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Long Distance Competition/Ultracycling, Randonneuring and Endurance Cycling Do you enjoy centuries, double centuries, brevets, randonnees, and 24-hour time trials? Share ride reports, and exchange training, equipment, and nutrition information specific to long distance cycling. This isn't for tours, this is for endurance events cycling

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Old 12-18-17, 09:52 PM   #26
joewein
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Originally Posted by Tourist in MSN View Post
But I still use enough chain links to make sure that if I accidentally shifted onto the big and big gear, I would not damage anything.
Yes, exactly! If the rear derailleur doesn't have enough capacity to cover everything from small-small to big-big, then one needs to err on the safe side, and that is to avoid getting the derailleur sucked against the cassette if one shifts to the biggest sprocket while on the big ring.

By providing enough chain length to avoid this case, a setup with insufficient RD capacity will then have the chain go slack with a small ring-smallest sprocket combination, but that is nowhere near as dangerous (or as likely) to accidentally happen as the other extreme of cross chaining.
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Old 12-19-17, 12:08 AM   #27
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Incorrect. I have been running a rear Deore M591 with a 11-36 cassette on one of my bikes for some 6+ years (roughly 12k miles). The B-screw allows for 36t in the rear with some room to spare, and shifting is great.

Not a problem, since such a derailleur does not need to exist.
A sane and experienced rider won't need to use the 4 smallest rear cogs with the granny (nor the 4 largest rear cogs with the large chainring for that matter), meaning that the total capacity practically needed is much less than the calculation quoted.

Incorrect. More theoretical hogwash.
116 links is OK for 50/36 with up to 465 mm chainstay, which is a very rare breed of a bike. One of my bikes with 50/36 and 435 mm chainstay gets the full wrap with 112 links.
I never said an M591 wouldn't work. Obviously you could coax an M591 to work okay with the B screw. Still, OP posted a link to Amazon, so I assumed he hadn't bought a new RD at that point. I was merely pointing him to 9 speed rear derailleurs designed to work with a 36 tooth large cassette cog so he didn't need to fuss with the B screw.

As far as using an 11-40 cassette with a 30-39-40 crankset, I, personally, would recommend against it. Far be it from me to dictate how another person sets up their own bicycle, however. Just be aware of the limitations of your equipment and operate within them.

The Marin 4 Corners has 450mm chainstays, while the Specialized AWOL has 455mm chainstays. I thought that as the models have such similar geometry, it was a point worth making, and my hogwash was somewhat more than theoretical. My AWOL really did not like the big-big combo with a 114 link chain when I accidentally changed into 50-36 and seized up my drivetrain, having to remove the rear derailleur to get everything moving again. I thought it was worth mentioning to OP in case he had the same issue as I did with a 114 link chain.

Last edited by PDKL45; 12-19-17 at 10:02 PM.
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Old 12-20-17, 01:28 PM   #28
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No, I haven't bought anything yet. I returned the 64mm 24t front ring and am currently looking for a 24t 74mm 4 bolt...which I'm not sure even exists. Seems the simplest solution would be to remove the 30t front ring and replace with a 24, or maybe a 26 and see if that works.
At the same time, before I do anything drastic, I may put a load on and try some steep climbs around here.

For clarity, I have a tendency to really push it when I ride on my carbon road bike. I now have this steel touring bike, and I have to force myself to try and just slow down. May be that if I adjust, and quit trying to get up a hill as quickly as I'm used to, and use the low gears I have, it may be sufficient. At the same time, I see most others on here obviously advocate much lower gearing for their long distance/touring bikes, especially considering long climbs.

But right now I'm not spending much time on it, I work in retail and this week is kinda crazy.

Thanks for the info, to all who have taken the time.
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Old 12-20-17, 02:50 PM   #29
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No, I haven't bought anything yet. I returned the 64mm 24t front ring and am currently looking for a 24t 74mm 4 bolt...which I'm not sure even exists. Seems the simplest solution would be to remove the 30t front ring and replace with a 24, or maybe a 26 and see if that works.
At the same time, before I do anything drastic, I may put a load on and try some steep climbs around here.

