dimitrous

I'm curious about converting a stock Specialized Sirrus 3.0 2021 from 2x9 to a 1x12 drivetrain.

Doing research on this I realized that not all wheels/frames are compatible with a 1x12 set-up, and frankly I'm getting lost in all the intricacies of it.

Is there a 1x12 groupset that would work for the Sirrus 3, and what additional parts/substitutions do I need to make this work?
NX Eagle 12-speed 11-50T, but with dead spots due to Low Point of Engagement? 11-speed road driver?

Insights are super appreciated!!

KCT1986

What rear hub do you have? Specific brand info please.

If it is a Shimano made hub, most of the 8/9/10 freehub body cannot be swapped for a 11 speed version. The interface between the freehub body and the hub shell is different for most pre-11 and 11 speed.

And Shimano road freehubs doesn't seem to specify the POE for these older hubs. Road use doesn't require high POE, that is more of a MTB thing. Road wheels are usually spinning fast enough that it doesn't matter.

For a non-Shimano hub, an 11 speed road length may be available. Think that this is what you are planning, a 12 speed HG style cassette on an 11 speed road freehub, right?

CrimsonEclipse

12 speed is where more specialized (pun not intended) equipment is more likely to be required.

What is the free wheel?
HG (up to 11 speed), Microspline (12 speed), SRAM (whatever it's called) 12 speed
That's your first obstacle.
11 speed 11-50T isn't that much of a compromise.

You'll probably need a new read derailleur that can handle the 11-50T, medium or long cage should work.
Just make sure it can handle 50T
Front chain ring should probably be a narrow wide chain ring to help prevent chain drop.
I'm guessing 42T-46T

Then you'll need align your front chain ring. (chainline)
I try to align it with the center of the cassette or slightly to the left (larger cogs)
Different cranksets can help move the chain line or offset chain rings can help.
I use spacers or mount on one side or the other of the crank.

(I hope this makes sense, I'm tired and may regret this post when I wake up)

Canker

KCT1986 post has incorrect info. He is confusing road and mtn standards. For mountain bike cassettes that start with an 11 tooth cog the NX 11-50 for instance you just need a standard old HG freehub which is what you have. 11/12 speed road cassettes require an 11 speed road freehub but there are exceptions to that too, 11-34 shimano 11 speed road cassette also fits the old standard freehub. Too be even more confusing the mountain bike cassettes that start with a 10 tooth cog are the ones that require a special freehub.

Does your cank have riveted or bolted chainrings? If you have riveted rings you need a new crank. That is the only real hang up other than $$$. Personally if you have to do this I'd go with a shimano deore 5100 11 speed setup. That would run $150 without a crank or $200 with, bang for the buck.

Duragrouch

Your reasons for "upgrading" would be helpful to know, and yes, it is perfectly acceptable to say the new systems look cool to you, or you want simplicity of shifts of 1X.

But purely on utility, it would be good to know your current setup in terms of chainrings and cassette range. For example, staying with 2X but going from an old typical 52/42 crank to 52/36 or 50/34, makes a really big difference alone. Add in a slight increase in cassette low cog, and the changes can be significant. (EDIT: Looking online, I think you may already have a wide range 2X crank, and either a 34T or 36T low cassette.)

What do you want that you do not currently have? Lower-low gear?

And... sorry... "Surely you can't be Sirrus." (You may be too young to understand that.)

PromptCritical 

Being unfamiliar with the latest in gear sets, what is a “narrow wide chainring”?

MilhouseJ

It's a newer 1x-specific chainring, having alternating thick-thin-thick-thin teeth. It corresponds to the wide-narrow-wide-narrow slots in the chain itself. I think it has something to do with better chain retention, though I can't be certain.

KCT1986

Thanks for the correction. Didn't know that the NX 11-50t cassette was different from the 11-42t version. Was not aware that it had more 'overhang' to the hub side.

