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  1. #1
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    Would 80mm fork work on Goblin Frame

    Thinking about buying/building a bike for my wife. I was looking at the Goblin frame and wondering if the 80mm Manitou Tower Pro would be a good fork for that frame. Is this frame designed to run with an 80mm fork or will the shorter fork mess up the geometry too much? I'm a little worried that the headtube angle might steepen out too much and steering could be a little quircky for her with that short fork.

  2. #2
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    I'm guessing that the angles of the frame are the same or pretty close to what they were when the Goblin came with an 80mm fork. If you look at the archived products section of the Airborne website, it shows that the Goblin 1.0 came with a 71.5 degree headtube angle. The new one is at 71 degrees. That .5 degree is probably the 20mm fork difference. That change also holds when you look at the Guardians.

    So, while Airborne is restricted in what they can recommend due to liability, I think that the geos suggest that there would be virtually 0 difference between what you are proposing and what used to be the standard on a Goblin. Besides, your EMD frame has a pretty steep HT angle as well. It works just fine with your Manitou Tower.

  3. #3
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    My Niner EMD has a 71 degree headtube with a 100mm fork. So at 71.5 its a pretty aggressive headtube. The short offset of the TowerPro would seem to compound the issue. That is my concern.

  4. #4
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    Quote Originally Posted by Fargo1 View Post
    My Niner EMD has a 71 degree headtube with a 100mm fork. So at 71.5 its a pretty aggressive headtube. The short offset of the TowerPro would seem to compound the issue. That is my concern.
    How are you at cutting and welding aluminum castings?

    Seriously, though, how big is the offset difference between the Rockshox and Manitous?

  5. #5
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    The offset on the TowerPro falls pretty much in the middle of the Rockshox and the G2 Geometry on the Trek/Gary Fisher bikes. From my past research the Reba has about 45mm offset, the G2 forks have 51mm ofset and the TowerPro has 48mm offset. So ideally I think the TowerPros would work best with a slack headtube. I don't think its enough offset to work with a G2 frame but I think its enough that it could make a 71.5degree Goblin frame pretty twitchy.

  6. #6
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    It's probably going to steepen up to near a 72 degree HT angle with an 80mm fork. We did tweak the Guardian and Goblin frame angles when we moved to a longer travel fork and tested them as such. The BB will also drop a little bit so there will be a compromise in regards to pedal strikes.

    We test the frames to 100mm and IMHO an 80mm fork would put less strain on the frame than the 100 due to the lever arm being shorter, so it while it won't be optimal in regards to angles, the frame isn't going to self-destruct or implode so you'll be OK.

    One question, since I'm not a Manitou expert; can the Tower Pro be lengthened to 100mm like the 80mm Reba can?

    Jeremy
    Airborne Dude.

  7. #7
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    Yes but that is assuming that the numbers you have on the EMD 9 are with a sagged fork. I haven't found anything (yet) that says that the 71 degree angle on your Niner is sagged. If not, it would explain why some folks feel that the first gen EMD 9 was crazy-steep. If we aren't comparing sagged numbers in both places, a Gob with an 80mm Manitou might still come in less twitchy than yours (which isn't bad at all IMO).

    Maybe you should give Niner a call and see how they measured the HT angle.

  8. #8
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    Quote Originally Posted by BigDaddyFlyer View Post
    One question, since I'm not a Manitou expert; can the Tower Pro be lengthened to 100mm like the 80mm Reba can?

    Jeremy
    "Fargo1" checked on that. Unfortunately, no.

  9. #9
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    Thanks Jeremy. You pretty much answered my question. If my wife was more aggresive that might be OK. But for her inexperience I better stick with a 100mm fork and keep things a little more slack.

    I'm no expert on the Manitous either. But that question was asked on Pricepoint and the response was that they are fixed travel and can not be adjusted. The TowerPro is a hybrid spring/air shock, and that might be part of the reason. I don't know.

    I've been doing lots of research on it this morning though. It appears the TowerPro has been discontinued for 2014 and replaced by the MarvelPro29 which is an all air shock. So I may have to wait and see how they compare in price/performance to the Reba and Recon Gold. I am also considering just getting Seeker or maybe a Guardian with the intention of upgrading as my wife progresses.

    Thanks again for the reply.

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