Of clamp on cages & seatpost sizing: an inquiry in 2 movements
06-21-20, 05:52 PM
#1
bill nyecycles
Thread Starter
Of clamp on cages & seatpost sizing: an inquiry in 2 movements
This is a two part inquiry.
Part I: Clamp on bottle cages
--My Raleigh has no bosses for cages, so I've clamped on 2 cages to the frame. My question is do any of you also wrap the frame with something to keep the clamps from scratching the paint or digging into the tubing to damage it? I've currently got electrical tape around the clamp spots and along the bottom of the tabs on the bottle cages. Anyone else do this? The first pic is my permanent cage mounted to the seat tube. The 2nd pic was a temp one I put on for a longer ride so I didn't have time to wrap around the downtube under the clamps.
Part II: Seatpost sizing
--I currently have a 25.8 seatpost in the same bike above. I'm fairly certain that's what I took out of it 6 years ago when I rebuilt it but I can't remember for sure. Does the seatpost clamp/collar area look too overly tightened to you? After doing some research and watching some videos I feel like it might be, and the required seatpost size is larger than 25.8. A '84/'85 Raleigh Sportif is conspicuously missing from Sheldon Brown's seatpost size encyclopedia so I couldn't find any help.
I'm going through this exercise because I'd like to upgrade from the standard kalloy post in there now, but there are basically zero 25.8 besides the one I have, but there are many more options with larger sizes like 26.8 for a Thomson Elite, or something else. Anyway, just curious what y'all think. Pics below.
Part I: Clamp on bottle cages
--My Raleigh has no bosses for cages, so I've clamped on 2 cages to the frame. My question is do any of you also wrap the frame with something to keep the clamps from scratching the paint or digging into the tubing to damage it? I've currently got electrical tape around the clamp spots and along the bottom of the tabs on the bottle cages. Anyone else do this? The first pic is my permanent cage mounted to the seat tube. The 2nd pic was a temp one I put on for a longer ride so I didn't have time to wrap around the downtube under the clamps.
Part II: Seatpost sizing
--I currently have a 25.8 seatpost in the same bike above. I'm fairly certain that's what I took out of it 6 years ago when I rebuilt it but I can't remember for sure. Does the seatpost clamp/collar area look too overly tightened to you? After doing some research and watching some videos I feel like it might be, and the required seatpost size is larger than 25.8. A '84/'85 Raleigh Sportif is conspicuously missing from Sheldon Brown's seatpost size encyclopedia so I couldn't find any help.
I'm going through this exercise because I'd like to upgrade from the standard kalloy post in there now, but there are basically zero 25.8 besides the one I have, but there are many more options with larger sizes like 26.8 for a Thomson Elite, or something else. Anyway, just curious what y'all think. Pics below.
06-21-20, 06:15 PM
#2
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1: The problem with electrical tape is that its adhesive tends to creep and bleed out; I would use inner tube rubber or self-fusing silicone tape instead. Here are some other ideas: https://recklesscognition.wordpress....ws-and-bosses/
Adding Water Bottle Cages to Bicycles without Braze
2: I would try to find a shop with a seat post sizer to check the seat tube. Putting a 0.2mm larger post in might not work; the gap at the clamp would have to open up more than 0.6mm larger to fit a 26.0 post (pi x D) which is kind of a lot. Measure the gap as-is, loosen the bolt and remove the post and measure again to check approximately.
Adding Water Bottle Cages to Bicycles without Braze
2: I would try to find a shop with a seat post sizer to check the seat tube. Putting a 0.2mm larger post in might not work; the gap at the clamp would have to open up more than 0.6mm larger to fit a 26.0 post (pi x D) which is kind of a lot. Measure the gap as-is, loosen the bolt and remove the post and measure again to check approximately.
06-22-20, 08:30 AM
#3
bill nyecycles
Thread Starter
1: The problem with electrical tape is that its adhesive tends to creep and bleed out; I would use inner tube rubber or self-fusing silicone tape instead. Here are some other ideas: https://recklesscognition.wordpress....ws-and-bosses/
Adding Water Bottle Cages to Bicycles without Braze
Adding Water Bottle Cages to Bicycles without Braze
I don't care for any of the other frame mounts because they sit too high off the frame and look dumb.
