hardtail frame for 38t

[lud1]

hi there, this is my first post, so please be gentle...I'm very frustrated with my first build, so I came here looking for help:

I recently bought my first chinese carbon frame to build a hardtail mtb. I chose FM-M009, I reckon many of you already know said frame. after the frame I bought a whole load of other parts, including just recently the xx1 eagle groupset with a 38t chainring. I had big trouble fixing the crank with this large chainring and only managed to with the help of a large spacer, which in turn totally f***ed up the chainline.

from what i can tell this frame won't even fit a 36t one, and since I mainly do long tours and not so much hillclimbing or downhill, I really want to use the 38t chainring.

so, to make it short, can you guys recommend a lightweight carbon frame I can fit a 38t chainring on?

thanks in advance! sorry if this topic already exists, I searched, but didn't really find anything...

[carbonazza]

I ride a 38T on a 041 frame with plenty of room left.
Which is unfortunately not produced anymore by Peter at xmcarbonspeed.com

Maybe it is built by another vendor still to be found.
I think I saw it popping out in an AliExpress search already.

Or you may ask him what frame he sells now that could do it.

The M009 frame is definitely a 34T frame.

[carbonazza]

I fit in a 38t with pretty decent chainline inline with the 4th cog from the 11t on a 10 speed cassette.

On a M009 frame ?
Do you know the distance between the ring and the center of the frame ?
Did you use a spacer ? If so how wide it is ?

[pumajr]

You will definitely have to modify the chain line to fit anything more than a 30.  We put a 30 on my sons build and even that was a tight fit. 

[carbonazza]

You will definitely have to modify the chain line to fit anything more than a 30.  We put a 30 on my sons build and even that was a tight fit.

It probably depends on the crank you use.
An Eagle GX crankset ( with GXP BB ) allows a 34T with still some room left, may be a 36T could even fit.

[pumajr]

That is good information to know for an upgrade in the future.  We used an older shimano deore crank set.  38t would definitely test the limitations of the frame. 

[dopestar]

instead of changing your frame try to use 9x11 instead so you don't need to use 38T

[Jerryno]

The CS-MB01 http://www.xmcarbonspeed.com/Productinfo.asp?f=1392 can fit up to 40T. It is made for large chainrings.

[John75]

Hello.
I am new to the group.  Will the CS-057 and OHR930C rims work with the SRAM GX Eagle 12 speed with a 38T front ring?
Thank you
John

[lud1]

hey guys, thanks for all the answers

just some feedback: I'm stupid as can be...I didn't fully close the chain lock when test assembling my bike, so thats why the chain jumped off..I have now fitted the xx1 eagle with the 38t chain ring with the help of a large spacer...the chain line still is pretty fucked up, but I think it will work out..couldn't really try the finished bike yet because of -10 °C outside...I'll keep you posted if anyone's interested

[carbonazza]

...the chain line still is pretty fucked up, but I think it will work out...

How much mm is the spacer?
Did you try to back pedal while on the larger sprocket?

[lud1]

this is basically the situation I'm dealing with. backpedalling seems to work fine, albeit being audible and "clunky", but the chain has stayed on all through my "dry runs", still too cold outside for my liking...

pleae excuse the terrible image quality, my phone is dying...

[johnnydamage]

I fit in a 38t with pretty decent chainline inline with the 4th cog from the 11t on a 10 speed cassette.

On a M009 frame ?
Do you know the distance between the ring and the center of the frame ?
Did you use a spacer ? If so how wide it is ?

here are a couple pics. I'll try to get the other measurement you asked for. I flipped the spider for the chainring as well as the chainring. made custom spacers with a drill and headset spacers

[jcen517]

38X11T-->3.45
36X10T-->3.6
34X10T-->3.4
Cassette 10-42

[lud1]

so I took the bike for its first 50 km ride today...and what can I say, I didn't run into any trouble with the chain line, au contraire, I'm really impressed with the Eagle's performance overall and I'm very content with what I've built :]