Why would you need Di2?

The AXS short cage derailleur will handle 10-26, 10-28, and 10-33 cassettes.
The AXS long cage derailleur will handle 10-28, 10-33, and 10-36 cassettes (although I've had issues getting it setup for 10-28).

I don't know why you mention di2 derailleur.

You just need to buy a 10-33 AXS cassette from SRAM. You'll also need to check your chain length and might need a new chain. If you want to go to 10-36, you'll need a new derailleur and a new cassette.

He knows he couldn't go to 33 with a short cage shimano derailleur, which is why he's asking instead of just throwing one on there.

What does a Shimano derailleur have to do with the OP's bike?

He's asking if this one thing (a sram derailleur), which which is he not familiar, has the same limitation as this other thing (a shimano derailleur), with which he is familiar.

I have no idea how you came up with that idea.

If you ordered it why not have them build it with what you want? may cost a few bucks more and delay it a little but doesn't hurt to ask.

Well the mechanic at my local shop said he is unsure whether it a 10-33 would fit and they wouldn't allow me to change the inital order anyways.
Only stock they said so i'd have to order the cassette seperarely anyways and sell the 10-28

Why would the mechanic not know if a 10-33 would fit?

Why do you think the bike comes with a 10-28 cassette?

Well he said i might need a long cage rear derailleur but was unsure about it.
That's why i figured i'd post here.

10-28 is what the stock bike ships with according to the specialized website.

SRAM specifically says that the Red AXS short cage rear derailleur works with a 33 tooth cog:

https://www.sram.com/...m/models/rd-red-e-d1


The Specialized website shows that the Shiv Red eTap AXS bike comes with a 10-33 cassette:

https://www.specialized.com/...earchText=97420-0101

There’s a lot going on in this thread. If bike comes with Sram red or force etap AXS then you should be able to add a 33t cassette

https://www.sram.com/...m/models/rd-red-e-d1

https://www.sram.com/...m/models/rd-frc-e-d1

Do you have any idea how Di2 fits into this?

No, trying to get past that apparent confusion.

I would find a new LBS then. As two of us have pointed out in this thread, the SRAM website gives you the answer with about 25 seconds of searching.

The Eagle 1X RD is compatible

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It's pretty obvious, he says he'd need a new derailleur with di2, since a short cage di2 derailleir can't fit a 33 tooth cassette, and was wondering if a short cage etap derailleur will be the same. It's ok to answer people's questions without feeling the need to belittle them for not knowing sometimes

What does Di2 have to do with this?

You really need to find a new mechanic.

Well, most short cage RD’s are not compatible with a 33t rear cog. The mechanic didn’t have the specs for AXS memorized, and maybe wasn’t online at the time the OP was asking the question.

Not sure why people are saying to get a new mechanic if they don’t have this one thing memorized.

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It took me 10 seconds to go to the SRAM website and see that it could handle 33 teeth.

And what does Di2 have to do with this?

Because
(1) I honestly would expect that to be the type of info a mechanic would or should know;
(2) if not, ok, fine, but i had confirmed what I thought to be the answer while typing out a response to this thread.

If your mechanic doesn’t know either of the above, I would move on. That’s just my opinion though.

Why should they know that specific question off the top of their head? Better to say “I’m not sure” than pretend you do know and give the wrong answer. I’m pretty good with excel as part of my job, but I don’t know what the max number of rows in a spreadsheet is (I used to, but not anymore)

And I’m not really sure how knowing that narrow answer has any bearing on his ability to do the tasks that require a bit of skill and/or experience.

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Sure I can answer your questions

(1) it’s a fairly new product and a point of emphasis for the new 1x product as the shirt cage RD’s use up to 33t cassettes
(2) there are really only 2 major manufacturers of components in the US. Sram is one. It’s not like he’ being asked to know something about a bike-brand-specific issue.
(3) of course he shouldn’t pretend or lie. But, better to know then not know. And much better to know where to look for the answer if you don’t know. Like, “ Hey, Shopper, I don’t know off the top off my head, but give me two minutes and I can find you the answer.” Or “I’m tied up right now, but I know where to look and will have the answer to you tomorrow.”
(4) I disagree with the premise that a Mechanic’s value proposition is limited to wrenching. I expect them to be able to offer insight/expertise on how to build a bike with compatible components, what works well/not well etc. I recently had my mechanic do a build and they offered me all sorts of advice on things like disc brake size, valve extender choice, use of grease in certain bike parts, and some issues that were specific to my bike (the proprietary stem and handlebar).