I am attempting to replace the RSX crank on my Randonee with a slightly older Sugino MTB set that lacks the pin/ramp features on the chainrings. The RSX rings just removed are 26, 36, 48. The rings are also worn out and bent which motivated me to do this. The shifter and front derailleur remain original RSX parts.

The donor crank has 24, 36, 46 rings that show very little wear. I can't seem to get the derailleur adjusted to shift the Sugino rings reliably. What gives? Are the pins and ramps really that critical for brifters?

Have you lowered the FD as the new big ring is a smaller OD than the 48T? Go for that 1mm clearance again but fiddle with up a whisker or two if needed. Is the FD outter cage plate still dead parallel with the big ring?

Otherwise I'm in the dark and cannot help. I would guess that the shifting should work - assuming the chain ring spacing is the same on both cranksets. Hmm?

I've wondered about this spec oncte or twicte. For a triple, you will always have a much larger ring-derailleur space for the middle-granny shifts. Positioning the FD as close to the big ring as possible isn't going to help much. On the Tommasini I just built the braze-on FD mount won't let me set the cage that close to a compact double's big ring, and it seems to shift just fine anyway.

So about the OP's question, try re-installing just the original big ring. See if its ramps help the middle-big shift. It will give you a clue what to do next.

Did you just swap out the rings or the whole crank? If just the rings then the previous advice should be all you need. However, if you swapped out the crank as well you might need a different BB spindle. Different cranks take different spindle lengths even within the same mfger.

Ramps and/or pins are nearly essential to have brifters work. What I do to get old rings to work with them is to file ramps on them manually with a small file. Angle them so the new "flat" is directed to where the chain comes off the next lower ring. It works great. A small "flat" gives the chain enough purchase to climb up to the next ring easily.

I have made all sorts of size combinations work with just a little work with the file.

Not so much IME. Shifting is fine when backing off the power like in the olden days.

I set the outer chain ring to FD cage as close as I can without the backside of the FD cage hitting the middle chain ring. BB width is important, but there is some wiggle room. My Sugino crank sets all spec a 113-115 mm spindle, but the STI shifted one has a 110 mm BB.

Brad

There are many here more experienced than me, Jim is one. However, You can probably get this to work. It just depends on how comfortable you are at messing with the derailleur.

What I have done in the past, is lower the derailleur down to just above the top ring and then tweek the derailleur with a pair of pliers inward on the front side slightly where the chain makes contact with the middle ring. Usually I can get this to work.

These two cranks aren't that far apart in chainring sizing so the derailleur should work. Also the cranks may not physically sit in the same location (RSX crank chain line may have been closer to the frame) as before so you may need to choke up the shifting wire and readjust the limits on the derailleur. Also is the new crank fully tightened onto the bottom bracket?

I'm not someone who thinks lack of shifting ramps should prevent this from working. It would probably work easier with ramps but it should still work.

I only have STIs on a double, but its a double without ramps and shifts fine. No idea on a triple though.

My experience with rings on my triples is that ramps and pins make little difference. But I have found that using something like this allows me to set up the shift to the granny ring to over shift, without any risk of dropping the chain:

https://www.universalcycles.com/shop...&category=1615

I'm a believer in setting the FD as low as possible, as others have suggested. But I've never had much luck attempting to improve front shifting by tweaking the shape of the FD cage. I always adjust the FD so that the outer plate of the cage is parallel to the chain rings.

Note also the advice about BB width for the different cranks. The relevant dimension for front shifting is the chainline, typically 45mm for road triples. Chain ring spacing doesn't matter much, IMHO.

I've found that Shimano triple brifters are trickier to setup (I use Campy Ergo, which is essentially friction shifting in front) due to their indexed front shifting, but works fine once setup properly without ramps/pins. With Shimano brifters, it is important to use a road triple FD (Sora, RSX, 105, Ultegra) rather than an MTB version, but presumably you haven't changed that.

Just a thought - couldn't you simply put the Sugino rings on your RSX crank? I'd bet they are both 110/74mm BCD's.

No trouble with any of my triples, But I have Thumb and Bar End-Shifters that are friction, not a preset index..

