# Bike Fit: How much seatpost exposed????



## bowler1 (Mar 19, 2005)

Hi,

Quick question about bike fit. I know all the formulas for bike fit etc. but here is a quick question looking at it from another perspective (since I fall inbetween frame sizes).....when you have a properly fitted bike, about how much seat post is normally exposed above the seat tube? 

I have a Lemond frame with sloping top tube (Victoire) and right now have about 6 inches of the seat post sticking out the top of the seat tube at the height where I feel comfortable. The top of my seat is 7 inches from the top of the seat tube. 

Sound about right to you?

Matt


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## Mr. Versatile (Nov 24, 2005)

I don't think there's any "rule of thumb" for this. It's just whatever it works out to be. That's one of the reasons I'm not a fan of sloping tube bikes. They just don't look right to me. they're all wheels & seatpost. IMO, it's just a cosmetic thing. I'm sure they ride nicely.


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## FatTireFred (Jan 31, 2005)

back in the day it was a fistful... of course it doesn't apply today


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## Dinosaur (Jan 29, 2004)

I don't think it matters as long as you don't go past the max insertion level on your seatpost. If your saddle is jacked way up it affects your bar to saddle drop...riders with long legs will have more seatpost exposed..if you noticed Leipheimers seatpost, he hardly has any showing at all..as opposed to Hincape..I think it's more of a anatomy thing then a fitting problem.. also-some of the new era seatposts with low profile clamps need to be jacked up higher, I need a 270mm with some models and a 250 with others, depending on the design and what saddle I am using...


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## Jim Nazium (Feb 3, 2004)

bowler1 said:


> Lemond frame with sloping top tube (Victoire) and right now have about 6 inches of the seat post sticking out the top of the seat tube at the height where I feel comfortable. The top of my seat is 7 inches from the top of the seat tube.
> Sound about right to you?


Yeah, that sounds pretty normal / average to me. I'm sure the bike looks fine that way. Just don't use more than 1.5 cm of headset spacers or you will get a ticket from the stem police. Seriously, if the fit is comfortable and the bike looks okay, you're good to go.


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## scslite (Nov 11, 2006)

I agree with most of the comments here. Seatpost should not matter unless it is integrated. ;-) Effective top tube is more important. Compact frames expose more of the seatpost. Personally I'm not to keen on the compact look. It looks more like a mtb frame than a road frame.


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## bowler1 (Mar 19, 2005)

Only reason I ask is because I am kind of between frame sizes. My bike right now is a 53.....just recently switched from a 55 (by a mishap but that's another story). I liked the long top tube on the 55, but the seat post was pushed down far into the frame. Only had about 4 inches or so exposed on the sloping top tube frame which made it seem like perhaps the frame was too big for me. The seat post was almost at its max insertion line.

Now I feel that the seat post exposure may indicate a better fitting bike...

I realize there is not necessarily a rule of thumb; however, it can be an indicator of frame fit in that if you seat is pushed way down you probably have too big of a frame and if the seat is as high as it goes, then the opposite is probably true. I figure that a certain frame size cooresponds to a certain inseam.....which cooresponds to a certain optimal seat height. This would then leave a certain amount of seat post exposed cooresponding to the optimal seat height for the average rider for that size frame. You get the picture.



Matt


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## mtbbmet (Apr 2, 2005)

Seat post exposure has about as much to do with proper bike fitting as the paint color of the frame. There is zero correlation unless you can't get your post low enough, or if you can't buy a post long enough. This is even more true for a sloping frame. Lets say that you have short legs but a long body, you want a 58TT but your seat is way down. Or you are all legs and no body, you want a 53TT but the seat is jacked way up. I both cases the frame fits the rider, but you get different post exposures.


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## culdeus (May 5, 2005)

Does post exposure affect the ride quality in any meangful way?


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## Dinosaur (Jan 29, 2004)

Well...if this means anything-I measured the amount of seatpost I have exposed on my Colnago Master X-Light, it's 6 inches...I think you are talking about cosmetic appearance in regards to fit..As long as you don't exceed the max insertion mark on your seatpost you are fine...riders with long legs have more seatpost exposed, shorter riders have less..compact frames throw everything out the window....


