xpost: 1.5" frame/fork noticeably stiffer than 1.125"?- Mtbr.com
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  1. #1
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    xpost: 1.5" frame/fork noticeably stiffer than 1.125"?

    So I been thinking about getting a Nomad and am curious if the 1.5" headtube and single crown forks make a huge difference in stiffness.
    About me, I'm 6ft, 230ish and currently riding a large bullit with either a 150mm Z1 or a SuperT. Not much into big air but that might change (ya right) but do enjoy speed. I do really prefer the SuperT's stiffness but as you know that thing is a tank so I'm wondering how much of a difference there is? I guess manitou would be the only fork company that one could do an apple to apples comparison.

    Thanks,

    -Sp

  2. #2
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    isn't there a German magazine that does tests like this?

    you could try a Lyric or Totem in both 1.125 and 1.5 and see if there is any difference but if you have a 1.5 head tube you might as well just get a 1.5 fork. All this new OS stuff was made for guys your size. The only reason not to go 1.5 is if you must have a Marzocchi now, you will have to tell yourself that the stiffness difference is so minute that the suspension performance overshadows it, and then get the 1.5 66 when they come out.

  3. #3
    Team Sanchez
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    I"m your size Single Pivot, and I just purchased a 66 SL ATA for my RFX. It is a 1 1/8th head tube with 180 of travel. I like to jump and descend a lot, and I gotta tell ya, so far I am very impressed with this fork. I'll betcha it would mate up well with a Nomad. Just something to consider.

  4. #4
    Just roll it......
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    SP....see my post in the DH forum.....

    Basically, Manipoo has been preaching this for a long time, but Rock Shox just confirmed this as well..... Rock Shox has stated the 1.5" version of the Totem is ~20% stiffer than the 1.125" version, plus the 1.5 is lighter. I run a 1.5" singlecrown and it's comparable to a dual crown fork in stiffness (when it's running).

    Also, worth noting is the 66 is coming in 1.5" for '07 for OE on bikes like the IH 7 point, etc.

    EBX

  5. #5
    FM
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    1.5 is definitely stiffer, since the fork is usually broken, causing increased stanchion overlap with creates more stiffness.



    Edit: 1.5 forks have been proven to be %20 stiffer by USPS. Those damn fork boxes just won't flex without an RA#.

    Edit Edit:
    The extra stiffness is really required for single-crowns since you typcially need to ship them to your LBS who relays them to the manufacturer. 1.125 usually only need to be shipped once each way, so a little flex is OK.

  6. #6
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    i think knolly -- who has a good engineering background -- has been testing out the 1.5 and 1.125 versions of teh marz 66 (the 1.5 is 'oem only') and feels a noticeable front/back stiffness difference. there are some posts on the Suspension forum on this.

    i'm still holding off on the nomad until i'm positive the aftermarket pivot kit fixes the VPP maintenance issues, but absolutely i'm going with a 1.5 fork for the 1.5 nomad if i do pull that trigger. i have a 1.5 manitou breakout that's a few years old that is stiff in the fwd/back direction for a fork with relatively small stanchion diameter.

  7. #7
    Just roll it......
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    Quote Originally Posted by FM
    1.5 is definitely stiffer, since the fork is usually broken, causing increased stanchion overlap with creates more stiffness.


    Touche FM, touche......but I've yet to bend my 1.5 steerer tube on it and I've landed that thing almost as poorly as I did my 66 - especially when I grossly overshot a tranny on Sidetrack smacking my helmet on my handlebars and throwing me off the trail. When my 66 bent, it sounded like a shriek from a Halloween movie or nails going down a chalkboard. A high pitched sorta thing......not good, mav...not good. On the Travis, it's the damn internals that keep blowing up on me. The fork itself is stiff as hell though. If they didn't have a service center in Whistler, I would've already switched brands.....that's for sure.

    My point is that other frame and fork mfgrs. are moving in that direction now and Manipoo doesn't have the market share to force that on their own (especially in the FR market), so something has to be driving that. Rock Shox putting the a fork out in both versions and saying the 1.5" headtube is stronger (and lighter) just backs up what manipoo has been saying all along.

    All things being equal, if someone were to buy a Totem (for example), why not get a 1.5" steerer tube version if their frame has a 1.5 headtube? Since you already owned your 66, it's not a good example, but if you were starting from scratch and could throw the new 180mm 66 with a 1.5" steerer tube on the HL, I'm guessing you would.

    It's not too dissimilar to stanchions on a fork. In order to make them stronger, you either need to A. make the tubing thicker (e.g. a steerer tube on a 66 which is thick as hell) or B. you make them a larger diameter (e.g. 35mm, 36mm, 40mm). There's a reason the Totem or Fox 40 are reasonably light for the amount of travel and that's because of the larger, but thinner, tubing. I can only imagine how thick a 30 or 32mm stanchion fork would need to be in order to be as strong as a 40mm stanchion fork.....

