The chain ring of a 1x drive train is normally going to be in between the 2 chain ring sizes on a 2x. That chain ring also has to work with the 36T of the cassette for hills.

Bernard Hinault was/is an outlier in so many ways, most notably he was a pro cyclist and didn't have to pay for his equipment.

For 'normal' human beings that buy bikes the 90rpm cadence is pretty standard advice. If you have found that pushing a slower cadence is faster for you, congratulations you are an outlier...you can spend $80ish and buy a chainring that fits your needs better. Nick has to spec his bikes for the biggest group of people that he thinks will actually buy his bikes....for that group I think a 48 tooth is perfectly reasonable.

If I had to bet though....most people's 11 tooth gears are pretty unused. Especially for a TT or Tri.

Well it might be the right choice for their average customer and I haven't given it a lot of thought outside of my own gearings needs. Given a lot of people use compacts at 50 with 34-36 maybe 48 makes sense.

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I run a 54 1x as well... I know for myself as a low cadence guy spinning at 100 plus just isn't my thing. Below is the comparison between a 54 and 48 using a SRAM 11-28 cassette w/ 170mm cranks. I know it's a balance of a few things... for me I'm not super comfortable spinning at 100 plus for extended periods of times and don't mind the bigger gear.


Table didn't cut and paste... but at the top end of the gearing the 54 is roughly +4mph over the 48 @ 100rpm.

That's kind of where my sweet spot is for pushing a big gear in certain situations... so that +4 @ that cadence works for me.

OK fair enough, it seems way too small for me. If there is enough climbing on a course that I need a 48/36, then there is likely plenty of false flat DH/true DH and 48 is too small for that. And if something like a 52 or 50 up front is too big for the climbing on a given course, then that's where maybe 1x isn't the right choice or it's time to get a 40T in the back.

Sorry for the thread drift. Back to the topic - yes there are lots of 1x options for TT use, both round and oval.

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[/quote]

Just to be clear....48 X 11T @ 90 rpm (that should be the low end of your cadence for a steady effort) is 30.8 mph.

http://www.sheldonbrown.com/gear-calc.html[/quote]
Just to be clear....that's pure dogma. Here's 3 reasons why.

1. Re: cadence of 90 being optimal - maybe if you're talking about untrained individuals. I haven't met a intermediate to advanced athlete who doesn't improve their total performance by lowering their cadence to 80-85.

2. You're leaving watts on the table by riding in the extreme end of your cassette. Better to ride a bigger chainring and sit in the middle of the cassette at race pace.

3. Your example ratios leave no scope for applying power during a descent, due to spinning out the gear.

I have asked them a couple of times, and it's always 1-2 quarters out. Latest reply is 6 days old. Not impressed.

Sorry for the delay, but we have a few ongoing projects which we are prioritizing. We expect to have some more sizes in SRAM DM in the first quarter of 2018 . Please sign up to our newsletter to stay up to date

Yup, some of us do better at lower cadence. Everyone is different, and for different events you might ride a higher or lower cadence. I Time trial around 80, but crits are around 90. Mtb rides my cadence averages in the 70s.
I use a 56/44 with a 11-26 for tts, I would love a 56 narrow/wide aero ring. The 54 from SRAM isn’t enough for me.

Just to be clear....48 X 11T @ 90 rpm (that should be the low end of your cadence for a steady effort) is 30.8 mph.

http://www.sheldonbrown.com/gear-calc.html[/quote]

Just to be clear....that's pure dogma. Here's 3 reasons why.

1. Re: cadence of 90 being optimal - maybe if you're talking about untrained individuals. I haven't met a intermediate to advanced athlete who doesn't improve their total performance by lowering their cadence to 80-85.

2. You're leaving watts on the table by riding in the extreme end of your cassette. Better to ride a bigger chainring and sit in the middle of the cassette at race pace.

3. Your example ratios leave no scope for applying power during a descent, due to spinning out the gear.[/quote]
Throwing another wrench in the works, cadence should increase & gearing reduced with shorter lengths too. rough math, going from 172.5s to 165's will increase cadence by about 5 rpm. When I was a pure cyclist doing a lot of TT's, I rode a 650c Cervelo with a single 56T on the front, 12-21 on the back. On typical flat - rolling courses, I don't think the 12 or 13 ever got used. I was fastest at about 95-100 rpm back then, now my preferred cadence is a little lower, but still around 90.

