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13

I personally wouldn't ride this frame. The degree of localized distortion means the steel will be work-hardened at that point and will fatigue, crack and the front of the bike will collapse under you. I like my teeth where they are. Yes, steel frames can be re-aligned if bent, but only if the deviation is spread out over the length of frame tubes, not ...


13

Not to disparage any of the very knowledgeable people here, but the best you'll get from a couple of pictures on the internet is a "good guess", or maybe even an "educated guess" but in my mind that's not very good when serious personal injury is on the line. Take the bike to a frame builder - preferably the one who built it for you, but any reputable one ...


12

That looks like the compression ring for a threadless headset. Images by keithonearth on Wikimedia Commons, reproduced under Gnu free documentation license More information found at Sheldon Brown


10

The frame has undergone plastic deformation, which took it close to failure, and there might be small points of failure hidden under the paint, for all we know. The fact that it has completely buckled on the downtube seems like a bad sign to me. You will need to plastically deform it again, meaning damage the metal again. The article you linked to suggests ...


10

One or more of the three options Change the stem to one with an angle, with such a short stem height gain will be limited. Replace the bars with a riser bar, these will give up to 40mm, maybe more of you shop around A stem extender (proviso - not on a carbon steerer). Presuming no carbon parts (bars, stem or steerer), replacing these is well within the ...


9

It is indeed a compression ring, David D’s diagram is helpful to illustrate the following: What it does is transfer the force of the cap bolt to the inner face of the cartridge bearing. That then compresses the ball bearings inside properly, as they need to be, which is why the split ring is called a compression ring. The angled face must fit into the ...


9

The degree of crumpling is relatively unusual and suggests a thin walled, high strength tube selection, which also frequently goes along with handbuilt frames. The material property that is the biggest factor in whether the frame would eventually fail is ductility, the material's resistance to flaws or stresses in the crystalline structure of the metal ...


9

You can get another handlebar with a different value of "rise": There are models with very high rise: You can go to the extreme (might be very flexy, but OK for e.g. commuting):


8

In practical terms, it's impossible to tell for sure in a case like this. It's probably fine, but there's no way of knowing absolutely via visual inspection. The surface indentations from the stem windows do occur naturally even with consistently correct torque on the fasteners. They're pretty normal to see. It would be a good idea to get it as clean as ...


8

Common threadless steel steerers have essentially no practical limit for this in either 1" or 1-1/8". There of course is a theoretical limit, but it's going to be a very large number, way over 12"/300mm. There have been a few companies over the years to make thinwall fancy alloy steel steerers (Alpha Q/Reynolds was a fairly popular one) that do have limits, ...


8

This is a traditional quill stem, meaning it's shaped like a "7", with the vertical part fixed inside the steerer tube by a wedge bolt. There should be an allen bolt at the top--it looks like it might be covered by a rubber plug here. Loosen that and give it a light tap with a mallet to dislodge the wedge. You should then be able to raise the stem. ...


8

You can buy a handlebar riser adaptor like this:


8

No, just move any spacers from below the stem to on top of it. Don't cut the steerer in case you want to sell the bike later, or even if you change your mind later.


8

A pipe cutter is an excellent tool for this application. Properly used it results in a perfect, burr free cut that is 90° to the longitudinal axis of the steer tube. The outer aspect of the cut remains burr-free by virtue of the rollers smoothing the outer aspect of the workpiece as they pass over. The tool, like any other, should be in good working ...


7

I went ahead with the rotary tool (Dremel) and general cutting disc. I cut two grooves side by side in the top spacer and prized one of them open with a flat screwdriver. Once the aluminium is thin enough, it will snap open with a little click, so it isn't necessary to cut all the way through. I carefully cut a little deeper each pass and tested with the ...


7

Here is a picture of instructions for a tool similar to yours. This picture shows putting a screwdriver in the holes to drive out the crown race. Since yours are threaded I'd put a bolt in each hole and hammer on that. Not a fan of hammering screwdrivers. Here's another similar tool close up to indicate orientation.


6

This is a very good question, and one that a lot of people get wrong or approach thoughtlessly. The answer is no, it's not significantly different in terms of safety whether your stem got where it is using an extender versus an uncut steerer. The spacer stack restrictions on carbon and aluminum steerers are concerned with limiting the amount of leverage ...