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## Argentius (Aug 26, 2004)

Not really. It's possible you could feel a little more flex with a load of post, but I doubt it


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## djg (Nov 27, 2001)

I wouldn't worry about this at all. From the various sizese that permit the contact points you want, choose the one that seems to offer the best balance/weight distribution. If you don't have a sense of which that is, find a good coach and/or fitter to help you choose. 

The most basic elements of fit have to do with getting your contact points in the right place--you need a certain extension and setback to get the butt/hips/pedals thing right, and you need a certain reach and drop to be comfotable and balanced. After that, there's the question how your body is draped over the bike--a 58 cm top tube and a 6 cm stem might give you just the reach you want (depending on you, obviously), but it's not likely to handle the way the bike was designed to do. How much seatpost you want to show really has nothing much to do with either of these stages of making a bike fit. Once upon a time, a "fistfull" (not really a standard measure) of seatpost was considered a good rule of thumb--but that figured on the deeper drop bars that were typical in the day, quill stems, and a rough correlation between leg extension, "typical" body geometries (which vary, of course, rider to rider) and lengths of level top tubes on more-or-less square measure bikes that tended to follow a fairly narrow range of geometry adjustments (although these, too, varied). In the last decade or so, riders tended to move to shallower drop bars, and to spend more time riding on the hoods, and folks started seeing more seatpost extension, even on level top tube bikes. Folks got used to a certain aesthetic, just as they had before, but once again, seat post extension only mattered at all to the extent that it (very) roughly correlated with a bunch of other bike and rider measurements. Now that horizontal top tubes are becoming less and less the norm, and we see "sloping" top tubes coming in various degrees (and headtube lengths varying more too), the sense in which some particular fixed quantity of seatpost showing is optimal is hazier than it ever was. You want enough extension that you can adjust the saddle as you like, and of course, independent of your reach requirements, the bike shouldn't be so large vertically that it's tricky to mount or dismount. You want the extension to be short enough that you don't have to go on a mythic quest to find the one special seat post that will work, and so that you're not taxing the physical properties of the post (say, by going past the insertion line). After that, it's just looks. Personally, I don't really like the way a foot of exposed seatpost looks, and I can't see what swapping an extra 6 cm of seat tube for seat post pillar would do for me, but that's just me. The real question to answer (if you can answer it before shelling out your bucks) is this: If you are "between" sizes, and you get your contact points right on both sizes, which one handles better in hard cornering? If there's an answer to that question, that's what you want. If there isn't, pick the one that looks better. If you're still stuck, flip a coin.


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## DaveT (Feb 12, 2004)

Both of these bikes fit me, the contact points are the same on each. As another poster said, the correlation of the amount of seat post showing to the correct frame fit has little, if any bearing.


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## zooog (Mar 18, 2002)

I believe it was C40 that had stated "X" amount of seat post is allowable. Anymore than that than the bike is too small. Maybe I am misquoting but it made sense to me...


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## JaeP (Mar 12, 2002)

*Exposing my 9 inches*

My 2001 XL Schwinn Fastback Comp has 9 inches of exposed seatpost (410mm Thomson Elite seatpost). She's my race bike hence the aggressive saddle to handlebar drop. As a previous poster stated, I think the longer seatpost gives me a more compliant ride.


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## AlexCad5 (Jan 2, 2005)

DaveT said:


> Both of these bikes fit me, the contact points are the same on each. As another poster said, the correlation of the amount of seat post showing to the correct frame fit has little, if any bearing.


The bike on the left is clearly much slower due to the all that resistance below.


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## cmg (Oct 27, 2004)

lot of seat post showing there. how much is left in the tube?


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## DaveT (Feb 12, 2004)

AlexCad5 said:


> The bike on the left is clearly much slower due to the all that resistance below.


I know. It's a bi*ch to maintain a high cadence in the snow!


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## FatTireFred (Jan 31, 2005)

cmg said:


> lot of seat post showing there. how much is left in the tube?



if that was a "normal" 250mm or old-skool 210mm post, the answer would be 0


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## JaeP (Mar 12, 2002)

*Thomson Elite MTB post*



FatTireFred said:


> if that was a "normal" 250mm or old-skool 210mm post, the answer would be 0


The seatpost is a MTB Thomson Elite seatpost that is 410mm long. There is approx. 7 inches (180mm) remaining in the seat tube.


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