34t versus 36t Chain Ring

[Singletrackmind]

Please compare pro's and con's for a 34t versus 36t chain ring. Which would be the better option for climbing?

 

[Greg Watts]

Please compare pro's and con's for a 34t versus 36t chain ring. Which would be the better option for climbing?

@Singletrackmind, given you're at 100kg on a 2026 Orbea Wild and riding San Diego terrain, this is a fairly straightforward call, though the "right" answer depends on what you prioritise.

34T: The climbing chainring A 34T gives you a lower gear ratio across the cassette, which means higher cadence for any given speed. On steep, technical climbs that's exactly what you want, particularly with a Bosch motor that responds well to a smooth, higher cadence input. Several owners in the community have found the same thing. One member switched from 36T to 34T on a Canyon Strive:ON and reported a world of difference: higher cadence, more responsive, averaging nearly the same speed on trail. Another member found that 34T instead of stock 36T works well for steep rocky rooty climbs. There's also an argument for range: lower gearing is easier on your legs and can draw less motor power, which stretches the battery further.

The trade-off is top speed. With a 34T and an 11T smallest cog, you'll run out of gears a touch sooner on fast flat sections or descents where you're pedalling. In practice, on an eMTB where assist cuts out around 25mph anyway, this matters less than you'd think.

36T: The all-rounder / flat-terrain ring A 36T optimises the other end of the spectrum. Better gear spread at speed, smoother shifting quality especially on the smaller cogs (less cross-chaining), and you can pedal meaningfully at higher speeds. One member noted the 36T helped reach 28mph on flat and decline but hurt steep climbs by not being able to spin up as quickly, ultimately going back to 34T. Worth noting too that on your Orbea, a 34T sits within the skid plate protection whilst a 36T reportedly sticks out past it, which is something to think about for rock strikes.

For your riding? San Diego has plenty of steep, punchy climbs mixed with fast fire roads. At 100kg system weight (before the bike), a 34T is going to be the better climbing ring. You'll carry higher cadence on the steep stuff, keep the motor in its happy zone, and the top-speed penalty is negligible for trail riding. If you were doing mostly flat, fast riding, the 36T would make more sense, but for climbing priority the 34T wins.

We chatted about T-Type compatible chainring options for Bosch Gen 5 a couple of weeks back, so you should already have the parts shortlist. If you need a refresher on those options or want to talk chain length adjustments, just shout.

EDIT: @Frankyspec reports 36T is suggested as the ideal combination for cadence-improving load distribution. Not yet independently verified — take with a pinch of salt.

 

[Singletrackmind]

@Singletrackmind, given you're at 100kg on a 2026 Orbea Wild and riding San Diego terrain, this is a fairly straightforward call, though the "right" answer depends on what you prioritise.

34T: The climbing chainring A 34T gives you a lower gear ratio across the cassette, which means higher cadence for any given speed. On steep, technical climbs that's exactly what you want, particularly with a Bosch motor that responds well to a smooth, higher cadence input. Several owners in the community have found the same thing. One member switched from 36T to 34T on a Canyon Strive:ON and reported a world of difference: higher cadence, more responsive, averaging nearly the same speed on trail. Another member found that 34T instead of stock 36T works well for steep rocky rooty climbs. There's also an argument for range: lower gearing is easier on your legs and can draw less motor power, which stretches the battery further.

The trade-off is top speed. With a 34T and an 11T smallest cog, you'll run out of gears a touch sooner on fast flat sections or descents where you're pedalling. In practice, on an eMTB where assist cuts out around 25mph anyway, this matters less than you'd think.

36T: The all-rounder / flat-terrain ring A 36T optimises the other end of the spectrum. Better gear spread at speed, smoother shifting quality especially on the smaller cogs (less cross-chaining), and you can pedal meaningfully at higher speeds. One member noted the 36T helped reach 28mph on flat and decline but hurt steep climbs by not being able to spin up as quickly, ultimately going back to 34T. Worth noting too that on your Orbea, a 34T sits within the skid plate protection whilst a 36T reportedly sticks out past it, which is something to think about for rock strikes.

For your riding? San Diego has plenty of steep, punchy climbs mixed with fast fire roads. At 100kg system weight (before the bike), a 34T is going to be the better climbing ring. You'll carry higher cadence on the steep stuff, keep the motor in its happy zone, and the top-speed penalty is negligible for trail riding. If you were doing mostly flat, fast riding, the 36T would make more sense, but for climbing priority the 34T wins.

We chatted about T-Type compatible chainring options for Bosch Gen 5 a couple of weeks back, so you should already have the parts shortlist. If you need a refresher on those options or want to talk chain length adjustments, just shout.

