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Tripple vs Double chainring.

Old 06-08-19, 08:23 PM
  #76  
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i guess it actually is hard to set them up. you know.
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Old 06-09-19, 09:10 AM
  #77  
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Originally Posted by carlos danger View Post
i guess it actually is hard to set them up.
Only for some. Donít blame the tool.

you know.
No. I donít know. Iím a long time volunteer at my local co-op. I see hundreds... possibly thousands... of triples per year. I send that same number of triples out the door without rubbing issues per year. They often go out the door shifting better than they did when they came out of a retail shop.

I have observed some things that can make for better success when setting up and tuning a triple, however. First and foremost is choosing the proper front derailer. Shimanoís front derailers arenít as good as they should be. Shimanoís engineers have added all kinds of channels, sculpting and chain lift structures to their derailers, especially the more expensive ones. 105, Ultegra, Durace, XT, and XTR are all more difficult to set up than the lower line derailers because of all the special features Shimano has put in them. Tiagra, Sora, Clairis, Deore, Alivio, etc. are all far better front derailers. They are easier to set up and accommodate a wider range of gearing than their more expensive brethren.

Or just use SRAM fronts. They work with Shimano shifters (at least to 9 speed) and they are far better mechanisms.
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Old 06-09-19, 09:36 AM
  #78  
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cyccommute.

How does Shimano's Altus front derailleur rate.

That's what Giant put on my 2018 Sedona, And for the most part seems to be fine, At least for recreational riders. I find if I overshoot the small to middle chainring shift I have few problems with it. I've never had a problem of it rubbing.

I tried it climbing a steep hill and found shifting the 2 lowest gears on my Shimano Megarange cassette to be more effective, as I get a quicker, more consistent shift, and a slightly bigger jump/drop vs shifting to the small chainring. I really didn't think I'd like the Megarange cassette. I thought a more even spacing was best.

Last edited by xroadcharlie; 06-09-19 at 09:44 AM.
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Old 06-09-19, 10:29 AM
  #79  
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Originally Posted by cyccommute View Post
Only for some. Donít blame the tool.



No. I donít know. Iím a long time volunteer at my local co-op. I see hundreds... possibly thousands... of triples per year. I send that same number of triples out the door without rubbing issues per year. They often go out the door shifting better than they did when they came out of a retail shop.

I have observed some things that can make for better success when setting up and tuning a triple, however. First and foremost is choosing the proper front derailer. Shimanoís front derailers arenít as good as they should be. Shimanoís engineers have added all kinds of channels, sculpting and chain lift structures to their derailers, especially the more expensive ones. 105, Ultegra, Durace, XT, and XTR are all more difficult to set up than the lower line derailers because of all the special features Shimano has put in them. Tiagra, Sora, Clairis, Deore, Alivio, etc. are all far better front derailers. They are easier to set up and accommodate a wider range of gearing than their more expensive brethren.

Or just use SRAM fronts. They work with Shimano shifters (at least to 9 speed) and they are far better mechanisms.
Boy I wish I had been able to read this a few days ago. I was trying to get a 105 triple FD to play nice with an 8 speed double. Those channels and the sculpting you mentioned made it a chore to get to work.
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Old 06-09-19, 03:25 PM
  #80  
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Originally Posted by onyerleft View Post
Triples will soon be as deservedly dead as 26" wheels. But by all means, keep expending energy and mustering up every argument you can think of to justify them.
I don't disagree that on mid-upper end road bikes this is probably true. But I think you're implying our arguments aren't worthwhile - why is that?
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Old 06-09-19, 06:55 PM
  #81  
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Originally Posted by xroadcharlie View Post
cyccommute.

How does Shimano's Altus front derailleur rate.

That's what Giant put on my 2018 Sedona, And for the most part seems to be fine, At least for recreational riders. I find if I overshoot the small to middle chainring shift I have few problems with it. I've never had a problem of it rubbing.

I tried it climbing a steep hill and found shifting the 2 lowest gears on my Shimano Megarange cassette to be more effective, as I get a quicker, more consistent shift, and a slightly bigger jump/drop vs shifting to the small chainring. I really didn't think I'd like the Megarange cassette. I thought a more even spacing was best.
Honestly, the Altus works well. It may be low end but it is easier to set up than the higher end derailers.

The Megarange is a work around. Itís meant to basically have a bailout low gear with a workable lower range. The large step is necessary because there arenít enough gears for the smoother transition for lower gears like a 9 to 12 speed cassette gives. You could get a better gearing system but it would require some (slightly) major changes to the bike. Itís likely that your crank is riveted which means you canít just change the chainring. If you could change the chainring, you could replace the inner one with a 22 tooth and replace the freewheel (itís not a cassette) with a 14-28 freewheel which would give you a similar low gear but a better shift pattern. This comparison shows the new system.

