# Seat Post Too Long! Cutting it an Option??



## RallyPunx (May 5, 2009)

I'm new to mountain bikes (serious riding anyway) and this is my first post. 

I just got a used GT XCR 2000 from a friend and I'm trying to set it up for my body/liking and noticed the seat post is very long. My friend is tall (over 6') and I'm 5'6". When I lowered the seat to fit my body height, it hits the shock on the frame. I went to a local bike shop to see if they sell a seat post that is a little shorter and they told me they could just cut it with a hacksaw for me. Is this common practice with these GT seat post?? Am I really messing the seat post by cutting it?? Do they even sell a shorter seat post for the GT mountain bikes if cutting is not a viable option??

I will appreciate your input. Thanx.


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## KevinB (Oct 5, 2004)

As BlackDiamond-1 says, it's not uncommon to cut seatposts. However, given that your friend is over six inches taller than you, I'd be concerned that the frame is too large. You may be able to get the seat to the right height by cutting the seatpost, but you might not be able to make the other necessary adjustments to make the frame work for you. In particular, you may find that the standover height is too high, and, more importantly, you may find out that the top tube is too long. You might be able to make the bike more comfortable by using a shorter stem, but I think that over time, you're going to find that the frame is simply too large for you.


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## Ken in KC (Jan 12, 2004)

*The problem...*

As Kevin pointed out, the problem is the size of the bike, not the seatpost. It's too big for you.

Yes, you can cut the seatpost. On most seatposts, there is a minimum insertion line machined in to them. You'll want to scribe your own minimum insertion line based on the amount of seat tube you cut off.


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## RallyPunx (May 5, 2009)

Thanx for the info. I figured the frame might be a little too big for me, but I got a heck of a deal on a good bike. It has over $1500 in upgraded gear that I can transfer to another frame later on. I just want to get riding while I save for a good frame. I just never heard of cutting the seat post before, so I was kind of skeptic of the bike shop. I guess they were on the right track. Again, thanx for the info. 

I'm glad I found this forum. Very informative and great people.


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## jonlong (Sep 29, 2004)

out of curiosity, what size is the frame?


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## KevinB (Oct 5, 2004)

jonlong said:


> out of curiosity, what size is the frame?


Yeah, that's a good question. Some folks intentionally get frames that are too small with the thought that they'll be able to huck it more easily or some such. Or, it could be that the previous owner has long legs and a short torso and therefore purchased a smaller than normal bike for someone of that height, perhaps also purchasing a long seatpost in order to get the saddle set to the correct height. If that's the case here, it could be that the OP has a reasonably sized frame.


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## 006_007 (Jan 12, 2004)

yes. but as others said make sure frame is correct size.


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## jonlong (Sep 29, 2004)

There are scenarios where a 6'3" rider could buy the right size frame for a 5'6" rider, but not many good ones. That sounds like it could be a really uncomfortable bike, even with the seat down appropriately. Might be good to start considering that frame swap in the near future. Remember that you can sell your current frame to offset the cost of a new one.


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## RallyPunx (May 5, 2009)

Thanx for the information. It seems that I have good clearance with the frame, so once I get the seat post fixed, I will be able to make a better determination. BTW, how do I measure the frame?? It would be good to know what frame size I have. With a 5'6" height, what sizes of frame would be in my range?


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## KevinB (Oct 5, 2004)

RallyPunx said:


> BTW, how do I measure the frame?? It would be good to know what frame size I have. With a 5'6" height, what sizes of frame would be in my range?


Frame sizes are often given by seat tube length, or sometimes by designations like S, M, L, XL.

To measure the length of the seat tube (not seat post), measure from the center of the bottom bracket to the top of the seat tube. Given that the previous owner was over six feet tall, I'd guess that the seat tube length will be somewhere between 19 to 21 inches (inclusive). I would think that a 16 to 18 inch frame might be suitable for someone of your height. (A lot of it is personal preference though.)

The more important measurement is top tube length. Sheldon Brown discusses this in his frame sizing article. It's well worth reading.


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## jonlong (Sep 29, 2004)

Even 18" might be too big for someone at 5'6". Often times, full sus frames have a sloping top tube, which will give you the requisite clearance, but you can still be stretched out too far on the bike. I'd ask your local shop what they think about the fitment, or post a pic of you on it and people here can let you know what needs to be adjusted (if anything).


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## sanjuro (Sep 29, 2004)

RallyPunx said:


> Thanx for the information. It seems that I have good clearance with the frame, so once I get the seat post fixed, I will be able to make a better determination. BTW, how do I measure the frame?? It would be good to know what frame size I have. With a 5'6" height, what sizes of frame would be in my range?


The problem with a too large mountain bike is your risk to crash.

The correct sized bike will give you enough standover clearance to minimize injury and the handlebars will be close enough so your weight is centered closer to the rear wheel.

Also sitting too high will raise your center-of-gravity and probably over-extended your leg while pedaling.

5'6" is a tweener height, between most Small and Medium sized bikes, but either size could work for you. A large, or even worse, an XL, will be extremely difficult to handle when you start riding technical terrain.


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## RallyPunx (May 5, 2009)

I'll see if I can take a picture tomorrow and post it to see what you guys think. Thanx.


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## rsilvers (Aug 23, 2015)

What size did it end up being?


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