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  1. #1
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    Opinions please. Trance X3 bike position (w/ pic)

    Hate to ask this in this forum but since the all Trance X riders go here, thought it is the better place to ask.

    Anyways, my son is 5'4.5" and rides a 16" X3 with 90mm stem. We were on the trails last night and he mentioned to me that the back-end seems to always want to come up or lift quite a bit. My initial reaction was to push the seat back. So now, I'm kinda questioning the stem size. Maybe he needs a shorter stem to get his relative position slightly towards the rear (?). Here's a pic of him on the X3. What do you think? It's almost as if he needs to move further back. In the pic, the seat is already pushed all the way back.
    Attached Thumbnails Attached Thumbnails Opinions please. Trance X3 bike position (w/ pic)-trancex3_riding_position.jpg  


    2009 Giant Trance X3
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    judging by that pic the frame seems a little bit too small for the boy

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    I have to admit I'm not familiar with situations where the back of the bike lifts uncontrollably (the front is way more common). I wonder if maybe there is not enough rebound damping and/or too much p.s.i. in the rear shock, thus catapulting him forward after going over an obstacle.

    In what situations does the back-end come up?

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    Quote Originally Posted by BEEB
    judging by that pic the frame seems a little bit too small for the boy
    I certainly hope that's not the case, not just because we just bought the bike, but coz Giant's sizing will be way off. The 16" was supposed to be for 5'4" to 5'7". I'm 5'7" and fit on it even with the 90mm stem and the seat higher. I did try the 18" but it felt big so I'm one of the in-between guys as well.

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    Quote Originally Posted by antonio
    I have to admit I'm not familiar with situations where the back of the bike lifts uncontrollably (the front is way more common). I wonder if maybe there is not enough rebound damping and/or too much p.s.i. in the rear shock, thus catapulting him forward after going over an obstacle.

    In what situations does the back-end come up?
    I wouldn't really categorize it as uncontrollably but I would ask him for more specifics as to when this happens. But it happens when he hits a big enough bump and it will bounce the back enough for a slight lift. Also during braking.

    He has been riding an oversized Wahoo (17.5") and with the Genesis geometry, it's really waaaay to big for him. So there might be habits he need to change to adapt to the X3.

    But your comment on rebound damping or shock pressure seems to make sense to me. The front is set to 65psi while the back is at 155psi, based on his weight on 155lbs. He has the rebound 6 clicks out both front and back.

    I really, really hope the frame size is not the problem. I'm about to pick up a 16" X2 myself because this size feels good. Our dimensions are pretty much the same except that I have longer legs (in-seam).

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    I have to agree with the boy looking a bit too big for that bike. His body seems a tad way too up front and on top of the front end.
    Ride

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    Is the seatpost extentension ok? Can't judge it from this picture, because the pedals are on the same height. If it's ok then the frame really looks small.
    Under bumps and harsh braking situations it's quite normal that the front end sinks and the back end lifts. He can counter it with correct weight distribution on the bike. If it occurs very fast then more rebound daming helps.

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    I am 5'10 and ride a 18" trance x2, i weigh the same as your son and have the exact same suspension settings psi and rebound except for the front where i have it 9 clicks out and have no problem with the rear end lifting.

    I took a picture of myself on the bike and my ass does hang over the back more than your son's does so maybe you could try a layback seatpost to move his weight futher back and see if that helps
    Last edited by guzz46; 08-12-2010 at 05:08 AM.

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    Quote Originally Posted by fda47
    I certainly hope that's not the case, not just because we just bought the bike, but coz Giant's sizing will be way off. The 16" was supposed to be for 5'4" to 5'7". I'm 5'7" and fit on it even with the 90mm stem and the seat higher. I did try the 18" but it felt big so I'm one of the in-between guys as well.

    i would never buy a bike based on the size the manufacturer recomends for a certain height...
    you have to sit 5mins on the bike to see if fits or not

    lets take commencal as an example... according to their size chart i would go either L or XL
    but L is 18.5 and the last time i went riding a bike that small the fork just went to bottom due to too much weight on handlebar

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    Slow down the rebound

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    Quote Originally Posted by guzz46
    I am 5'10 and ride a 18" trance x2, i weigh the same as your son and have the exact same suspension settings psi and rebound except for the front where i have it 9 clicks out and have no problem with the rear end lifting.