6

Official website says that these are the only models available: 1-1/8" STKM steel, 1-1/8" aluminum (-163g), XL 1-1/8" steel, XL 1-1/8" aluminum, 1.5" to 1-1/8" tapered aluminum (-123g), 1.5" aluminum (-146g) Your fork is straight, the taper at the bottom is required for interference fitted crown race. I've measured straight Suntour XCM just in case ...


6

Yes this is totally normal. The crown race is fitted to the base of the fork steerer with an interference fit. If the steerer didn't have a slight lip at the base, the interference fit would be all the way down the tube! The reason it is called a straight steerer is because it has the same size bearings top and bottom. Tapered meanwhile means having larger ...


6

Based on Swifty's suggestion, I will make this a formal answer. In summary, I would (carefully!) use a high-speed rotary cutter to deeply incise the spacers and pry them open. Note that it's probably simpler if you have a router attachment and a suitable bit for cutting metal; most of the rest of this still applies, but making the required cut is much ...


5

Absolutely. If they actually put anything but a French headset on a French fork, it should be 100% on them. Hopefully they will fess up and cover the whole thing. Just to be clear, measuring the difference between a French fork and the more common ISO/British is super easy. The OD of a French steerer is 25mm, and common 1" is 25.4. The thread pitch is also ...


5

Possible causes: Deformation of the steerer around the clamp area, possibly from overtorquing. The steerer is cracking and hence lacks dimensional stability. I've seen this cause the exact issue you're talking about and it's scary, so I recommend looking very closely for it. Take off any spacers below the stem to get a better look when doing so. Using a ...


5

The steering is not supposed to have significant resistance. Have you adjusted the preload? Set it to just tight enough that there's no play and that's the correct setting. If there's then a bit of drag from grease or seals don't worry about it. The way you adjust the preload on this type of headset is loosen the stem bolts and then adjust the bolt on the ...


5

Should you be worried, I wouldn't be. The alloy expander will stop the carbon steerer from being crushed. Remember the max torque on the stem bolts will likely be less than 6nm. (Use appropriate retaining paste and don't over tighten it!) As you mentioned, a lot of people (me included) will recommend a 5mm spacer on top of the stem, with the steerer a bit ...


5

The standard line from the carbon repair shops is they don't do forks because new ones are a lot cheaper. My understanding is that safe steerer repairs are technically possible in a lot of cases, so if you want to go nuts or if the original is unique in some way you might be able to find someone to do it, but it's probably not worth it. I think in practical ...


5

Replace the stem with one that has a bit of an angle. Stems are available in many combinations of lengths and angles, so if you're dissatisfied with the reach on the bike too you can solve that in one go as well Every respectable LBS should have a ton of options on hand. Btw many forks require a minimum of one spacer above the stem, especially those with ...


5

Cause I would have called this a witness mark from rubbing on some kind of protrusion. If it were a cut, it would be narrower and concentrated in one place. Also notice the tiny swarf pushed out of the channel, cutting does not do that. I think this fork was wearing on something, possibly while installed in another bike. Is it safe to ride? Hard to say - ...


4

Threadless quill stem adaptors do commonly come with a shim, so that they can be used with either size steerer, e.g. http://harriscyclery.net/product/velowerx-universal-stem-adapter-quill-to-threadless-5423.htm I've never seen such a shim sold separately, but a search shows up https://www.amazon.co.uk/Alloy-Aluminium-Quill-Adapter-Quillstem/dp/B00K7ECRLO, ...


4

I think the important question is stem length and not stem height. The largest component of the maximum force vector applied to the handlebars is force coming down from above. Minimal force is forward or side to side onto your handlebars while riding. The stem length creates a force mechanical advantage onto the headset and headtube, and the stem height does ...


4

how is it possible that it was completely loose? It's impossible to tell. Since the compression plug really doesn't do anything other than hold the stem in place until the stem's pinch bolts are tightened (it's the stem's pinch bolts that hold a bicycle's fork in place), it's likely that the compression plug wasn't assembled with sufficient torque to ...


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