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I asked ChatGPT about lowering the gearing on my (700c wheeled) gravel bike and I'm impressed with the results but are there any other options (like Goat Link?) for 2x setups which ChatGPT has missed?
This is ChatGPTs answer:
Here’s how to get lower than a SRAM Force AXS 2× wide setup (43/30 crank + 10–36 cassette). I’ll go from “smallest change” to “biggest change,” with what you need and how much lower you actually get.
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First, know your current low
Lowest ratio now: 30/36 = 0.83
On 700c tires, that’s already very low for a 2× road/gravel setup.
SRAM’s 2× AXS Wide system with a 10–36 cassette is basically at its official limit, so lowering further means changing wheels/tires or changing the drivetrain format.
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Option A — Quick win: smaller wheels/tires (keep 2×)
What you change: Swap to 650b wheels/tires (e.g., 650×47) or run smaller-diameter 700c tires.
How much lower: ~5% drop going from a typical 700×40 to 650×47 (wheel diameter shrinks from ~712 mm to ~678 mm → ~0.95×).
What you need: 650b wheelset (XDR driver if you keep 10T cassettes), tires, new tubes/sealant.
Pros: Cheap-ish, simple, keeps front shifting and your cadence gaps.
Cons: Lowers all your gears and slightly changes handling.
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Option B — Go 1× with XPLR (10–44 cassette)
What you change: Convert to 1× with an XPLR rear derailleur and 10–44 cassette. Pick a small chainring.
With a 36T ring, low = 36/44 = 0.82 (≈ 2% lower than your 30/36).
With a 34T ring, low = 34/44 = 0.77 (≈ 7% lower than your 30/36).
What you need:
SRAM XPLR rear derailleur (1× only).
SRAM 10–44 XPLR cassette (fits XDR freehub; you likely already have XDR for a 10T).
1× narrow-wide chainring (direct-mount or spider specific to your crank; pick 34–38T to taste).
Flattop 12-speed road chain (XPLR uses Flattop).
Pros: Noticeably lower with a 34T, tight 1× gravel spread, simple.
Cons: You lose front shifting and some high gears; 36T ring is only a hair lower than you have now.
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Option C — “Mullet” 1× with Eagle (10–50 or 10–52)
What you change: Use an Eagle AXS MTB rear derailleur with an Eagle 10–50 or 10–52 cassette and a small 1× ring.
Examples of lows:
36 × 50 → 0.72 (≈ 14% lower than 30/36)
36 × 52 → 0.69 (≈ 17% lower)
34 × 52 → 0.65 (≈ 22% lower)
What you need:
Eagle AXS rear derailleur (non-Transmission; standard hanger OK).
Eagle 10–50 or 10–52 cassette (XD/XDR driver works—many road XDR hubs accept XD with a different driver body; some drivers are convertible).
Eagle 12-speed chain (not Flattop).
1× narrow-wide chainring compatible with Eagle chain.
Pros: By far the lowest gearing; huge range for steep bikepacking.
Cons: Big jumps between gears, loses front shifting and some road-speed top end; parts mix changes (chain, cassette, RD).
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What you can’t really do in 2× AXS
Bigger than 36T cassette with a 2× road rear derailleur isn’t supported.
Smaller than 43/30 chainrings for the SRAM 8-bolt AXS 2× Wide crank aren’t offered by SRAM, and true plug-and-play aftermarket 2× options for the 8-bolt road DM interface are effectively unavailable. (There are lots of 1× rings; 2× super-compact for 8-bolt road is the blocker.)
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My practical recommendations
Want a small but noticeable drop, minimal fuss?
Try 650b wheels/tires first (≈5% lower). Cheap, reversible, keeps 2×.
Want a cleaner gravel setup and ~7% lower than today?
Go 1× XPLR with 10–44 and a 34T ring.
Need truly tiny gears for loaded climbing?
Go mullet: Eagle AXS RD + 10–52 + 34–36T ring. That’s 17–22% lower than you have now.
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Setup notes (to avoid headaches)
Freehub: 10T cassettes require XDR (road) or XD (MTB). XPLR uses XDR; Eagle cassettes use XD (some hubs swap bodies easily).
Chain:
Road AXS/XPLR = Flattop chain.
Eagle mullet = Eagle chain (not Flattop).
Rear derailleur limits:
XPLR is 1× only, max 44T.
Road AXS Wide is 2× but max 36T cassette.
Eagle AXS handles 50/52T cogs (1× only).
Chain length: Size on the lowest gear combo for 1× (big cog) and with big-ring/big-cog for 2× per SRAM method; don’t reuse your 2× chain if going Eagle.
Crank/chainring interface: Force AXS Wide uses 8-bolt direct-mount; pick rings that explicitly state compatibility.
