new RED xplr 13speed UDH

[solarider]

Bear in mind that most MTBs running Transmission are Boost spaced (148mm) and most road/gravel bikes are still 142mm, plus the largest ring on Transmission is dished right over the hub flange and spokes, I would be surprised if they fit 13 in there. Plus, surely SRAM want to retain cross-compatability across all of the AXS ecosystem? I think the jury is still out on it being 13. Even the picture with the dots isn't clear.

[Salespunk]

It is 12 spd, this is just Red with a Transmission cassette finally. Problem is that most road bikes don't use UDH so you can't mount this RD. It is applicable to some gravel bikes and 5Dev makes a conversion kit that is almost ready to bring to market. Unfortunately it is only Specialized right now.

[magnusss]

The largest sprocket on the cassette is 46 tooth. Current XPLR is 44.

[satanas]

The images are too low resolution to be able to tell anything. If the largest cog really is 46T and it's 12 speed (likely) that means bigger gap(s) somewhere, not great. If it's actually 13 speed that could mean smaller gaps and more range, better IMHO. We'll find out eventually...

[TobinHatesYou]

The images are too low resolution to be able to tell anything. If the largest cog really is 46T and it's 12 speed (likely) that means bigger gap(s) somewhere, not great. If it's actually 13 speed that could mean smaller gaps and more range, better IMHO. We'll find out eventually...

For reference the existing XPLR cassette is 10-11-13-15-17-19-21-24-28-32-38-44.

I counted each of the largest 5 cogs. They are 24-28-32-38-46, so only the last jump is larger.

If this really is 13-speed, then they could just add the 12t cog and change the last cog to 46t and be done: 10-11-12-13-15-17-19-21-24-28-32-38-46

[jih]

The images are too low resolution to be able to tell anything. If the largest cog really is 46T and it's 12 speed (likely) that means bigger gap(s) somewhere, not great. If it's actually 13 speed that could mean smaller gaps and more range, better IMHO. We'll find out eventually...

For reference the existing XPLR cassette is 10-11-13-15-17-19-21-24-28-32-38-44.

I counted each of the largest 5 cogs. They are 24-28-32-38-46, so only the last jump is larger.

If this really is 13-speed, then they could just add the 12t cog and change the last cog to 46t and be done: 10-11-12-13-15-17-19-21-24-28-32-38-46

If it's transmission compatible, that means only having even-numbered cassette sprockets, since the cassette is narrow-wide

[Karvalo]

If it's transmission compatible, that means only having even-numbered cassette sprockets, since the cassette is narrow-wide

Factually wrong, and possibly a complete misunderstanding of what narrow-wide does.

[jih]

If it's transmission compatible, that means only having even-numbered cassette sprockets, since the cassette is narrow-wide

Factually wrong, and possibly a complete misunderstanding of what narrow-wide does.

Care to explain where I'm wrong/missunderstanding?

[Hexsense]

Factually wrong, and possibly a complete misunderstanding of what narrow-wide does.

You possibly didn't update your technical info and miss that narrow-wide is used on the cassette to a great effect?

search first instance of "narrow-wide" in this Sram Transmission review and read that sentence from the beginning.
https://enduro-mtb.com/en/sram-eagle-tr ... et-review/

11 out of 12 cogs of Transmission cassette are narrow-wide. That's up from 3 out of 12 cogs on previous generation Sram Eagle drivetrain (pre-Transmission).
It's done that way for 2 reasons:
1) Sram wants the chain to ride on cassette in a specific way. When they design shift ramp, it then can be shaped to match the chain width precisely at each inner or outer link.
2) It keep chain on the cog better. It doen't allow the chain to dislodge to a neighbor cog at all until it rotate to reach shift ramp. All-narrow teeth cassette cogs don't have this chain holding power, so you can force a shift without a shift ramp on normal cassette.
Sram doesn't want that kind of shift out of their designated ramps. So, with narrow wide cogs, they can be sure chain only shift when it hits the ramp. This may delay the shift, but make every shift between narrow-wide cogs perfect.

Narrow-wide on most of cassette cogs is literally the whole reason Sram Tranmission shift different from generation before the Transmission. So I think jih made a fair assumption. If you take this element out, then you are left with just the "look" of Sram Tranmission without its core feature that make the Transmission different from other drivetrains.

