Tight seat post on ti frame

[TBLS]

Working on refinishing my litespeed classic ti frame. Seat post has always fit tight but can work it in by rotating back and forth.

Tried other 27.2 seat posts (Thompson and Carbon Easton) and they fit just as tight as the American Classic I was using. 26.8 seat post slide in easily and is loose. 27.2 is correct size per litespeed catalog

Frame has the braze on for binder bolt

Any idea if can be modified so easier to insert seatpost? Cost?

I can live with but am thinking about selling and not comfortable selling as is

Thanks

[tuscanyswe]

You can take it to a shop and have them use a reamer.

[palincss]

Wouldn't it be easier to slightly reduce the diameter of the seat post?

[buldogge]

Get out the ball hone...work slowly...re-check often.

-Mark in St. Louis

[oldpotatoe]

You can take it to a shop and have them use a reamer.

Reamer too gross for what the gent needs. Flex hone, a new one, drill and patience.

[tuscanyswe]

Reamer too gross for what the gent needs. Flex hone, a new one, drill and patience.

I stand corrected

[weaponsgrade]

I think the same sized seatposts, but from different manufacturers have slight variations in their actual diameters. I originally had a Campy carbon post on my Kirk. It fit, but the fit was really tight. I mentioned this Dave and I think he said Campy posts tend to run large, Shimano small, and Fiziks in between. Eventually I got a Fizik and it went in a lot easier.

[RMcRee]

I have the same frame but the opposite problem, the fit is a bit loose.

You could try sanding the inside using a smaller post and some emery paper--320 grit--after first making sure the inside is completely clean.

Of course, make sure that the binder bolt is actually working properly, is there a good one-eighth inch clearance at the seat-tube cutout when the bolt is loose?

Where does the seat post start binding--how far in does it go easily?

Randy

[Yossarian]

TBLS, if you don't know what a "flex hone" is I did a quick search and found these at Harbor Freight, http://www.harborfreight.com/catalogsearch/result?q=brake+hone

The ball type of flex hone I did find on Amazon and uses many small stone balls attached at the end of flexible wire to get the same job done.

What happens is where the top tube and seat tube are welded to the seat tube the frame may acquire some minor distortion. As stated be slow and patient, using oil as a lubricant, with the hone. You cannot undo it if you over-hone the tube, but very unlikely with a Ti frame. BTW, this is not uncommon, good luck.

Just thought of this before I hit submit, does your frame have the aluminum sleeve in the seat tube? If so, be very slow and patient!

[Tony]

I think the same sized seatposts, but from different manufacturers have slight variations in their actual diameters. I originally had a Campy carbon post on my Kirk. It fit, but the fit was really tight. I mentioned this Dave and I think he said Campy posts tend to run large, Shimano small, and Fiziks in between. Eventually I got a Fizik and it went in a lot easier.

This.

I've noticed the same, variations in diameters with the many different 27.2 seat posts I've used on the same bike.

[staggerwing]

FWIW, used properly, a hone will only erase isolated high spots or projections, which hopefully is all that is required. Use with plenty of lightweight oil lubricant.

[johnniecakes]

I want to get a ball hone to clean up a few seat tubes. They are all 27.2 dia so is the 29mm the correct size or should I go one size bigger? I see several different grits, which one should I order?

Thanks for the help!!

[11.4]

First, if you're determined to do it, do it with a flex hone. And preferably have a frame builder do it.

But I recommend against it. Some frames are finished to exactly 27.2, and they require a slightly undersized 27.2 post (like a 27.17). Others are finished slightly oversized so they are 27.23 or so and fit a precise 27.2 seat post. If you get a true 27.2 frame and a true 27.2 post, or anything close, it gives problems. If you flex hone it out, it'll be loose for some seat posts but will fit your post properly.

Thomson used to make their seat posts undersized so they fit a seat tube smoothly, but they got a reputation for having loose posts. As a result, a couple years ago they started making their posts precisely on dimension, which meant the builders were expected to go slightly oversize. Now you have a few thousandths' that makes your post too tight or too loose. It's not enough to make the next 0.2 mm jump in seat post size work properly. You really have to try different posts with a vernier caliper until you know you have something slightly smaller than what you have now. Do be sure that your post is round -- if it's ovalized at all it isn't going to fit right. But a 27.2 post and a 27.2 frame don't work together -- somebody has to give. And one who buys a frame has to find the post that fits. That's all there is to it. Tolerances are pretty tight these days and that's the only viable solution. Sanding down a seat post makes it look like a mess and ruins the post for anything else. Honing the frame makes it an odd size and makes other seat posts loose in the frame. So just find the combination that works. There are lots of really good seat posts out there now, so just get a good one that fits. Sorry about that.

[parco]

Has the OP measured the inside diameter of the seat tube and the OD of the seat post yet? I'd want to know those dimensions before I modified anything.

[bicycletricycle]

flex hone in a drill will do it.