Effect of G2 geometry with Niner geometry- Mtbr.com
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  1. #1
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    Effect of G2 geometry with Niner geometry

    Apparently, some manufacturer ordered a bunch of Fox forks and then didn't take all of them or the factory made too many. Anyway, a guy in China was blowing bunches of them out on ebay for $650 shipped.

    They were black with shades of grey and silver Fox decals
    Float 29
    FIT
    RLC
    Tapered steer tube
    32mm stanchions with Kashima coating
    100 mm travel
    He had both QR and 15 mm

    I got mine today and it is the best looking fork ever (I want to say stunning)

    Anyway, the guy didn't know what he was selling since he described them as 110 mm travel and didn't mention the Kashima coating although it looked like that in the picture and it arrived without the little brake guide which I found online for $11. Looking closely at the fork it seems like the stanchions are a little further out than my other forks and I don[t think it is because my other forks are 29mm as opposed to 32 mm. Nowhere on the fork does it say G2, but I strongly suspect it is. I have read other posts that claim you can't feel the difference, it will be way off, etc. Since Niner geometry is pretty specific, is there a consensus among Niner riders that have tried both? This is a new build but when I get it built, I will have other Niners to compair it to but I don't want to cut it if I am probably not going to be happy with it. I would rather sell it if it is not going to work well

    Also, Is there any way to tell for sure if it is a G2 fork or not? I was under the impression that Fox G2 forks said G2 somewhere on the fork. I am planning to put this on an Air9 Carbon I am building but I have a Jet9 that currently has a Reba XX. Is it possible that if this fork is G2 it would work better if I swapped it to the Jet as opposed to the hardtail? Sorry for the many questions in this thread.
    Full rigid SS, Hardtail SS, Hardtail Geared, Full Suspension Geared.

  2. #2
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    Did you ever get an answer to your question? Did you put the forks on the bike or sell them?

    I'm looking at some G2 forks on ebay right now and was trying to determine what effect it would have on my non-G2 bike.

    Thanks!

    --
    Bryant

  3. #3
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    I never got an answer but here is what I think about the fork now that I have ridden it and a RockShox Sid on the same bike. The Fox fork appears to be 110 but that is because it does not use all its travel. Putting it next to a RockShox 100mm fork the Fox fork is taller by about 10 mm but you can't get the Fox fork to go the last 10 mm up the tubes. So I am certain it is a 100 mm fork. This extra height was confirmed in a conversation I had with Suspension Experts. They said the Fox forks don't go all the way up and are longer. As far as the G2 part, I can't tell for sure because if you put it next to a RockShox fork it looks different but is hard to tell if it has more offset. This is because some of the offset is in the crown and some is the position of the dropouts. Since it doesn't say G2 I am of the opinion it is not G2. Also, the Fox fork seems to be slower on the bike and I can feel the extra height. I think the slowness is because of the extra height not because it has different offset. The Fox is currently on the bike because it is easier to engineer a remote lockout for the Fox. The Sid is going to need some original engineering work and I haven't had time but overall, I will probably end up with the Sid.
    Full rigid SS, Hardtail SS, Hardtail Geared, Full Suspension Geared.

  4. #4
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    Effect of G2 geometry with Niner geometry

    Hit up Fox and they'll set you straight. I bought a similar OE fork from a bike shop in the US and sent them the serial number. From that it told the whole story for me.

  5. #5
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    Steeper Geometry

    Long story short if you put a G2 fork on a frame such as a niner, your bike with be a lot more twitchy because you've increased the head tube angle. What the G2 forks do is make the geometry of the bike steeper and more agile/twitchy. 29er bikes like the Trek Superfly have a relaxed geometry and with the G2 fork it evens it out and brings it back to a "normal" x-country geometry by increasing the head tube angle. I personally would not instal a G2 fork on a frame that was not designed around the G2 geometry because I like a more relaxed head tube angle for high speed stability.

  6. #6
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    Quote Originally Posted by ToneyRiver View Post
    Long story short if you put a G2 fork on a frame such as a niner, your bike with be a lot more twitchy because you've increased the head tube angle. What the G2 forks do is make the geometry of the bike steeper and more agile/twitchy. 29er bikes like the Trek Superfly have a relaxed geometry and with the G2 fork it evens it out and brings it back to a "normal" x-country geometry by increasing the head tube angle. I personally would not instal a G2 fork on a frame that was not designed around the G2 geometry because I like a more relaxed head tube angle for high speed stability.
    G2 geometry does not change the head tube angle. There is also no such thing as 'effective head tube angle' ; other than in the minds of some technically bereft marketing bozos.

    The HTA is the angle of the steering pivot to the ground. That's it. It will change constantly on a suspension bike but is conventionally measured static, unloaded. All 'G2' geometry turns out to be is a decision by Garry Fisher to order some forks with 51mm [2"] offset rather than the more conventional 45mm [1/34"] . This reduces the trail which is the amount the tire contact patch is behind the point where the steering axis meets the ground.

    Another way to reduce trail is to steepen the HTA. This moves the axis point back towards the contact patch. G2 moves the contact patch forward towards the axis. As you increase the offset you decrease the trail.

    The reality is that you're only decreasing the trail by the width of one tire knob - 1/4". Sure, you can feel it, and it may matter to you, but it's not like they did anything else magic in 'G2 Geometry' thats going to force you to buy a Trek to use the fork.

    The bike will not be 'steeper'. It will have less trail. It will steer quicker. So will a narrower or smaller tire.

    If 1/4" bothers you, a quick analysis of how much the trail changes as the suspension dives or the ground transitions up is going to have you in tears. As long as the contact patch stays behind the pivot axis I'm not getting overly worried.

  7. #7
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    Didn't Garry Fisher also change the head tube angle slightly to somewhat mitigate the loss of trail? Also, wasn't his main reason for doing this to make it easier to make extra small 29er's without huge toe overlap problems because this effectively moves the front wheel slightly forward?
    Full rigid SS, Hardtail SS, Hardtail Geared, Full Suspension Geared.

  8. #8
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    Quote Originally Posted by yourdaguy View Post
    Didn't Garry Fisher also change the head tube angle slightly to somewhat mitigate the loss of trail? Also, wasn't his main reason for doing this to make it easier to make extra small 29er's without huge toe overlap problems because this effectively moves the front wheel slightly forward?
    Yes. A half to one degree. There's a back and forth between bike designers and suspension makers as to what standard and normal should be. It doesn't take a lot to alter the angle the fork tubes coming out of the crown just a smidge and have the offset change; this is cheaper than modifying the lower casting. Regardless of how it is achieved, I have to give Fisher credit for raising the question.

    I don't think 6mm is going to make much difference to whether an XS can be made to work. It's not like you're going to change the whole corporate fork offset for a few XS size bikes. Besides, you could add 10mm to the top tube and take 10mm off the stem and end up at the same place. Standover is the big conundrum anyway. But GF doesn't do the marketing, which these days will grasp at minutiae and create a proprietary acronym for just about anything.

    I'm not sure what the overall trail figures are typically, but I seem to remember 80 -90mm[??] If so, then 6 mm isn't all that much really.

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