Saw no need to complicate that , Although marketing drives that way..

My experience with Shimano brifters and triples is that the indexing basically doesn't work, pins and ramps or not. It might be made to work briefly on the workstand but almost never in the field. This includes both my own bike and those of friends that I ride with. Perhaps newer stuff works but I've never been able to get the older components to shift properly without significant overshifting and a bit of cursing.

There are thousands of riders who would disagree with this. Every brifter I've worked with has some overshift built into it. Andy

My experience is that if you want indexed front shifting to work quickly and reliably, you need to use ramped and pinned rings. If you use friction front shifting, you can achieve quick, reliable shifting in the traditional manner by overshifting and then trimming the front derailleur.

If all else fails it might be worth trying a 34T ring in the middle. Shimano's triple front derailleurs have a spec that is currently described as "Applicable Top-Mid tooth difference" but used to be "Top-middle minimum capacity". It's 11 for their current road FDs. I have no idea what this spec would have been on the RSX FD. My understanding is that this is an indication of whether or not the cage will be too high on the big chainring if it's set up properly to clear the middle ring.

While I think getting the cable tension dialed in just right is more likely to cause shifting problems, I can imagine the chainring size coming into play, particularly in light of the fact that the 46T ring is probably smaller than the FD is designed to handle.

Folks can tell I've already posted all my tricks/advice, so now I'm learning too. But I'm puzzled about the assertion that "brifters need ramps and pins". The brifters just yank on the cables, don't they and the chain does the climbing and diving. And I already use modern 9 sp SRAM and KMC chains on my outmoded crank sets with friction shifting and those chains work just great (3 old wrecks now and a 4th on the way). NO overshifting nor trimming needed on the FD - flip the lever and just keep going.

Another topic: I have Shimano 105 9 spd brifters and derailleurs on my C'dale (2000 R600) with an Ultregra triple. Like a Bic pen: works first time every time - very reliable and predictable action. Only around 5000 miles of experience though. Time will tell.

So back to the OPs question. How much are the pins and ramps needed for traditional non-powered shifting? I've always viewed FD/RD shifting like a driving a manual shift car (which I still do). Off the gas - punch the clutch - shift gears - blip the gas and ease out the clutch - go to the store. All this in a fraction of a second. I shift my bikes the same way. Maybe that's why I don't seem to need pins and ramps.

I look forward to more experienced input an advice.

It's not that a standard ring won't work with brifters, just not very well and definitely not under pedal pressure. Four or five pickup points make shifting fast enough to avoid "pressuring it up". It lifts as the first order of business.

The difference in anger is like a syncro transmission vs double clutching.

That said some standard rings work better than others. Some not well at all.

The analogies above are not lost on me. My daily driver is a non-synchro manual trans (T-18 to be precise). I just bought a Yaris for my daughter to drive. I was shocked to learn that Toyota no longer sells manual trans vehicles.

The willingness to give up control and involvement in many activities is called "improvement' by many. I call it wanting to withdraw from responsibilities. Andy

For mtb shifters I've never had any particular problems with front shifting on triples w/o ramps and pins. It's a little slower and noisier but to me entirely tolerable outside a race mindset.
Even with ramps and pins shifting under power is kinda nasty, so I simply don't do it regardless.

Must be different from market to market. They still do in Sweden, and presumably other European countries.
Although auto trans have become more and more common as the difference in fuel consumption have been reduced. Some cars can even boast a lower fuel consumption with an auto trans these days.

There was a very interesting treatise on front shifting in BQ last year. Lots of these points were discussed. They also followed my experiences with brifters and triples.

I had one of the first gen tri-color brifters from '97 and the left shifter sucked - only three shift points with no little "in between" half-shift points. No trim capability whatsoeve so my ranges without chain rub were severely limited. Shifting always required cursing. I took them off and replaced them with newer Microshift brifters.

I like the older ergopower brifters that are basically ratcheting shifters for the FD.

I like indexing for the RD, but FD's need more finesse. My wife's 2012 Sora brifters have more microshift spots. Its like they are trying to be like old ergopower shifters.