Front derailleur: Remove it for 1× (XPLR or mullet). Keep it only if you remain 2×.
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TL;DR
You’re already at the 2× road limit.
Easiest: 650b wheel/tire swap → ~5% lower.
Best 1× road/gravel compromise: XPLR 10–44 + 34T ring → ~7% lower.
Maximum low: Eagle mullet 10–52 + 34–36T → 17–22% lower.
If you tell me your wheel/tire size and whether you want to keep 2× or don’t mind going 1×, I’ll map your exact gear inches and speed-at-cadence for each option.
Is that not all incredibly basic maths and reading a few product specs?
I for one am very glad we’re boiling the oceans to save ourselves the most minor cerebral challenges…
What, you don't have a gear inch calculator app on your phone? Even I do and I am a proper luddite. Obviously the correct answer is do the basic maths yourself, but the app is handy for quick checks when swapping things.
Lol. Ive already done the Gear inch calcs but I wanted ChatGPT to tell me which hardware options were possible.
And now I want STW to tell me whether there's any other obscure/unofficial options. I know, for instance, that Shimano are conservative with gear capacity for their derailleurs and you can usually push the limits a bit.
I'm not sure whether this option is possible with SRAM and/or whether someone makes a 10-38 cassette for instance...
And Goat links don't seem to work for 2*12 spd drivetrains but someone here has probably tried it already 🤷
I don't know about SRAM AXS, but Shimano 2xGRX claims biggest cassette is 34. But you can definitely put a 40t on no problem, as I've done it. I've seen reports of people going bigger than that.
The shifting is not quite as nice but it's good enough. That might just be that I only spent about 30 seconds adjusting it before going for a ride.
Gives you a really nice range.
Going Shimano is a non-starter as I might as well just sell this bike and buy a completely different bike! I had 2*10 GRX on my previous bike and used a larger Sunrace 11-40 cassette...
I asked ChatGPT about lowering the gearing on my (700c wheeled) gravel bike
What are you actually wanting here, to lower the low end but keep the high ratios as is, or lowering the whole range (& how much lower)? If the later smaller chain rings keeping the same tooth difference would be simplest if the rings exist.
TA do aftermarket rings for GRX (28/44 for example) but I'm not sure about SRAM.
I'm really not a fan of "AI" but I have to admit this is one of the more impressive things I've seen it do. Yes, the arithmetic is simple, but getting all the specs, giving you a judgement (presumably scraped from a forum thread) on what's normal, and what works but isn't officially supported, and giving you some extra bits of related info that you didn't ask for, but would probably be useful...
It's not really intelligence, but it's useful.
Did it tell you to htfu and push that 30/36 a bit harder? 😉
It's impressive, but it's still AI though isn't it, so it's doing exactly what you asked in a logical way, coming up with the answers you give.
Just a couple of observations,
SRAM’s 2× AXS Wide system with a 10–36 cassette is basically at its official limit, so lowering further means changing wheels/tires or changing the drivetrain format.
I don't know anything about SRAM AXS, but my GRX400 drivetrain was at full capacity with 46/30 & 11-36. I put on a 28T ring, pushes both the front mechs. over capacity and it works.
The AI here seems to have taken the idea that the drivetrain is it full capacity to mean that, that's effectively immutable and hasn't discussed 'hacks' of which I'm sure there are several (you mention Goatlink & you may simply be able to get away with a larger cassette or smaller inner ring).
Also, you asked about lower gearing, so that's what you're getting. A human rider might think "so you're struggling a bit on climbs" & suggest that lighter wheels & tyres might be something to think about.
It'd be interesting to know what ChatGPT might have offered up if you'd asked it how to hack your drivetrain or perhaps modify your bike to improve climbing instead of specifically asking about gear ratios.
I know very little about AI (it's very beyond me) but I'm increasingly getting the opinion that it's what & how to ask that's the key (in the not to distant future someone might ask evolved AI to solve the climate crisis & which point it would undoubtedly exterminate humanity).
MTBR has a new AI assistant you can summon to answer questions. It's quite effective, but also quite creepy.
It also looks for new threads with no replies and responds to them if a certain amount of time has passed.
Whoever runs it has tried to humanise it's responses too so it tries to be funny/quirky.
As I said, quite creepy.
AI appears to have answered the question you actually asked, STW is so advanced it either skips that bit and answers the question you should have asked or answers the original question without even having to have read it 😂
I use https://www.sheldonbrown.com/gear-calc.html for gearing calculations.
Slightly practical answer is find a (second hand?) triple crankset and run it as a double using the smallest gear you like, (I'm on 28t) and something like 42 or 44 on the middle ring, nothing on the outer ring position. Google alpine chainset.
Works a treat for me, nice straight chainline mostly and rarely spin out with my puny legs!