Chinese Carbon MTB > 29+ & 27+
Sanity check my P9 build, please!
deezums:
Hello everyone!
I'm pretty new to MTB, went riding with some friends a while ago and had a few nice bikes to try. I rode a specialized epic sworks, and a stuntjumper fsr comp carbon 6fattie. I had a lot more fun on the stuntjumper! According to this the ican p9 is pretty similar.
https://geometrygeeks.bike/compare/ican-p9-2017-m,specialized-stumpjumper-fsr-carbon-6fattie-2016-m/
I've ordered a P9 frame from Ican, as well as a 40mm wheelset which should all be here well before spring! I found a deal on a new rockshox monarch plus 210x60, and I'm about to pull the trigger on a 180mm dual position lyric. The frame geometry calls for a fork crown to axle of 571mm, the rockshox lyrik 180 is happily 572mm! I have noticed rideczech mention wanting a fork 20mm longer, when it comes available!
I've noticed most P9 builds I've seen seem to use shorter forks, in looking at forks for the past week I'm thinking this might just be because the market isn't there yet? I've searched a lot and can't find much I would like that has 110 front axle and fits 3" tires!! It's not easy finding options within my budget that are still available, then finding geometry and tire fitment specs is always hit or miss. I am open to suggestions, if you would like to share!
Would it make sense to use a dual position shock to have the option of ~1.33 deg steeper head angle on the fly or would a cheaper, simpler solo air be better? Is it a bad idea to run so much front shock travel? I think I would like the extra bb height, and if I understand correctly I need 571mm crown to axle to maintain 66 degree head angle as shown on the geometry drawing?
I plan on running GX eagle components, 165mm crankset. Is this the adapter I need for BSA?
https://www.ebay.com/itm/SRAM-Bottom-Bracket-GXP-Team-Cups-English-73-68mm-New/382257639479?epid=2254439874&hash=item590054b037:g:xcEAAOSwO7hZ6-5u
Thanks for reading, and for any and all advice!!
Carbon_Dude:
I don't know anything about the P9, but I hope your build is as fun to ride as my SJ6F! Good luck with your build!
deezums:
Thanks, I hope everything I've picked works out alright in the end too!
I've been ordering parts and waiting for them to arrive for a while now, it's all finally showing up! I got the frame and wheels, they made it through shipping in excellent shape!
Here's a list of what I'll be running...
Ican P9 Medium frame
40mm ican carbon wheels with novatec hubs
Maxxis DHF/DHRII 2.8"
Rockshox Monarch plus RC3 210x60, 8x30mm upper bushing, 8x25.4mm lower
Rockshox Lyrik RCT3 180mm dual position
Reverb 125mm Post
Eagle GX groupset, 165mm GXP crank and 73mm adapter
Magura MT Trail Sport brakes, 203mm front/180mm rear
35mm stem, 740mm Ican riser bar
deezums:
Most parts have come in! Still waiting on brakes, and some bleeding tools for the post...
https://s17.postimg.org/fy44dvxp9/IMG_20180120_190801.jpg
https://s17.postimg.org/5bab8ga4d/IMG_20180120_190709.jpg
https://s17.postimg.org/9kf1an88t/IMG_20180120_190745.jpg
https://s17.postimg.org/i2ohez71p/IMG_20180120_190721.jpg
Some notes on what's been done...
My steerer tube is weird looking, I am leaving it long for a while till I know how I want it permanently.
I taped up the Ican rims using Kapton tape, I ordered 35mm width and I had 20mm on hand from previous projects. The 20mm works much better as it's easier to pull tight with no wrinkles. The 35mm is perfect considering the drop center geometry (34mm inner width) but it's impossible to tension the drop center enough while keeping the bead surfaces flat and wrinkle free. No sealant yet and I can hold pressure for days with the 20mm tape, the tire is still easy enough to install and remove with no tools using the drop center. Partially mounting the bead by hand is all that's needed for seating the bead with an air pump. I am super happy with the wheels so far!
The routing for an internal dropper post is confusing, there are three outlet holes on the down tube as well as an inlet hole on the seat tube. At first glance it seems the routing is meant to go inside the down tube, out around the lower shock eye, then into the seat tube on the non-drive side. There is a hole inside the BB threaded shell, this makes it easy to run the internally routed dropper post internally the entire way with no aggressive bends and no worries on crank clearance to cables on the non-drive side. If the seat tube hole is an outlet for an external dropper post it's angled the wrong direction! I'm not really sure what's going on with the extra holes...
I found the chain length sizing kinda confusing, but I managed to work it all out using the bike itself. The chain growth is pretty radical with 60mm shock travel, keeping the chain short enough for full droop travel on the 10 cog while keeping a chain long enough at full compression on the 50 cog is tricky. These limits are pretty radical, not normal operating conditions by any means, but I managed to make it perfect. The lower chain guide I picked actually helps, it shortens the chain at full droop but does not do so as much at full compression. I'm not sure if this is the intended design, I didn't know it when I bought it but I like it! I am using 118 links on my chain, if this helps anyone else.
I also purchased Linakge software and modeled the frame as best I could using the given documents, hopefully they are at least to scale for this to be anything accurate. The most descriptive PDF does not give XY dimensions of piviot points, only direct dimensions in some places and no angles, useless!!
https://s17.postimg.org/b0vlpqp59/image.png
The following is a graph of anti-squat with 21-32. 50t is around 125% at 20% sag, and 215% on the 10t.
I wonder how well I can ride with no brakes?
;D
chetosmachine:
I have modeled the frame so let me know what dimensions you need. I based my drawings on the pdf plan from mtbr, they showed to be quite accurate. At least most measures where in the mm range proximity.
Your build makes me drool ;)
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