apg

Hi everyone.

I'm building up a Pinarello 1980s Amatore track bike as a track bike (as it's intended!). Some questions:

1) I'm having trouble getting the seat post in - I thought it was a 27.2mm post but it seems like it might be a 27mm or a 26.8mm. Any ideas people? Seems like I should be looking for 26.8mm according to one measurement I could find online.

2) The bike came with a Colnago fork with 170mm of steerer. When I tried to use it with a Dura Ace headset. it was slightly (10mm or so) short. Any ideas of if I could use a bit of locktight on it instead of using a locknut instead until I find a new fork? I know it's not a great idea, but is it suicide?

Thanks!

FBinNY 

I don't know the seatpost size for your frame. If it was built with Columbus tubing there's a good chance it wants a 26.8, but that's no assured (depends on the specific tubeset). If my memory serves, no Columbus tubeset uses a 27.0 post (don't hold me to that).

If you want to measure, measure the slot top and bottom and use the binder bolt to bet those dimensions to match, so the top is at the diameter before the slot was cut. Then measure in two directions at right angles and average the readings. That'll be about as close to spot on as you can get measuring from the top.

If the fork is 10mm short for a Dura Ace headset, you definitely need a new fork. You can use the locktite for a while as long as there's some upside room for the top race to loosen before falling off. If it were me, I'd want the fork to fully engage the top cup and hopefully extend a bit beyond. Though being short a thread or so wouldn't be a deal breaker. Besides the Locktite to try to hold adjustment, make a backup plan by putting a hose clamp or collar on the stem, pushed down against the headset so it has little or no room to turn and move up.

Loose headsets aren't a real issue. Some decent percentage of bikes out there have them. However be warned that a loose headset can make a high end bike very skittish at high speed, so stay attuned to how you're riding it. The hose clamp on the stem, will ensure that you won't have anything worse than a loose headset to deal with.

HillRider

Since Shimano never made threadless headsets and you refer to a locknut, I assume your Dura Ace is 1" and threaded. How can you even get the top race to thread on if the steerer is 10 mm too short (and I certainly wouldn't call 10 mm "slightly short")?

JohnDThompson 

How much stack is available with your fork? Measure the length of the steer tube, from the crown race seat to the top of the threads, and subtract the length of the head tube from the bottom edge of the lower jug to the top edge of the upper lug. That difference is the maximum stack height available. If it's less than about 30mm, you will not likely find a headset that will work with your fork, and will have to replace the fork with one that has a longer steer tube.

Andrew R Stewart 

The questions have easy first choice answers. Get the frame and tester posts in the same room and test slide the post till the correct fit shows it's self. The easiest way for this to happen is take the frame to a better shop. And BTW buy the correct size post from the shop as the payment for their help. Get a properly sized fork. Andy.

alcjphil

Older track frames are often built with Colunbus SP or SPX tubing for extra stiffness. My touring bike is built with SPX tubing and requires a 26.8mm seatpost

apg

Thanks all. I am looking for an imperfect solution so I'm going to try loctite and a clamp. I'll look for a better seatpost in the time following. It is a threaded 1". Fingers crossed...! Thanks for all you help on here.

fietsbob

mid 70's I built a frame out of Columbus Aelle, it is a straight gage tube set 1.125" seat & down tubes 1" top, my seat post is a 26.8.

Butted seat tubes are thicker on one end , thinner on the other.. then you get the 27.2 post specs..

Amatore, (amateur) suggests it may use the straight gage tubeset, as well .

apg

It's 26.8mm for sure. Got a nice Ritchey Nitto that fits well.

apg

Ended up finding a perfect Kinfolk fork - one of the last to be make by Kasuka, which has given the bike perfect geometry. It's sick. I'll sell the Colnago fork on ebay.