Trek-Segafredo disagrees with SRAM AXS gearing

[Mark McM]

Originally Posted by benb

I'd once again think this is not a problem the Pro Peloton thought they needed a solution to.

The Pro Peloton has frequently used this solution. When races started adding mountains with ridiculously steep pitches (such as the Angliru), racers started using what were previously considered "touring gears". A few used triples, but now that there are lots of Compact options, many now use Sub-compacts. Sub-compact drivetrains in the Pro Peloton is now not uncommon at all during the grand tours.

(Remember, racers were still using single speed bikes after many "tourists" had adopted derailleurs.)

[Heisenberg]

Originally Posted by Mark McM

All told, 10 tooth sprockets make no sense for my riding, and probably don't make any sense for many others either.

you should really think about getting your cranks re-anodized.

[82Picchio]

Snip:

Originally Posted by saab2000

I mostly mean that for most cyclists, most of the time, a 10-tooth cog is a wasted gear and nothing more than a spacer, reducing it to an 11-speed. The compact and sub-compact cranks are for weight reduction.

I agree with the above and would add that the same is true for the 11-tooth cog on my bikes. It gets use only on straight 8+% descents, of which there are precious few where I ride. For the animals among us, of course, YMMV............

[dddd]

Originally Posted by Mark McM

SRAM says that cassettes with 10 tooth sprockets increases the number of 1 tooth sprocket differentials, which they claim decreases the jump between gear sizes, while at the same time increasing gear range. This is a clear deception. The laws of physics dictate that gear size differentials and gear range must be proportional - for a given number of sprockets, you can't increase one without also increasing the other. SRAM's cassettes with smaller sprockets increase, not decrease, the size jump between gears.

By downsizing the sprockets, SRAM does actually increase the gear range of the cassette as they claim. But by using smaller chainring differentials, their double chainring drivetrains end up with a smaller total gear range then other drivetrains (with standard size cassettes and larger chainring differentials).

There is no doubt that there will be some who like the AXS gearing. But their advertising claims are all smoke and mirrors.

I think that there is some quantitative validity to their "increased range" claims made about their 10t cog cassettes.
The difference is that if you take two cassettes, each with say six 1-tooth shift gaps, the cassette with the 10t (vs. 11t) first cog offers greater range across those first seven cogs (or six shift gaps).

Since a 1t shift gap from 10t to 11t is not too big of a gap, they are exploiting the proportionally-greater change of ratio offered by smaller cogs, despite the other problems that you mentioned like chain friction and sprocket wear.

At my age I still like having tall gears for all of the even gentle descents here in the foothills. But I ride several vintage bikes mostly and find that I don't really need any taller gears than 50/12 or even 52/13t, especially when 27" wheels might be part of the equation. I feel like 52/12t is pretty tall, so works out well when I have at least seven cogs in back.

The 50-39t chainset is a great one that was once popular on 1960's Schwinns and also on quite a few early Dura-Ace cranksets out of the box. Combined with at least a 7-speed cassette with 12t top cog makes for useful and user-friendly gearing.

Up through the 10s era, Shimano still offered "B"-series 50t 130mm chainrings to be combined with their most-common B-39t chainring available at the Dura-Ace level and for a time I believe 105 as well.

Here's one of my 50-39t setups, paired with 12-26t and 1/2" clipless pedals:

[Dave]

When cassettes have no larger than an 11T for the first cog that is seldom used, that's when changing to cranks with smaller rings is the best option.

The 48/11 on my bike is used on some of the more minor downhills, when there's a tail wind, or at the start of a descent, I'll wind it up to 38 mph, before coasting.

[Mark McM]

Originally Posted by dddd

I think that there is some quantitative validity to their "increased range" claims made about their 10t cog cassettes.

Yes, I did agree that the use of a 10 tooth sprocket can increase the gear range (for the same differential between small and large sprocket). For example, compare an AXS 10-33 cassette with a Campagnolo 11-34 cassette: Both cassettes have the same sprocket size differential of 23 teeth, but the AXS cassette has a 3.3:1 range of gears, while the Campagnolo has only a 3.09:1 range.

But SRAM also claims that they can achieve the increase in range without increasing the size jump between gears. This is the deception. Yes, the tooth differentials between sprockets are the same with both cassettes, but the ratio differences don't depend only on the tooth differential, they also depend on the absolute sprocket size. SRAM is just hoping that consumers don't catch the math fallacy behind the deception.

But that's just on the cassette side of the drivetrain. Because SRAM's chainring differentials are smaller than others, the AXS 2x drivetrain actually ends up with a smaller range of gearing than their competitors 2x drivetrains.

[earlfoss]

I'll chime in only to say that I am now on SRAM Force AXS 12 speed, and it's operated great for me. I'm a Cat 1 on the road and in the time I've been using it there have been zero issues mechanically, and I haven't felt I'm lacking any level of practicality from it.

It's a new gadget and the options SRAM provides is going to work for 99.9% of the riders out there.

Seems like any move SRAM makes gets met with a lot of haters, but at the end of the day a lot of people are using their products problem-free, and without compromise. Makes for good forum threads though!

[polar8]

Wondering if this means they'll just limit screw block the 10?