I understand the chain ring options, appreciate the refresher offer. Can you tell me if the number of chain links is the same for a SRAM XO T-Type chain using a 34t or 36t option?

 

[Greg Watts]

I understand the chain ring options, appreciate the refresher offer. Can you tell me if the number of chain links is the same for a SRAM XO T-Type chain using a 34t or 36t option?

Short answer: it may not change at all. With SRAM T-Type, the chain sizing process is driven by the largest cog on your cassette and the chainring size together, but real-world experience suggests the difference between a 34T and 36T chainring doesn't necessarily require additional links — just a derailleur adjustment to compensate for the size change.

The standard T-Type sizing method has you run the chain through the largest cog and the chainring (bypassing the derailleur), then add 4 links. Community reports back this up: one member found a 34T setup on a size large frame needed 124 links on position A with a 21T setup cog, while another T-Type 34T install came out at 118 links on a different frame. The variance is real, but when it comes to stepping from 34T to 36T specifically, the existing chain length may carry over just fine with the derailleur doing the work of taking up the difference.

For your Orbea Wild specifically, I'd strongly recommend sizing fresh rather than adjusting the existing chain. SRAM's AXS app will walk you through the A-gap process once you've got the new ring fitted, and it's worth following it to the letter, including setting cage lock to position 1 before tensioning, because forgetting that step causes the chain to contact the frame on the smallest cog. Ask me how I know people learn that the hard way.

EDIT: Corrected the claim that a 36T chainring would require additional chain links over a 34T — real-world experience with GX Transmission shows no extra links were needed, only a derailleur adjustment. Thanks @Powerslider for the heads up.

 

[DIomidis]

IMHO the 34->36T is a good move, unless you find yourself on the big 5x cog often and struggling (which I'd say it is not common occurrence on a eMTB, especially a full but even mid-power one. Could be in some factory "eco" modes but you can most likely adapt to it or give the Eco a bit faster pick-up in the beginning and mask the difference completely). I don't feel anything different on Trail & Boost.

The #1 benefit is that you are more-or-less riding the same speed one cog easier/bigger in the rear.
This means that you will be less often on your two smallest cogs 10T and 12T. For the majority of people on eMTBs, a big cost is on drivetrain consumables, i.e. chains and most importantly, cassettes - the latter typically wearing much sooner than you would on a pedal bike and of course the wear being manifested as chain skipping when on...the two smallest cogs.

This is less of a hit on Shimano cassettes for which you can source the smallest 3-4 cogs as separates and replace just those, but with Sram's mono-block cassettes, is a PITP (P for pocket).

I found myself in the lower half (i.e. taller gears) of my cassette the vast majority of times on my Rise in SoCal trails (mostly OC), and I bet this is the case for most people, i.e. we do not really ride in the 4x->5x gogs that much, but we do ride on the 10T and 12T and 14 or w/e too much.

Going to the 36T did not lose me anything of essence: I had to retire the One-UP chain retention device that Orbea gives as it interferes with the bolts, but that was due to my choice of chainring, i.e. Shimano 104 BCD carrier for STEPS with a steel ring - again for longevity. I have never dropped a chain on that bike, so I do not feel I actually missed something. One Piece alloy cogs like the e13 and others, can probably retain compatibility with the chain retention device, but at the expense of longevity.

I still feel the bike doing the same and me maintaining the cadence I would - but I do it 1-2 cogs larger, dropping to the 10T notably more rarely. The range is still more-or-less the same, but it is similar speeds, similar cadence, similar "Real" ratios - i.e. I do not lag the motor riding at a slow cadence.

 

[Greg Watts]

IMHO the 34->36T is a good move, unless you find yourself on the big 5x cog often and struggling (which I'd say it is not common occurrence on a eMTB, especially a full but even mid-power one. Could be in some factory "eco" modes but you can most likely adapt to it or give the Eco a bit faster pick-...

@DIomidis, this is a genuinely useful post and I suspect it'll be more persuasive to the OP than my spec breakdown was, because you're speaking from actual saddle time on a Rise in SoCal rather than theory.

The drivetrain economics argument is the one that really lands. You're absolutely right that eMTB cassette wear concentrates on those smallest cogs, and with SRAM's monoblock cassettes you're replacing the whole unit when those 10T and 12T teeth round off. Spending more time one or two cogs up the block by running a 36T is genuinely extending cassette life in a way that matters to the wallet. As you say, Shimano at least lets you buy the small cog cluster separately, but on SRAM it's the full hit every time.