    I took a picture of myself on the bike and my ass does hang over the back more than your son's does so maybe you could try a layback seatpost to move his weight futher back and see if that helps
    You mind sending me, or posting the pic of yourself on the bike that you referred to above?
    It may be that he needs a layback seatpost.

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    Quote Originally Posted by Biohazard74
    I have to agree with the boy looking a bit too big for that bike. His body seems a tad way too up front and on top of the front end.
    That's what it seems like. We may need to shift his weight a little to the back by proportionately shortening the stem and using a layback seatpost.

    Our upper body dimensions are pretty close. My seat is a bit higher and when I used it on the trails we go to all the time, it felt pretty good.

    With his seat lower, I think that effectively reduces the cockpit length enough to make his weight front-biased.

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    Quote Originally Posted by madtrix
    Is the seatpost extentension ok? Can't judge it from this picture, because the pedals are on the same height. If it's ok then the frame really looks small.
    Under bumps and harsh braking situations it's quite normal that the front end sinks and the back end lifts. He can counter it with correct weight distribution on the bike. If it occurs very fast then more rebound daming helps.
    Seatpost may be a little lower that what it ideally should be. I'll take another pic with the pedals on the 6 and 12. Now with all the helpful comments here, I think it all boils down to weight distribution.

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    Quote Originally Posted by BEEB
    i would never buy a bike based on the size the manufacturer recomends for a certain height...
    you have to sit 5mins on the bike to see if fits or not

    lets take commencal as an example... according to their size chart i would go either L or XL
    but L is 18.5 and the last time i went riding a bike that small the fork just went to bottom due to too much weight on handlebar
    I agree 100%, he did ride this bike around for more than 5mins before we bought it. He got on an 18" as well and that did not work out too well, it was way too big for him. Given that, we went for the 16" so I guess now it's all fine tuning.

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    Quote Originally Posted by Anthem1
    Slow down the rebound
    I suppose you mean slow down the rebound in the back? Gonna try that next time we're out.

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    FDA I'm the guy in Derry that had been talking to you via PM... I like the bike you got your son, may I ask where you got it.. But yes he does seem small for the frame..

    If your looking for a bike for you still, we might be able to work something out with mine, as I was improperly sized by Bensons, and they won't take it back for a larger frame.. Fwiw its a Diamondback Response Sport 16".. Nothing wrong at all, you could keep all my upgrades, (seatpost, Odi Lock ons, chainstay protector) and I'd sell it for $300.. I paid $489 in May for it..

    We are heading to the rail trails tonight if you guys want to meet up, about 6-630..

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    Fda, take a trip to the Bike Barn in Manch.. Pick up a Bontrager seat post with a 20mm offset.. Also theres no chainstay protector on your sons bike, they have them there for $2.. The seatpost is $20, which I just bought this weekend, and I really like it..

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    Quote Originally Posted by madtrix
    Is the seatpost extentension ok? Can't judge it from this picture, because the pedals are on the same height. If it's ok then the frame really looks small.
    Under bumps and harsh braking situations it's quite normal that the front end sinks and the back end lifts. He can counter it with correct weight distribution on the bike. If it occurs very fast then more rebound daming helps.
    This boy is going to continue to grow too.. Bring him in and tell them you want a good half hour on the 18" for the $$ your spending..

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    hey there Iboated

    Ya I know we haven't gotten to ride with you yet. I'm sure one day

    Anyways, the 18" Trance X will really not work out. It's gonna be hard to make that one shrink to fit him now. Even for me, the 18" feels a tad bit big.

    Read about your experience with Benson's. We are going full-sussies thus the Trance X. Going away from hardtails We got the X3 from S&W Sports in Concord.

    Actually, I already spoke with the LBS and they will take a look at the bike fit again tomorrow to see if it's really bad. I do feel though it's simple fine-tuning. It fits me and I feel it's better than an 18" as I can move the bike under me compared to the feeling of sitting on the bike.

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    Well I am 5'6" with a 29" inseam and my S (16") Trance x2 fits me fine. I also run a 90mm 6 degree stem with 3/4" riser bars with a 20mm setback seatpost. Whats his weight? I am around 170lbs and run 170psi with the rebound set two clicks down from fastest. Never had any issues with it other then my front end coming up off the ground on some tech uphills, but thats more riding style then anything else.

