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32

tl;dr heating chromoly to brass-brazing temperature doesn't really change it, at all; the steel was born hot and heating it back up does nothing to it other than oxidizing the surface if you don't protect it with flux. For special proprietary exotic steel tubes heating them up may or may hurt or it may help; there is no rule. There is much wrong, and not-...


20

Don't use cable stops. The biggest load those stops will ever see is when you grab your brakes hard for an emergency stop. So you're likely to find out that whatever you did to bond the stops to the frame wasn't strong enough or fatigue-resistant enough at the absolute worst possible time. And you'll never be able to know if your work is fatigue-resistant ...


16

Beside a professionally done welding, clamp-on cable stops should be a reasonably reliable solution.


14

This is actually a matter of the force multiplication that each chainring provides, and the size/mass of each chainring. Force difference Let's propose, only for a moment that you had a chainring as big that the radius of it is almost the same as the crank length. If the rider stood to pedal while using that chainring (and using simple platform pedals). ...


14

You'll need to very carefully inspect the area around the boss that's been ripped out, as well as your usual second hand frame check. If the bike was ridden after the damage cracks could easily have spread and you might be well on the way to a two piece seat tube. This groove could be the start of a problem, but it's probably just a scar from where the cage ...


13

To identify a frame firstly see if a magnet sticks, if it does it's steel, if not it's carbon, aluminium alloy or titanium alloy. If not steel look down the seat tube if it's metallic inside it could be aliminium or titanium if black and plastic looking, carbon. Tap the frame with a screw driver, aluminium and titanium will have a definite metallic 'tink' ...


13

I have 4 bikes, and the one I keep for just riding around a city is high-ten steel. Yes, they're heavy, and normally cheap, but they can be tough and practical. What's more important is that it works for you - that it's the right size and convenient.


11

I'm answering my own question because I took a combination of the steps above, plus some other steps. I took steps to make getting it back in event of theft more likely: registered the bike with the Chicago police: https://portal.chicagopolice.org/portal/page/portal/ClearPath/Online%20Services/Bike%20Registration I plan to register it with https://www....


11

I've worked on a couple bikes that have had frontal impacts. Check the underside of the downtube for any abrasions or rubber marks. You might find the front tyre has touched the downtube in the collision, giving you an idea of how far it bent and has come back. Theres a fold in the downtube and I can see a completely broken top tube, so That frame is ...


10

My best guess is that you have a frame made of Gilco Design Columbus tubing used on Italian bikes in the 80s. I could find no mention of Oberriet bike brand anywhere. Maybe a small custom frame builder that didn't get much (any?) coverage. This frame tubing looks a lot like yours In researching Colnago came up often as a bike maker that used shaped tubing. ...


9

Buying parts alone is sadly a rather expensive way to get a bike and I doubt anyone would be able to tell you if it's worth it to you. That said, I'd be very tempted. I like old bikes and it's better they get rebuilt and used than end up in landfill. You should spec up the components you want/need and compare the price with a new one of similar quality and ...


9

Get in touch with Surly even if it out of warranty. The worst they can do is say no, and even if they won't fix it, they should be able to offer advise on the the best way to proceed. They live or die based on peoples perception of the brand, so have a vested interest in helping you resolve this kind of problem. Any competent engineering shop should be ...


9

If it were mine I wouldn't ride. It appears there is a crack connecting the two holes. This would indicate there has been enough flex to cause the frame to crack.


8

As a cyclist who had a hard time getting comfortable on road geometry with drop handlebars, I will recommend that you ride as many different bikes as possible for a long time before you consider dropping money on a "custom" bike. Considering frame material and construction, geometry quirks, wheel sizes, brake types, drivetrain compatibility, tire clearance, ...


8

Others have answered the second part "what are the differences..." Here's an answer for the first part "why not many at the dump" In in my city 2015 light grade clean steel is worth $0.02/kg. Aluminium extrusion is worth $1.83/kg. Brass like nipples is $3-$4/kg and stainless steel is about $0.90/kg. Recycling metal pays money, but I'm not going to ...


8

High tensile or 'hi-ten' steel is the lowest end material used for inexpensive bikes. The next level up is so called 'cro-moly' steel (alloys using chromium and molybdenum). High tensile steel frames are relatively heavy because the steel is relatively weak necessitating thicker wall tubes be used. A steel frame is also more susceptible to corrosion, but ...


