Tapered steerer with 9QR or straight steerer with 15QR, which one is stiffer?- Mtbr.com
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  1. #1
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    Tapered steerer with 9QR or straight steerer with 15QR, which one is stiffer?

    I currently have a Fox 120RL on a Fuel EX bike. Tapered steerer with the standard dropout 9QR setup. I found a 140 Talas that looks very interesting, and it has a 15QR but it's a straight steerer. The bike has an E2 headtube, so I would need some sort of adapter from Crane Creek, that I'm sure I can get.

    Which one is stiffer? Wanted to get some opinions. Friends so far have said the 15QR with straight is going to be better.

    -Tom

  2. #2
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    I personally wont ride anything other than a thru axle anymore. Stiffness aside, just the peace of mind knowing that I have an axle going through both dropouts and threaded in is worth it.

    I think wether you notice the difference in stiffness is going to matter on what type of trail you ride. I cant comment on the 15QR, but I can comment on going from a 9QR to a 20mm thru axle. I notice a big difference, mainly when going through rocks. I can turn the bars and the wheel turns too. No more flexing. I also notice that before when I would hit the front brake hard, I could see the wheel lean to the side. I would also hear the rotor rubbing the pads on hard turns. Now the wheel stays put when hitting the front brake, no matter how hard I hit it. I also get no rotor rub even if I almost lay the bike over if turning extremely sharp on pavement.

  3. #3
    TNC
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    Interesting question. Without absolute lab testing and a lot of engineering mumbo-jumbo, we'll probably never have an absolute answer...and even then you'd have to test every fork and bike headtube in existence. But we probably have enough real world experience to make a logical assessment.

    I don't think the fork's steerer size...1.125 vs. 1.5...makes a big difference until you get to 150mm or maybe even 160mm. Design and materials have yielded some very strong and reliable 1.125" steerer forks. At 140mm I wouldn't be concerned with the rigidity of a 1.125" steerer. Of course all this is based on a bike with a solid headtube and a quality fork.

    On the axle size, however, I think most of us who've ridden all manner of axle interfaces can agree that solid axles, even the 15mm, is generally always going to deliver better steering precision. Again however, this is somewhat dependent on the wheel stiffness and fork stiffness. For example, a 30mm stanchioned Suntour fork with a 20mm axle...a stretch, I know...would probably still be a wet noodle.

    In your case I'd go with the 140mm Talas with 15mm axle as being noticeably stiffer. I don't think the F series Fox has as stiff a chassis as the Talas you're referring to. While they're both 32mm stanchioned, the arch and other design elements on the F are not as substantial. Remember though, that how and where you ride will also be a big part as to whether you'll notice a big difference.

  4. #4
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    Thanks for the opinions so far.

    The whole idea is to convert my Fuel from a "trail and race all around bike" to a "burlier but still light trail bike" and have 140mm of travel in the front for the times when I want to point it downhill, but be able to go 120mm of travel for normal trail riding. I like the 120mm of travel in the back and DRCV shock feels great back there, and I think 140 front/120 rear will be enough travel for my type of riding/skill level for the next year or so

    To be honest, the front of the bike feels pretty stiff now, so I mainly want to make sure I'm not giving up something going to the straight steerer tube. I think anything I give up should be cancelled out by the 15mm TA.

    -Tom

  5. #5
    MattSavage
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    Quote Originally Posted by trhoppe
    I currently have a Fox 120RL on a Fuel EX bike. Tapered steerer with the standard dropout 9QR setup. I found a 140 Talas that looks very interesting, and it has a 15QR but it's a straight steerer. The bike has an E2 headtube, so I would need some sort of adapter from Crane Creek, that I'm sure I can get.

    Which one is stiffer? Wanted to get some opinions. Friends so far have said the 15QR with straight is going to be better.

    -Tom

    Go with the through axle. there's no discernable difference between the steerer stiffness, but you will notice a difference between the axles. But, since you need a new front wheel (probably) due to the new hub, I'd go with a heavier gauge butted spoke/stiffer rim than you had before. I believe with the stiffer front end, more torsional forces are being transmitted to the wheel build that were previously being soaked up by the flexy qr dropout and skinny axle.
    "I wrote a hit play! What have you ever done?!"

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  6. #6
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    I've got Hope Pro2s with the adapters already, so I'm good there.

  7. #7
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    I'd imagine the steerer primarily enhances for/aft stiffness...the ability to withstand the leverage a long fork exerts on the frame, especially under braking. The 15 mil axle would be more for steering stiffness and being able to hold a line....ensuring both fork legs are pointed the same direction.

  8. #8
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    Quote Originally Posted by @dam
    I'd imagine the steerer primarily enhances for/aft stiffness...the ability to withstand the leverage a long fork exerts on the frame, especially under braking. The 15 mil axle would be more for steering stiffness and being able to hold a line....ensuring both fork legs are pointed the same direction.
    Exactly. Each part is about stiffness in a different direction. One cannot influence the other.

    The main question is, how much stiffness do you need? Many people are happy with 1 1/8" steerers and wouldn't bother changing but going the other way you might feel it.

    Can't you simply strip each fork and build up the one you want from the parts, build up the parts you don't want and sell them on.
    Owner of www.shockcraft.co.nz, Mech Engineer, Tuner, Manitou, Motorex, Vorsprung EPTC, SKF, Enduro
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  9. #9
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    Quote Originally Posted by Dougal
    Exactly. Each part is about stiffness in a different direction. One cannot influence the other.

    The main question is, how much stiffness do you need? Many people are happy with 1 1/8" steerers and wouldn't bother changing but going the other way you might feel it.

    Can't you simply strip each fork and build up the one you want from the parts, build up the parts you don't want and sell them on.
    Woah, is something like that possible? I figured the talas uppers and steerer were 1 piece and different then the regular 120RL

  10. #10
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    Quote Originally Posted by trhoppe
    Woah, is something like that possible? I figured the talas uppers and steerer were 1 piece and different then the regular 120RL

    The uppers and steerer will be one piece. But everything else interchanges so I'd expect them to as well.
    Owner of www.shockcraft.co.nz, Mech Engineer, Tuner, Manitou, Motorex, Vorsprung EPTC, SKF, Enduro
    www.dougal.co.nz

  11. #11
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    They are different part numbers on fox's site. Worth a phone call to em though

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