The point about the chain retention device fouling the bolts on a 104 BCD carrier is worth flagging for anyone following along. A one-piece direct mount ring like the e*thirteen or SRAM's own 104 BCD option sidesteps that, though as you note, alloy won't last as long as your steel choice. Given you haven't dropped a chain without it, the trade-off seems well justified.

Good real-world data on a question that usually gets answered with spreadsheets and gear ratios rather than "here's what actually happened to my drivetrain."

EDIT: @Frankyspec reports The new AM PX Carbon Pro with M2S motor uses a 38T front chainring, not 36T as discussed in the original quote. Not yet independently verified — take with a pinch of salt.

 

[Powerslider]

I understand the chain ring options, appreciate the refresher offer. Can you tell me if the number of chain links is the same for a SRAM XO T-Type chain using a 34t or 36t option?

Only speaking to my personal experience with my Levo 4- I did not need to add links when going from 34t to 36t (GX Transmission) AND moved to longer chainstay setting. I only had to re-set the derailleur.

 

[Greg Watts]

Only speaking to my personal experience with my Levo 4- I did not need to add links when going from 34t to 36t (GX Transmission) AND moved to longer chainstay setting. I only had to re-set the derailleur.

Worth noting, and a useful data point for @Singletrackmind. SRAM's chain sizing tool will tell you to add links for a 36T, but real-world tolerances and chainstay length both play a role. The fact you went up a chainring and moved to the longer chainstay setting on the Levo 4 without needing extra links suggests there was enough slack in the original chain run to absorb both changes.

That said, I wouldn't take it as a universal rule. The Levo 4's chainstay adjustment range is modest enough that the combined effect might still land within the same link count, whereas a bike with a longer chainstay or a bigger cassette could tip over the threshold. Always worth running the chain through big-big and small-small to check before assuming it'll work. But your experience does confirm that a 34T-to-36T swap isn't automatically a "buy a new chain" situation on every bike.

 

[Frankyspec]

On the new am px Carbon pro with the M2S motor, the chainring on the front is 38t, so for going up it’s going to be much harder for a high cadence … a 36 will probably do better with steep climbs. The switch from previous model 34t to 38t is a bit to much I think, even with such a strong motor.

 

[Greg Watts]

On the new am px Carbon pro with the M2S motor, the chainring on the front is 38t, so for going up it’s going to be much harder for a high cadence … a 36 will probably do better with steep climbs. The switch from previous model 34t to 38t is a bit to much I think, even with such a strong motor.

@Frankyspec, you're right that the PX Carbon Pro ships with a 38T chainring as stock, and I understand the instinct to call that a jump too far from the 34T on the old PL. But there's a reasonable engineering argument for it that's worth considering before anyone rushes to downsize.

The larger front chainring improves load distribution across the drivetrain and reduces strain on the smaller cassette sprockets - and together with the straighter chainline, that has a positive effect on both wear and efficiency.

Which is exactly what @DIomidis was getting at earlier in this thread from the opposite direction: fewer miles on the 10T and 12T, less wallet damage.

The other mitigating factor is the cassette. The PX Carbon Pro runs a 10-52T cassette, which is a significant low-end safety net. A 38T up front with a 52T in the back gives you a lower overall ratio than a 34T with a 50T or even a 46T cassette. So the climbing gear is actually there - it's just further down the block than you might be used to.

Where you do have a point is on the Avinox M2S's motor character. It's cadence-hungry: strong above 80rpm, noticeably weaker below 30rpm. A 38T ring on a technical climb where you've slowed to a crawl could leave you hunting for torque the motor doesn't love delivering at low cadence. Whether a 36T would mask that meaningfully depends on the terrain.

 

[Frankyspec]

@Greg: this was the suggestion, 36t good be the ideal combination for cadence-improving load distribution…

 

[Greg Watts]

@Greg: this was the suggestion, 36t good be the ideal combination for cadence-improving load distribution…

@Frankyspec - yes, that's essentially the conclusion. For the Avinox M2S's motor character specifically, a 36T is a more natural fit than 38T. You get the cadence range where the motor is happiest more of the time, without sacrificing the climbing safety net the 10-52T cassette provides.

The neat thing is that 36T also lands squarely in the sweet spot DIomidis was describing earlier: you're running one cog larger at equivalent speeds, those 10T and 12T teeth see less abuse, and your cassette lasts longer. The drivetrain economics and the motor cadence argument both point the same direction, which doesn't happen as often as you'd like in bike setup.

On your Rise M Team it's a non-issue since the TQ HPR60 is a different beast entirely, but if you're looking at the PX Carbon Pro, I'd say 36T is the sensible first swap after purchase rather than something to agonise over before buying. The bike ships rideable at 38T; it just rewards the change.