# How to stop your seat post from sinking downwards into the seat post tube by using an internal spacer



## mike cates (Nov 19, 2022)

Things I've learned and done along the way to restoring bicycles:

Once in awhile you will get a bike that no matter how tight you tighten the cinch bolt the seat post will eventually still move downwards.
The fix for this is as follows:
1) Set the seat post height that is the best height for you with your seat attached.
2) Wrap some tape around the seat post where it becomes exposed at the top of the cinch bolt seat post bracket.
3) Remove the seat post with the seat attached and take a measurement from the tape line to the bottom of the seat post and write it down.
4) Drop a tape measure or rod down into the seat post tube until it bottoms at the bottom bracket and note this measurement as well.
5) Subtract the seat post to tape measurement you took in 3 above from the measurement you got in step 4 above.
6)You now have the internal measurement from the bottom of the seat post to the bottom bracket inside the seat tube.
7) Find a round wooden dowel, broom handle, PVC or ABS plastic pipe or whatever just slides into the seat post tube but not so tight that you can't retrieve it if later.
8) Cut whatever material you find to the length you got in 6 above.
9 Drop in the internal spacer, install the seat post with you seat attached, sit on the bike to compress everything downwards, tighten the cinch bolt and now your seat post will never sink downwards again and you cannot tell you have this installed because everything is inside the seat tube.

Note: If the bike is used by different riders from time to time, you can stack different length internal round spacers so one can be removed for the shorter legged rider. You can also make fine height adjustments via stacking/removing shorter spacers or flat washers so you don't have to make the longer spacer again.

Mike Cates, CA.


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## Thee (Nov 19, 2022)

What about the fact that if a dowel or long post go’s past the seat post tube and into the bottom bracket ? This will interfere with the crank rotation ! 
                        No I’m not being a smart a%s I had this happen as a young kid with a long seat post lowered to accommodate me, the bike would not pedal, I told my Dad & Uncle they lowered it to much causing the problem, 

they said no no that’s not it, they scratched their heads for what seemed like forever,  until they raised it some and said yup the kids right !  Off I went 😎


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## 49autocycledeluxe (Nov 19, 2022)

I have only experienced the opposite where they don't raise up or go down.


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## DonChristie (Nov 20, 2022)

I use a strategically cut piece of an Aluminum can for shim stock around the seat post.


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## 49autocycledeluxe (Nov 20, 2022)

another option would be to ride more and not be a big fat guy. I lost 50 pounds over the last several years.


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## Junkman Bob (Nov 20, 2022)

DonChristie said:


> I use a strategically cut piece of an Aluminum can for shim stock around the seat post.



Works every time…..


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## coasterbrakejunkie1969 (Nov 20, 2022)

49autocycledeluxe said:


> . I lost 50 pounds over the last several years.



That is awsome


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## madpixl (Nov 20, 2022)

Borrowing from the modern world, friction paste is used on carbon frames. I use it on my AL fat bike frame for the dropper post. Might work as a last resort before shimming.


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## J-wagon (Nov 20, 2022)

Also pipe joint compound


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## phantom (Nov 20, 2022)

I usually remove the seat post and go straight to the tube.


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## GTs58 (Nov 20, 2022)

phantom said:


> I usually remove the seat post and go straight to the tube.
> 
> View attachment 1735983




You keep throwing me with that new Avitar!! I don't see him around much anymore, just occasionally on a Facebook group.


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## phantom (Nov 20, 2022)

GTs58 said:


> You keep throwing me with that new Avitar!! I don't see him around much anymore, just occasionally on a Facebook group.



I haven't seen him around in a long long time. I have his phone number but put off calling, know what I mean ?  No news can be good news.


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## GTs58 (Nov 20, 2022)

phantom said:


> I haven't seen him around in a long long time. I have his phone number but put off calling, know what I mean ?  No news can be good news.



He also lives in Florida right?


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## phantom (Nov 20, 2022)

GTs58 said:


> He also lives in Florida right?



Yes, St. Petersburg   Was here last 4 years ago. Was a hoot on the old Schwinn Forum.


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## Thee (Nov 20, 2022)

phantom said:


> Yes, St. Petersburg   Was here last 4 years ago. Was a hoot on the old Schwinn Forum.



Who is he ? Looks very familiar ? Actor ?


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## phantom (Nov 20, 2022)

@mike cates  sorry for answering a question that led to derailing your thread.🤜🤛


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## Cooper S. (Nov 21, 2022)

phantom said:


> I usually remove the seat post and go straight to the tube.
> 
> View attachment 1735983



Are you that short or do you hate your knees


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## Thee (Nov 21, 2022)

Cooper S. said:


> Are you that short or do you hate your knees



O’rale he’s a low rider holmes !!


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