I need a miche supertype seat post for my fixed conversion. The problem is that my frame only accepts 26.4 mm seat posts and every supertype I've ever seen is 27.2 mm.

According to miche.it it's available from 24.8 mm to 27.2 mm. This kinda implies that there are more sizes available in between 24.8 and 27.2. If not I'd settle for 24.8 and some shims.

Could someone please help me find a small enough supertype? I've emailed miche several times but they won't respond. I've mailed lots of stores but noone can help me.

In the US, they're only available in 27.2. Maybe check some international sites.

damn! i have a brand new miche super type black f/s 27.2

You could always just ream out your seat tube to accept the extra 0.8mm. Any reputable shop should be able to do it in a matter of minutes.

what? 0.4mm of wall thickness seems like an awful lot to be removing. eg: reynolds 853 *is* 0.4mm thick (presumably not at the butts)! how much thicker is aluminum?

it's one thing to flex-hone the tube, but you'd need a machine shop to take out 0.4mm and a cut that drastic would have to compromise the strength of the tube.

this sounds like really bad advice to me.

+1 . Please don't do it, but if you do, be sure to post the photos of the results .

good lord!

I consider my shop reputable, but I have a feeling it would take us more than a few minutes to do that, if we even have the tools (which I doubt).

If your shop doesn't have a hand expansion reamer, maybe you should get one? As far as how much time it might take, reaming a seat tube is significantly less work than cutting a crown race.

Heh.

Yes less time right before you ownt the frame.

my first thought was, "expansion? ok, maybe he's talking about stretching the tube, not machining." not that this is obviously preferable, or even possible...but then i googled to find out what exactly those fancy words meant:

"Expansion reamers are used in high-production runs in abrasive materials. An adjusting screw expands the reamer diameter so shops can regrind it to original dimension and re-sharpen it to prevent rapid loss of size or finish. Expansion reamers should not be considered as adjustable for producing holes of different sizes."
https://www.cutting-tool.americanmach...bdeee16_1.aspx

apparently, expansion reaming is still cutting? so my second thought is, "nope...still bad advice."

damn dogg jsut drill speed holes in a regular post

You may want to consider getting a frame that doesn't have a lame seattube size.

OK... here is what you do....

1-get a dowel the same diameter as the inside diameter of the smallest post you can find.
2-drill a small hole 1/4 inch from the bottom of the post all the way through both walls of the post (these
will be way down in the seat tube when installed)
3-mill down end of the dowel to something that will fit in the chuck of a drill press.. most likely 1/2"
4-insert fat part of dowel into bottom of seat post, and put two screws into the holes you drilled. (predrill
first)
5-chuck it up and set the drill press to a vert low speed (or you will die) and apply a file or sand paper to it while spinning, check with calipers occasionally.
6-when you get close step down on sand paper till you get to about 1000, and it will look good.

trick is to ever so slightly taper it in at the top, or you could create a small step.

good luck, BWAHAHAHAHA.



remember SLOW SPEED.

nobody needs a supertype for a conversion, period

Sorry, I missed this post earlier...

Let's assume the OP is converting a frame w/ a 28.6mm ST. Let's, for the sake of argument, assume that it's made out of SL (which it probably isn't - it's probably made out of something cheaper, thicker and heavier). I've seen and touched SL STs with a bunch of different internal diameters - 26.8, 27.0. 27.2, etc. So, if the outside diameter of these various STs remains constant at 28.6, but the internal diameter varies, that would mean that there's a difference in wall thicknesses even within one tubing type. If one SL ST is safe at 27.2, why wouldn't another be safe at 27.2? Either way, it's still .8mm of material at the top end.

When you're building a steel bike, you ream out the seat tube as one of the finishing steps to account for distortion from the heat, etc. Scary it may seem, it's not rocket science and is no more likely to make your bike explode into a pile of firey slag than drilling out your track fork. It's just part of the process of building the bike.

As far as 853 goes, show me a frame made of 853 that takes a 26.0 seat post. Ain't gonna happen.

damn straight! it's criminal!....

Nice Regal. I've been looking for a perforated Regal (or Rolls) for about a year. Do you have a source for parts like that?

i think i got the regal from repartocorse.com, but i haven't seen any perf. white ones in awhile. actually i kinda wish i had gotten the smooth white one, the perforations get grimy and are hard to get clean.

You know how to say the right thing. I now feel much better about the white Regal Ti I just had my shop order.