Measure the minimum insertion length there and however much you cut off, you need to insert the post that much. Or mark a new minimum insertion length
GANGofFOURSTAR on
See that line?. measure the distance from the end to that… Make sure you have at least that much left from the cut end to where the seatpost first comes out of seattube
Automatic_Leg_2274 on
I recommend you don’t. My friend did and it to save weight and it constantly slides down. Ultimately had to throw out
HieiTF076 on
I wouldn’t, too. Better buy a shorter one. And it’s not like you will have a big weight gain, seems
pretty useless…
Wise_Code5804 on
How much are you planning to cut off also?
iwasfastonce on
The safest method..
Measure from the top edge of your frame’s seat tube (where the clamp is) to the underneath of the top tube where it’s welded to the seat tube. Add at least 25mm (1″), preferably nearer 50mm (2″) to this length. This is the minimum amount of post that you need inserted into your frame.
Any less and you risk breaking off the top of your seat tube.
CargoPile1314 on
As an occasional weight weenie myself, I got some info for you. A 100mm section of cheap aluminum seatpost is about 50g. Less than 2 oz of water. And, it’s static weight. So, at the start of each ride, take a healthy squirt of water from your bottle and spit it out. Mission accomplished.
If you still want to cut it, the situation is this: The most that you should reasonably cut off is the length of post between the existing minimum marking and the bottom of the head. Anything less than this is perfectly fine. The thing you need to ensure is that you insert the seatpost into the frame at least the minimum amount that is currently marked on the post. So, if you cut 100mm off, you have to move the minimum insertion line 100mm up.
Assuming the tap mark is where you usually insert the saddle to, I’d cut about 110mm below that. Minimum insertion for an EA50 post is 90mm, and having a bit of adjustment should you want to change saddles or tweak your fit is probably a wise idea.
Ok-Active-8321 on
**DON’T DO THIS!**
Unless you are riding your bike professionally it is really not worth your safety to modify a part that is really not intended to be modified. I saw a long seat post on-line that weighs 380 grams. Assume the clamp is 80 g and you can remove 1/3 of your post. You have saved a little over 3 ounces on the weight of your bike. There are many better and safer places to save that much weight. If nothing else, just buy a new post of a length appropriate for you.
razorree on
Most free manufacturers say 8cm min insert, but you can do more to be safe10 ? 12? 15?
What’s the problem now?
[deleted] on
[removed]
mtbsam68 on
I have already chimed in my response on how the cut can be made, but just know that the weight loss will be negligible berdering on pointless. If someone taller wants to ride the bike later, it may mean you or the next owner has to buy a seatpost but they are cheap. If you still want to cut it, go for it! Just follow the details provided by other commenters and ensure you maintain minimum insertion.
CargoPile1314 on
Hey OP. After being directed back here to defend a prior comment, I see something that didn’t click before. I’ve now noticed the packing case. Have you weighed it full, found it to be overweight, and that’s why you’re looking to shave weight?
14 Comments
Measure the minimum insertion length there and however much you cut off, you need to insert the post that much. Or mark a new minimum insertion length
See that line?. measure the distance from the end to that… Make sure you have at least that much left from the cut end to where the seatpost first comes out of seattube
I recommend you don’t. My friend did and it to save weight and it constantly slides down. Ultimately had to throw out
I wouldn’t, too. Better buy a shorter one. And it’s not like you will have a big weight gain, seems
pretty useless…
How much are you planning to cut off also?
The safest method..
Measure from the top edge of your frame’s seat tube (where the clamp is) to the underneath of the top tube where it’s welded to the seat tube. Add at least 25mm (1″), preferably nearer 50mm (2″) to this length. This is the minimum amount of post that you need inserted into your frame.
Any less and you risk breaking off the top of your seat tube.
As an occasional weight weenie myself, I got some info for you. A 100mm section of cheap aluminum seatpost is about 50g. Less than 2 oz of water. And, it’s static weight. So, at the start of each ride, take a healthy squirt of water from your bottle and spit it out. Mission accomplished.
If you still want to cut it, the situation is this: The most that you should reasonably cut off is the length of post between the existing minimum marking and the bottom of the head. Anything less than this is perfectly fine. The thing you need to ensure is that you insert the seatpost into the frame at least the minimum amount that is currently marked on the post. So, if you cut 100mm off, you have to move the minimum insertion line 100mm up.
just use a [tube cutter](https://www.amazon.ca/dp/B087FCM4GY), available for less than $15 on amazon
Assuming the tap mark is where you usually insert the saddle to, I’d cut about 110mm below that. Minimum insertion for an EA50 post is 90mm, and having a bit of adjustment should you want to change saddles or tweak your fit is probably a wise idea.
**DON’T DO THIS!**
Unless you are riding your bike professionally it is really not worth your safety to modify a part that is really not intended to be modified. I saw a long seat post on-line that weighs 380 grams. Assume the clamp is 80 g and you can remove 1/3 of your post. You have saved a little over 3 ounces on the weight of your bike. There are many better and safer places to save that much weight. If nothing else, just buy a new post of a length appropriate for you.
Most free manufacturers say 8cm min insert, but you can do more to be safe10 ? 12? 15?
What’s the problem now?
[removed]
I have already chimed in my response on how the cut can be made, but just know that the weight loss will be negligible berdering on pointless. If someone taller wants to ride the bike later, it may mean you or the next owner has to buy a seatpost but they are cheap. If you still want to cut it, go for it! Just follow the details provided by other commenters and ensure you maintain minimum insertion.
Hey OP. After being directed back here to defend a prior comment, I see something that didn’t click before. I’ve now noticed the packing case. Have you weighed it full, found it to be overweight, and that’s why you’re looking to shave weight?