I've tried all of the available cassettes and my current preference is as follows

10-45 shimano
10-50 sram
10-51 shimano
10-52 sram

I really like the spacing on the 10-45t with a 36t chainring.

 

Yeah, that 10-52 is a stinker.

 

If you have long steep climbs where you are switching around on the top 2 or three cogs then I think the 10-51 Shimano is great. The cadence is more natural between the shifts imo.

 

With the 39-45-51 I find I (almost) never use the 51 except on the very rare really long really steep climb.

SRAM 36-42-50 I find the 42 just a hair too tall and I would switch to 50 which is a hair too low.

Guess I never thought about it but I guess I prefer the Shimano spacing.

 

Came from a 26er 3X9 (22/32/44 X 11-34). Used all cassette gears but only the middle chain ring (32). I find I rarely use the two largest gears on my 29er 10-51 SLX cassette. Will most likely go with a 10-45 for a replacement (when the OEM wears out).

 

I have found I really like the ratio of a 28 front and 42 rear. It was a good all around gear for me. With eagle and 30 I don’t have that sweet spot and hunt between the 42-50 a lot. As soon as mine wears out I plan to go shimano 10-51 because the 30-45 gearing is identical to the 28-42. I like the closer gearing at slower speeds.


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Really depends what your comfortable cadence range it. I never really struggled with the 42->50 jump on a SRAM cassette, but at the same time I appreciated the smaller jump of the 45->51. But someone who has a narrow cadence range might struggle with a SRAM cassette.

 

You are asking about the suitability for racing. I think it's worth considering in the context of what type of profiles you are likely to be racing on. If my courses were XCM, 100s or anything like that, and had significant stretches of open fire roads and doubletrack with flat to low grades, then I'd probably find it useful to have more closely spaced smaller cogs. Contrast that to typical XCO courses with many quick grade changes in which those closely spaced cogs actually drive me a bit nuts. When I want a gearing change I want a real gearing change dammit without having to click 2 cogs every time. Or, if my courses had pronounced long and steep climbs then I'd also prefer to have closer spacing on the larger cogs.

 

You are asking about the suitability for racing. I think it's worth considering in the context of what type of profiles you are likely to be racing on.

When ordering 12s I defaulted to the smallest cogset I could find, that being the 10-46.

Wasn't really a tough decision, as for 5+ years my "climbing gear" has been a 36-34. Yes, that's dumb, even in Ontario, and no, I'm not sorry.

Anyway the 12s stuff is still sitting in my garage awaiting the arrival of obscure DTswiss hub parts, so the jury's still out.

 

I guess it all depends on how steep and how long, I’ve used SRAM (50) and Shimano (51). I found Shimano better for long, sustained climbs. The Shimano has a better second gear, and the 51 is always welcome on the ugly pitches (and available with all product lines). Basically SRAM’s gear steps are not optimal when compared to Shimano.

This may be off topic, but I also found that Shimano shifts smoother. When I shifted the SRAM, I always felt like it was a big production (loud and rough).

However, the 10,000 pound gorilla in the room is the near inability to find Shimano 12 speed drivetrain parts.

 

However, the 10,000 pound gorilla in the room is the near inability to find Shimano 12 speed drivetrain parts.

On a completely unrelated note, my stockpile of 12-speed drivetrain parts is holding up really well.

 

No. This would depend more on the very rare situation that their gear combos more closely match your local racing track. I know pro-racers on both setups and neither seems to hold them back. I'm also top-10 and 42 as my biggest gear doesn't hold me back. There are far more things that contribute to racing than this. Fact: you are probably in way easier gears than most pros and elite experts, even up steep stuff. So we aren't even comparing the same thing. To go as fast as those racers go, you gotta be in much harder gears, even uphill. What does this mean for average joe rider? Nothing. This is just ridiculous banter that doesn't mean anything.

 

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I used to race a lot and was never a masher, always picking the lowest gear for a high cadence setup, similar to Neff. Tempier couldn't care less about the 50+ cog.

I find the shimano spacing much better for overall riding, training, and racing, not pivotal (although helpfull) for XCO but very important for XCM).

SRAM is big on weight and they keep the cogs smaller to reduce it while having the top one as large as possible so they have bragging rights on range.

Really depends how sensitive a rider is on cadence specificity. I know I am.

 

On SRAM the biggest cog seems like a bail-out. The jump is too big.

