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-   -   Forbidden Druid (https://forums.thepaceline.net/showthread.php?t=275645)

Eli Bingham 11-05-2021 07:03 PM

Forbidden Druid
 
I had a ton of fun on my Evil Following, but my riding style has changed over the last few years and I felt like I was reaching its limits. The Evil is off to TPC, and after reading a lot about Forbidden and the wonders of high-pivot suspensions, I took the plunge on this new XL trail bike that happened to come together despite supply chain craziness, thanks to the best Marin LBS out there. This build also happens to have some pretty insane wheels, which will either turn out to be the greatest wheels I've ever owned, or will completely implode somewhere in the Tahoe backcountry next season.

It's also possible I may mullet this thing at some point, thanks to the Ziggy link Forbidden now offers. But first I need the 29er mode as a basis for comparison. Don't give me any bad ideas.

This 1263mm wheelbase monster has barely gone beyond a parking lot test, as I'm temporarily off the bike after a minor surgery (don't ask). I will have a lot more to report soon. In the meantime, build and photos. This build is 100% Kashima-free for reduced caloric value and lower fat content.

Frame: Forbidden Druid XL
Fork: Fox 36 GRIP2 Performance Elite 150mm w/ Fox Mudguard
Shock: Fox Float DPX2
Drivetrain: XTR 12 speed, 10-51 cassette
Cranks: Raceface Next R, 30T chainring
Brakes: Shimano XTR 4-piston, sintered pads
Rotors: SRAM 6-bolt Centerline - 200mm front, 180mm rear - cats and dogs living together!
Seatpost: Fox Transfer 200mm, Fox Remote
Wheels: Roval Control SL 29
Tires: Specialized Eliminator T9 Grid 2.3 front (measures at 2.41 mounted), Ground Control T7 Grid 2.35 rear
Handlebars: OneUp Carbon
Stem: OneUp
Saddle: Specialized Phenom 155mm
Headset: Cane Creek 40 plus OneUp EDC Lite top cap tool storage
Cage: King Ti

Total weight with pedals and EDC tool: 31 lbs 1 oz

https://www.dropbox.com/s/cln6mdmn3o...963.jpeg?raw=1

https://www.dropbox.com/s/vfpa600jd4...964.jpeg?raw=1

https://www.dropbox.com/s/8cxwzo63sd...965.jpeg?raw=1

https://www.dropbox.com/s/y6os2lphg6...966.jpeg?raw=1

Jaybee 11-05-2021 09:46 PM

This thing is nuts. It's... sculptural. I love it. You'll have to report back on how you like the high pivot, which I had always thought of as gravity rider silliness but also find intriguing. And welcome to Fox36. It's super buttery, in both the Kashima and non-K flavors. Having owned both, I can't tell the difference in performance.

Eli Bingham 11-05-2021 10:28 PM

Will definitely report back. It’s certainly unique even when applying just the parking lot tests. As the shock compresses, the rear center grows 25mm - and it’s already at 450mm static length on the XL due to the aggressively designed size-specific chainstays. In fact it’s built up without the bash guard installed but I might end up putting it on as the thing is so long under compression I’m a little worried it will bottom out when launching off drops or steep knuckles!

Matt92037 11-06-2021 09:02 AM

You built that one up right! That is a perfect do everything trail bike build.

I cannot wait to hear what you think about the wheels. With wheels that light that bike will be a rocket ship set up with a few extra clicks of LSC and 750g trail tires or a trail crusher running something like DHF/DHR’s.

Eli Bingham 11-06-2021 09:10 AM

Quote:

Originally Posted by Matt92037 (Post 3006910)
You built that one up right! That is a perfect do everything trail bike build.

I cannot wait to hear what you think about the wheels. With wheels that light that bike will be a rocket ship set up with a few extra clicks of LSC and 750g trail tires or a trail crusher running something like DHF/DHR’s.

That is the idea. But I’m a little worried - the things are ridiculously light in the hand - lighter than Roval’s highest end road tubeless wheels. If the durability claims hold up they will be truly next level. Good thing they have a NQA warranty!

pritchet74 11-06-2021 09:21 AM

"what da f**k is going on with the chain on that high pulley" I ask myself???

I had never seen that before (because I live in a box limited mostly to pavement) - that's pretty cool - let me know how you like it on the trails!

Eli Bingham 11-06-2021 09:52 AM

Quote:

Originally Posted by pritchet74 (Post 3006920)
"what da f**k is going on with the chain on that high pulley" I ask myself???

I had never seen that before (because I live in a box limited mostly to pavement) - that's pretty cool - let me know how you like it on the trails!

High pivot/idler suspensions have been a thing off and on in downhill racing but Forbidden is the first company to bring one to a trail bike (that I’m aware of). They are also starting to show up on some longer travel enduro bikes.

The idea is that by placing the pivot upon which the rear center moves higher up in the frame, the path of wheel travel changes to be rearward under compression. Normally the path of wheel travel on typical designs is either vertical, or even slightly forwards as you reach the top of the wheel travel. This rearward path means that when the wheel hits an obstacle, especially a sharp-edged one, it can track to the rear instead of going straight up, which enables it to get out of the way more naturally, and increases the traction over that kind of bump at speed.

