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Bike fit concerns

Old 06-18-20, 05:02 PM
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Illinest
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Bike fit concerns

I just bought my first mtb - a large framed Giant Talon 2. I'm just wondering if I should have bought a medium instead.

I'm 5'11" and the charts say I have the right size but I lowered the seat as far as it would go and I feel like it's still in my way. I adjusted the seat forward too. I see videos of people who are practically scraping their nuts on their rear tire but I can't get that far back/down. I just end up sitting.


I want to learn to manual and bunny hop but I don't see how I can get the bike up if I can't shift my weight back behind the rear axle.
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Old 06-18-20, 10:46 PM
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Depends on the geometry of the bike...but most MTBs you either have to move WAY back behind the seat...or you get a dropper post...which drops the seat just for that reason. Question...when you are riding at the normal seat height...how much bend do you have at the lowest part of the pedal stroke. Rough fit guide would be that at the bottom of the pedal stroke, you should have a slight knee bend in your leg. If that is how the large fits...you probably have the correct size...Can;t imagine a 5' 11" guy in a Medium...I'm 5' 10" and I ride a L....but its all about inseam too. You could have a really long torso and shorter legs and that would require maybe a M....
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Old 06-19-20, 05:51 AM
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Originally Posted by jrhoneOC View Post
Depends on the geometry of the bike...but most MTBs you either have to move WAY back behind the seat...or you get a dropper post...which drops the seat just for that reason. Question...when you are riding at the normal seat height...how much bend do you have at the lowest part of the pedal stroke. Rough fit guide would be that at the bottom of the pedal stroke, you should have a slight knee bend in your leg. If that is how the large fits...you probably have the correct size...Can;t imagine a 5' 11" guy in a Medium...I'm 5' 10" and I ride a L....but its all about inseam too. You could have a really long torso and shorter legs and that would require maybe a M....
I would need to raise the seat back up if I wanted to get my knees to have that slight bend.

You gave me an idea though - maybe my arms are the problem? Maybe I just have short arms for the size of my body? I wonder if I can drop my butt better if I do something with the bar?
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Old 06-19-20, 06:18 AM
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New or used?
A Giant dealer should have advised you on the differences, based upon your build, and the purpose of the bicycle.
Fit is a matching of the rider and geometry of a given bicycle in a given size.

Taller equates to longer.
That is the top tube and generally the crank arm length and stem are longer on a taller bicycle frame size than the
equivalent "medium" of the same model.

Shorter cranks and stem still leave a longer top tube and lower relative seat height. Shorter stem affects the steering
geometry and handling of the bicycle. Shorter cranks impact the spin.

As I recommend when asked about fitting, there is no advantage to a larger bicycle than what is needed.

The top tube always wins!

rusty
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Old 06-21-20, 05:41 PM
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100bikes has some excellent info ....also did you ride a M? I rode lots of bikes. I narrowed it down to 3 or 4 bikes and rode all of them M and L. Specialized has a fit calculator where they take measurements of bone lengths and things like that. It told them I was a L, but just barely and if I wanted a M, they could make it fit. So I rode both the M and L and the L "felt" better. In other brands neither the M or L felt as comfortable as the Spesh. So thats what I bought.

When I FIRST got a MTB (decades ago), I was comparing it to my BMX bike that I was super comfortable on and rode for a decade...jumps, tricks, everything was EASY. Got on a MTB and it felt HUUUUGE. Couldn't do ANY of those things easily....bunny hops...broncos....tabeletops...cross ups..all the things that were commonplace on a BMX bike became foreign. MTBs now are better for doing these things so I am re-learning to do alot of these things...technique is crucial.
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Old 06-21-20, 06:49 PM
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Illinest
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Originally Posted by 100bikes View Post
New or used?
A Giant dealer should have advised you on the differences, based upon your build, and the purpose of the bicycle.
Fit is a matching of the rider and geometry of a given bicycle in a given size.

Taller equates to longer.
That is the top tube and generally the crank arm length and stem are longer on a taller bicycle frame size than the
equivalent "medium" of the same model.

Shorter cranks and stem still leave a longer top tube and lower relative seat height. Shorter stem affects the steering
geometry and handling of the bicycle. Shorter cranks impact the spin.

As I recommend when asked about fitting, there is no advantage to a larger bicycle than what is needed.

The top tube always wins!

rusty
Originally Posted by jrhoneOC View Post
100bikes has some excellent info ....also did you ride a M? I rode lots of bikes. I narrowed it down to 3 or 4 bikes and rode all of them M and L. Specialized has a fit calculator where they take measurements of bone lengths and things like that. It told them I was a L, but just barely and if I wanted a M, they could make it fit. So I rode both the M and L and the L "felt" better. In other brands neither the M or L felt as comfortable as the Spesh. So thats what I bought.

