Meet Gnarmac Frankenbike

[dem]

For those of you who followed my gravel frame thread ( http://forums.thepaceline.net/showthread.php?t=185685 )and wondered what I built.. here it is.

I ended up getting the FM286 Miraclebike frame because literally I could not find anyone to take my money for a US "branded" frame. Miraclebike delivered in a week for $500 all-in. I figure eventually I'll find a deal on a Scott CX10 or similar frameset.

Why is it a Frankenbike?
R685 Mechanical Shifting/Hydraulic Brake brifters
M985 XTR 44/30 Mountain crankset
FD-6800 Road 11 speed front derailler
SRAM 10-42 XX1 Cassette
XTR M9000 Mountain 11 speed rear derailler + Tanpan travel agent
KMC X11SL chain

The shifting works surprisingly well, although not with the XTR clutch engaged.

http://www.haphazard.com/bikes/gnarside.jpg

Drivetrain:
http://www.haphazard.com/bikes/gnargears.jpg

[ceolwulf]

That is cool. :cool:

[Dired]

:beer:

[kramnnim]

You need a larger rear sprocket.

[geordanh]

Very cool build man.


Sent from my iPhone using Tapatalk

[sandyrs]

MTB gearing and road tires? What kind of stuff are you riding?

[dem]

South SF bay area - lots of climbing with either dirt bypasses or just flat out ridiculously steep fire roads - 30%+ sections are not unusual. Tires are the Compass 700x35 Bon Jon Pass, mounted on wide (25) wheels.

It is almost like having 2 single ring bikes, one for road and one for MTB:

High comparison:
50/11 (road compact) ~38 mph @ 100 RPM
44/10 (frankenbike) ~37 mph

Low comparison:
34/32 (road compact) - ~5.3 mph @ 60 RPM
44/42 - ~5.2 mph

Then a "typical" mountain bike with a 30 ring and a 10-42 cassette.

http://www.haphazard.com/bikes/gnarwild.jpg

[Gummee]

I've liked my 3 chinese carbon bikes so far.

Should be a great thing to ride.

M

[Dustin]

I've been thinking about a similar set up; but how would you describe the shifting with the clutch engaged? For me, that's one of the biggest attractions of using a MTB derailleur.

[dem]

With the clutch engaged, you basically can't get the cable tension right - it's like it is wrong both directions when you go up/down the cassette. I'd guess the road shifter + tanpan doesn't have enough oomf?

Maybe I'll try again after running it in for a while.. did a 40 mile loop yesterday and everything held up so far. :)

http://www.haphazard.com/bikes/gnarwild2.jpg

[RudAwkning]

With the clutch engaged, you basically can't get the cable tension right - it's like it is wrong both directions when you go up/down the cassette. I'd guess the road shifter + tanpan doesn't have enough oomf?

Maybe I'll try again after running it in for a while.. did a 40 mile loop yesterday and everything held up so far. :)

http://www.haphazard.com/bikes/gnarwild2.jpg

Try loosening the clutch a tad.

Also, check out the SFR mixed terrain series. That would be the perfect bike!

[Mikeys]

looks great. about to switch to a tanpan/xt derailleur setup as well. did you use the medium gs or long sgs cage derailleur? i'm thinking 48/32 x 11-42. thanks

[dem]

Hey Mikey,

Your cage length is based on the chain uptake capacity of the derailleur, usually listed as "total capacity" on the specs.

M9000 Medium cage: 37T
Long cage: 45T

If it doesn't have enough capacity, your chain will be floppy in small-small.

You just add up your cog differences and that's how much capacity you need:
48 minus 32 = 16
42 minus 11 = 31
16 + 31 = 47T

So by the math you definitely need the long cage.

PS, 1000 mile update on this bike: Everything working great! The Compass tires were a bit of a bust as tubeless, and the saddle is squeaky and the rubber on the nose split - I plan to replace both for this season and put a bunch more miles on it.

[rnhood]

Great looking bike, and a bargain to boot. I am jealous.

[Hindmost]

Cool images.

Black Mountain and I want to say Freemont Older.

[dem]

Black Mountain and I want to say Freemont Older.

Hindmost knows his dirt! How about this one? Maiden Voyage with Specialized Trigger tubeless (Rock Cobbler Feb 12!)

[Hindmost]

Nope, don't know it. So I will guess that it is above Sanborn Park.

[ColonelJLloyd]

I'm not sure I could keep a bike upright spinning a 20" gear. Kudos to your balancing skills.

Sleek build.

[dem]

Nope, don't know it. So I will guess that it is above Sanborn Park.

Jeez, you're good! That is indeed - the section of skyline trail above John Nicholas heading to Highway 9.

And I use allllllll that gearing, nearly every ride. The fire roads are relentless in some areas. And I'm still walking in some places because I can't maintain 400+ watts at 3 mph. :)