Q: Convert SRAM Apex CX bike to 1x10

Underscore

I have a cross bike (Raleigh Rx Comp) with SRAM Apex - 46/36 chainset and 11-28 cassette. However, I only really use for cyclocross and similar riding so I almost never use the big ring on the front. I was thinking of changing to a single 38t ring up front and going 11-30 out back to keep a similar (or slightly easier) bottom gear. As I see it, I need 3 things:

1. A new cassette
2. A new mech (as the one I have maxes out at 28t) - probably the new Apex 1 clutch mech
3. A 38t narrow-wide chainring

So, I have two questions:

1. Is the Apex 1 mech compatible with my 10-speed Apex shifter?
2. Will the Force 38t X-Sync chainring fit on my Apex crank? Or is there a better option for the chainring?

And, yes, I know that is 3 questions!

Thanks in advance,

_

bendertherobot

https://roubaixcycling.cc/2016/02/22/iv ... sometimes/

You don't need very much.

1. Get a Shimano MTB cassette, they are cheaper.

http://www.ribblecycles.co.uk/shimano-1 ... #pid=20513

2. SRAM GX medium should be ok http://www.chainreactioncycles.com/sram ... prod135896 hunt around and you can find old SRAM X9 etc for cheap. 10 speed medium should do it. Should get a clutch one but works well enough without actually. Because of direct actuation you can mix apex and SRAM mtb mechs.

3. Yes it will. But it's expensive. http://www.superstarcomponents.com/en/c ... -style.htm I can't remember the BCD on apex. You will need a 5 bolt 110 I think

trek_dan

Don't forget the shorter chainring bolts too

Underscore

Thanks both for your responses. Re the mech, is X-actuation the same as Exact Actuation? I came across different mechs with the two different 'compatibility' descriptions...

Those Superstar rings look good (and, with a 36t option, I could try it with the cassette that I have without changing the gearing). The only thing is that I had heard that the chainline with the SRAM rings was better; is that true?

Thanks again,

_

trek_dan

"Exact Actuation (Road 10 & 11sp, Mtn 10sp) is 3.1mm while X Actuation (Mtn 11sp) is 3.48mm" according to SRAM so there is no cross compatibility with some 11 speed MTB - this doesn't effect you as all 10 speed stuff is the same. I think what SRAM mean by better chainline is that if buy a singlespeed specific chainset the chain sits bang in the middle, whereas if you just loose a ring you decide whether to mount it on the inner or outer.

bendertherobot

trek_dan wrote:

Don't forget the shorter chainring bolts too

I got away with that on both hope and absolute black with apex cranks!

bendertherobot

What Dan said re actuation. All 10 will be fine. And I doubt sram has any real effect on chain line.

thegibdog

I've running a GX2.1 and a Superstar narrow-wide ring on my 1x10 set-up cross bike, works well. The mech doesn't have a barrel adjuster though so you'll need an in-line one if you run the cable fully covered (my local bike shop gave me one for free )

Underscore

thegibdog wrote:

I've running a GX2.1 and a Superstar narrow-wide ring on my 1x10 set-up cross bike, works well. The mech doesn't have a barrel adjuster though so you'll need an in-line one if you run the cable fully covered (my local bike shop gave me one for free )

That's good to know. Are you running the chain ring in the inner or outer position? For the mech, I'm inclined to get an Apex 1 mech as it has a barrel adjuster and it also looks like it might be a bit more tolerant of mud - all for £10-15 more...

trek_dan wrote:

I think what SRAM mean by better chainline is that if buy a singlespeed specific chainset the chain sits bang in the middle, whereas if you just loose a ring you decide whether to mount it on the inner or outer.

I thought that SRAM chainrings are dished so that they fit in the outer position but the chainline runs between the inner and outer position...

_

tgotb

I bought a Superstar chainring for my 3PCX bike. Just as good as the (more expensive) Absolute Black ones I have on my regular bikes.

A free alternative to buying shorter chainring bolts is to make a set of spacers out of an old worn-out chainring. Takes 15 minutes with a hacksaw and a file...

You can move the chainring between inner and outer position to optimise the chainline on the gears you use most, but in practice it'll be fine in any gear.

thegibdog

Underscore wrote:

That's good to know. Are you running the chain ring in the inner or outer position? For the mech, I'm inclined to get an Apex 1 mech as it has a barrel adjuster and it also looks like it might be a bit more tolerant of mud - all for £10-15 more..

I'm running the ring on the outer as it looks better and I spend more time on the outer half of the cassette. I went for the cheaper mech as I'll be less annoyed the next time it gets destroyed by sticks or mud!

Underscore

Just an update: I bought a Superstar chainring, fitted it at the weekend and had my first training session with it last night. Despite only having the stock Apex mech (not clutch) and only having shortened the chain, it worked flawlessly.

Thanks for the advice!

_

skyblue337

I think take care if you decide in future to get the Apex mech with the clutch. It's listed as 11 speed and I think there is some confusion over the cable pull of sram 10 and sram 11
road being the same. Lennard Zinn on the velonews website states that he measured it at 2.9mm not 3.1. If you think about it the gap between the cogs on 11 speed is narrower than 10 so either the shifters must pull less cable or the derailleur must have a different actuation ratio. Either change renders them incompatible across speeds without a device like a shiftmate

Underscore

skyblue337 wrote:

I think take care if you decide in future to get the Apex mech with the clutch. It's listed as 11 speed and I think there is some confusion over the cable pull of sram 10 and sram 11 road being the same.