If you have co-op near you, you might be able to find a used mountain bike crank which would allow you to change the gearing rather cheaply.
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Old 06-09-19, 08:28 PM
  #82  
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Oh how I wish the late, great Frank Berto was still with us to weigh in on this
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Old 06-09-19, 09:39 PM
  #83  
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Originally Posted by cyccommute View Post
Frankly, I think most of the problems that people have with triples are either from using old friction systems or from memories of old friction systems (like pre1995).
I dunno, things like "rub" get mentioned a lot which makes no sense in a friction-shifted context. And if you get much before 1990, there's almost nothing triple-specific going on, since neither shift gates nor interestingly-sculpted front derailleurs existed.

I certainly don't see how the friction shifting itself would be a culprit. In my experience, flawless indexed front shifting is generally still flawless when used with a friction shifter, and friction shifting can allow all kinds of crazy setups that would never work with indexed shifters to behave somewhat reasonably. Like half-step-plus-granny arrangements, or those absurdly wide-range doubles like 44-20 that "shift fine" according to the people who use them.

Everything crank or chainring made since about 1995 has shifting ramps and pins which make shifts on doubles or triple trivial.
I'm wonder how much the shift ramps have to do with it, given the typically small size of shifts on triples. I've got multiple unramped triple setups in my stable that shift flawlessly.

Ramps are also only a consideration when a factory-standard gear combo is being used; unmatched shift gates in custom setups don't seem to accomplish much of anything in my experience.

The return springs in derailers are far stronger than they used to be as well.
This probably does matter. One of my drivetrains is running a 1970s Sugino Mighty Tour triple, currently fitted with 52-42-34 chainrings, with a 1970s straight-cage Suntour Cyclone front derailleur. The middle-to-small shift can be a little baulky if the upper run of the chain is kept under high tension.

That's not an issue which actually affects me very much, though... on my ride yesterday I had a moment where I was chasing an ex-pro up a steep hill*, and even there, that front downshift was snappy and clean. Amusingly, I actually had more trouble with my rear shifting: the switch from the 24T to the 28T on my TZ20 freewheel clanked a couple times under the strain before completing.

But, I suppose that it could be a big problem for someone with poor technique, who doesn't shift until the cadence has already badly bottomed out.

*There's a segment that contains the rise that averages about a 4% gradient where we averaged just under 17mph, and his power meter was clocking a sustained 550W on the steep bit, so I was pedaling pretty hard.
Not to say that I'm a particularly strong cyclist... this guy was cruising along at those intensities on a 50-mile ride, I only rode along with him for about 10 minutes. One of many interesting pieces of a whacky 109-mile road adventure.

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Old 06-09-19, 10:05 PM
  #84  
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Originally Posted by carlos danger View Post
aka 300% what more do you need?
Depends on the ride, but there have been times where I wanted a lot more than that.

The 305% range on my 70s Fuji was mostly adequate for yesterday's ride, since even though it was very long, it didn't go into many very aggressive hills. The 34-28 low gear was always comfortable (but only just), while the 52-14 top gear started to get slightly strained a little on a shallow descent where a very strong cyclist at the front was absolutely hammering.

For rides that venture into the gravel roads of the Cascades foothills, I want a much lower bottom gear. Significantly sub-1:1. I could climb most of those hills on 34-28, but when I'm faced with a mile of loose rocks at a 12% gradient, I'm much faster and fatigue much less on an itsy-bitsy gear.
Obviously that kind of low-end is doable with a double, but if I also want classic road gearing with a high top-end and tight spacing on the same bike at the same time, a triple makes that much more doable.

Loaded touring is another situation where a super-wide range is desirable. If I've been riding into headwinds for the last 90 miles, and suddenly a 16% hill shows up, and I don't want to burn my legs up (because I'm going to go over a big mountain pass on the next day and the next and have another big ride the next day after that), I'm going to want some very small gears. And again, I'm road riding, so I don't want 18% gaps between all my gears.
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Old 06-09-19, 11:56 PM
  #85  
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Originally Posted by cyccommute View Post
Honestly, the Altus works well. It may be low end but it is easier to set up than the higher end derailers.

The Megarange is a work around. It’s meant to basically have a bailout low gear with a workable lower range. The large step is necessary because there aren’t enough gears for the smoother transition for lower gears like a 9 to 12 speed cassette gives. You could get a better gearing system but it would require some (slightly) major changes to the bike. It’s likely that your crank is riveted which means you can’t just change the chainring. If you could change the chainring, you could replace the inner one with a 22 tooth and replace the freewheel (it’s not a cassette) with a 14-28 freewheel which would give you a similar low gear but a better shift pattern. This comparison shows the new system.