Look at image below and tell me you don't see that 11 out of 12 cogs use narrow wide teeth?

[TobinHatesYou]

Transmission clearly does not force you to use only cogs with an odd number of teeth since even the MTB cassette doesn't satisfy that "rule."

If SRAM actually wants Transmission on road bikes, having several cogs with an odd number of teeth will be a necessity. This isn't MTB where 10-52 is the only option, road users won't accept 10-12-14 at the the high-end.

[Hexsense]

Transmission clearly does not force you to use only cogs with an odd number of teeth since even the MTB cassette doesn't satisfy that "rule."

If SRAM actually wants Transmission on road bikes, having several cogs with an odd number of teeth will be a necessity. This isn't MTB where 10-52 is the only option, road users won't accept 10-12-14 at the the high-end.

Yeah, there is one cog in MTB Transmission cassette that isn't narrow wide. It's 21t, the only odd number tooth count in the cassette and arguibly the shift out of this cog to its neighbors is the clunkiest shift out of the entire cassette as well. It only shift perfect 50% of the time depend if it align right for the ramp and narrow-wide teeth of neighbor cogs.

I think Sram will have to compromise for road groupset. Release a drivetrain that have the "Transmission" look but not getting such synchronized shift of real Eagle Transmission. Perhaps lower half aren't narrow wide. Then only start to use narrow wide teeth on top half of the cassette?

[jih]

That's fair. I checked and the mountain bike cassette is 10-52t:10,12,14,16,18,21,24,28,32,38,44,52 - so clearly biased towards even numbers, but with 21 standing as the odd one out.

So, not quite that Transmission requires even numbered sprockets, but strongly prefers them. At least in its mountain bike version.

[Karvalo]

If it's transmission compatible, that means only having even-numbered cassette sprockets, since the cassette is narrow-wide

Factually wrong, and possibly a complete misunderstanding of what narrow-wide does.

Care to explain where I'm wrong/missunderstanding?

A) Look at the list of sprocket sizes on a Transmission cassette.
B) Look at a Transmission cassette.

[Karvalo]

Look at image below and tell me you don't see that 11 out of 12 cogs use narrow wide teeth?

I see that after all that you've talked yourself into agreeing with me. Good stuff.

[Hexsense]

Look at image below and tell me you don't see that 11 out of 12 cogs use narrow wide teeth?

I see that after all that you've talked yourself into agreeing with me. Good stuff.

You mean 11 out of 12 cogs? Nah. I know that from the beginning. It is also mentioned mid way on my paragraph.

So you already know that Transmission shift the way it does because of narrow-wide cogs, then. It shift perfect between 11 out of 12 cogs they have, which are narrow wide. Then the odd one shift to any narrow wide neightbor is clunckiest shift, relatively.

I typed long because I thought you don't think narrow wide is the integral design of how Transmission cassette shift by the way you word this part

and possibly a complete misunderstanding of what narrow-wide does.

It literally does what narrow-wide always design to do. Hold chain on the cog. And don't allow inner chain pin to mash on wide teeth.
Tooth that deviate away from regular narrow wide pattern exists because it still need to shift. But outside of those teeth, it's narrow wide on 11 out of 12 cogs. 11 out of 12 cogs don't allow you to mash chain the wrong way. Narrow chain link don't go on wide tooth on any of these 11 narrow wide cogs. As shown in any Sram Transmission review and also verifiable on one that is on my mtb.

For others to see clear picture without having to read Transmission review. Quote below might help to get that they use narrow wide to strictly select which tooth mash with inner or outer chain link.

In addition, the new Flattop chain can only mesh with the cassette in a certain position, ensuring that it is always perfectly engaged and distributing the pedalling forces equally. If it does end up in the wrong position, it won’t mesh with the cog and will simply slip back into the correct position as soon as you apply a light load.

src: https://enduro-mtb.com/en/sram-eagle-tr ... et-review/

Still, I think we'll get a "Transmission-look-a-like" road cassette. But the perfect shift nearly all the time MTB Eagle Tranmission famous for might not come with it due to the neccessity to use less narrow wide cogs.