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    Quote Originally Posted by fda47
    It may be that he needs a layback seatpost.
    It might be that he even doesn't need anything new.
    Maybe you have to teach him to go out of and behind the saddle more on the trail or in braking situations?
    Also pushing down the bike after small bumps (like you do it in 4x or pump track riding) helps to don't get bucked off.

  22. #22
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    Set back seat post . You can see in the photo that the rider's knee is ahead of the pedal spindle center line , needs to be seated further back to get the knee @ or behind the pedal center . Here is a link to Sheldon Brown that may help ;

    http://rds.yahoo.com/_ylt=A0oG76deDG....com/kops.html

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    Excellent points all. I'm taking all these new-found knowledge with us to the LBS (who btw has been extremely helpful) who will help him with the correct body positioning.

    Quote Originally Posted by jdgang
    Well I am 5'6" with a 29" inseam and my S (16") Trance x2 fits me fine. I also run a 90mm 6 degree stem with 3/4" riser bars with a 20mm setback seatpost. Whats his weight? I am around 170lbs and run 170psi with the rebound set two clicks down from fastest. Never had any issues with it other then my front end coming up off the ground on some tech uphills, but thats more riding style then anything else.
    He is 155lbs with the shock set to 155psi and 6 clicks from slowest. So maybe that's why the rear end is slow to track back? Gonna try less damping in the back. I believe the stock Giant seatpost is not setback at all. LBS has one that they will have him try tomorrow, one with a 20 or 25mm setback.

    Quote Originally Posted by madtrix
    It might be that he even doesn't need anything new.
    Maybe you have to teach him to go out of and behind the saddle more on the trail or in braking situations?
    Also pushing down the bike after small bumps (like you do it in 4x or pump track riding) helps to don't get bucked off.
    You are most probably right. With the 17.5" Wahoo, he did not have the need to do that as it has like 23.8" ETT so his weight is further back with a shorter stem. He would need to unlearn old tricks and learn new ones

    Quote Originally Posted by AZ.MTNS
    Set back seat post . You can see in the photo that the rider's knee is ahead of the pedal spindle center line , needs to be seated further back to get the knee @ or behind the pedal center . Here is a link to Sheldon Brown that may help ;

    http://rds.yahoo.com/_ylt=A0oG76deDG....com/kops.html
    That's exactly what I noticed while watching him pedal. He is not centered on the bike at all.

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    Here is mine, i use a 80mm stem, sounds like you already have the same rebound setting as jdgang, his is 2 clicks from fastest and yours is 6 clicks from slowest and there should only be 8 clicks available, if you wanted to slow it down a bit you could try 4 clicks from either way which is what i used to run but found it didn't rebound fast enough over braking bumps.


    Opinions please. Trance X3 bike position (w/ pic)-130820105981.jpg

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    Some things to consider.
    I'm 170 lbs and race xc[ firm set up] using only only 140 psi in the rear shock and 50 psi in the fork He is running 165 psi and is only 150 lbs.[ pump gauges do vary, but try lowering shock pressure.] Ignore mfg recommended pressures. Try to keep fork and shock pressures feeling similar[ firm or soft to balance out the ride. the fork or shock will xfer force to the other through the bike.]
    The x3 has built in platform in the shock which adds additional kick over tree roots etc.and does require lower pressures[ more sag] than shocks without platform.

    The Trance x has one of the steepest seat post angles in the business[steeper than most xc bikes] to offset it's long wheelbase. Hence, you see many Trance x riders who want to ride a smaller frame with offset seat posts so they can get the seat back far enough.

    I ALWAYS take measurements of effective top tube,seat to bar , seat to BB etc measurements on old bike to xfer riding posn stem length etc to new bike. The effective top tube is the most important bike fit measurement .

    What was he riding before and how does seat / BB/ bar position , effective top tube measurement compare to the Trance x?
    Last edited by gvs_nz; 08-13-2010 at 12:05 AM.

