The Perfect AM/Enduro Geometry... chime in and help design your perfect bicycle!- Mtbr.com
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  1. #1
    moaaar shimz
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    The Perfect AM/Enduro Geometry... chime in and help design your perfect bicycle!

    Hi. Many may know me from the DH forums, but I've always ridden my bike in an agressive All Mountain style (climb to the top of the mountain pedalling, then descend and then shuttle for the rest of the day). Right now I ride a Duncon Tosa Inu (6.7 in of travel) with a 2006 Marzocchi 66 SL and a Roco WC coil.

    I have been given the oportunity from a frame company to design my own bike. I want this bike to accomplish what other frame companies have been lacking and try to please the public as well as pleasing my riding style as I will do the proto testing.

    Right now I am basing it on a 66.5 degree head angle (with Lyrik fork), 6.5-6.7 in of travel, 71 degree seat tube angle, and as much standover height clearance I can fit without affecting tubing integrity and suspension linkage design... among other things.

    I want to know what you guys want in a bike, if you want 1.5 in headtubes, what geometry in general, if you want Hammerschmidt ready suspension design and BB interface, frame material (I may be able to do the frame in 7005 or 7020 al, but 6061 is the first option) air or coil shock designed etc.

    Feel free to comment about any aspects of the bike!

    Tacubaya

  2. #2
    Its got what plants crave
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    1.5 HT, 66ish degrees, uninterupted seat tube, ISCG guide mounts, Maxle rear dropouts, tire clearance for a TRUE 2.5 tire, designed around a coil shock, I like to spank the shred.
    Ocala Mountain Bike Association - www.omba.org

  3. #3
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    I read your post and didn't think AM / Enduro - sounds more like a light DH / shuttle bike. Everyone has their own idea of AM / Enduro but a 66.5 * HA & 6.5 + travel wouldn't be on my list of AM choices. Maybe the market needs a bike as such but I don't know what the best use "label" would be - light DH, shuttle bike ???

  4. #4
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    All angles with Fox 36 axle to crown height

    66.5 H/A
    13.7 BB Height
    17in Chain Stays
    46 in wheel base (large size)
    1.5 head tube
    6.5 rear travel
    Actually work well with an air shock
    Frame come in at 7.5lbs with air shock or less

    Not sure if this geo all gives with each other but this sounds about right.

  5. #5
    I dig trails!
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    Why go coil when you can build the linkage rates around an air spring curve?

    I used to be a coil guy, until I got a bike that is designed for an air spring curve and (this is important) runs the low volume air can.

    Air spring curve weaker beginning stroke = active on smaller bumps
    Air spring progressive end stroke = FR friendly killer ramp up in the last 50% of the stroke.

    + save some weight for maneuvering & jumping the bike.

    P

  6. #6
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    Quote Originally Posted by smithrider
    All angles with Fox 36 axle to crown height

    66.5 H/A
    13.7 BB Height
    17in Chain Stays
    46 in wheel base (large size)
    1.5 head tube
    6.5 rear travel
    Actually work well with an air shock
    Frame come in at 7.5lbs with air shock or less

    Not sure if this geo all gives with each other but this sounds about right.
    All this and cost less than $800 for a frame. That's what I want.

  7. #7
    Fort Valley = Gnarl Fest
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    Quote Originally Posted by Jim311
    1.5 HT, 66ish degrees, uninterupted seat tube, ISCG guide mounts, Maxle rear dropouts, tire clearance for a TRUE 2.5 tire, designed around a coil shock, I like to spank the shred.
    Jim nailed it here... I'll take 2
    "It sucks because that's what Boxxers of that generation were good at." -- XSL_WiLL

  8. #8
    Praise Bob
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    Quote Originally Posted by smithrider
    All angles with Fox 36 axle to crown height

    66.5 H/A
    13.7 BB Height
    17in Chain Stays
    46 in wheel base (large size)
    1.5 head tube
    6.5 rear travel
    Actually work well with an air shock
    Frame come in at 7.5lbs with air shock or less

    Not sure if this geo all gives with each other but this sounds about right.
    Kinda described the Mojo HD

    Heck my Moment has nearly those specs with a 36 up front, but that puts my BB too high at 14.2

  9. #9
    moaaar shimz
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    Quote Originally Posted by Jim311
    1.5 HT, 66ish degrees, uninterupted seat tube, ISCG guide mounts, Maxle rear dropouts, tire clearance for a TRUE 2.5 tire, designed around a coil shock, I like to spank the shred.
    Right now my idea of the design would fulfill all those suggestions.