06-22-20, 08:40 AM
#4
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Yeah I used to have the Tacx behind the saddle holder on it for the last 5 years but I wanted something different and got tired of constantly having to fight with it to get into my saddlebag.
I don't care for any of the other frame mounts because they sit too high off the frame and look dumb.
I don't care for any of the other frame mounts because they sit too high off the frame and look dumb.
One of the mounts in the article dsbrantjr linked to that you may have missed is the Elite VIP cage clamp. They are low mount and work surprisingly well. And they won’t scratch the paint.
As to the seatpost, the frame looks a bit deformed but I really doubt you’d be able to get a 26.0mm seatpost is there. I think your “26.8mm” was mistyped...at least I hope it was. Do you have a bike co-op in your area? Go get a used 26.0mm post and see if it fits. I found lots of 25.8mm posts on line...even a two bolt Origin 8 like the Thomson.
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Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Last edited by cyccommute; 06-22-20 at 08:51 AM.
06-22-20, 12:34 PM
#5
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If I was going to use strap clamps to secure a bottle cage or cages to a frame, I'd coat the inner surface of the strap (the section that'll touch the frame) with a cleaar silicone. That'd stop slippage and it'd look good too.
Cheers
Cheers
06-22-20, 01:27 PM
#6
bill nyecycles
Thread Starter
I agree with dsbrantjr that electrical tape is a mess. I use vinyl fusion tape (aka Tommy tape) wherever electrical tape is usually used. It leaves no residue and doesn’t even use adhesive.
As to the seatpost, the frame looks a bit deformed but I really doubt you’d be able to get a 26.0mm seatpost is there. I think your “26.8mm” was mistyped...at least I hope it was. Do you have a bike co-op in your area? Go get a used 26.0mm post and see if it fits. I found lots of 25.8mm posts on line...even a two bolt Origin 8 like the Thomson.
As to the seatpost, the frame looks a bit deformed but I really doubt you’d be able to get a 26.0mm seatpost is there. I think your “26.8mm” was mistyped...at least I hope it was. Do you have a bike co-op in your area? Go get a used 26.0mm post and see if it fits. I found lots of 25.8mm posts on line...even a two bolt Origin 8 like the Thomson.
As for the seatpost - Thomson makes a 25.4 sized one, which I saw prior to making my original post, but shims for 25.4 to 25.8 do not exist which makes sense because they'd be paper thin. All I could find really were shims to make 27.2 size.
The collar can be spread wider than what it actually should be - I guess what I really need is the measurement of the inside of the seat tube. But that's kinda hard lol.
Also, that Origin8 post is sold out and I'm not sure they're making all those sizes anymore. Even on the O8 website when you click the post it comes up as a missing page.
Last edited by the sci guy; 06-22-20 at 01:31 PM.
06-22-20, 02:30 PM
#7
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I'll have to check out that tape, thanks.
As for the seatpost - Thomson makes a 25.4 sized one, which I saw prior to making my original post, but shims for 25.4 to 25.8 do not exist which makes sense because they'd be paper thin. All I could find really were shims to make 27.2 size.
The collar can be spread wider than what it actually should be - I guess what I really need is the measurement of the inside of the seat tube. But that's kinda hard lol.
Also, that Origin8 post is sold out and I'm not sure they're making all those sizes anymore. Even on the O8 website when you click the post it comes up as a missing page.
As for the seatpost - Thomson makes a 25.4 sized one, which I saw prior to making my original post, but shims for 25.4 to 25.8 do not exist which makes sense because they'd be paper thin. All I could find really were shims to make 27.2 size.
The collar can be spread wider than what it actually should be - I guess what I really need is the measurement of the inside of the seat tube. But that's kinda hard lol.
Also, that Origin8 post is sold out and I'm not sure they're making all those sizes anymore. Even on the O8 website when you click the post it comes up as a missing page.
You could also measure it. Caliper measurement is questionable and Steins are far too expensive for home needs but the IceToolz Pupa works well enough without breaking the bank.
__________________
Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
06-22-20, 02:45 PM
#8
If the bike is not valuable, and you're up for a bit a frame molestation, go the riv-nut route. I installed riv-nuts on my gas pipe Schwinn about 10 years ago and there have been no problems.
