My LBS measured the inside of my seat tube at 21.6mm. They didn't have anything to measure standard. So, that comes out to 0.86 of an inch. Anyone know what size that is in standard speak? Anything I do will be just guessing.
measurement gurus, need help
- Thread starter CRASH
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close to 7/8",prolly a 13/16. Idont have my machinists rule on me...
it's .85 inches. I'm doing the calculations now.
Ok, that's 17/20ths. I haven't used any math in years. This may take awhile but we'll get there.
Ok, that's 17/20ths. I haven't used any math in years. This may take awhile but we'll get there.
Shouldn't the outside diameter be the one that gets measured?
0.850393 = 7/8"... good enough for the girls we dance with
http://www2.whidbey.net/ohmsmath/webwor ... in2fr.html
http://www2.whidbey.net/ohmsmath/webwor ... in2fr.html
Yes, the seat tube is what was measured. The seat post that came with it was too small, having electrical tape to shim it. I'd like to get a custom laid back post made, but need to know what to ask for.
So.. 7/8" should do the trick? That would make sense since I believe that 7/8" inch is the standard size of most seat clamps on the seat.
So.. 7/8" should do the trick? That would make sense since I believe that 7/8" inch is the standard size of most seat clamps on the seat.
Ok, I threw away the calculator. What kind of bike is it?
if the seat tube Inner Diameter was .86 and it had a post that was too small, the top of the seat tube where the clamp is may have gotten crushed a bit. There is usually a vertical slot cut in the seat tube to allow it to compress around the seatpost so it may need to be opened back up a bit and it sounds like its most likely a 7/8 (.875) post which is very common.
I'm told a Monark. I'm guessing a Pilot. 20". I ordered a cheap 7/8" foot long post. We'll see how that fits.Wildcat said:
Hold the phone, some of these old Monarks and I think a Rollfast I have that are late 40s IIRC(I'll check later) actually had 27/32" seatposts works out to 0.84 and change. Forcing a 7/8" down the seat tube may cause damage. Found one on ebay, but might be better to try shimming a 13/16" which are easier to come by.
Just remembered I sold that Rollfast but it was the one. Might try looking on the Cabe also.
Just remembered I sold that Rollfast but it was the one. Might try looking on the Cabe also.
If that is the case I have used sections of an aluminum can as a shim. Cut a strip of aluminum and roll it around the post until its snug (scissors work for this). Be careful of the edges, they will be very sharp, you can sand them to reduce risk of injury.
There's also a Wald shim made for 13/16" seatpost -> 7/8" seat tube that might work(#905?) which is nice cuz there's a lip to it. It'll be really close though fits semi loose in that configuration have no idea 13/16 -> 27/32. 0.875 vs 0.85, leave 0.3mm thickness to spare think I have one at home I can check.
Nothing I can with it right now. The frame went to a friend's house for some work while I'm out of state for a couple months at a school (gotta love the Navy).
I'll have that 7/8" post when I get home and get the bike back. If it doesn't smoothly go into the seat tube, I'll revisit this post. Hopefully it does.
I'll have that 7/8" post when I get home and get the bike back. If it doesn't smoothly go into the seat tube, I'll revisit this post. Hopefully it does.