  10. #10
    moaaar shimz
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    Quote Originally Posted by keen
    I read your post and didn't think AM / Enduro - sounds more like a light DH / shuttle bike. Everyone has their own idea of AM / Enduro but a 66.5 * HA & 6.5 + travel wouldn't be on my list of AM choices. Maybe the market needs a bike as such but I don't know what the best use "label" would be - light DH, shuttle bike ???
    That's why I give you the option to chime in and tell me what YOU want too. Something you can pedal to the top of the mountain and rock on the way down (including jumps and stuff). Think of a Giant Reign X, Turner Highline, Santa Cruz Nomad, Banshee Rune etc.

  11. #11
    moaaar shimz
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    Quote Originally Posted by Mr.P
    Why go coil when you can build the linkage rates around an air spring curve?

    I used to be a coil guy, until I got a bike that is designed for an air spring curve and (this is important) runs the low volume air can.

    Air spring curve weaker beginning stroke = active on smaller bumps
    Air spring progressive end stroke = FR friendly killer ramp up in the last 50% of the stroke.

    + save some weight for maneuvering & jumping the bike.

    P
    I could. Not that hard to make it either coil or air based.

  12. #12
    mtbr member
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    67 deg HA with 545mm A2C. Lyrik 170 puts it at 66.5 deg.
    1.5 HT so you can use +/- 1deg Headtube cups. I don't mind 1.125" steerer tubes.
    Rear shock needs to be sized 8.75" x 2.5" so you can swap i2i to 8.5" for lower/slacker
    Dropouts should be thru bolt with holes not actual dropouts. So no rear dropouts in essence.
    I could care less about a tool free rear axle but I prefer a thru type. Replaceable DO's a plus.
    73mm BB and 135mm rear hub.
    Cable mounts for dropper type seatpost.
    160mm post mount rear caliper mount with replaceable inserts.
    Grease ports for linkage bearings
    13.7 mm BB height @ 545 A2C fork.
    Target weight just shy of 8lbs. No need for uber light IMO.
    Full length seatube @ 30.9mm I.D.

  13. #13
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    Sounds close to the Banshee Spitfire, a little more trail oriented, but close.

  14. #14
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    I have no complaints about my 2007 Kona Coiler with 160mm Wotan, DHX coil and 2.4 tires. Geometry wise would not change a thing.

    As far as frame features - would be nice to add a tapered head tube, ISCG 05, rear post mount calipers, 12mm Syntace rear axle - and 30.9 seatpost.

  15. #15
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    yes to Hammerschmidt compatibility, however you decide to design it in. be it an idler pulley (ala Canfield Jedi or the BMW SR6/8 or the Corsair Maelstrom/Marque), or pivot placement, or whatever. if you go the idler pulley route, a rearward axle path starting with a super short chainstay would be lovely, to help it gobble up the rough and chop and make it easier to flick around. random specs wise, 135X12mm rear axle, post mount disk mounts, 73mm BB with both ISCG standards built in ('03 and '05) for maximum chainguide compatibility, and as much standover as is physically possible. oh, and the already mentioned 1.5 HT and 30.9mm seatpost and roughly 13.7" BB height and 66.5 degree HA with a Fox 36/Lyrik 160, but a beefy enough HT to handle a Lyrik 170 or a Totem
    Quote Originally Posted by teamdicky View Post
    My butthole would pucker and invert until I was inside-out before I got to the bottom.