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    Quote Originally Posted by guzz46
    Here is mine, i use a 80mm stem, sounds like you already have the same rebound setting as jdgang, his is 2 clicks from fastest and yours is 6 clicks from slowest and there should only be 8 clicks available, if you wanted to slow it down a bit you could try 4 clicks from either way which is what i used to run but found it didn't rebound fast enough over braking bumps.
    Thanks. That's what we're aiming for and what the LBS thought last night as well when they re-fitted my son on the X3. Unfortunately, they don't have a setback seatpost wit at least 20mm setback, or 25mm ideally so have it on order.

    I just picked up my 16" X2 as well but this one came with a 23mm setback seatpost so it fit me really well with a 100mm stem.

    Will play more with the rebound.

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    Quote Originally Posted by gvs_nz
    Some things to consider.
    I'm 170 lbs and race xc[ firm set up] using only only 140 psi in the rear shock and 50 psi in the fork He is running 165 psi and is only 150 lbs.[ pump gauges do vary, but try lowering shock pressure.] Ignore mfg recommended pressures. Try to keep fork and shock pressures feeling similar[ firm or soft to balance out the ride. the fork or shock will xfer force to the other through the bike.]
    The x3 has built in platform in the shock which adds additional kick over tree roots etc.and does require lower pressures[ more sag] than shocks without platform.

    The Trance x has one of the steepest seat post angles in the business[steeper than most xc bikes] to offset it's long wheelbase. Hence, you see many Trance x riders who want to ride a smaller frame with offset seat posts so they can get the seat back far enough.

    I ALWAYS take measurements of effective top tube,seat to bar , seat to BB etc measurements on old bike to xfer riding posn stem length etc to new bike. The effective top tube is the most important bike fit measurement .

    What was he riding before and how does seat / BB/ bar position , effective top tube measurement compare to the Trance x?
    Thanks for the tip on pressures. You know what, that never came to mind, the fact that his Float R has medium tune, so that may very well be the reason why the back end is bouncing around. Had it set up at 155psi (his weight) but will lower it accordingly later when we get to the trails.

    As for measurements, unfortunately his older bike is the wrong size for him so we really cannot transfer those measurements.

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    When I had my TX1, to achieve 25-30% sag my rear PSI was at 180 and I weighed 187lbs (and carried a heavy pack). However, my wife weighs 115lbs and her rear psi is set to 90psi to achieve 25% sag.

    I'm guessing that lighter Trance X riders should run lower pressures in relation their weight to achieve proper sag and a better ride.

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    I think it looks okay on the boy, he is just "big size" that's all.

    As for rear lifting up, try adding damping to the rear suspension, one simple way to test the rear for proper damping is ride off a curb(not too short) and the rear should bounce back once, faster rebound or slower rebound is up to rider's preference.

    An improper damping set up rear suspension will bounce a couple times when you ride down the curb.

    As for pressure, use the chart as a guide, +/- the pressure to achieve your desired sag.

    And remember, switch off the propedal!

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    Quote Originally Posted by fda47
    Thanks. That's what we're aiming for and what the LBS thought last night as well when they re-fitted my son on the X3. Unfortunately, they don't have a setback seat post wit at least 20mm setback, or 25mm ideally so have it on order.

    I just picked up my 16" X2 as well but this one came with a 23mm setback seat post so it fit me really well with a 100mm stem.

    Will play more with the rebound.
    I have a large frame and run a 120mm stem and seat right back on std seat post[xc set up]. That gives me exactly same seat to bar measurement I have always used . And if anything the effective top tube is marginally small for me. I have no handling problems that you describe .
    You shouldn't have to get alternative stem or seat post to get it to handle correctly.
    Either the frame is too small or the shock or fork is set up in correctly. Or your son is used to riding the wrong frame with seat set right back and to low?
    To me it looks like he is in too small a frame, but I have been riding mtb 20 plus years and traditional xc background. Others like to squeeze in to too small a frame to save weight or shorten wheelbase or they only ride downhill or jumps with their seat set low and back. They will say the frame is ok. Find out which camp the person at your LBS is in.

    Squeezing in to a smaller frame will always affect the handling of a full suspension bike though. It's better to be as centered as you can on a larger frame. If the handling is not quick enough then they should change designs. Trance is built for stable handling not flickability.The Trance X should feel very stable going over terrain you described because it has a very long wheelbase compared to other trail bikes.
    Last edited by gvs_nz; 08-13-2010 at 04:21 PM.

