Мелкие технические вопросы (с)

да

спасибо

покупал головку накидную по внешнему диаметру подшипника и бил через нее всегда.

промы не очень любят пиковые боковые нагрузки

если бить по внешней обойме то там не будет нагрузки на шарики

карбо подседел застрял в карбораме
как вытаскивать его правильно?

Suggestions for carbon fiber frames and seatposts by Witold Walkwski, with interpolated comments by John Allen.

I bought recently a used Kuota Kalibur carbon frame with carbon post. The post got stuck in the frame while being shipped by Fedex. Both the post and seat tube are not round but with a drop shape profile so you cannot even turn it. I tried to lubricate the post with soapy water and with oil. [Bad idea: oil expands the resin binder of the composite material and can deteriorate it.] I installed a piece of steel rod in the seat rail clamp, inverted the bike, stood over the inverted bike, stepped on the bar with both feet and pulled on the frame with all the force I had. Nothing happened. Tried to warm up the frame by friction (rubbing with clean soft cloth). Wiggled the post. Not even a sign of improvement. Then I have studied all the posts on the web in this matter. Tried the same exercises again, with zero results, except some pain in my back. Then I confronted the situation, that the only option left would be to cut out the post with a long straight blade which is absolutely crazy and risky on the carbon frame.

Then I stepped back to my engineering thinking (for last 20 years I design and build special prototype machinery). First I checked on the heating / cooling options and found that the thermal expansion of carbon epoxy composites is only 0.000001/F which makes it one of the materials with absolutely best thermal stability - forget about heating or cooling carbon - it will not help and may only damage the frame.

Then I started to analyze the physics of pulling one composite tube out of another. I was sure it was not glued together, as the frame is old enough to be perfectly cured and the tube was there only for a few weeks. It was only held there by friction. It was not inserted with a lot of force so it must have created some mechanism that locks the pieces together. My further conclusion was that if you pull on the frame trying to pull out the post you are causing the seat tube to elongate, which in turn reduces its diameter and causes even tighter clamping on the post. The more force you apply pulling on the seat tube, the It is exactly what happens when you put one piece of plastic tubing in another piece of tubing and then try to pull it out. [like a Chinese finger puzzle -- John Allen]

The best way to do it is not pulling on the outer tubing, but pushing the big tubing off the small tubing, just pressing on the edge of the outer tube while pulling on the end of the inner tube. Now I knew I would be able to do it. I only needed some way to apply reasonably large force just on the top edge of the seat tube. I took two aluminum plates that just fitted nicely between the seat rail clamp plate and the top of the seat tube (one plate on one side of the seat post and the other on the opposite), with the seat rail clamp screws extended by a few turns. Then I gently turned the rail clamp screws in and the seat post just came out without any struggle I did not apply any more force then, just slight finger pressure on the Allen key while turning the screws. I am sure that a similar method may be used on metal frames and seat posts or any combination of the material. You just need the right length of spacer blocks or some kind of screw attachment to do the pushing off the seat tube from the seat post.

У пацана була дорога новенька карбонова рама і навіть не круглий, а каплевидний підсиділ, що застряг в ній під час перевезення. Він довго думав, і придумав, що треба прикладати силу не до підсиділа на пряму (тягнути вгору), а до верхнього краю підсидільної труби (до рами - "витягувати з рами"). Для цього він взяв алюмінієві пластини, одним боком впер в раму, іншим - до болта підсиділа. Тут він не вказує прямо, але очевидно що він просто за принципом П-подібного профіля зробив собі таку "підставку" вздовж підсиділа, до якої приклав силу болта (без сідла почав закручувати - болт почав тиснути на "П"-подібну підставку) і це легко витягнуло підсиділ. Візуально можу намалювати, але кажись ясна ідея.