When I FIRST got a MTB (decades ago), I was comparing it to my BMX bike that I was super comfortable on and rode for a decade...jumps, tricks, everything was EASY. Got on a MTB and it felt HUUUUGE. Couldn't do ANY of those things easily....bunny hops...broncos....tabeletops...cross ups..all the things that were commonplace on a BMX bike became foreign. MTBs now are better for doing these things so I am re-learning to do alot of these things...technique is crucial.

Okay so.... Believe it or not my crackpot theory about arm length appears to be correct.

I measured my wingspan at 67". Compared to my height of 71" it means I have a ratio of less than .95 which puts me at an absolute extreme of short arm length. Check out this chart.

https://erj.ersjournals.com/content/...5/F2.large.jpg

I think what this means is that a large frame is the right size for my legs and torso, but I think I'm far enough outside the normal arm length proportions that "the book" might not apply to me.

Last edited by Illinest; 06-21-20 at 07:03 PM.
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Old 06-21-20, 06:54 PM
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I'm no expert...and other may chime in...but maybe swept back bars and shorter stem, maybe slightly narrower bars as well. I would think the bars would have the least effect on handling as geometry isn't changed...shorter stem may have some effect on the steering. how much clearance do u need to clear the saddle? If you just need a few inches, then maybe these adjustments will be enough.
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Old 06-22-20, 03:50 AM
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I'm 5'11" with a disproportionally long torso and would definitely size a large Talon.

Seat height should be set to result in an approximately 30 degree bend in your knee at the bottom of the stroke with a level foot for pedaling. To practice manualing and hopping, you'll have an easier time if you mark your saddle at your pedaling height and then slam it low to drill. Really this is why dropper posts are such a big deal for non-XC trail riding--I recommend buying one; the Giant branded ones are pretty decent and the current model Talons have routing for an internally routed post. Fore-aft of the saddle should be set for knee and hip comfort, not as a means to adjust reach (although many MTBers, myself included, will run a more forward position on a mountain bike than they would on a road bike to shift the center of gravity forward while climbing). Try a shorter stem to compensate for your short arms. This will have the advantage of shifting your COS backwards when you're in the attack position making it easier to manual.
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Old 06-22-20, 05:34 AM
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Originally Posted by Illinest View Post
I just bought my first mtb - a large framed Giant Talon 2. I'm just wondering if I should have bought a medium instead.

I'm 5'11" and the charts say I have the right size but I lowered the seat as far as it would go and I feel like it's still in my way. I adjusted the seat forward too. I see videos of people who are practically scraping their nuts on their rear tire but I can't get that far back/down. I just end up sitting.


I want to learn to manual and bunny hop but I don't see how I can get the bike up if I can't shift my weight back behind the rear axle.
Dropper post. Gets the seat out of the way. Get one.
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Old 06-24-20, 01:19 PM
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Originally Posted by jrhoneOC View Post
I'm no expert...and other may chime in...but maybe swept back bars and shorter stem, maybe slightly narrower bars as well. I would think the bars would have the least effect on handling as geometry isn't changed...shorter stem may have some effect on the steering. how much clearance do u need to clear the saddle? If you just need a few inches, then maybe these adjustments will be enough.
^^^this, which stem size is one it now? Could easily go down to 40-50mm and a move the seat forwardish before switching bars. If the bars aren't high rise consider a stem with 10-15 degrees
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Old 06-24-20, 02:59 PM
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Originally Posted by qclabrat View Post
^^^this, which stem size is one it now? Could easily go down to 40-50mm and a move the seat forwardish before switching bars. If the bars aren't high rise consider a stem with 10-15 degrees
I just bought a 35mm stem. The existing stem is 70mm. I hope I love it.
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Old 06-26-20, 07:21 AM
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Originally Posted by Illinest View Post
I just bought a 35mm stem. The existing stem is 70mm. I hope I love it.
I think you're on the right track. I'm 6'0" and have long legs and a short torso. I buy large bikes so my pelvis is in the correct position relative to the cranks (more efficient to make power), and then shorten the bike at the stem. Some say shortening the stem messes up handling, but I think that's exaggerated, I've never had an issue.
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Old 06-29-20, 07:30 PM
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So I got the new stem installed today and it almost feels like a different bike. Just 35mm off the stem and the whole bike feels smaller. In a good way. The bars feel like they're in the right spot. Less reaching and I can get back further.
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