On a Shimano 10-51 there's no big jump, so it's more usable on steep climbs.

In any case, spacing in 1x systems is bad, whatever system you choose. I've been riding a Shimano 1x bike for more than a year and I still hate the 10-12 jump with passion, and I still think there's a lack of ufseful range compared to even a 3x9.

 

On SRAM the biggest cog seems like a bail-out. The jump is too big.

On a Shimano 10-51 there's no big jump, so it's more usable on steep climbs.

Yup. 42-50 is bad enough, but 42-52 is over the top.

 

Sounds like a fanboy. Gear ratios seldom have that much influence to a trained rider.

 

I race Expert XCO, XCM and MTB 100s on Sram AXS 10-52. For XCO, the 10-52 allows me to use a 34 front chainring while still having a bailout gear, though I’m not sure I ever use the 52 during an actual race. Though it’s good for my training and it’s my setup for 99% of my riding/racing. I needed the 34 because I was spinning out on my 32 x 10.

For XCM (under 4 hours) I also use a 34 front chainring and the 52 helps me keep the power down on the punchy steep climbs where I’m trying to pace myself rather than go all out like XCO.

For MTB 100s I switch to a 32 front chainring and this allows me to spin (4-5mph) up long climbs in my 32 x 52. It’s ridiculously slow but it allows me to save the legs for later in the race after 8+ hours. I don’t need the 52 very often, but when I do, I need it really bad! Late in the race on a particularly punchy climb I’ve been known to try and shift down only to realize I’m already in my 52. That’s when you know you’re in a really dark place. There is a hole between that 42 and 52 though, a 46 or 48 would be nice, but it’s extremely rare where I feel like it’s missing.

I’ve never used Shimano 10-51 but I’d assume this would allow you to adjust the front chainring to the particular trail/race as Sram’s 10-52.

 

I race Expert XCO, XCM and MTB 100s on Sram AXS 10-52. For XCO, the 10-52 allows me to use a 34 front chainring while still having a bailout gear, though I'm not sure I ever use the 52 during an actual race. Though it's good for my training and it's my setup for 99% of my riding/racing. I needed the 34 because I was spinning out on my 32 x 10.

For XCM (under 4 hours) I also use a 34 front chainring and the 52 helps me keep the power down on the punchy steep climbs where I'm trying to pace myself rather than go all out like XCO.

For MTB 100s I switch to a 32 front chainring and this allows me to spin (4-5mph) up long climbs in my 32 x 52. It's ridiculously slow but it allows me to save the legs for later in the race after 8+ hours. I don't need the 52 very often, but when I do, I need it really bad! Late in the race on a particularly punchy climb I've been known to try and shift down only to realize I'm already in my 52. That's when you know you're in a really dark place. There is a hole between that 42 and 52 though, a 46 or 48 would be nice, but it's extremely rare where I feel like it's missing.

I've never used Shimano 10-51 but I'd assume this would allow you to adjust the front chainring to the particular trail/race as Sram's 10-52.

Do you not find your full suspension bikes bob a lot more using the 34T and the reduced Anti-Squat that the larger front chainring creates?

This has became one of the primary motivating factors in how I choose my front chain ring size. It's a balance between the excessive shifting that small chainrings cause (gears too tight) and the AS.

I spend a lot of time very near the high end of my cassette, but actually never quite spin out.

 

We have lots of climbing around here. I've never been the strongest legged guy of the group, but usually have the best lungs. The 45-51 gears have made it so much easier for me to keep a high cadence and a good rhythm on the super long technical climbs.

 

I'm old school. I'm rocking the 11 speed still. 36t x 11-42t

I guess if I had to do an epic long endurance ride at a good pace I'd either drop to a 34t or 32t up front and call it a day.

 

For my riding (not racing), I find that the 10-50 to 10-52 cassettes are largely more range than I need. I'm on a Shimano 10-45 setup. To get the low gear I want, I run a 28t chainring. On the bigger climbs, I occasionally want lower, but it's even rarer that I want taller gearing than 28 x 10. I do actually spread use out across a bigger range of my cassette. It can be annoying at times that getting the gear I want means I need to dump 2-3 gears to get my cadence where I want, instead of just shifting 1 gear, but the XTR shifter lets me make those shifts with fewer presses so it isn't too bad.