    To the OP, I rode arguably the best year for the Super T (2003) for a year and a half and really loved that fork. I'd say my current fork (and the 66) outperforms it in every way (again when my travis is running). Plenty stiff, loads more adjustability and the added versatility that a single crown brings. I wouldn't shy away from the new crop of single crowns for your Nomad.

    Cheers,
    EB

  8. #8
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    werd is 1.5 66 RC2X for aftermarket by Jan.

    good one FM. The benefits of 1.5 can not be appreciated when the fork is in the mail .

  9. #9
    FM
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    Quote Originally Posted by ebxtreme
    My point is that other frame and fork mfgrs. are moving in that direction now and Manipoo doesn't have the market share to force that on their own (especially in the FR market), so something has to be driving that.

    It's not too dissimilar to stanchions on a fork. In order to make them stronger, you either need to A. make the tubing thicker (e.g. a steerer tube on a 66 which is thick as hell) or B. you make them a larger diameter (e.g. 35mm, 36mm, 40mm). There's a reason the Totem or Fox 40 are reasonably light for the amount of travel and that's because of the larger, but thinner, tubing. I can only imagine how thick a 30 or 32mm stanchion fork would need to be in order to be as strong as a 40mm stanchion fork.....
    Cheers,
    EB
    I'm pickin' up what you're layin' down.

    Really what you want is the 1.5 steerer with more reliable guts. Looks like 2007> marzocchi might have you covered!

    I am still skeptical about bigger being better. If something is larger in diameter and also lighter in weight, then you know that wall thickness has been decreased. Can you imagine how thin a 40mm tube must be, to be lighter than a 32mm tube? This means it is more likely to dent or crack instead of bending. Not a good thing for Alu. stanchions or steerer tubes! You are trading stiffness for strength, not getting more of both.

    I am not 1.5 bashing here. What I am bashing, is that the bike industry puts out new standards that aren't proven yet, and guess who finds out the pro's and cons. You found out manitou has reliability problems, and that 1.5 does work well. Sounds like lots of guys are going through the same thing with Rockshox.

    It all has me thinking that buying last years gear NIB is the way to go. Prices drop and reliability is known. Sign me up for a cheap 1.5 Marzocchi 66 in 2009.

  10. #10
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    There was a post on the shock board by a guy that was claiming to have done FEA on forks for a particular manufacturer, although he wouldn't name the one. He said during the tests and calcs that he did, that he found the stanchion size made a bigger difference in fore-aft stiffness, this doesn't mean that 1.5 fork isn't stiffer or stronger because it's 1.5, but it means that as far as what is percieved an increase in stanchion size will have a bigger effect on percieved "stiffness" than an increase in steerer tube size. The 1.5 standard was originally invented to prevent headtube ovalization, but manitou ran with the idea to build long travel single crown forks. Not a bad idea at all, but all of a sudden there became a lot of confusion as to "why" the 1.5 standard existed, was it for frames or for forks? You can run a 1.125 fork in a 1.5 frame with a reducer and still get the benefits of the 1.5 headtube, but pretty obviously the 1.5 fork allows designers to push the limits a little further as far as single crown technology and capabilities.

    That said, I have run DC forks in 1.5 headtubes and I can't tell that my 66 is significantly "less" stiff fore and aft, and that's comparing a SC with a DC, but again, the real difference here is that the 66 has far larger stanchions than most of the DC forks that I've ran, and today with the fox 36 and new RS offerings, they are only getting bigger.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

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  11. #11
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    Jayem is totally bang on about the reasons the 1.5" head tube was created for sure.

    However, long travel single crown forks can really benefit from a 1.5" steerer. a 34mm stanctioned Travis with a 1.5" steerer absolutely kills both the 1.125" 66 and the 36 forks (35 and 36mm stanctions) in any kind of for/aft rigidity. That doesn't mean that the 66 or 36 are bad forks by any means, but for me (210-215 pounds), i can definitely feel the difference. It's not as noticeable on technical North Shore style trails, unless it involves convoluted switch back corners or something else that can nastily twist up a fork, but it is VERY noticeable up at Whistler on trails like Frieght Train, Dirt Merchant, A-line, etc...

    We are going to be offering the 1.5" 66RC2X as an option for the V-tach frame this year - delivery is supposed to be towards the end of January. I have not tested one personally, but based on my experience with the 1.5" Totem and Travis I'm guessing that it should be a pretty sweet fork. Marzocchi plushness and damping quality with the advantage of a 1.5" steerer.

    The 2007 Marzocchi stuff is pretty awesome - the SL1 forks are really really impressive for air forks. The only thing I wish they would do is to offer teh 66SL1 ATA in 1.5. I'll think I'll try and make one once the 1.5" 66RC2Xs are available.

    Cheers,

    Noel
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