to frantically doing its experimentation out in public, with four or five completely different technologies being sold at the same time out of a desperate attempt at survival and relevance. Simplex had great shifting derailleurs, and they could be seen as cutting-edge, using space-age plastics, but their insistence in sticking with Delrin in high-stressed parts, when it so obviously didn't work in the consumer products world made them deserving of their demise. When they finally switched to all-metal designs, they managed to do so in a way that didn't improve the fragility of their derailleurs much at all. Their pushrod front derailleur would have been an amusing amalgam of high-tech materials and obsolete design, if you didn't have to sell new bikes with them. About the only thing good I can say about Simplex after 1960 is that they came up with those amazing retrofriction downtube shifters. You do have to hand it to Simplex, though, in being the only manufacturer to come up with a product called a "demultiplicator" so you could get decent shifters from other manufacturers to work well with their crappy derailleurs. (Technically, they were to get the cable pull of their barcons to work with their own derailleurs, but they were useful for other shifter swaps as well, as the plastic Simplex shifters were truly horrid.) Simplex did make metal shifters for people who actually rode their bikes.

Russ Roth

From what I've seen and worked with there will be slight improvements but Altus is one of those levels that if set up with good cables and housing just works well, nothing exceptional but reliable. Where better shifting comes from at this level is replacing worn cassettes and chains with better quality ones. A lot of shifting performance comes from the chain design, ramps on the cassette and ramps and pins on the crank. Altus cranks have gotten slightly better so you might see a little improvement but if chain and cassette are worn better will help.

HTupolev

Your old SunTour was designed to be used with friction shifters. SunTour did start building indexed derailleur drivetrains in the mid-1970s, about the same time that the Seven was introduced, but these were specialty systems where the indexing mechanism was integrated into the derailleur: they were very complex derailleurs, and the Seven definitely isn't one of them. Modern systems where the indexing happens at the shifter didn't take off until the launch of Dura Ace 7400 in 1984.

That's not how the b-pivot works.
The purpose of b-pivot adjustment isn't to modify the chain tension, it's to modify how far the upper pulley wheel (the jockey wheel) is sitting away from the cogs. You want this gap to be small enough that the shifting is good, but big enough that there's no interference between the derailleur and the rear cogs.

You are not supposed to adjust the angle of the SunTour Seven with the bolt that holds it to the hanger. You're supposed to adjust it with the much smaller bolt that rests against the stop on the hanger:



The Acera has a similar bolt that is intended to be used for the exact same purpose.

The reason that the hanger pivot on the Acera is sprung isn't so that it adjusts itself automatically to a given setup, it's because the derailleur is intended to rotate during use. Shimano's modern "Shadow"-geometry derailleurs are actually more like the old SunTour derailleur in this regard: the upper body of the derailleur is not intended to rotate during use, and there is no spring on that pivot.

The open cage on the old SunTour isn't "primitive", SunTour did it intentionally so that you can remove the chain from the derailleur without breaking the chain. For long-cage derailleurs, I also personally think that it achieves better aesthetics: it allows the entire part to cohesively flow together in a "sigma" shape, whereas with closed-cage derailleurs, the cage often looks weirdly flat and chunky next to the knuckles and parallelogram.

The open cage does make it possible for a chain to escape the cage during use, and I wonder if modern chains are more prone to this because of their lateral flexibility. I have one bike that I swapped from a Cyclone to a slightly-newer SunTour XC with a closed cage, because the chain escaped the Cyclone a couple times.

Anyway, SunTour definitely understood how to make the closed derailleur cages that you consider to be a less "primitive" design. Plenty of SunTour derailleurs that predate your Seven had closed cages.

rydabent

I would say that after the patents on the first indexed shifters ran out, probably in about 2000, their slant parallel geometry has been adopted by most makers. That just leaves the quality of bearings, and how pretty they are to define them. When adjusted right most brands shift very well these days.

HTupolev

The slant-parallelogram geometry was developed by SunTour in the 1960s. The relevance of the patent to indexing is that Shimano introduced modern indexing in 1984, the moment the patent expired. The only thing that stopped other companies from adopting the geometry at the same time was their own lack of foresight.

While Shimano's RD-7400 was innovative in 1984, I'm not sure that it was actually very patentable. None of its mechanical features were really "new," at least not independently. When Campagnolo finally stopped flailing around in 1990, the new Record R010 was pretty much a Campy-styled copy of the RD-7400.

rekmeyata

Mechanical Shifting has NOT improved. Vintage late 80's index down tube shifting derailleurs actually work a tiny bit faster and snappier at shifting than modern briftors, why is that as you scream while cussing at me? All briftor technology is, is index shifting, that's all it is, they simply moved the downtube shifters to the brake levers, why is the downtube shifting a wee bit faster and crisper you scream while pounding your keyboard demanding an answer? because the cable length is shorter than a cable run from the briftor to the derailleur.

Ironfish653

Lighten up, Francis. No one here is yelling except you.
We're discussing deraillieurs; take your downtube shifters and go here: (indexed) Downtube shifters should make comeback

Most of the animation in this discussion came when Moist turned up. He's been doing a 'Reverse Columbus' of the last 40 years of design and development of the bicycle, based on his pair of strange, cobbled together beater bikes. Since apparently these things are rideable for a few miles, he's making new discoveries that have to be shared with us native Dirty Heathens (TM)

rekmeyata

Well look here SuzieQ, I think your blood pressure got too high, I wasn't yelling, just explaining the facts, so go see your doctor and get that prescription of pills that make you nice again filled. By the way SuzieQ, I was talking about derailleurs, or did you not know that derailleurs went from a rod to friction to index to electronic?

Ironfish653

Wow, projection much?
If you really want to get pedantic, derailleurs aren't indexed, the 'shiftors' are. I also know that you can change gears without a derailleur or a shift lever, at all.

And, if you'd read the OP, rather than just wading in to awe us with your DT shifting prowess; The question that was asked was whether there was any benefit in upgrading a 2004 Alivio RD to a 2020 version of the same Alivio RD.
It started going sideways when Moist weighed in that older is better because his '80 Norco beater has a Suntour Honor, and it's made out of steel.

I bet your sock lines are razor sharp

rekmeyata

Phil_gretz

fify

HarborBandS

The main difference I can see is shifter throws and resistance, particularly with regard to “brifters”. It’s more apparent at the 105/Ultegra/DA level. The front derailleurs in particular took more force to move up to the big ring.

I had a Trek 8700 with Deore XT drivetrain in 1995, and it shifted as well as any bike I’ve ever owned. Shimano had the chainring pins and ramps on higher end drivetrains dialed in by the mid 1990s. And those trigger shifters were pretty slick.