I have read a few older posts, and didn’t really get an answer I’m looking for. I currently ride a 53-39x11-28. What AXS gearing would most closely mimic it? Or possibly lean towards giving me a tiny bit more climbing ability? Thanks for your help.
I recently switched from your exact 2x setup to Sram Red tap AXS 1x 48x10-33.
Works perfectly and never feels too much. I’ve tried it on gradients up to 16%.
I went from 53/39 x 11/25 to 48/35 x 10/26 . . . I think it is perfect!
I have Dura Ace 53-39 / 11-28 on my road bike and wanted something similar for my new Tri bike. Went with AXS 48 / 10-33 and I am happy. The low on my Tri bike is not quite as low as on my road bike, but still good.
I have read a few older posts, and didn’t really get an answer I’m looking for. I currently ride a 53-39x11-28. What AXS gearing would most closely mimic it? Or possibly lean towards giving me a tiny bit more climbing ability? Thanks for your help.
48/10-33
50/110-36
The latter has a slightly lower bottom gear, but a couple of big gaps in the middle…
I also went from 53x39 - 11-25 to 48x35 - 10-28 (note that 26 is not compatible with all AXS RD’s, I did have to go for the 28 … don’t regret this at all though! I didn’t see any disadvantage in the 28 vs 26 anyway; all cogs on the top-range are the same, only the lower gearing is slightly more spread out (21-23-26 vs 21-24-28)
Now for the OP, are you sure you need a 48 or even 50T front?
I’ve done some calculations and would probably have settled for a 42T or 44T front if I had opted for 1x (this would have been sufficient for even my fast-paced group-rides (for reference avg. pace > 40kph, with extended stretches near/over 50kph … although this is on pancake flat terrain)
44x10 is close to 50x11 (which is a large gear on a compact crankset I would say) and even 42x10 is slightly larger than a 50x12
Regarding the cassette choice; my bike came with a 10-36 however this doesn’t work for me on flat roads (I prefer a closely spaced cassette on the top-end range)
Anyway a 44x10-33 would give you a top-end that is a little lower than you’ve got right now but a lower gear that is almost identical
Ideally you might be able to switch cassettes or chainrings depending on the terrain you’re riding on (guess you don’t need 39x28 all the time? as this seems to be a gear for big Alpine climbs normally?
This is for a TT bike, so I wanted to get one of the aero rings, which I believe only comes in the 48 or 50? I am in an area with fairly punchy climbs of roughly 3-5 minutes, but nothing mountainous. However most of the triathlons I do typically have fairly flat bike courses. I thought about getting both a 10-33 and 10-36 and swapping. Seems like that might be the best solution.
This is for a TT bike, so I wanted to get one of the aero rings, which I believe only comes in the 48 or 50? I am in an area with fairly punchy climbs of roughly 3-5 minutes, but nothing mountainous. However most of the triathlons I do typically have fairly flat bike courses. I thought about getting both a 10-33 and 10-36 and swapping. Seems like that might be the best solution.
OK, for tri bike; for some reason I was thinking of a road bike.
Anyway since you’re looking into these larger chainring sizes I assume you’re a fairly strong cyclist. so cruising speed in races is appr. 45kph?
In that case be aware that the 10-36 cassette has 2 large jumps (13-15-17) in the sweet-spot of this cruising pace. And also the 10-33 does have an annoying 15-17 gap
I’d think you would be better served with a 10-26 or 10-28 cassette* for the flatter races and a 10-33 or 10-36 for the races with steep climbing?
- you’ll have to check the capacity of your RD
You can check out max, average, and min speeds and compare on this calculator with cadence at those speeds on those gears. I would also add that you should check the cadence differences for the big jumps where they exist. I typically use 50rpm for the floor, and 120rpm for the ceiling, just because that’s about the range of longer term sustainabille pedaling for me. As we all know, no one is going to sustain >35mph for very long on a normal day, and when one could, the benefits of pedaling are fairly limited except ultra short TTs where the energy expenditure is potentially worth it. So I would tend to pick the most comfortable cadence and speed, then optimize for thereabouts.
https://www.j-berkemeier.de/gear-calculator.html
You can play a little with it, maybe find the ratio you are looking for
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This is copy paste from another thread:
https://forum.slowtwitch.com/forum/Slowtwitch_Forums_C1/Triathlon_Forum_F1/1x’s_users_P7254665/#p7254665
but here is what I did:
Not to make this messier (you have already gotten some good advice), but I think the best gearing setup for 1x takes some effort. First some background, and then what I think is best approach:
Cat 2 crit racer
I switched to 1x gearing on my main road / crit bike 5 years ago and like it a lot for simplicity and reliability.
Used 52 x 11-32 for most of that and seemed good. Definitely never spun out in a race and only rarely did I wish I had a smaller gear
But re-evaluated when I changed to AXS
Here’s what I did:
Went through about 30 power files from hardest and hilliest races and group rides in the past year or so.
Figured out what gearing I was in the most during really hard efforts (I used 150% FTP, but whatever) – turns out it was lower than I expected – about 78 gear inches. Hard to know for sure, but looks like most of my hard efforts of more than a minute or so were on false flat sections or strong crosswinds.
So, for a perfect chainline on the AXS 10-33 cassette, that would put me in the 15t cog. 78 gear inches would mean a 44t front chainring.
That seemed crazy small. So I looked at the same power files to determine how much more often I would be spun out at 44x10 (116 gear inches) versus 52x11 (125 gear inches). Answer was almost none. I could only identify 2 times in any of those files where I would have wanted to have more than 116 gear inches, but wouldn’t have also been spun out at 125.
Then I thought about average race speed. Looked like most of my races last year had an average speed of 28mph or so.
Looking at the 10-33 gearing and 44t chainring, at 100 rpm that would put between the 12 and 13t cogs with 2 single cog jumps on either side of that. So no real issues about bad gear jumps at race speeds.
So, I went with that this year and it’s been great. No races yet, but several hard group rides that have been at race-like speeds and I find that I’m in the sweet part of the cassette more, have not spun out in any setting, and have some lower gears for steeper hills than I had before. I might end up kicking myself if I ever end up in a downhill / tailwind sprint and am spun out at 40mph. But that seems like such a rare event that I’m not too worried.
TL;DR version: you can figure out for yourself what your optimum gear ratio is with a few appropriate power files, a gear calculator app, and a bit of effort.
Andy