25.4 to 25.6 seatpost shim?
#1
Newbie
Thread Starter
25.4 to 25.6 seatpost shim?
My 2015-ish Raleigh Back Alley uses the most annoying seatpost size on the planet - 25.6. I've already replaced the stock seatpost with a cheap Sunlite post a few years back, but now it also needs to be replaced. I want to replace it with a nicer 25.4 post, but can't find a shim that thin.
Any suggestions?
Any suggestions?
#2
Cantilever believer
That should be a good recycle assignment for an empty aluminum pop or beer can. Might take 1/2 to 1 full diameter wrap - as I recall, they're about 0.11 to 0.14 mm in thickness. I did something similar with my Raleigh Pro and it's been as solid as a unshimmed assembly.
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#4
Beat me to it. It also cuts easily with scissors without dulling them. I've used to shim the outside of a bushing for a better fit. Make the shim as long (deep) as you can, it will keep the seatpost straighter in the seat tube, plus you'll have enough for sufficient to stick out to grab with your finger and/or tape it to keep it from dropping into the seat tube when loosening the clamp.
Last edited by Duragrouch; 03-27-24 at 11:49 PM.
#5
My 2015-ish Raleigh Back Alley uses the most annoying seatpost size on the planet - 25.6. I've already replaced the stock seatpost with a cheap Sunlite post a few years back, but now it also needs to be replaced. I want to replace it with a nicer 25.4 post, but can't find a shim that thin.
#6
(above) Turning down a slightly larger seatpost: a) Only if taking off very little material, because otherwise it's a much thinner wall than designed, and b) that final turning cut on the lathe better be at very slow feed to have a really smooth finish; Any circumferential grooves will be fatigue crack initiation points when the tube is under bending load under rider weight.
#7
Droid on a mission
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My 2015-ish Raleigh Back Alley uses the most annoying seatpost size on the planet - 25.6. I've already replaced the stock seatpost with a cheap Sunlite post a few years back, but now it also needs to be replaced. I want to replace it with a nicer 25.4 post, but can't find a shim that thin.
Any suggestions?
Any suggestions?
I'm just curious why you are replacing seat posts. What is the issue why your seat post needs to be replaced?
I just googled the part and found these offerings in 25.6
https://www.modernbike.com/seatposts+diameteris25.6-
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p4432023.m570.l1313&_nkw=seat+post+25.6&_sacat=0
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JoeTBM (The Bike Man) - I'm a black & white type of guy, the only gray in my life is the hair on my head
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#8
Newbie
Thread Starter
I agree that 25.6 is not a common size but they are out there.
I'm just curious why you are replacing seat posts. What is the issue why your seat post needs to be replaced?
I just googled the part and found these offerings in 25.6
https://www.modernbike.com/seatposts+diameteris25.6-
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p4432023.m570.l1313&_nkw=seat+post+25.6&_sacat=0
I'm just curious why you are replacing seat posts. What is the issue why your seat post needs to be replaced?
I just googled the part and found these offerings in 25.6
https://www.modernbike.com/seatposts+diameteris25.6-
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p4432023.m570.l1313&_nkw=seat+post+25.6&_sacat=0
I'm considering a C19 Carved saddle and don't want to trust an expensive saddle (or my groin) to another cheap $20 seatpost. The Sunlite post you linked to is what I have now and the even cheaper Kalloy post doesn't inspire confidence. I also want 2-bolt adjustment, so I'm looking at the Thomson Elite.
#9
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The clamp is bent and corroded, as are the rails on my B17. So, I also have to replace the saddle, which I haven't been too happy with in the first place. I've been experiencing a lot of pain and discomfort. Recently, the nose on my saddle rocked up during one of my long commutes which made the problem even worse.
I'm considering a C19 Carved saddle and don't want to trust an expensive saddle (or my groin) to another cheap $20 seatpost. The Sunlite post you linked to is what I have now and the even cheaper Kalloy post doesn't inspire confidence. I also want 2-bolt adjustment, so I'm looking at the Thomson Elite.
I'm considering a C19 Carved saddle and don't want to trust an expensive saddle (or my groin) to another cheap $20 seatpost. The Sunlite post you linked to is what I have now and the even cheaper Kalloy post doesn't inspire confidence. I also want 2-bolt adjustment, so I'm looking at the Thomson Elite.
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JoeTBM (The Bike Man) - I'm a black & white type of guy, the only gray in my life is the hair on my head
www.TheBikeMenOfFlaglerCounty.com
JoeTBM (The Bike Man) - I'm a black & white type of guy, the only gray in my life is the hair on my head
www.TheBikeMenOfFlaglerCounty.com
#10
Senior Member
The clamp is bent and corroded, as are the rails on my B17. So, I also have to replace the saddle, which I haven't been too happy with in the first place. I've been experiencing a lot of pain and discomfort. Recently, the nose on my saddle rocked up during one of my long commutes which made the problem even worse.
I'm considering a C19 Carved saddle and don't want to trust an expensive saddle (or my groin) to another cheap $20 seatpost. The Sunlite post you linked to is what I have now and the even cheaper Kalloy post doesn't inspire confidence. I also want 2-bolt adjustment, so I'm looking at the Thomson Elite.
I'm considering a C19 Carved saddle and don't want to trust an expensive saddle (or my groin) to another cheap $20 seatpost. The Sunlite post you linked to is what I have now and the even cheaper Kalloy post doesn't inspire confidence. I also want 2-bolt adjustment, so I'm looking at the Thomson Elite.
#11
Francophile
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For a shim, I recommend a steel can rather than aluminum. I use them on old French bikes that seem to have a 25.5 mm seat tube. The cans to look for have a rim on the outside of the lid, which helps them stay in place at the top of the seat tube. I prefer the Old Fisherman brand of roasted eel (Love that stuff) but tuna cans also will work.
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