  16. #16
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    Interesting that most of the people here are in a violent agreement about a whole lot of choice - down to seatpost diameter. I guess the only way to start a fight would be to to mention DW vs. monopivot vs Horst vs. whatever... (Personally, I do not care. Stiff monopivot, with linkage driven coil works fine for me).

  17. #17
    wuss
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    A lot of this sounds close to what I'm aiming for with an Intense uzzi / Fox 36 Van. Replaceable / adjustable dropouts allow different axles and about 66.5-67.5 HA depending on terrain. Travel is a bit long at 7", but not that far from 6.5" which people are hoping for. I don't understand why the seem to be fairly rare as AM bikes, but maybe I will when I get mine togeather and try.

  18. #18
    moaaar shimz
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    Thanks for the suggestions. No one has mentioned seat tube angle nor if they want a Hammerschmidt specific frame.

    Btw, it's going to be a parallel link suspension bike.

  19. #19
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    My $.02: If I were designing a frame for what you described, the suggestions pretty much all sound good, but I haven't heard anybody mention adjustability. Look at some of the newer Intense frames, where they have two shock mount points on the rocker & the adjustable axle location (the G3 dropouts). I would do something similar to that- you can adjust geometry at the rear axle and rear spring stiffness quickly and easily.

    I'd probably go steeper than 71 on the seat tube angle, but then again, with seat post offsets and saddle adjustments, that angle isn't super important.

    Oh yeah, and I run a Hammerschmidt, it's awesome. I would definitely design the frame for one of those also.

  20. #20
    "El Whatever"
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    Quote Originally Posted by tacubaya
    Thanks for the suggestions. No one has mentioned seat tube angle nor if they want a Hammerschmidt specific frame.

    Btw, it's going to be a parallel link suspension bike.

    Firstly, congratulations!! Makes me really happy.

    Good suggestions around.

    As for seat tube angle, IMHO if it's meant to be pedaled upwards, 72 degrees is as slack as I would go.

    I'd keep the adjustable stuff to a minimum but yet, provide some.

    Firstly, average Joe will end up with improper set up 90% of times and blaming the bike.
    Then, if it is not designed/fabricated/installed properly, it's one more thing prone to fail and dirt likes to make moving stuff to creak.

    Hammerschmidt... tough choice because either the bike is optimized towards it, or 99% of other cranks.

    Don't forget good pivots, either journal or needle bearings.
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  21. #21
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    Warp, one way to solve that issue about Hammerschmidt optimization would be to run an idler pulley. include two options, one being a fixed (non-sliding) pulley for Hammerschmidt usage, the other being a pulley that can slide side to side on the shaft it spins on, similar to the setup Corsair has, but have little itty bitty chain-keepers on that idler to keep the chain from jumping off. Hammerschmidt compatibility AND 2x9 compatibility all in one
    Quote Originally Posted by teamdicky View Post
    My butthole would pucker and invert until I was inside-out before I got to the bottom.

  22. #22
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    Quote Originally Posted by Warp
    As for seat tube angle, IMHO if it's meant to be pedaled upwards, 72 degrees is as slack as I would go.
    Knolly seems to do it the right way - slack uninterrupted tube, with lower attachment point moved forward to provide suspension clearance and have a steep enough effective angle (from seat to BB center). Added benefit is that lowering the seat move it further forward then with a regular seat tube placement..

  23. #23
    moaaar shimz
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    Quote Originally Posted by Curmy
    Knolly seems to do it the right way - slack uninterrupted tube, with lower attachment point moved forward to provide suspension clearance and have a steep enough effective angle (from seat to BB center). Added benefit is that lowering the seat move it further forward then with a regular seat tube placement..
    Yeah I was thinking about that but I don't like having a small tube on top of the BB for derailleur attachment, maybe if the bike was Hammerschmidt specific, a Knolly-based seat tube would be very appropiate for clearance.

    About the idler pulley... I don't know, how much would a Hammerschmidt specific frame would sound to you guys? The frame would come with a Hammerscmidt and an Elka shock as default.