If you have co-op near you, you might be able to find a used mountain bike crank which would allow you to change the gearing rather cheaply.
Thanks for the info. Very useful. That chart is great too. I will have to save the link. Seems like my math is correct. Took me hours to set up a chart on Excel using the 25.9" diameter of my 26 x 1.95" tires with almost identical results. Looks like the chart is set for 26" tires.

Bingo on the riveted chainrings too.

As you can see on the chart, The biggest gap is from the two lowest gears. I have found very few situations around here with mostly short hills that require any less then the 30 gear inches the 28/24 combo provides, and the available steps to 89 gear inches (which I seldom use) using the 3 chainrings are reasonable IMO.

I was also looking at Giant's handsome Cypress 7 speed bike with it's 34 - 83 GI range, Which is enough for my needs, but with only one chainring and the big jump from 1'st to 2'nd of 34 to 48 GI on the Megarange freewheel is way too high before the steps are more reasonable, even for a recreational rider.

Last edited by xroadcharlie; 06-10-19 at 12:07 AM.
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Old 06-10-19, 12:13 AM
  #86  
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I've been running triples for 45 years. Many had rub. Some of them I set up intentionally so they rubbed. (Before ChainWatchers, that stopped a lot of deraillments.)

I'm still wondering what is the crisis that rub causes. Is it leading folks with sensitive ears to deafness? Insanity? Are there laws against rub I don't know about? Yeah, it does wear out FD cages but on quality FDs with substantial cages, that takes quite a while. And that wear is very easy to check. Are front derailleurs an endangered species? (That might be it! With 1X, we need to protect every living one.)

I guess I will have to keep studying this issue unless someone here can help me.

Ben
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Old 06-10-19, 12:26 AM
  #87  
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Originally Posted by 79pmooney View Post
I'm still wondering what is the crisis that rub causes.
This:
Insanity
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Old 06-10-19, 08:16 AM
  #88  
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I read a lot of this thread an here is my totally worthless opinion.

It's like vitamin supplements. If you are taking them there is no reason to stop, if not, no reason to start. If you have a triple there is no reason to sell it if not there is no reason to buy one.
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Old 06-10-19, 08:45 AM
  #89  
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Originally Posted by HTupolev View Post
I dunno, things like "rub" get mentioned a lot which makes no sense in a friction-shifted context. And if you get much before 1990, there's almost nothing triple-specific going on, since neither shift gates nor interestingly-sculpted front derailleurs existed.

I certainly don't see how the friction shifting itself would be a culprit. In my experience, flawless indexed front shifting is generally still flawless when used with a friction shifter, and friction shifting can allow all kinds of crazy setups that would never work with indexed shifters to behave somewhat reasonably. Like half-step-plus-granny arrangements, or those absurdly wide-range doubles like 44-20 that "shift fine" according to the people who use them.
I wasn't thinking in terms of "rub" but in the lack of "snappiness" that people complain about with triples. Old friction systems with flat rings were a bit more balky than more modern index systems.

By the way, I'm one of those people with what most would consider a crazy set up like a 44/34/20 for mountain biking and a 48/36/20 for a touring bike. But I'm using index systems on both mountain and road bikes. Shifts are never a problem in any situation I've run across.


Originally Posted by HTupolev View Post
II'm wonder how much the shift ramps have to do with it, given the typically small size of shifts on triples. I've got multiple unramped triple setups in my stable that shift flawlessly.

Ramps are also only a consideration when a factory-standard gear combo is being used; unmatched shift gates in custom setups don't seem to accomplish much of anything in my experience.
I think the shift ramps help tremendously. Gone are the days of a lot of clattering to get the chain from the middle ring to the outer ring. Doubles clattered just as much but the fog of nostalgia clouds people's memories.


Originally Posted by HTupolev View Post
IThis probably does matter. One of my drivetrains is running a 1970s Sugino Mighty Tour triple, currently fitted with 52-42-34 chainrings, with a 1970s straight-cage Suntour Cyclone front derailleur. The middle-to-small shift can be a little baulky if the upper run of the chain is kept under high tension.

That's not an issue which actually affects me very much, though... on my ride yesterday I had a moment where I was chasing an ex-pro up a steep hill*, and even there, that front downshift was snappy and clean. Amusingly, I actually had more trouble with my rear shifting: the switch from the 24T to the 28T on my TZ20 freewheel clanked a couple times under the strain before completing.

But, I suppose that it could be a big problem for someone with poor technique, who doesn't shift until the cadence has already badly bottomed out.