But there is a trade off - all things being equal, that pivot placement results in a large amount of chain growth as the wheel moves backwards, resulting in the pedals actually kicking back as the chain force pulls the pedals backwards. To avoid that undesirable and unpleasant effect, a high idler pulley is used to isolate the chainring (and hence the pedals) from the chain growth under compression. But there is no free lunch - the downside of the idler is slightly increased drag from the pulley (about a 2% wattage reduction) and increased maintenance, since the pulley and it’s bearing are wear items.

I figured 2% was a reasonable trade off given that I’m not in a huge hurry to get the top these days - a set of burly trail tires have a bigger cost than that in terms of rolling resistance. Can’t wait to report back on how the overall performance is.

Andy sti 11-06-2021 10:14 AM

So rad!!! Looks like a blast.

I put a set of those wheels on my Spur (maybe a better match than yours :)) and they’ve been great. Certainly spin up well and they are so wide.

Have fun with that thing!

Eli Bingham 11-06-2021 03:04 PM

Still have some healing to do before a full ride is indicated, but just tuned the suspension a bit and did a few spins around the block and up a local grade. This thing climbs like a rocket ship. Even with the idler it is a far more efficient climber than the Evil Following.

d_douglas 11-06-2021 04:18 PM

Awesome! There is one exactly like yours for sale locally and while it’s a size too small I kinda still want to feign interest in it just so I could check it out! They’re apparently amazing bikes to ride.

Eli Bingham 11-08-2021 11:47 AM

1 Attachment(s)
Turns out the lower chainguide and bashguard are required to maintain minimum chain wrap on the chainring, not so much for chain retention. So I put the guide back on and extended the chain to 130 links - fortunately have a few spare XTR 12 speed chains lying around because supply chain hoarding.

Setting up the derailleur with the lower guide in place is an interesting adventure - it requires *far* lower b-tension than normal to maintain good shifting performance, and since the bike tensions the chain further when under compression, the chain actually ends up resting on the lower stay when in the 10 tooth cog, like in the attached photo. Still dialing in the setup and I may take another 2 links back out. If this type of drivetrain becomes more popular I can see the drivetrain manufacturers redesigning their cages to provide a more ideal path of chain travel for high pivot bikes.

Burning Pines 11-08-2021 01:42 PM

Very cool! I'd love to ride one of these someday.

bironi 11-10-2021 10:22 PM

Wow!
As a fixed gear rider for the last 10~ish years, I have no idea how to maintain this rig. But you do. Enjoy the ride. It looks like fun waiting to happen.
By

charliedid 11-11-2021 04:09 PM

Interesting design that I was unaware of.

Dig it.

Eli Bingham 11-13-2021 02:31 PM

Finally got in a proper first ride!
 
Took the Druid to China Camp for the first real ride (and my first bike ride after a minor surgery a few weeks ago). CC is running great after the early season rain we've been getting. Incredible traction on the climbs and in the steeps.

https://www.dropbox.com/s/60d4vud0x0...A48.jpeg?raw=1

Eli Bingham 11-17-2021 10:54 AM

frame storage FTW
 
1 Attachment(s)
Top tube mounting bolts + Wolf Tooth B-RAD medium strap + old Silca tool roll I forgot that I still had = clean tool storage FTW

Jaybee 11-17-2021 05:01 PM

Oh man. Totally stealing that idea for my pivot that also has tt underside bolts. Pivot sells a little tool box that goes there but it doesn't look nearly so clean.

Props on the bike from heaven China Camp photo too.

Indy 11-17-2021 08:49 PM

Quote:

Originally Posted by Eli Bingham (Post 3011952)
Top tube mounting bolts + Wolf Tooth B-RAD medium strap + old Silca tool roll I forgot that I still had = clean tool storage FTW

Brilliant!

Eli Bingham 11-24-2021 01:21 PM

Fully dialed in... Hello Diablo
 
Just the fourth ride out on this thing and really getting her dialed in. Setting the b-tension on this bike is very weird - on my last ride up on San Geronimo Ridge, the chain managed to get out of sync with the idler, causing a terrible racket. But I think I finally nailed the chain tension, and have not had shifting problems since. The descending performance is phenomenal - riding Coast View and singletrack near Coyote Ridge today, I was coming out of corners carrying more speed than ever. Truly a "hover bike" on the downs.

The only drawback so far is that the bike is very very long, so it's a bit of a bear to get around climbing switchbacks properly - you have to plan ahead, enter the corner as far as possible to the outside, and really push hard around the corner without letting up on the gas. Not the most fun bike to ride on the traditional Tamarancho loop, which sometimes feels like an entire hour of climbing switchbacks.

Photo from this morning, looking out at Mt. Diablo from the top of Coastview.

https://www.dropbox.com/s/x9bs4f5txn...070.jpeg?raw=1


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