About twenty years ago I bought a bike from a friend of my brother’s. He was trying to get a custom frame shop off the ground and he built me two frames from Columbus El\/OS steel. <\/p>\n
Great bikes. Many fun miles. <\/p>\n
I realized that my seat was not moving up and down as well as it should this weekend. I also realized that I hadn’t greased the seatpost in too many years. <\/p>\n
Pulling it out was difficult. Really difficult. Really difficult. <\/p>\n
Here’s the rub. I have a Thompson seat post (SP-E124) 28.6mm x 410mm, model number 12263. <\/p>\n
The seat tube opening, no compression, is at 30.25mm. (The clamp ring is welded onto the frame.) <\/p>\n
Problems: The current shim has walls that are 1.3mm thick, which I think is the major problem. If the post is 28.6 and the shim adds 2.6mm, I’m at 31.2mm. No wonder it’s tough to get in and out. I need a thinner shim, one that takes me from 28.6mm to 30.25mm; basically one that adds 1.6mm to the post. <\/p>\n Looking at various bike supply sites, a post at 28.6mm seems to have gone out of style (they’re not made any more), so it doesn’t seem as though I can buy a ready made product. I’d also note that Thompson seems to be pretty clear that they don’t recommend using a shim with their posts but that ship has sailed. <\/p>\n Question: what would be the problem with buying this product<\/a>? It would get me really close to the right width (30mm). Would it be wide enough? Would clamping make up the difference? Would it rattle in the frame? <\/p>\n I realize I’m trying to solve a problem created within the design. But I really just want to ride my bike without worry. <\/p>\n","protected":false},"excerpt":{"rendered":" About twenty years ago I bought a bike from a friend of my brother’s. He was trying to get a custom frame shop off the ground and he built me two frames from Columbus El\/OS steel. Great bikes. Many fun miles. I realized that my seat was not moving up and down as well as … Continue reading Seat post blues<\/span>
\nThe current shim is 50mm long. From what I’ve read, you want the shim to extend past the joint of the seat tube and the downtube. This isn’t even close. I need a longer shim, say 100mm.<\/em> <\/p>\n