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    looks too small to me, maybe try a setback post and then play with stem length. I'm 5'8 and ride a medium x4 with a thomson layback post and a 100mm stem with no spacers and it's spot on, however everyone is different in how they like a bike to feel
    Last edited by nmdbase; 08-14-2010 at 03:48 PM.

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    Judging by those pics, i think you could both more your seats back a bit - your knees aren't in line with the pedal axle. It could also be becuase you're using platforms and not clipless. Make sure the balls of your feet are on the pedal and check again.

    I think though you've suggested the best fix - go to your LBS and get them to fit your son (and you perhaps?). Much easier to do when you see someone's leg in motion on a trainer. As for stem length, your son does seem a little cramped there, so a layback seatpost may be good
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    And a longer stem can help you fit the frame and make him feel more balanced between bars and seat.. General rule is short and high or longer and lower to stop the tippy over syndrome. Shorter stem slows the steering and longer quickens the steering. For that size frame I would say 110 would be max length.

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    Shorter stem slows the steering and longer quickens the steering. For that size frame I would say 110 would be max length
    Shouldn't that be the reverse? shorter stem = quicker steering, longer stem = slower steering, thats why i went for a 80mm stem over the standard 100mm

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    Wink Saddle needs going back.............

    ..............that's about the size of it and that's all, frame looks fine, just saddle is way far forward.

    I downloaded your pic and drew in lines to show you what you have and what you should have as far as where the saddle should be. Th green line is known as K.O.P.S = knee over pedal spindle and it's the general starting point for setting your saddle position. As I said, starting position, as in set it so it'slike this and then adjust rearward if you want by about as much as 2cm,, depending on his pedaling style - likes to spin, then use KOPS, likes bigger gears, send saddle further back. I also uploaded a pic of me on my Trance so you can clearly see my knee is slightly back of the pedal spindle. If you can't get the saddle back far enough with the current post you'll have to find a post with some setback and if this one alreayd has, then look for one with more.
    Attached Thumbnails Attached Thumbnails Opinions please. Trance X3 bike position (w/ pic)-trancex3_proper_riding_position.jpg  

    Opinions please. Trance X3 bike position (w/ pic)-positioning-march_9_07.jpg  

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    Quote Originally Posted by guzz46
    Shouldn't that be the reverse? shorter stem = quicker steering, longer stem = slower steering, thats why i went for a 80mm stem over the standard 100mm
    Wrong word.Less stable is what I should say.Shorter is technically quicker but has a more draggy feel from the tire and less effect from subtle body language.Add that to body weight shift away from the front wheel gives shorter stem more stable feel.
    Last edited by gvs_nz; 08-16-2010 at 12:22 AM.

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    Quote Originally Posted by LyNx
    ..............that's about the size of it and that's all, frame looks fine, just saddle is way far forward.

    I downloaded your pic and drew in lines to show you what you have and what you should have as far as where the saddle should be. Th green line is known as K.O.P.S = knee over pedal spindle and it's the general starting point for setting your saddle position. As I said, starting position, as in set it so it'slike this and then adjust rearward if you want by about as much as 2cm,, depending on his pedaling style - likes to spin, then use KOPS, likes bigger gears, send saddle further back. I also uploaded a pic of me on my Trance so you can clearly see my knee is slightly back of the pedal spindle. If you can't get the saddle back far enough with the current post you'll have to find a post with some setback and if this one alreayd has, then look for one with more.

    Good pic. Shows a classic case of too small a frame. Shouldn't need an offset post to fit a frame. The lbs should have got the frame size right first time. My knee is always right over the pedal center and that is an aggressive xc, but nearly unstable, riding position. Must be terrible trying to ride with it over an inch fwd of the pedal.
    Last edited by gvs_nz; 08-16-2010 at 01:06 AM.

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    Wow, are you a real fit specialist or do you just play one on the internetz? If you knew anything you would know that for some people a setback post is necessary no matter if they are riding the right size frame or not, because of their leg length.

    On ANY bike I have owned I have needed a setback post for this very reason, I have long legs and more importantly long thighs, so to get to where I need to be I have to use the setback - It has to do with the seat tube angle, as most companies DO NOT decrease the STA when they go up in frame size, hence most taller riders need a setback post. just so you can add to your internetz skillz.