For clarity, I have a tendency to really push it when I ride on my carbon road bike. I now have this steel touring bike, and I have to force myself to try and just slow down. May be that if I adjust, and quit trying to get up a hill as quickly as I'm used to, and use the low gears I have, it may be sufficient. At the same time, I see most others on here obviously advocate much lower gearing for their long distance/touring bikes, especially considering long climbs.

But right now I'm not spending much time on it, I work in retail and this week is kinda crazy.

Thanks for the info, to all who have taken the time.
On a road 30-39-50 triple, it will be 74 BCD with five bolts; four bolts is used on MTB cranksets. This is what you are looking for:

wiggle.com | TA 74 PCD Zelito Triple Inner Road Chainring 24-30T | Chainrings

However, and keeping in mind that it may just be theoretical hogwash, the Sora front derailleur for triples is designed for a 20 tooth difference btween the smallest and largest chainrings. While Shimano are conservative in their numbers, adding a difference of six more teeth may result in slightly rougher shifts or degraded performance in that derailleur.

It shouldn't be a big problem, and as this is a solution I was very interested in before I went in another direction, I would be interested to know how it pans out for you if you go forward with it.
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Old 12-20-17, 03:15 PM   #30
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This seems a simple solution, though as stated, I'm not a mechanic and don't know if there is anything that would make this NOT work.
You think ???

There are only two concerns needing to be addressed when considering an optimal gearing /gear ratio for a given bicycle application.

1. What is the aggregate weight of the cyclist/bicycle/load to be comfortably moved?

2. What is the lowest top-speed the cyclist expects to maintain at a comfortable cadence/pedal rpm?

Reply and explain your thoughts regarding my questions and I'll advise your equipment needs accordingly.

Unfortunately, many cyclists believe that discomfort during a ride can be mitigated without sacrificing efficiency in another area. (lucky bike shops) :-)
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Old 12-20-17, 03:40 PM   #31
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You think ???

There are only two concerns needing to be addressed when considering an optimal gearing /gear ratio for a given bicycle application.

1. What is the aggregate weight of the cyclist/bicycle/load to be comfortably moved?

2. What is the lowest top-speed the cyclist expects to maintain at a comfortable cadence/pedal rpm?

Reply and explain your thoughts regarding my questions and I'll advise your equipment needs accordingly.

Unfortunately, many cyclists believe that discomfort during a ride can be mitigated without sacrificing efficiency in another area. (lucky bike shops) :-)
So your completely discounting gear steps in the mid range and shifting patterns?
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Old 12-20-17, 03:59 PM   #32
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No, I haven't bought anything yet. I returned the 64mm 24t front ring and am currently looking for a 24t 74mm 4 bolt...which I'm not sure even exists. Seems the simplest solution would be to remove the 30t front ring and replace with a 24, or maybe a 26 and see if that works.
At the same time, before I do anything drastic, I may put a load on and try some steep climbs around here.

For clarity, I have a tendency to really push it when I ride on my carbon road bike. I now have this steel touring bike, and I have to force myself to try and just slow down. May be that if I adjust, and quit trying to get up a hill as quickly as I'm used to, and use the low gears I have, it may be sufficient. At the same time, I see most others on here obviously advocate much lower gearing for their long distance/touring bikes, especially considering long climbs.

But right now I'm not spending much time on it, I work in retail and this week is kinda crazy.

Thanks for the info, to all who have taken the time.
Four bolt 74? Can you post a photo of the crank, or a photo from each side?

After 6 or 7 or 8 or 9 hours in a day, you can burn out quickly if you do not pace yourself. One day on one of my tours I rode for 14 hours straight and did not bonk. Thus, you fill find that most of us will want to gear down and avoid pushing too hard. I will blow out a knee if I stand on the pedals to power up a hill, I have to stay in the saddle and push less hard in lower gears.
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Old 12-20-17, 04:06 PM   #33
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So your completely discounting gear steps in the mid range and shifting patterns?
Well, we're up to four pages of hardware minutiae without much long-distance ride reporting from the OP, so @Richard Cranium has a good point that we should circle back to the basics.
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Old 12-20-17, 05:33 PM   #34
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Well, we're up to four pages of hardware minutiae without much long-distance ride reporting from the OP, so @Richard Cranium has a good point that we should circle back to the basics.
Actually no need. Except for what I would call silliness, he already has his solution: 26T 74 BCD inner ring and experiment with current cassette. His current FD will shift the new small ring just fine.

