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  1. #1
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    Using a 30.9mm seatpost on an HDR?

    Hey guys,

    Anyone tried running a 30.9 seatpost on their Ibis with one of the available shims, like this:

    Problem Solvers | New Seatpost Shim Size: 30.9 to 31.6mm

    or this one:

    wiggle.com | USE 30.9 Internal Shim | Seat Posts

    Wondering how it works or is it just not worth it. I'm looking at switching to an Ibis frame and ideally keeping my 30.9 Reverb.

    Thanks.

  2. #2
    Kaj
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    Never used one on an Ibis, but a few hundred other bikes. Shims for this application work great.
    Helping folks shred in Boulder & Colorado since 1982 www.fullcyclebikes.com

  3. #3
    aka dan51
    Reputation: d-bug's Avatar
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    If you are buying a new post and plan to have it on an Ibis for many years, get the 31.6 model post.
    If you have a 30.9 or don't think the Ibis will be around long, get the 30.9 and use the shim. The 30.9 will be transferable to most frame brands.
    The shims work great.
    Those who know, ride a Mojo AND a Mojo HD.
    Quadzilla
    Quote Originally Posted by benja55
    Ok, whatever, cold water on my bike boner right there.

  4. #4
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    Thanks guys. Exactly what I was looking for. Sounds like it's doable.
    d-bug: I have a 30.9mm Reverb on my current frame so ideally I'd prefer to transfer that over (than get a new one) as it works great and it would mean a few hundred less dollars to shell out.

  5. #5
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    I had a 30.9 reverb with a shim on my old HD for over a year with out any issue. I would just recommend using some carbon friction paste on and in the shim to prevent any slipping/twisting of the post.

  6. #6
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    fuenstock - which shim did you use?

  7. #7
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    I have used a DIY shim cut from a coke can on my Mojo HD, works perfectly..

  8. #8
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    Quote Originally Posted by jon123 View Post
    fuenstock - which shim did you use?
    I bought my 0.7 shim on eBay long ago. His auction didn't have any info on make or model for shim, just said 0.7 seat post shim so I have no idea who made my shim. It does look like the problem solvers one, but the top detail is different. It is a very thin shim, I have heard of some people cutting an aluminum can and using as shim, but since my shim works I didn't need to go that route.

  9. #9
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    I had the Problem Solver's shim between a HD seat tube and a Reverb post for a while (before the Reverb died) and was is an extremely tight fit. SRAM just sent me a warranty replacement Reverb but I will try to alter the shim a little before I try to ram it down the tube again.

  10. #10
    Stupid is, as stupid does
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    YesI do as well. I always buy the 30.9 sized post and use shims. It's easier to resell in case something better comes around. Anyway I buy my shims from gravity dropper.
    2012 Ibis Mojo HD (155mm 650B)
    Yeti SB95 Carbon
    1993 Brodie Expresso
    RIP 1997 Santa Cruz Heckler.In 2010 the frame cracked

  11. #11
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    I use a 30.9 seat post on my Ripley. Had a shim that I used on my SLR but it was just a tad to big for my Ripley. So I used a coke can for a shim and had no issues for the past 6 months.

  12. #12
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    reviving an old thread rather than start a new one...
    I Just tried installing a Problem Solvers 30.9 to 31.6 shim my recently acquired Mojo HD and the fit is not even close. It's so tight I can only insert about 1.5" of either of my 30.9 posts (KS Lev and Easton Carbon).

    Anyone have thoughts if its the shim or frame tolerance, or has anyone successfully used aluminum can shims in this frame?

  13. #13
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    Quote Originally Posted by k1creeker View Post
    reviving an old thread rather than start a new one...
    I Just tried installing a Problem Solvers 30.9 to 31.6 shim my recently acquired Mojo HD and the fit is not even close. It's so tight I can only insert about 1.5" of either of my 30.9 posts (KS Lev and Easton Carbon).

    Anyone have thoughts if its the shim or frame tolerance, or has anyone successfully used aluminum can shims in this frame?
    Yep. I gave up on that alum shim from PS and got a plastic shim (USE?) instead.

  14. #14
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    Quote Originally Posted by StiHacka View Post
    Yep. I gave up on that alum shim from PS and got a plastic shim (USE?) instead.
    Thanks StiHacka! I'll look into the USE shim.

  15. #15
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    Quote Originally Posted by k1creeker View Post
    Thanks StiHacka! I'll look into the USE shim.
    I believe I got mine on Amazon, one like this. Amazon.com: USE Seat Post Shim: Sports & Outdoors

  16. #16
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    Quote Originally Posted by k1creeker View Post
    reviving an old thread rather than start a new one...
    I Just tried installing a Problem Solvers 30.9 to 31.6 shim my recently acquired Mojo HD and the fit is not even close. It's so tight I can only insert about 1.5" of either of my 30.9 posts (KS Lev and Easton Carbon).

    Anyone have thoughts if its the shim or frame tolerance, or has anyone successfully used aluminum can shims in this frame?
    I get all of my shims from Gravity Dropper. Never had a problem.
    2012 Ibis Mojo HD (155mm 650B)
    Yeti SB95 Carbon
    1993 Brodie Expresso
    RIP 1997 Santa Cruz Heckler.In 2010 the frame cracked

  17. #17
    Kaj
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    I've seen PS shims not be the right size before, since you tried 2 seatposts, I would guess that's the issue.
    Helping folks shred in Boulder & Colorado since 1982 www.fullcyclebikes.com

  18. #18
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    Thanks to all. I ordered up a couple USE shims last night. If they fit, I'm going to try and double the length just to be safe.

  19. #19
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    My USE shims arrived last night and they work perfectly. While the black anodize and thin nature of this size shim make them feel like plastic, they are finely milled aluminum. The finish quality makes the Problem Solvers shims look like they were made with a rock and a pair of tin snips.

  20. #20
    Kaj
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    awesome you're up and going.

    I know what you are saying on tin snips, it's just a shim and most of Problem Solvers stuff is good quality. for some reason they skimp on their seatpost shims.
    Helping folks shred in Boulder & Colorado since 1982 www.fullcyclebikes.com

  21. #21
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    I was in the same position, have a 30.9 post thought about shimming it, then I decided that I'd rather shell out the $ for the proper post and not have to worry about one extra piece of metal floating in my $3000 frame.

    Carbon prep aside, this is no place to save money IMO. The resell value of a good post is pretty high too. Just my cautious 2 cents. I wouldn't think twice about shimming a metal frame FWIW. Maybe I'm paranoid?
    My one says BRAP!

  22. #22
    Kaj
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    Quote Originally Posted by plume View Post
    Maybe I'm paranoid?
    Yep. There is a sleeve glued in your frame already to support the seatpost. This sleeve can be reglued if it comes loose. So you are just putting a shim in this sleeve, no big deal.
    Helping folks shred in Boulder & Colorado since 1982 www.fullcyclebikes.com

  23. #23
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    ^^^ this. If I am not mistaken, that sleeve is 4" long, just like a good shim.

  24. #24
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    Quote Originally Posted by StiHacka View Post
    ^^^ this. If I am not mistaken, that sleeve is 4" long, just like a good shim.
    I ended up buying 2 USE shims (recommended). I cut the top ring off one of them and adhered it (super77 spray glue) to the bottom half of my LEV post (above the screw off bottom cap). The second shim I use as normal. Combined, I get about 7" of frame contact....assuming the factory frame insert is that long to begin with. Extra piece of mind, and I didn't have to go through the hassle of selling/ahipping/buying a new post.

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