    I see no issues with this frame for this kid, it's about the right size, just the saddle needs to go back. Now if he already has a setback post and the saddle is all the way back, then yes, he might need a size up or to consider looking at another bike with different geo.

    Quote Originally Posted by gvs_nz
    Good pic. Shows a classic case of too small a frame. Shouldn't need an offset post to fit a frame. The lbs should have got the frame size right first time. My knee is always right over the pedal center and that is an aggressive xc, but nearly unstable, riding position. Must be terrible trying to ride with it over an inch fwd of the pedal.
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    Many thanks again all. Very, very helpful response we're getting here. I'm so glad I posted the photo as a reference. I feel that it's helping a lot with advices.

    guzz46 and LyNx: thanks for posting your photos on the bike, very good reference point for us. Oh LyNx, his original seatpost had 0mm setback.

    We did go to the LBS and as I mentioned earlier, a setback seat post is now on order. I found a cheapo Giant seatpost with 20 or 23mm setback, per advice from LBS, and pushed the seat back. My son felt the difference right away. The bike's rear end no longer lifts. The stem on there was a 90mm and we switched it to a 70mm to shift his weight a little to the back and that even made it better for him. Not a single over the bar situation.

    To sum it up, first I think he needs to do a lot of adjusting. He has to raise his seat higher to get the correct knee bend and get comfortable with it. This he is doing now. The couple of adjustments done on the seatpost and stem helped immensely. This was done to get his knees properly lined up with the pedal spindle (KOPS) and get his weight off the front-end

    The one last thing that we will experiment with is the height of the handlebar relative to the seat height. It's higher that the seat right now. If we lower the handlebar to the same height as the seat, that will allow him to be in a slightly more attack position which in turn will force his butt to slide back.

    Again, can't say thanks enough to everyone. It's been very educational. We came from a ride in NJ and not a single complaint from my son. We are almost at the correct body positioning for him to be safe and effective on the bike. I can tell that the changes he's done made him more confident on the trails.

    As for me, I ride the same size, a 16", with a much higher seat than his, handlebars at or lower than seat height and it's perfect with a setback seatpost and 80mm stem (had a 100mm before). And I'm 2" or so taller than him. His body proportions are just slightly different than mine thus the adjustments.

    I'll post a final pic of what we ended up with on his setup.

    The Trance X is an excellent trail bike. I has handled what we've thrown at it so far. Climbs great and rewards you with stability going down.
    Last edited by fda47; 08-16-2010 at 07:46 PM.

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    Quote Originally Posted by LyNx
    ..............that's about the size of it and that's all, frame looks fine, just saddle is way far forward.

    I downloaded your pic and drew in lines to show you what you have and what you should have as far as where the saddle should be. Th green line is known as K.O.P.S = knee over pedal spindle and it's the general starting point for setting your saddle position. As I said, starting position, as in set it so it'slike this and then adjust rearward if you want by about as much as 2cm,, depending on his pedaling style - likes to spin, then use KOPS, likes bigger gears, send saddle further back. I also uploaded a pic of me on my Trance so you can clearly see my knee is slightly back of the pedal spindle. If you can't get the saddle back far enough with the current post you'll have to find a post with some setback and if this one alreayd has, then look for one with more.
    Good post - definitely helpful. I can't tell if my eyes are playing up, but it looks as if the 'plum line' on your picture isn't quite straight? Top seems slightly further right than bottom.

    Am i going crazy?

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    Quote Originally Posted by LyNx
    Wow, are you a real fit specialist or do you just play one on the internetz? If you knew anything you would know that for some people a setback post is necessary no matter if they are riding the right size frame or not, because of their leg length.

    On ANY bike I have owned I have needed a setback post for this very reason, I have long legs and more importantly long thighs, so to get to where I need to be I have to use the setback - It has to do with the seat tube angle, as most companies DO NOT decrease the STA when they go up in frame size, hence most taller riders need a setback post. just so you can add to your internetz skillz.