There will be no need to exceed a 34T big cog, so his proposed RD will be fine. And there's s good chance his current cassette might be too large and no need for changing RDs, chain, etc., anyway. He'll know after he rides his first 300.

Just change 1 ring and ride. Simple.

My guess is that someone put the 50 on there after changing out the 42 for a 39 and finding that it wouldn't shift into the 52T big ring anymore. Because it wouldn't. If he wanted to, he could go to a B-type 53T because it's designed to shift from a 39T, as I said in post 8. I don't use the 53 much on my single with a 12-27 cassette, but I use it a very great deal on our tandem with a 12-34 cassette, more than I use the middle ring.
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Old 12-20-17, 05:51 PM   #35
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Actually no need. Except for what I would call silliness, he already has his solution: 26T 74 BCD inner ring and experiment with current cassette. His current FD will shift the new small ring just fine.

There will be no need to exceed a 34T big cog, so his proposed RD will be fine. And there's s good chance his current cassette might be too large and no need for changing RDs, chain, etc., anyway. He'll know after he rides his first 300.

Just change 1 ring and ride. Simple.

My guess is that someone put the 50 on there after changing out the 42 for a 39 and finding that it wouldn't shift into the 52T big ring anymore. Because it wouldn't. If he wanted to, he could go to a B-type 53T because it's designed to shift from a 39T, as I said in post 8. I don't use the 53 much on my single with a 12-27 cassette, but I use it a very great deal on our tandem with a 12-34 cassette, more than I use the middle ring.
Yes, that answers the technical questions. I love talking hardware as much as anyone, but that wasn't my point. Like you said, he'll know once he's ridden some brevets.
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Old 12-20-17, 07:43 PM   #36
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On a road 30-39-50 triple, it will be 74 BCD with five bolts; four bolts is used on MTB cranksets. This is what you are looking for:

wiggle.com | TA 74 PCD Zelito Triple Inner Road Chainring 24-30T | Chainrings
No, that won't work. It is a 4 bolt.

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Four bolt 74? Can you post a photo of the crank, or a photo from each side?
See below

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Actually no need. Except for what I would call silliness, he already has his solution: 26T 74 BCD inner ring and experiment with current cassette. His current FD will shift the new small ring just fine.
Just change 1 ring and ride. Simple.

My guess is that someone put the 50 on there after changing out the 42 for a 39 and finding that it wouldn't shift into the 52T big ring anymore.
It's a new bike, I assembled it out of the carton. So no one has changed anything yet.

The photos explains some of my confusion. Trying to measure between bolts with it mounted in the BB was difficult as the frame prevented getting calipers in there to accurately measure. And so I pulled the whole shebang out and realized it is not an evenly spaced bolt pattern, which was also somewhat hidden by the frame.

FullSizeRender.jpg

FullSizeRender (2).jpg

FullSizeRender (3).jpg

And so, in my searching for a ring, I do not recall as yet, running across a ring with this asymmetrical bolt pattern.





Also below is the rear derailleur. While I intend to pursue the "easy route" of trying to find a smaller front chainring, just to satisfy my curiosity... Is this a "long cage" derailleur? I believe I recall somewhere back in this thread in the discussion about changing to a 9 speed mtn cassette, that it would require a long cage rear mtn. derailleur (I may be wrong on that. How does it differ from a mtn. rear?

FullSizeRender (4).jpg
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Old 12-20-17, 07:55 PM   #37
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I will say quickly playing with my Google & I'm finding no chainring, shimano or otherwise under 30t with anything greater than a 64mm BCD.
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Old 12-20-17, 07:59 PM   #38
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I have never delt with one of the newer Shimano asymmetric cranks, so I have no clue what is available in alternative rings. And I have no clue if any aftermarket companies make rings that will fit on it either because it is very non-standard at this time.

Sorry.
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Old 12-20-17, 08:02 PM   #39
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Hey mate, sorry for steering you wrong, I was thinking about an FC 3503 which was 130-74 BCD with a five bolt pattern.

That's the new FC-R3030 Sora Triple; it changed to 110-74 BCD with a four bolt pattern. I don't know of a four bolt 74 BCD chainring that will fit that, sorry.