CrimsonEclipse

As stated above (thanks Milhousej!) chain ring that is thicker and thinner to optimize the fit in the links if the chain (inner and outer plates)

I've used narrow/wide (which is basically an industry accepted terminology) chain rings on mountain bikes, pavement bikes and folders.
On the folders, it eliminated the need for dual bash guards to prevent chain drop.
(some folders had problems with chain drop due to short distance between chainring and cassette)

noglider 

Before you go through all the expense and trouble, you should have a good reason. The system you want to use may not be better than the one you have.

Duragrouch

Small additional: Narrow-wide chainrings only come in even-number of teeth, and must be installed with the chain narrow link on narrow tooth, and wide link on wide tooth. This is why they only work on 1X chainrings, because with a front derailleur, it can't line that up each time it changes chainrings. But yes, it also should result in less dropped chains on a 1X. But this would also make a front derailleur more difficult to use, because the greater lateral movement of the wide link on standard narrow teeth, is what makes easily moving the chain laterally from one chainring to another, possible.

dimitrous

Thank you!!


I looked and looked, but was not able to figure out the exact rear hub that I have. There are no markers on the outside, and the only info from the manufacturer is "Alloy, 6-bolt disc, 8-/9-speed freehub, loose ball bearing, quick-release, 32h"


Another source indicates that it "accepts a Hyperglide style cassette", which makes it Shimano I guess. I understand it's a "standard freehub", and NX should fit.


A couple remaining questions then:


1. Is it possible, and how, to upgrade the freehub to a) Sram XD, b) microspline and c) Shimano 11-speed HG road to allow for Sram 12-speed road / XPLR, Shimano 12-speed mountain, and Shimano 12-speed road respectively? Do I need a new wheel altogether, or can I get away with a simpler/cheaper upgrade?


2. For non-competitive city riding, should I target a road or mountain biking groupset, and why? I don't really get the practical difference of the two. I live in a fairly hilly city: 5-7% grades are common.

dimitrous

For my reasons for doing this... Well, I got this bike thinking "I'll spend a little less upfront, but over time I'll deck it out exactly how I want, instead of spending 5x more upfront and not having it not be perfect anyway". Turns out it's a bit more complicated.

I don't love the 2x9 set up - would prefer more simplicity. The gearing is fine - it handles both the up and down hills where I am. I rarely use the lowest gear (downhill) and frequently use the highest ear (uphill).

But it just so happens I need to replace the cassette (the brand new chain is slipping on a couple gears). I figure now is the time to consider swapping the whole group set, if I'm ever going to do it. In the grand scheme of things this is not important, at all. I get that. But I also don't mind tinkering a bit. Within reason...

Trav1s

Are you sure on the year? I was looking for original bike specs in the Specialized archive for 2021 and it does not show a 3.0 for 2021.

As for a new chain slipping, I'm wondering if it is more about alignment/indexing than wear.

tcs

Drop bar "mullet" shifted with a Microshift 'SRAM MTB 1x12' bar end.




This was a new build, not a 'conversion'. SRAM & Shimano:

RH Clark

This is my thought as well. I might convert a 1X12 to a 2X9 for better gearing, a less expensive system, stronger chain, and less finicky shifting, but never the other way around. I don't care what the cool kids think.

RH Clark

For me a 1X12 wouldn't be simpler it would mean that the gears are so close everything needs to be perfect all the time. That means constant tweaking and adjustment. You might consider an internal geared hub or whatever they call the ones with the geared transmission. Shifting there is reported simpler and less maintenance.

Personally, my best advice is to not do anything to your current bike. Just ride it until you cannot do what you want to do with it. Then you will know exactly why you can't do what you want to do and what you need to do what you want to do.

grumpus

You seem to have your highs and lows confused - high gear is fastest downhill, low gear is easiest uphill.

oldbobcat

You can't get much simpler than 2x9. The big ring is for easy flats, downhill, and downwind. The little ring is for uphill and upwind. Choose the ring to match the general terrain, then choose the rear cog to fine tune your effort to the terrain. It's not that hard.

