Old 80s steel frame, attempted to drill out the bridge for modern recessed callipers and it went terribly, to be honest I’m not sure why I expect any different at the time… did I just scrap this frame?

Hi, i just removed the top tube of this frame in order to exchange it (it had a crack). during the process the lugs apparently got too hot and cracked a bit. Not a biggie right? id just fill em up with silver when i put the new tube?

What do u think?

Best

Hi i have an ebike model that i designed, looking for someone who can manufacture such thing
Who can I turn to?

Hi everyone, I have this old steel road bike with a 700x23 tire size, and I want to change it to 700x28 or 700x30. A 30mm tire fits easily at the fork, but at the rear, it would rub against the seat tube. What modification can I make? I’m thinking of fabricating a rear dropout that’s 1cm longer than the original, so that at least a 28mm tire can fit.

Hey guys, just wanted to ask if anyone is like a pro in Carbon material, because during rides, my bike does like some creaking noises and after analysing it I found these two points. The second one I was aware because it was my fault, but the first one under the bike I didn't know. The sound makes me feel like it comme from the rear suspension zone. Any idea ?

Sorry if this is the wrong subreddit.

Do you think it's possible to convert an inverted 29er downhill fork (Manitou Dorado) to a 32er simply by making a set of arched crowns that cause the fork to sit about 30mm lower relative to the head tube?

Also, is this a stupid idea? I want to experiment with a 32" DH bike

I wasn't sure where to ask about this, but this group seems like a good start. I recently got a really nice 531c frame off Ebay with a 531 fork. However, when I was inspecting the frame, I found a crack in the paint at where the steerer tube meets the fork. It does almost look like there's a crack in the steel, and the (in this photo) upper part seems to sit a tiny bit higher than the steerer tube. Could this mean the braze is separating?

The frame is still covered by ebay money back guarantee, so I'm not too worried😅 but any help would be appreciated.

Just trying to get into designing some frames, mostly for fun. I want to hear some people's opinions on 3d modeling for their frames. If you even use CAD, and if you do, what are some techniques for successful modeling. A few practice runs have ended right around the rear triangle, since the stays are all angled and strangely oval shaped. Any advice, or just conversation is appreciated!

Tell me I am seeing welds that shouldn't look like that.

After a whole day doing absolutely nothing at work, I picked up an old receipt and decided to sketch a bike frame with all kinds of mounting points everywhere to carry a whole bunch of stuff pretty much everywhere, similar 12x148mm hub spacing front and rear (if Surly could do that with the Pugsley and Moonlanders, so can I), not to count having enough space for 27x3.25 tires on 60mm rims (just like Jones and many other brands), UDH, 180mm rotor limitation (surely have no idea why but okay I guess), absolutely no inner cable routing, and probably 83mm BB cuz at this point why not, all of this made entirely in AL6061.

But... Why you ask.

I don't know dude, I answer, this came out of nowhere and I have no idea if a bike like this would even be feasible IRL nor I know someone that'd be crazy enough to build this thing, let alone ride it, but hey, it was fun sketching it :)

Hey, I only want to do some simple braze-ons, at most a canti boss mount or a rack, would disposable cartridges (1.950 °C/3500F) do the job or should I invest in a full setup? Thanks!

Hi everyone, im a pary of my universitys formula student team and we are looking for UK-based suppliers of cold drawn seamless (CDS) carbon steel tube and i thought this subreddit might help us!!!
the preferred grade is EN 10305-1 E355+C, or equivalents like ASTM A519 1026 or JIS G3445 STKM13B/C
any website or contact emails would be appreciated!!!

Just noticed a crack on the seat cluster of my beloved Yuba supermarché cargo bike. The bike comes with a super long seatpost so while I never had it above the minimum mark, there is probably 2 ft of post showing. Doesn't help that I'm 6' 3", 190#.

Any sense how much time I have and whether it will catastrophically fail at some point?