The rear derailleur is a RD-R3000-GS, the "GS" meaning medium cage, you can see specs here: 2017-2018 SHIMANO Product Information Web

That has a max of 34 teeth on the large cog, but as another poster helpfully pointed out, you might be able to use the B screw to get it to work with a 12-36 tooth cassette, like an HG400 12-36 Alivio.

I assume you're going to a bike shop, so maybe talk to the mechanic about adjusting the B screw to get the RD to work with a slightly larger cassette.
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Old 12-20-17, 08:42 PM   #40
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Okay thanks. Last 1+ hour spend with google and various parts sites and I've come to the conclusion that
A. A smaller 4 bolt ring with that pattern & 74 BCD doesn't exist apparently,
and
B. Perhaps a 12/36 cassette could be fiddled with to work, but may require a mtn. RD. And from what I've seen, that will only get me one more lower gear which I'm not sure would be significant enough to be worth it.


Beyond that I would think I the next option would be changing out to a mtn. crankset and FD but then I'm not sure the current shifters would work.

Anyway, I think I'm at the point of just keeping what I have and getting some mileage on it before doing anything drastic. I may find I don't even need to do anything.

Maybe work on bigger quads!
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Old 12-20-17, 10:06 PM   #41
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Okay thanks. Last 1+ hour spend with google and various parts sites and I've come to the conclusion that
A. A smaller 4 bolt ring with that pattern & 74 BCD doesn't exist apparently,
and
B. Perhaps a 12/36 cassette could be fiddled with to work, but may require a mtn. RD. And from what I've seen, that will only get me one more lower gear which I'm not sure would be significant enough to be worth it.


Beyond that I would think I the next option would be changing out to a mtn. crankset and FD but then I'm not sure the current shifters would work.

Anyway, I think I'm at the point of just keeping what I have and getting some mileage on it before doing anything drastic. I may find I don't even need to do anything.

Maybe work on bigger quads!
I've never seen a 74 BCD 4 bolt rig like that. Must be a MTB crankset with changed-out rings? New one on me. Shimano, but what is it?

Yeah, you may not have to do anything. OTOH fixing/maintaining probably isn't going to go well.

Oddly it looks to me like the teeth are quite worn or maybe it's the viewing angle or something or weird shaped teeth? When my chainring teeth look like that I replace them.

9 or 10 speed Shimano road triples (130/74 BCD) are so great for rando. Looks like ~$400 on ebay if there's one your size.

If you have Shimano road brifters, maybe NOS or used 9-speed crankset?
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Old 12-20-17, 10:42 PM   #42
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I've never seen a 74 BCD 4 bolt rig like that. Must be a MTB crankset with changed-out rings? New one on me. Shimano, but what is it?
FC-R3030 Sora Triple. Sora triples were changed to 110-74 BCD for 2017-2018, in line with the changes to other road groupsets.

http://productinfo.shimano.com/#/lc/2.4/sora/3x9
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Old 12-20-17, 11:35 PM   #43
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FC-R3030 Sora Triple. Sora triples were changed to 110-74 BCD for 2017-2018, in line with the changes to other road groupsets.

2017-2018 SHIMANO Product Information Web
Might take a while for the aftermarket 74 BCD rings to come out.
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Old 12-20-17, 11:47 PM   #44
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Might take a while for the aftermarket 74 BCD rings to come out.
Yeah, exactly. Still, Absoluteblack have oval CX narrow-wide chainrings for 1x9-1x11 set ups available in the new asymmetrical four bolt 110 BCD pattern.

I considered going to a 38t chainring with an 11-speed 11-46 cassette on my AWOL (as well as a 32 chainring on a 9-speed 11-40 cassette), but have decided to go with a 9-speed 26-36-48 trekking crankset and a 12-36 cassette when my current road triple crankset wears out, as I converted to a flat bar which the trekking stuff works with.
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Old 12-21-17, 08:27 AM   #45
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Until 5703 (105) and 4503 (Tiagra) road triples could be converted using third party 74 BCD rings of 28T, 26T or 24T because they used 5 bolts in that size.