12-speed is bleeding edge stuff. You'll be dealing with a new shifter, a new rear wheel, a new chain, a new rear derailleur that will likely use a clutch, and a new crank that will work the the thinner chain.

Get your 2x9 setup properly serviced. On a Sirrus it should be nothing less than delightful.

dimitrous

There's a page on 99spokes for the 2021 Sirrus 3.0 - I can't post a link, but googling should get you there! It seems identical, or at least close, to 2022/2023 models.

Can you tell me more about the alignment/indexing? I'm trying to learn how to do this myself, but so far my research indicates that if it's only one gear slipping then there's not much you can adjust.

dimitrous

Folks, I hear you all on "stick to 2x9/don't mess with a good thing/trendy-does-not-equal-good". I getcha.

I transferred over from a road bike due to back issues, and got the Sirrus 3 for its comfort and relative versatility. I swapped the handlebars for very upright/swept-back ones, added seatpost suspension, and a cushier seat. I'm making a bike I love riding, so that I ride even more. There won't be a "future bike", I'm making it now, bit by bit.

I admit I'm not fully sold on 1x. But I do hear people raving about it, and if the whole world is going in that direction it's worth exploring. I didn't mean to turn this into 1x vs 2x thread - right now it's more about "how". But I really do appreciate everyone's opinions and guidance!

KCT1986

So, we don't know exactly what hub you have. Many companies use less expensive 'house' brand hubs on their wheels when equipping their bikes. Hard to know the actual hub maker and thus find out what optional freehub driver may be available (XDR?, XD?, Microdrive?). 'Hyperdrive compatible' is a very common standard, so the hubs could be from just about anyone.

As far as installing a 12 speed cassette, it was noted in other post (& pictured), a SRAM NX 11-50T will work on an 8/9/10 speed freehub body, (NX 11-44T seems to need a road 11 speed length HG body). The 11-50T can work because the 50T sprocket is large enough that it can be offset further inward while not interfering with the spokes.

FYI, 11 speed road freehub bodies are about 1.85mm longer than 8/9/10 speed bodies. For MTBs, the standard for 11 speed is the same as 8/9/10, (also using an offset large sprocket to allow this). To add more confusion, some hubs are listed as 11 speed but are for MTB use, and thus are the shorter length.

So, in summary, with your current freehub body, the 11-50T cassette should work but lower range 12 speed cassettes will need a different freehub body.

Lot of good info has also been posted about the 'need' to go 1x12. It would entail replacing quite a few parts. As for 'road' or MTB groupset, road 12 speed is relatively new, so less selection, mostly with electronic shifting ($$$).

Duragrouch

Hyperglide compatible: While the freehub spline pattern was an invention of Shimano (asymmetric, one groove wider than the rest, to ensure all the cogs are "indexed" in rotation position the same), that is no longer patent-protected and has become perhaps the most widely used standard among all component makers, other than dropout widths, the BSA "English" bottom bracket shell size and threading standard, handlebar clamp diameters, seat rails, etc. However, there are now great variations in hyperglide compatible freehubs in terms of length, profile under the most outboard cog, and interface with the hub body.

Don't get me wrong, I am NOT an authority on those variations. But I sorta know what I don't know. My first source of info is always the Sheldon Brown website, but even that can be a little behind on the newest standards.

oldbobcat

I've worked on dozens of these. They're like a Trek FX or a Cannondale Swift. Problems indexing on a cog on either end of the cassette usually indicates a limit screw is a little too tight. Problems indexing on a cog in the middle of the cassette usually indicates that the hanger is bent.

So the first step to fixing a non-indexing RD is to align the hanger. Here's the video. https://www.parktool.com/en-us/blog/...nger-alignment

The second step is to adjust the limit screws, b-screw, and cable tension. https://www.parktool.com/en-us/blog/...eur-adjustment