Gr048 with Tansmission?

[landboard]

Hello

I am looking to build an endurance gravel bike with 1x/transmission. I am eying the GR048 frame. They currently only offer the M size with UDH, but with 179/83 that should fit okay.

http://www.tantancycling.com/index.php?_m=mod_product&_a=view&p_id=1094

Would love if you can help with 2 questions:
1. Geo seems nice slack ST/HT with 74/71. Anything i am missing on fit for a touring gravel?
2. Has anyone tried this frame with SRAM transmission? Chainline?

Thanks for your help!

[carbonazza]

I've built a few gravel bikes with the Transmission system with the CFR-505 from Carbonda.
All the riders are extremely happy!
I'm a bit jealous now, still riding the old Eagle AXS on my gravel 

The chainline of the SRAM gravel/road crankset (wide) is 47.5mm, which may cause chain rub on a couple of small sprockets if your chainstay length is on the short side (420-430mm).

I contacted SRAM to see if I could safely widen the chainline a bit. A colleague of the person who responded to me had the same issue with a mullet setup. I mentioned that the chain rub would cause some noise and lateral chain wear, but they said he was managing it fine...

I escalated the issue and eventually got someone who, after some back and forth, confirmed that SRAM has 47.5mm max only.
If I remember well, they didn't say it directly, but implied that it would be okay to use a wider chainline if found, as MTB setups allow for much more.
I added a 1mm shim on the right side, which solved the rub issue.

In addition, the app from SRAM to know the chain length, and the position of A/B setup key is not reliable.
It stops at around 38T, so add one link per additional teeth.
And it puts the setup key to A while it should generally tell B. Test both options and see which one works better.

Now, I'm about to build another one, and this time I'll try with XX1-Quarq/104BCD crankset with a 49mm chainline

[landboard]

Thanks a lot for your comprehensive and insightful reply.

Its a good point on the spacers - given that the wide and non-wide BBs are the same and only differ in the included spacers, there should be a good bit of flexibility. I will check the spacer recommendations from SRAM. Aftermarket chain ring with 6mm offset might be an alternative here.

RE frame: Carbonda, especially the 707 might be the better option. The GR048 in M might just be a tad small, when looking at it in bike-stats. The 707 in M also has a 435mm chainstay and a generally longer wheelbase. 

[landboard]

So I bought the GR048 frame in Large with the UDH from the Seraph Ali store. So far the contact has been very nice.

On the components I will stick with a black theme. So think that narrows it down to X0 and Rival. Wont be the most cost efficient nor lightest build, but i hope it looks cool when its done.

I will update this thread as things are moving along.

[merlin]

Seraph/Tantan don’t advertise that it is a UDH compatible frame, did you ask them or am I missing something from their website/ali store? I’m also interested in this frame but want a UDH so I don’t have to wait for weeks to get a new hanger. Also for the possibility of an 13sp apex xplr transmission in the future. 

[landboard]

Yes I asked them on the Ali store. Availability seems to be limited though only in S, M and L.

I bought a different frame in the end - the SPCycles bike with the Grail like geo.

For me UDH is the way to go, especially after the Red release. Enjoy the build.