5800 abandoned the triple altogether while Tiagra 4603 switched to a non-standard BCD for the inner. 4703 now uses a 4 bolt pattern for which there are no smaller replacement rings.
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Old 12-22-17, 01:33 AM   #46
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You know what I'd do WNCGoater? Just take your bike (or crank) to a decent bike shop and ask them to supply the right chainring, either 24 or 26 (I reckon 26 will be small enough). It's probable they've got access to parts you don't and will be able to measure the right stuff to get the right answer.
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Old 12-22-17, 04:41 AM   #47
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You know what I'd do WNCGoater? Just take your bike (or crank) to a decent bike shop and ask them to supply the right chainring, either 24 or 26 (I reckon 26 will be small enough). It's probable they've got access to parts you don't and will be able to measure the right stuff to get the right answer.
Good luck with that, but I would bet you that no such parts exist. What model of crank set would it be made for?

For the past couple of years, ways to arrive at lower gearing has been something of an obsession of mine, as I was contemplating getting a 700C or 650B bike in addition to my 20" Bike Friday and didn't want to lose the low gears enabled by the smaller wheels.

5 bolt has been the established standard for 74 BCD with Shimano (e.g. Tiagra up to 4503, 105 up to 5703, Ultegra up to 6603), FSA, Sugino, etc. Virtually all road triple cranks use either a 5-bolt 74 BCD inner or a tripleizer 110 BCD middle ring. Dura Ace 7803, Ultegra 6703 and Tiagra 4603 Shimano used a 5-bolt 92 BCD inner on a 110 BCD middle tripleizer. Neither of those could use after-market rings smaller than 30T.

Since Tiagra 4703 would basically be the only crankset a 4-bolt 74 BCD inner would fit and that's only been around for like the last two years, there would only be a tiny market for a 4-bolt 74 BCD sub-30T ring, if one existed.

So I think that rules out lower gearing via a smaller inner on any Tiagra triple after 4503. You either need a larger cassette or swap the crank set.

Last edited by joewein; 12-22-17 at 07:30 AM.
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Old 12-23-17, 06:46 AM   #48
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Transmissions can be designed to for efficiency across a wide-range of a given speeds - OR - for efficiency of a given load under a narrower range of speeds.

You all know that - why get caught up with silly studies of gear teeth or inches? Understanding how large and how heavy the load is - and how much top speed can be sacrificed to accommodate efficient gearing for the total load are the sentient issues.

Gee-Zusss fff-inngg Christmas - ya got a triple crank and a ten-cog cluster - how can you not have enough gearing ???????
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Old 12-25-17, 01:59 AM   #49
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ya got a triple crank and a ten-cog cluster - how can you not have enough gearing ???????
Sometimes I hear comments like "it has a 1:1 lowest gear, why would anybody need more?" or "it's got a 28 at the back, that should be enough for any hill." Those ratios may be sufficient for some, but we're all different.

A friend of mine who, back in the days, used to mash up alpine cols on week long tours now only cycles flat routes around town because his knees are too worn out. I don't want to end up like him. If I ride a standard compact, I get knee pain which is not a good thing. My knees are thanking me for the 26/32 lowest gear on my main bike. I intent to cycle until I turn 80 (which is still more than two decades away) and lighter gears will help me make it to that goal.

If you have stronger legs and more robust knees, good for you!
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Old 12-25-17, 03:44 AM   #50
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Originally Posted by joewein View Post
Sometimes I hear comments like "it has a 1:1 lowest gear, why would anybody need more?" or "it's got a 28 at the back, that should be enough for any hill." Those ratios may be sufficient for some, but we're all different.

A friend of mine who, back in the days, used to mash up alpine cols on week long tours now only cycles flat routes around town because his knees are too worn out. I don't want to end up like him. If I ride a standard compact, I get knee pain which is not a good thing. My knees are thanking me for the 26/32 lowest gear on my main bike. I intent to cycle until I turn 80 (which is still more than two decades away) and lighter gears will help me make it to that goal.

If you have stronger legs and more robust knees, good for you!
I agree. My knees have damaged cartilage and I am looking for to going from a 30-36 low gear to a 26-36 low gear. My doc recommended a low gear, a very high cadence and warm knees for climbing, especially in some of our local brevets, which feature some big climbs.

I am sure it is okay to climb 500 meters in 34-28 if you have healthy young knees, but I would find it debilitating.

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