    I see no issues with this frame for this kid, it's about the right size, just the saddle needs to go back. Now if he already has a setback post and the saddle is all the way back, then yes, he might need a size up or to consider looking at another bike with different geo.
    I'm not an expert but i've owned a rat load of bikes. Some were marginal in size because I wanted quick handling short wheelbase and had to compromise by setting back seat etc. None of those bikes ever handled the same. So I can offer some real world experience.
    The Trance is not as weight shift sensitive as other frames or have as short a chain stays as others so may not have as radical effect as on some designs.
    If you want to give advise give good advise.It's your upper torso/ vs leg length, not your knee length which has most effect on your for/aft seat posn and frame size. Seat height can also adjust for effect of thigh length. The knee over the pedal is not critical it's an indicator that your balanced on the frame but not critical for pedaling efficiency. If you want a balanced set up no mfg is going to recommend extending yourself further over the rear wheel than they have the designed the frame for.
    He obviously has no other option now to use a set back post and slightly longer stem or return the bike. Doesn't mean he can't learn from this and get the right size bike next time.
    If he wants raise the bars lower his seat to just do jumps and walk back up the hill it's probably a perfect size.

  42. #42
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    To the OP, forgot to address the other issue of the rear coming up, as some said, check the rebound and air pressure in the shock, sounds like maybe the PSI is to high and/or the rebound too fast. Also not sure how long your son has been riding, but he does know that even though it's an FS you still spend a lot of time out of the saddle going over the rought stuff

    Just an FYI, but nearly all GIANTs, actually most bikes, come with setback posts which is essense negate the steep STA the tote. As to torso lenngth Really, cause mine's really not long, but I have super long arms, hence I use longer ETT/stems than most might at my height. Moving your seat higher still isn't going to get you back where you need to be for your knee to be in the right place once you already have the saddle at the correct height - saddle height and saddle placement are things that SHOULDN'T be moved or compromized to make a bike fit, that's what the stem is for. Now in your advice if you'd said if you use a stem over 120mm then the bike is probably too small for you, THEN I would say that's closer to the truth.

    Quote Originally Posted by gvs_nz
    I'm not an expert but i've owned a rat load of bikes. Some were marginal in size because I wanted quick handling short wheelbase and had to compromise by setting back seat etc. None of those bikes ever handled the same. So I can offer some real world experience.
    The Trance is not as weight shift sensitive as other frames or have as short a chain stays as others so may not have as radical effect as on some designs.
    If you want to give advise give good advise.It's your upper torso/ vs leg length, not your knee length which has most effect on your for/aft seat posn and frame size. Seat height can also adjust for effect of thigh length. The knee over the pedal is not critical it's an indicator that your balanced on the frame but not critical for pedaling efficiency. If you want a balanced set up no mfg is going to recommend extending yourself further over the rear wheel than they have the designed the frame for.
    He obviously has no other option now to use a set back post and slightly longer stem or return the bike. Doesn't mean he can't learn from this and get the right size bike next time.
    If he wants raise the bars lower his seat to just do jumps and walk back up the hill it's probably a perfect size.
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  43. #43
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    Quote Originally Posted by LyNx
    To the OP, forgot to address the other issue of the rear coming up, as some said, check the rebound and air pressure in the shock, sounds like maybe the PSI is to high and/or the rebound too fast. Also not sure how long your son has been riding, but he does know that even though it's an FS you still spend a lot of time out of the saddle going over the rought stuff

    Just an FYI, but nearly all GIANTs, actually most bikes, come with setback posts which is essense negate the steep STA the tote. As to torso lenngth Really, cause mine's really not long, but I have super long arms, hence I use longer ETT/stems than most might at my height. Moving your seat higher still isn't going to get you back where you need to be for your knee to be in the right place once you already have the saddle at the correct height - saddle height and saddle placement are things that SHOULDN'T be moved or compromized to make a bike fit, that's what the stem is for. Now in your advice if you'd said if you use a stem over 120mm then the bike is probably too small for you, THEN I would say that's closer to the truth.
    If you read previous posts suspension set up has already been covered.
    Giant's do not come with a set back seat post. You will find the front of the rail not go further back than than level with the front of the seat post. A set back seat post has a bend in it so the front of the seat rail can go past the front of the seat post like this
    http://autobus.cyclingnews.com/tech/...omson_seatpost.
    All I have been saying is If he needs to use that sort of seat post then he is very non average in body shape. The majority should be looking for a bigger bike.