Seems to me, though, that regardless of whether you're racing or not, gear spacing is an intensely personal thing. I'll agree that you were hearing mostly useless banter at the shop. That one guy liked the spacing better, sure, but other people won't.

 

10-12-14-16-18-21-24-28-33-39-45-51 is Shimano
(2) (3) (4) (5) (6)
10-12-14-16-18-21-24-28-32-36-40-45T

10-12-14-16-18-21-24-28-32-36-42-50/52
(2) (3) (4) (6) (8) /(10)
10-11-13-15-17-19-21-24-28-32-38-44

Now go play with a gear ratio calculator.
It becomes obvious that in order to climb faster with the shimano cassette you need to operate at a higher cadence

 

I like my 11-48 AdventX ratios...
11-13-15-18-21-24-28-34-40-48

 

I am not sure I agree with that - I am positive Tempier "got the advice" that his cadence is off probably more times he could count. And a cadence monkey such as Froome also would ride a harder gear if he was quicker with a harder gear.

So yes, you can adapt to accept it, but it probably won't make you quicker (actually it will probably make you slower), otherwise Sky with their machinery would have defined it is 87 rpm, and all Sky riders would have been on 87.

 

For my riding the spacing on the Shimano looks like it would be better than the SRAM 10-50 I currently run, and one of these days, I may make the change.
My climbs are on the Wasatch Back in Utah, where it's often a 3000 foot climb to almost 10,000 feet. So far, I almost never have had to use the 50 tooth, but the last bit of the climb is a .48 mile 12.3 percent average grade suffer-fest that starts at 9500 feet up Puke Hill - and my age is becoming a factor. At least a third of that is in 50, and an easier second/third gearing would be pretty nice there! I don't need to get there faster, I just need to get there without stopping.
Better shifting under load and more durable low gears would also be welcome, I'm just not sure Shimano gives me that.

 

The only time I use my 50t is when I have to come to a near stop to get my son’s bike trailer up and over the curb, then up our 30% grade driveway.


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The only time I use my 50t is when I have to come to a near stop to get my son's bike trailer up and over the curb, then up our 30% grade driveway.

Well la-dee-dah. Get back to me when you're 62!

Seems to me that everywhere I live and/or visit (yes, even Bend) has a couple of short, but essential, segments where my 50 gets called into play.

Slickrock, Pig Ridge, the "up" route on Tiddlywinks, OG Amasa Back to the ATV overlook, that climb in the Rattlesnake I can never remember the name of.......

But put me in the coffin when I need a 52, that's where I'll draw the line! ?

 

To contribute to the topic, I run AXS with an XTR chain and 10-51 cassette on my main enduro bike. It's amazing. The terrain I ride can be soul sucking to climb and the 45t 2nd gear is just a gem, rendering the 1st 51t gear for emergencies only. I would LOVE to have a midcage electronic deraileur 11 speed 10-45 XTR cassette, also it doesn't exist (yet).

However, that's for an Enduro bike. I also have a (new) lighter weight trail bike (Spur) and I set that up with 11 speed SRAM because it is inexpensive, good ground clearance, and saved a heap of weight in a great place to save it. It's working very well for me with a 30T front but I do wish it was more like a 10-44 or 10-46. But in addition I don't plan to take this bike on the soul sucking climbs with all the ledges, loose rocks, and steep pitches that I usually take my SJ Evo on.

I watched the GBN Enduro bike check the other day and the male Pros were generally running 10-45 cassettes with a 32 front. There really is a hole in the manufacturers lineups missing a good wide ratio 11 speed option built to be premium but also lightweight with better clearance.

 

I’m still in (and will likely remain for a good long time) in the world of 11 speed. Because it’s what was available, I tried using the Shimano 11 speed 11-46 cassette. I hated—HATED—the spacing at the top of the cassette. Back to the Sunrace. Kinda heavy, but certainly last a long time for me. 10-45 Shimano would be my choice if I wanted 12 gears.

 

Yep, 11sp shimano sucks with the large 46 jump, I've even had broken tooth on the 46 cog probably due to the large jump. I still use better spaced 11sp sunrace 46 cassette on my autumn winter beater xc bike, works fine and refuses to die.

12sp shimano on with 39-45-51 works great for me in the upper range, all 3 cogs perfect for the purpose, my cadence style and terrain. Tried the 12sp sunrace hg cassette before freehub conversion, and it sucked (not on range, spacing but shifting)