7

Depending on what you consider a "major brand", there really are a lot of nice steel bikes around these days. If I were going this route, I'd look to some of the brands that focus on the steel frames, rather than complete bikes. The list below should get you started. While they aren't the biggest names in the industry, they do have good distribution so ...


7

All steel frames of any age get a few dings from serious use. The failure point for steel frames is usually the highest stress points: the joins. That is why we used to have fancy tubing sets likes Reynolds 351 double butted, and I notice that your frame does too. So, if the dent is away from the joins I say the frame is ok for general use. Steel is quite ...


7

It's hard to tell from the photo ( is that large vertical streak said crack? ), but if your frame is cracked, don't use it. Riding on a cracked frame is risky as it could result in a catastrophic failure / injury / death. It looks like that's probably a steel frame, so find a local frame builder ( not your buddy who's handy with a welder ), and depending on ...


7

I am going to get beat up for this but steel frames don't fail catastrophically. Pull that post. If the end of the post is in the middle of the crack then look for a longer post. Get a seat post that extends at least 2" below the bottom of the crack and ideally 4". The post reinforces the frame. Mark the two ends of the crack. If the crack grows ...


7

Answer: Its not worth doing, from a financial stand point. Adding disk brakes to a frame is expensive, risky, and ruins any vintage value the frame had. The stays are not engineered or designed for the new sideways loading. Also, you talk about stays, but braking on the rear wheel is nowhere near as good as braking on the front. If you're dead-keen ...


7

Just getting it welded by a non-framebuilder could have a couple caveats: I think most framebuilders would approach this in a way where they get full access to the broken face of the dropout, so they could work it down smooth, and then replace either all or part of the chainstay, the goal being to re-do the miter between the chainstay and the dropout to get ...


7

The dimpled chainstay may have less stiffness in certain directions at that point, but if forces are not concentrated there, or in the direction of less stiffness it just doesn't matter. A u-shaped beam (which is what the heavily dimpled tube essentially is) has less resistance to twisting forces than a tube, but there isn't any significant twisting forces ...


6

If you're talking about the crack running from the opening down into the fillet, that doesn't appear to be likely to seriously affect integrity (though I'm sure there are some here who will disagree). The lug in that area is reenforced by the steering tube, so there's very little stress at that point. (In fact the crack may have been there since ...


6

The problem I had was getting the ammonia to the corrosion. I hung the bike upside down by both tires so the seat post was vertical. You can either remove the bottom bracket or as I did the bottle cage screw and fill the seat post with straight ammonia. If possible plug the hole so the ammonia doesn't evaporate. I let it hang for 2 days. I then laid the bike ...


6

Good question! There are a couple important reasons for the differing materials: Wear: Steel lasts longer than aluminum, plain and simple. So why not use steel on all the rings? The larger rings have ramps on the sides that facilitate shifting and cannot be flipped as the ring wears. The granny ring can, therefore it can last a lot longer. Flexion/Bending: ...


6

Presumably you're talking about a Profile or one of the other BMX hubs with ti hop-up bolts available. Yes, there is no issue. Were a bolt loose and able to rub dynamically against the frame, they could in theory chew it up because they'll probably be way harder. But if you're riding around with loose axle bolts you'll have other much more imminent problems.


6

The quick answer is NO, you can't bend back the fork. Or at least not at a reasonable price. Your bike looks right knackered. You could maybe find a used fork off a donor bike for free or cheap at a bike coop - but you might put said fork on and find your frame is bent. I'd say your bike is what we kindly refer to as a said "donor bike." It's brain dead ...


6

I expected the question to be about bent legs/tines on the fork. That is a bent steerer tube on the fork, which means it was one/both of one heck of an impact exacerbating an existing weakness in the fork. Impact Did your front wheel get bent? The one in the photos looks fine, so if that's the one then your fork was weak and took all the force. I'd have ...


6

Any amount of rust is removable by sandblasting or chemical means. That's not the problem here though, the real concern is how much frame material have you got left after the rust is removed. The top tube walls may be too thin for the frame to have structural integrity. Remember the steel may be rusted on the inside too, and there may be rust 'pits' that go ...


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