Hmm, worth knowing. However, the SRAM web-site says that all Apex derailleurs are Exact Actuation (which, from above, should make them the same cable pull?) Certainly the Apex 1 mech is cross compatible between 10 speed and 11 speed:

SRAM website wrote:

Compatibility: 10-speed and 11-speed SRAM 1x™ road systems

So, unless 1x uses a different pull ratio to 2x - which would be odd, I should be OK.

_

thegibdog

I think skyblue337 has misinterpreted the issue. The shift activation ratio is the same for SRAM 10 and 11 speed (1.3) - it's the cable pull of the shifters which handles the difference in the cog spacing. So the speed of the mech doesn't matter - an 11 speed mech will work fine within a 10 speed set up, as the mech just does what the 10 speed shifter tells it to do.

skyblue337

I was just trying to draw attention to the fact that there seems to be different numbers floating around for the cable pull. Indeed further up the thread it says the cable pull for 10 and 11 is the same. The Arts Cyclery blog on compatibility also has the same figure for 10 and 11 sram. According to these numbers, if the cable pull was the same the activation ratio for the derailleur would have to be lower.

As long as its the cable pull that changes between 10 and 11 and not the derailleur activation ratio then an 11 speed derailleur should be a straight swap on a 10 speed system.

Sorry for any confusion caused. Shouldn't post late at night

thegibdog

skyblue337 wrote:

As long as its the cable pull that changes between 10 and 11 and not the derailleur activation ratio then an 11 speed derailleur should be a straight swap on a 10 speed system.

This is indeed the case. Your previous post seemed to suggest that the 11sp Apex clutch mech might not work with 10sp shifters? Maybe I'm reading it wrong?

skyblue337

thegibdog wrote:

skyblue337 wrote:

As long as its the cable pull that changes between 10 and 11 and not the derailleur activation ratio then an 11 speed derailleur should be a straight swap on a 10 speed system.

This is indeed the case. Your previous post seemed to suggest that the 11sp Apex clutch mech might not work with 10sp shifters? Maybe I'm reading it wrong?

You're correct, the last sentence of my first post does imply that and is lacking in detail. Just out of interest do SRAM publish the acitivation ratios or is it well known that 11 speed derailleurs will drop into 10 speed systems? It's a shame ArtsCyclery have not updated their incorrect figures for 11 speed cable pull

Edit:
I see the compatibility is on the apex product page as mentioned above.

joey54321

Just to add to fun and games of SRAM compatibility, does anyone know if a 10 speed SRAM mtb rear mec is compatible with SRAM Rival 22 (11 speed) shifters? As far as I know both have exact actuation...so should be that the shifters just have an extra click and pull the mech a lil' bit more?

thegibdog

Yep, a 10 speed SRAM mech will work fine with an otherwise 11sp setup.

joenobody

Is there a rear mech option, compatible with an Apex 10 shifter, where I could run a larger low gear here, up to 46t? Although, it does look like SRAM and Shimano 10sp MTB cassettes only go to 36...

trek_dan

JoeNobody wrote:

Is there a rear mech option, compatible with an Apex 10 shifter, where I could run a larger low gear here, up to 46t? Although, it does look like SRAM and Shimano 10sp MTB cassettes only go to 36...

Any SRAM MTB rear mech will work. You may need a longer screw to push the mech further away from the dropout, these are often included if you buy a 1 up type kit, and is definitely included when you buy a Sun Race 11-42 cassette.

joenobody

Great, thanks

joenobody

I'm on my way

So far I have a GX rear mech, and a Sunrace 11-42 cassette, and not spent over £60 yet.

Am thinking about a 50T chainring as it looks like it gives me a comparable range to my current compact 11-28 setup (have been playing with the Sheldon Brown gear calc), although at the cost of what looks to be 4 useable gears.

Can anyone who's gone down this route share some insight on my proposed chainring choice? Also, I guess a new chain would be a good idea?

trek_dan

JoeNobody wrote:

I'm on my way

So far I have a GX rear mech, and a Sunrace 11-42 cassette, and not spent over £60 yet.

Am thinking about a 50T chainring as it looks like it gives me a comparable range to my current compact 11-28 setup (have been playing with the Sheldon Brown gear calc), although at the cost of what looks to be 4 useable gears.

Can anyone who's gone down this route share some insight on my proposed chainring choice? Also, I guess a new chain would be a good idea?

If your combined current big-big is say 50-28 you'll need a longer chain to go 50-42.
Can't comment on ratio as I'm guessing your use if very different to mine if you need a 50t chainring.

joenobody

trek_dan wrote:

If your combined current big-big is say 50-28 you'll need a longer chain to go 50-42.

Of course, had overlooked the addition of larger sprockets :shock:

Can't comment on ratio as I'm guessing your use if very different to mine if you need a 50t chainring.

Probably will be mainly turbo time, and maybe autumn/winter road riding (can get mudguards on this bike, but not on my "main" bike). I guess it'd likely be something that I need to run for a while and then look at whether I have the right size chainring. It's relatively flat round here, so wouldn't necessarily need the lower gears so much on the road, but conversely, the higher gears would probably see most use on the turbo. So I have to think about how much road vs turbo time I'll be doing.

joenobody

JoeNobody wrote:

I guess it'd likely be something that I need to run for a while and then look at whether I have the right size chainring.

Without wanting to appear to be talking to myself, it may also be that 11-42 is too wide a range, and I could do with both something narrower at the back and smaller at the front.

thegibdog

50 sounds too big to me, unless you do a lot of sprinting? If you’re riding on flat roads then the gaps in a 11-42 cassette will get annoying. Probably something like an 11-28 with a 42 on the front would best suit winter road riding.