    Not interested in going tit for tat on bike set up because I am not an expert. As you say everybody is different but designers have the average person set within a frame size. Women don't fit the male mold because of different upper body/ legs ratio[ roll your eye] You might want a womens bike it sounds like your fit. But you are contradicting yourself on previous post of thigh length used for bike set up. Now it's arm length and longer stems ? And your knee doesn't have to be in any place exactly as long as it is not going to put to much strain on your knees.That's a roadie philosophy and is used in practice on different style road bikes depending on how much standing, tri posn riding etc where body weight can help pedalling.
    MTB are designed to be ridden seated where body weight has no influence on pedaling.Ever noticed seat tube angles change from one mtb design to the next when they change the head angle! For MTB balanced is the most important element.

    I use a 120 stem on a large frame.I've checked my last bike setups by paying the professionals. I am well balanced between wheels without using a set back seat post. My knee just happens to be exactly over the pedal which is my preferred posn.
    If he wants to check it out correctly and avoid bad info from all of us amateurs,he should go to a good lbs or use
    http://www.wobblenaught.com/ and get it done properly like I did .
    Last edited by gvs_nz; 08-17-2010 at 10:21 PM.

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    gvs_nz. That's a great site. Thanks for the link. Definitely will get him professionally fitted. Just need to find the "good" ones. Then we will find out if that frame is in fact too small for him.

    Edit: Oh yeah, if we use the frame sizing method on wobblenaught.com, it will put my son on a 14.5" frame. Of course, and I do understand 100%, that seatpost length is just one of the criteria for frame sizing and that ETT is more important. competitivecyclist also recommended a 14.5" frame with an ETT of 21.5" to 22.3".

    The recent changes we've done made him more confident and comfortable on the bike going up and especially down. He's learned to modulate the brakes more as they're far stronger than his old mech brakes on the Wahoo. His braking technique probably contributes a lot to rear wheel lift. But the suspension tweaks suggested on this thread have helped immensely. As I mentioned a few posts above, we just came back from probably an 18-mile ride in NJ and I have noticed the difference. I have to keep up with him.

    He also needs to learn sliding his butt behind the saddle more on steeper descents.

    We will keep experimenting with setups while I have not found the "good" fitter. Next in line is the handlebar height which as you can see from the pic, is an inch or even 2 higher than his seat.

    This has been a great learning experience for us, seeing what effects any of the changes do to the bike and rider.
    Last edited by fda47; 08-18-2010 at 07:23 AM.

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    Where in Jersey are you...you can ask on www.mtbnj.com. If you are in South Jersey I heard Halters in Monmouth Junction is a good shop. If you are up in North Jersey I use CycleWorks in Byram, both are Giant dealers

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    jdgang: actually, we live in NH. just went down to NJ to visit wife's family and we took the opportunity to ride in Allaire.

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    Again, that is WRONG information, a setback post DOES NOT have to have an actual bend in it, it only has to have the mounting hardware setback from the post. Take a look at the images of the posts below the 1st is a Thomson setback the next is a Thomson straight and the last is an Easton setback. Fact of the matter is, that most posts these days have some degree of setback. Another FYI, nearly ALL Giant's come with a setback post - please get your facts right before "helping".

    Quote Originally Posted by gvs_nz
    If you read previous posts suspension set up has already been covered.
    Giant's do not come with a set back seat post. You will find the front of the rail not go further back than than level with the front of the seat post. A set back seat post has a bend in it so the front of the seat rail can go past the front of the seat post like this
    http://autobus.cyclingnews.com/tech/...omson_seatpost.
    All I have been saying is If he needs to use that sort of seat post then he is very non average in body shape. The majority should be looking for a bigger bike.
    One day your life will flash before your eyes, will it be worth watching??
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  48. #48
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    Here's an updated pic after changing saddle height, 23mm setback seatpost, switch from 90mm stem to 70mm, then flip the stem upside down to lower the handlebar further. I think we are getting there. He has never been as confident as he is during our last 2 rides. No more rear wheel lift.
    Attached Thumbnails Attached Thumbnails Opinions please. Trance X3 bike position (w/ pic)-img_1805.jpg  


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    That looks better, before his riding position looked like he was getting ready to do a stoppie.

    Is it just the angle of the photo or does the front wheel look like it comes close to hitting his toes if you turn the bars?

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    I still say frame too small - Unless its the angle of the pic that makes me think i'm seeing some toe overlap.
    -Don "LordDRIFT" Draper.

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