[Heisenberg]

Originally Posted by earlfoss

I'll chime in only to say that I am now on SRAM Force AXS 12 speed, and it's operated great for me. I'm a Cat 1 on the road and in the time I've been using it there have been zero issues mechanically, and I haven't felt I'm lacking any level of practicality from it.

It's a new gadget and the options SRAM provides is going to work for 99.9% of the riders out there.

Seems like any move SRAM makes gets met with a lot of haters, but at the end of the day a lot of people are using their products problem-free, and without compromise. Makes for good forum threads though!

this.

i'm an ex conti bike racer. it is very ****ing good stuff, and i'd have no issue toeing the line at a euroland stage race with it on my bike.

if we're going down "THEPROSTHEY'REJUSTLIKEUS" dumbrabbithole, the 10-33 cogset is a bit gappy. for general racing and threshold intervals i'd probably size down to the 10-28, which has so many buttery gears in it. paired with the 48/35 it's spicy. if things are flat AF and it's an option, the big chainset+tiny cogs for maximum happy. or just 1x, because that works too. the gaps on the two smaller cassettes are very wee near the bottom of the cassette.

the TS team wanting a big chainset sounds like oldschoolbikeracing being oldschoolbikeracing (hullo, italy). i sincerely wish that PL Armchair Engineer validation could be from teams eeking the last .09% of (very) variable efficiency from their drivetrains, but that is not the case here. for all its faults, it is extraordinarily capable crap.

ps: if you want to sooth your gear range woes, rotor's direct mount round chainring 2x setups work great with it. i've put a few thousand miles on both 48/32 and 46/30 setups.

[bigbill]

I used to bitch about using a Shimano 12-23 8S cassette because it didn't have a 16. Seems pretty minor now.

[Dave]

While Campy may only have a range of 3.09 on the cassette, they have a range of up to 1.5 on the 48/32 crankset, to give a total range of 4.64. SRAM has nearly identical range of 4.6 with the 46/33 and 10-33. That range drops to 4.46 with the 50/37. Campy's 53/39 with an 11-33 is 4.48. It's all a wash, unless you really need a 5/1 top gear.

I like the lower 32/34 compared to the 33/33.

[polar8]

Originally Posted by bigbill

I used to bitch about using a Shimano 12-23 8S cassette because it didn't have a 16. Seems pretty minor now.

Same!!

[oldpotatoe]

Originally Posted by Mark McM

The Pro Peloton has frequently used this solution. When races started adding mountains with ridiculously steep pitches (such as the Angliru), racers started using what were previously considered "touring gears". A few used triples, but now that there are lots of Compact options, many now use Sub-compacts. Sub-compact drivetrains in the Pro Peloton is now not uncommon at all during the grand tours.

(Remember, racers were still using single speed bikes after many "tourists" had adopted derailleurs.)

Yup..what was the quote? Cyclo-tourists and nurses?

Variable gears are only for people over forty-five. Isn’t it better to triumph by the strength of your muscles rather than by the artifice of a derailleur? We are getting soft. Give me a fixed gear. – Henri Desgrange first Tour de France organiser

I think it should be mentioned again that more than a few carbon bikes, with brazeon front der tabs, will have difficulty getting the front der low enough on some of these micro compact cranks...again, sram is 'almost' all in on 1by...

It's a new gadget and the options SRAM provides is going to work for 99.9% of the riders out there.

wow, I didn't know sram had that high of a market share..

[Gummee]

Originally Posted by oldpotatoe

I think it should be mentioned again that more than a few carbon bikes, with brazeon front der tabs, will have difficulty getting the front der low enough on some of these micro compact cranks...again, sram is 'almost' all in on 1by...

My CX bike fits that bill. Evidently I don't do enough intervals, so I run a Wickerks 34/44 set during race season.

Can't get the derailleur down far enough, but even with the big gap, it seems to shift.

IME the solution to SRAM front derailleur woes is Shimano. Just like their brakes.

M

[Mark McM]

Originally Posted by Dave

While Campy may only have a range of 3.09 on the cassette, they have a range of up to 1.5 on the 48/32 crankset, to give a total range of 4.64. SRAM has nearly identical range of 4.6 with the 46/33 and 10-33. That range drops to 4.46 with the 50/37. Campy's 53/39 with an 11-33 is 4.48. It's all a wash, unless you really need a 5/1 top gear.

I like the lower 32/34 compared to the 33/33.

This is basically my point. The SRAM AXS "solution" is much ado about nothing. And in many ways, it adds more to the "con" column than it does to the 'pro' column (at least for 2x systems).

Pro: It uses slightly smaller cassettes, and a slightly smaller outer chainring.

Cons: It adds extra drag (which is not offset by its lower weight), and smaller sprockets will cause faster wear (of the entire drivetrain).


If the AXS 2x group had a smaller than normal inner chainring, then it could have had the benefit of more tire/chainstay chainring - but because it doesn't, the AXS group ends up as a net loss in just about every category.

The only application where the AXS appears to have any advantage is in 1x groups. where it can use a smaller chainring. And many people think SRAM is trying to drive people to 1x systems. But even here, the disadvantages may outweigh the advantages due to lower efficiency and faster wear.