  24. #24
    moaaar shimz
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    Quote Originally Posted by Warp
    Firstly, congratulations!! Makes me really happy.

    Good suggestions around.

    As for seat tube angle, IMHO if it's meant to be pedaled upwards, 72 degrees is as slack as I would go.

    I'd keep the adjustable stuff to a minimum but yet, provide some.

    Firstly, average Joe will end up with improper set up 90% of times and blaming the bike.
    Then, if it is not designed/fabricated/installed properly, it's one more thing prone to fail and dirt likes to make moving stuff to creak.

    Hammerschmidt... tough choice because either the bike is optimized towards it, or 99% of other cranks.

    Don't forget good pivots, either journal or needle bearings.

    Thanks Warp!!

    Yeah good pivots are a must, I think I'm going to use bushings with zerk fittings.

  25. #25
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    Quote Originally Posted by smithrider
    All angles with Fox 36 axle to crown height

    66.5 H/A
    13.7 BB Height
    17in Chain Stays
    46 in wheel base (large size)
    1.5 head tube
    6.5 rear travel
    Actually work well with an air shock
    Frame come in at 7.5lbs with air shock or less

    Not sure if this geo all gives with each other but this sounds about right.

    Ditto this too, but geometry sounds about the same as an 2010 Spesh Enduro with 6.3" instead of 6.5" of travel (pretty much the same).
    Ride On!

  26. #26
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    Quote Originally Posted by tacubaya
    Yeah I was thinking about that but I don't like having a small tube on top of the BB for derailleur attachment, maybe if the bike was Hammerschmidt specific, a Knolly-based seat tube would be very appropiate for clearance.

    About the idler pulley... I don't know, how much would a Hammerschmidt specific frame would sound to you guys? The frame would come with a Hammerscmidt and an Elka shock as default.
    i like the idea of using one of the braze-on standards. Gives you so much more freedom with the seat tube/bb/rear suspension, and wouldn't negate the hammer option.

    I think you should decide early on if this is going to be climbed on fire roads or on technical singletrack, and if the descents it will see are going to be smooth with jumps or chunky gnar. There's so many bikes already running around that are the 'best' everywhere, it'd be nice to see something AM with some real clarity of purpose. Decide exactly what the design is for, and pick your suspension/geo to best accommodate that. Throwing out half the geo figures on bikes that i've liked won't create anything better.
    "Things that are complex are not useful, Things that are useful are simple."
    Mikhail Kalashnikov

  27. #27
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    Quote Originally Posted by tacubaya
    Thanks Warp!!

    Yeah good pivots are a must, I think I'm going to use bushings with zerk fittings.
    if you want good pivots, look no further than the canfield brothers. Been power washing my bike for a year and a half now on a regular basis as well as riding in very muddy wet conditions, and the bearings feel good and stiff as they day I bought the bike.

  28. #28
    moaaar shimz
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    Thanks for all the comments.

    Scottzg: I use my bike for everything... climbing singletrack, fireroads, descending gnarly DH tracks and easy singletrack. But from the looks of it I think people here consider riding some shuttles after a long climb and descent a mini dh bike. So that's why I'm throwing out some examples of comparable bikes.

    Any information, comments and suggestions are welcomed.

  29. #29
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    Put aluminum face IS tabs there and anyone can use HammerS . Not sure if HammerS is worth the weight for a climbing bike, also backpedal engagement is reported to be multiplied for AM climbing. DWL's work just fine with HS. DW hypes the high gear downhill jack problem to prevent novice rider warranty issue problems for his dealers. Any low squat design has the same issue with HS. IMO, a squat design is a compromise to better optimize HS.

    I like your frame geo suggestions. I test rode a Mojo HD w/ 160 fork, about 28 lbs, and it felt fine for XC-Enduro to heavy AM. With a 170 - 180 coil fork and shock to 31 lbs it would be easy for highest speeds and extreme drops. Same geo as you suggest.

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