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I've been crit racing on a 1x setup for 3 years now and like to experiment with a lot of different chainrings. So, my thoughts on the most common available options:

SRAM: solid, durable, good chain line. Good chain retention, at least with a clutch RDR. I would call this gold standard at this point. If chain line were an additional 3-5 mm inboard, would be perfect.

Wolf tooth: my favorite. If your frame has the clearance, a 52t mounted in inner position has perfect chainline (in the 6th cog, chainline is within a couple of mm of being perfectly straight but only a couple of mm of clearance between the ring and chainstay). Have never dropped a chain. And by far the most quiet. One of my rings has about 6K miles on it and shows almost no signs of wear.

Absolute black oval SRAM direct mount. Looks super cool. Good chain line. Wears out fast. Obviously only fits with certain cranks and doesn't allow crank based PM.

Garbaruk. On paper, looks great, but it is very loud. Highly ovalized, which takes a bit of getting used to. I rode a 50t for about 2000 miles and it never quieted down -- I suspect that hurts drivetrain efficiency, but dont have data to prove it.

Fiberlyte: look cool. Bad chain retention. The only ring where I routinely dropped chains. Only rode for a couple of hundred miles because it wasn't dependable.



Haven't tried rotor or aerocoach. Both look good if chainline is good.

As others have pointed out, chainline for your type of riding is key


Andy

Hi Andy,
did you check the geometry of all teeth? I just got a round 50t from Garbaruk and two chamfers of the wide teeth were missing. Machining quality in general still has potential... I hope to test it soon.

Marco

Interesting.

Looked at it closely just now and it looks like 3 of the wide teeth and substantially wider than the others. Which would fit with the rhythmic noise I hear from it.

No time to mess with it now, but I'll see if I can grind them down and make it work.

Thanks for the tip.

Andy

Hey AB,

Any hint on when (more) 1x DM aero rings with 54t are going to be available??

Thanks!

Late follow up on this.

I ground down the three teeth that seemed too wide and it is much better now. Rode it last night for hard training ride and seemed good. Still makes some noise, but not much. Plan on using it for Glencoe this weekend.

Thanks for the tip.

Andy

No problem, glad it worked. I am also finding the round 50T a bit noisy. However, chain retention, with a DA chain, has been flawless.

I have now ordered a Stone 54T (ebay, aliexpress...). The chainrings look ok and are available up to 60T. Does somebody have any experience with them?

Garbaruk will make a custom 1x aero chainring for you if you ask nicely :)

https://garbaruk.com

I got my 50t 110bcd two weeks ago and will finally mount it this week.

That’s interesting
I run the Rotor CX1 52 110bcd ring but i’d love to find an oval 54

I would love to try 1x on my Felt IA-10....just waiting for it to become a bit more mainstream but I love the idea in principal. :))))) 1x12 with a 54 and I don't know what in the back (cause I am just in love with the idea but haven't thought it through...don't judge me...I'll get there). :)

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"see the world as it is not as you want it to be"

I have one in a 56, works great. No chain drops so far, but it is a little noisy when in lower gears on the cassette.

Yep, that is also my experience. With the input of an other ST member, we now have our own design ready. Hybrid aluminum/carbon, offset for better chain line and so on... prototypes in the making.

Let me know. I need a 56 or even a 58

Cool. Most of us mortals need a 50 or 52t :)

No worries, the plan is to make 50, 54 and 58T versions ;-)

I'm going to take a stab at this, it's because aero works across all ability and power levels. So, people will own super expensive aero bikes to save time.

That doesn't mean they need a big front ring though.

Check this page for a 10 mile TT I did, only about 20 people here would even need anything in the 52t range. I bet the bell curve on a 1/2 IM or full IM is similar for speed. A very small part "need" even a 52t ring.

https://racesonline.com/events/cms-time-trial-series-1/results/2018?utf8=%E2%9C%93&category_id=&gender=&search_term_display=&commit=Search

We’re not talking about needing it based upon average speed

We are talking about downhill and with the wind and still maintain a desired cadence of 80 to 85