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0

It is a very minor dent but horizontal mid tube is not a good spot. Creasing a tube does reduce the strength. A hard landing or hard bump is where that would likely be the first point of failure. Even if that section has lost 50% strength it would take a lot for the bike to fail. The rest of the frame is there and even 50% strength on that section is a lot ...


1

Beyond rebuilding the frame with a tapered headset, not practical. Effectively you need to fit an 1.5" OD tube into a 1.125" ID hole. This could theoretically be done by using a spacer and locating the taper part of the steerer under the frame. The effect would be raise the headset height and change the bikes geometry. The advantages of the tapered ...


0

I'd say that's fine to ride. Seems like got created by applying distributed pressure over a pretty big area. Therefore no chipped paint etc. Even if that cracks apart, I wouldn't expect the entire bike to fall apart immediately, you still have the lower tube supporting stuff together:)


1

Just off the picture I'd say it's fine. Aluminum is more durable than many people think (you know they build airplanes out of the stuff?!) That said, I would carefully look at the areas where the tubes are welded together. Use a bright light and look for any small, hairline cracks in the paint. Most of the aluminum bikes I've seen fail usually snap at the ...


-1

Don't ride that. Aluminum will randomly snap at the best of times, and a fold-looking bend like yours only makes it worse.


0

No. If nothing else you'd need to strip the frame to have it repainted after the guides are brazed into place.


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I start by breaking down the bike completely, brake components and all. I strip off all old paint and decals and sand the frame with 220 grit paper then smooth it over with steel wool. Clean the frame with engine de-greaser let sit for a day. Tape off all undesired openings: Head Tube Bottom Bracket seat post, and dropouts. I apply one thin coat of ...


0

I decided to punt and just have the bike shop grind down the nut. The head mechanic at the local shop sounds confident that he can grind down the nut to fit without over-heating it (and making it brittle etc.). I actually looked at another, older Bianchi frame I have and I see that the rear caliper nut has been ground down on that bike too! Perhaps this is ...


1

To shorten a bolt, get two nuts with the matching thread. Screw them onto the bolt and "lock" them together (tightened against each other) such that the nut surface farthest from the head lines up with the place where you want to cut. Place the bolt in a vice (taking care to not mash the threads) and use a fine-toothed hacksaw or other cutting device to ...


0

I believe you are taking about a bolt, rather than a nut ( nuts hold bolts onto things ). Anyway, you aren't going to damage the bolt if you file it down or cut it with a metal cutting saw, it's done all the time.


0

I can see why Chris King would talk down on integrated headsets about being a flawed design since they first came out into the BMX scene,what,12 or 13 years ago?His business was based on the old cup design!Integrated headsets not only eliminated 1 or 2 grams of weight,which is really nothing,but also simplified assembly by a long shot.Who would still want to ...


2

The trend towards compact frames goes back to the early 90s and an Englishmen named Mike Burrows. Burrows helped design several time trial frames which featured a radically lowered (but not sloping) top tube and a very long seat post. During this time most time trial bikes had top tubes that sloped from the seat DOWN to the head tube (the opposite of what ...


5

I think my rough estimate would be 10 to 15%, although an argument might be made for less taking into account markup. Cannondale was one of the last big manufacturers to produce all their frames in the US. We carried them in a shop I worked at during the time they transitioned over. Basically, one year all their bikes were ten to fifteen percent more ...


2

Practically speaking? Assuming that the "virtual geometries of the bikes is similar (in other words if you measured the bikes as if there was a horizontal top tube), the big differences will have to do with fit. You have three choices: A standard frame with a horizontal top tube. A frame where the top tube hits that head tube at the same place a ...


1

Apparently Raleight Techniums are weird combination of aluminum and steel. Rear triangle of Techniums are steel (chro-moly, I'd wager) so they should be repairable. Looking at the pictures of Technium rear dropouts, they seem to be cast pieces that are brazed to the rear triangle. If the joint between the dropout and seat/chain stay is broken, then the fix ...


0

The only Fort frames I've seen have been their cyclocross bikes and all of those were aluminum. Assuming we're talking about the same Czech made Fort frames then your only option is a new frame. Aluminum is effectively not repairable the way titanium, steel or carbon are. Depending on the age of the frame you might be able to get it replaced by the importer ...


1

Well, it depends… Would you be happier cleaning a bunch of stuff out and getting a shiny new bike that reflects all you've learned? One that will "just work," or Would it be a fun project to build up a bike from scratch? Would it feel good to know that you'd "built it yourself?" Do you have the time for the project? Is it ok with you to get stuck and make ...


0

The notion that stiffness equals greater performance is more true in the lab than on the road. Sean Kelly won hundreds of races - often in sprints - throughout the 80s and he won most of those on a Vitus 979 aluminum bike that was probably the most flexible bike used in professional racing in the past 50 years. It's pretty unlikely you'll notice much ...


1

I've seen three bicycles with what appear to be stress fractures at the bottom of the seat tube and top of the bottom bracket shell. A bike nut friend with more metallurgical knowledge than me tells me that this is caused by work hardening -- which is the same thing that causes a paper clip to become brittle after repeated flexing. Now that this has ...


1

As with motoring, you can use stiffer engine mounts so as to help transfer more power from the engine to the wheels. However, I'm told that it can make for a hideous ride quality in the vehicle. Now Imagine that on an ultra stiff road bike. Great on silky, smooth, new tarmac - but in the real world, wincing on every little bump in the road will affect ...


1

Having spent years figuring out that I was riding bikes too big for me, I'd have to agree with commenters above about the frame size. A crappy bike that's the right size, or even a little too small, is way easier and more fun to ride than a sweet bike that's too big. Also, in my town -- Vancouver, BC -- that's already a commuting bike. Different handlebars ...


1

Because of the era of production, the length of the bike is actually fine, and it's just the hight that is off. Where is the problem then? Saddle too high even when lowered as far as possible? The wheel size is completly irrelevant for that problem. Or are you unable to stand on the ground without your privates hitting the top tube?



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