*There's a segment that contains the rise that averages about a 4% gradient where we averaged just under 17mph, and his power meter was clocking a sustained 550W on the steep bit, so I was pedaling pretty hard.
Not to say that I'm a particularly strong cyclist... this guy was cruising along at those intensities on a 50-mile ride, I only rode along with him for about 10 minutes. One of many interesting pieces of a whacky 109-mile road adventure.
The failure of the chain to drop from the middle to the inner ring was always a problem in mountain biking. That's why the reverse action front derailer was such a breath of fresh air. Mountain biking is usually done on the edge of that low cadence problem and it's also done on steeper angle trails which slows the cadence even more. There was a real art to shifting soon enough, throwing the shift lever fast enough, easing off on pedal pressure just enough to avoid stalling out and getting the chain to drop but not drop off completely. I can do it but it would be so much nicer not to have to.
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Old 06-10-19, 08:53 AM
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Originally Posted by xroadcharlie View Post
cyccommute.

How does Shimano's Altus front derailleur rate.
I find chainrings are far more a critical factor in front shifting than the derailleur. Good pick-up points matched to the chain, and pretty much any derailleur will work well as long as it's not wildly out on size or adjustment.

Steel chainrings can have wilder pick-up shapes, resulting in a more secure shift. And usually do.
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Old 06-10-19, 09:07 AM
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Originally Posted by MikeyMK View Post
I find chainrings are far more a critical factor in front shifting than the derailleur. Good pick-up points matched to the chain, and pretty much any derailleur will work well as long as it's not wildly out on size or adjustment.

Steel chainrings can have wilder pick-up shapes, resulting in a more secure shift. And usually do.
I agree. The front derailer is fairly unimportant. The only problem I have with Shimano's expensive ones is that they are more finicky about set up. Most of them function like they are supposed to but the more expensive ones are less forgiving and tend to be more difficult to tune so that they don't rub in some gears.

That said, the most useless of front derailers that Shimano has ever made is the SHIMANO XTR FD-M952 carbon fiber e-type. It looks really cool but it functions really horribly. The carbon fiber plate is too flexible and it bends during shifting which means that it bends back when not being shifted and the bike drops the chain to the next inner ring. Just pulling with the cable can make it go through about a 6mm arc. It alone could have killed triples!
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Old 06-10-19, 10:36 AM
  #92  
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Update on my above post. I did my first longish ride on the '78 Super Course with the Sakae 52/42 double and a 34t 6 speed Megarange. On a 44 mile Malibu run, I had a 17.2 mph personal best average. My other Super Course has an identical drivetrain, except for the Suginio AT 50 /40/32 triple. I've ridden it several times on that ride, but yesterday's ride was the fastest. Not scientific, might have been a great tail wind, or trying to keep up with the aluminum and carboned other riders, but what a great day on the bike. I've always been a triple guy, but my last two builds have been doubles, and as long as you don't carry a lot of weight, or do big hills, I'm liking the double's crisper shifting, and think I may try a 52t on the Super Course triple and see what happens. The two biggish hills yesterday were doable with the 34t rear and 42t front ring. I built the other SC with a triple and Megarange 34t for Eroica, and still walked three hills!
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Old 06-10-19, 10:54 AM
  #93  
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Originally Posted by cyccommute View Post
I wasn't thinking in terms of "rub" but in the lack of "snappiness" that people complain about with triples. Old friction systems with flat rings were a bit more balky than more modern index systems.
What I was getting at with the comment about "crazy" setups, and about where pins and ramps help, is that this is very contingent on the particular gearing arrangement. I've got several bikes with 10-tooth unramped jumps between the small/middle and big rings, and they don't balk at all. The chain just snaps into place every time.

Here's one setup on the stand, but it works pretty much the same on the road:


By the way, I'm one of those people with what most would consider a crazy set up like a 44/34/20 for mountain biking and a 48/36/20 for a touring bike.
I meant "crazy" in terms of straining the design of front derailleurs. Those are a little bit non-standard in that it looks like you've swapped in smaller inners on what might be OEM combos, but they're still within the bounds of what a standard triple FD might cleanly handle: the middle ring is sufficiently smaller than the big ring that the inner plate can clear on middle-to-big upshifts without the derailleur being positioned too high, the middle ring is still big enough relative to the big ring that the outer plate of the FD is low enough to cleanly kick the chain down to the small ring on middle-to-small downshifts, and although small-to-middle and middle-to-small jumps are big, at 14-16 teeth they're not absurdly big.

The really challenging triples are things like 50-46-28, or 50-32-28, where you can't really position an FD so that all of the four possible shifts are handled in a sensible way.
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Old 06-10-19, 12:14 PM
  #94  
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Originally Posted by MikeyMK View Post
I find chainrings are far more a critical factor in front shifting than the derailleur. Good pick-up points matched to the chain, and pretty much any derailleur will work well as long as it's not wildly out on size or adjustment.

Steel chainrings can have wilder pick-up shapes, resulting in a more secure shift. And usually do.


That makes perfect sense now that you mention it. The chainrings on my Suntour XCC crankset are steel. And despite being a low end Crankset and derailleur, This combination seems to work surprisingly well.
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