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PaperclipPerfector  6d ago (text post)   1537 thread views

Friday Fun Thread for March 28, 2025

Be advised: this thread is not for serious in-depth discussion of weighty topics (we have a link for that), this thread is not for anything Culture War related. This thread is for Fun. You got jokes? Share 'em. You got silly questions? Ask 'em.

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Chatgpt told me which kit to buy, and then I was blown away when it instructed me to go take a picture of both sides of my crank/cassette so it could be certain what we were ordering would fit.

Can it really estimate the dimensions of the bike? Impressive.

Yes and no. I'll see if I can paste the conversation:

I ask it if the amazon kit I want to buy has everything I need to replace the bracket:

Final Verdict: This kit looks 90% complete for threaded bottom brackets (square taper, Octalink, Hollowtech II, etc.). If you’re running a press-fit BB (BB30, PF30, BB92, etc.), you’ll need a press and possibly an extractor tool too — but those are specialized and not usually in multi-tool kits like this one.

Want me to help identify your BB type before you order the kit? A quick check of your bike model or a photo of the BB area can tell us a lot! 🚲✨

It piqued my curiosity by asking for a photo.

If I upload a photo you can tell what kind of bottom bracket it is?

Reply:

Yes — if you upload a clear photo of the bottom bracket area (where the crank arms meet the frame), I can usually identify the type of bottom bracket you have.

Here’s what to focus on in the picture:

A side view of the crankset and bottom bracket area.

A close-up of the crank arm connection to the BB (is it square, splined, or hollow?).

Any visible markings or labels on the bottom bracket shell.

Once I see the setup, I’ll figure out whether you have a square taper, Octalink, Hollowtech, Press-fit, or something else — and confirm if that tool kit covers it all. 🚲✨

At this point I'm cracking up as I'm now a slave to the machine, running errands for my AI overlord. I trundle outdoors and take a photo of my chainrings.

Looks like you’ve got a square taper bottom bracket — I can tell from the square-shaped spindle poking out where the crank arm attaches. This type is super common on older bikes and some modern budget models.

Here’s what you’ll need from that tool kit:

✅ Crank puller — To remove the crank arms (make sure it supports square taper). ✅ Cartridge BB tool — For unscrewing the bottom bracket (a splined tool like the Park Tool BBT-22 or similar works for most square taper BBs). ✅ 8mm hex key — For the crank bolts. ✅ Grease/anti-seize (not in your kit) — Good for keeping things quiet and preventing seizing when installing the new BB.

Once you’ve got the tools, the steps are:

Remove crank arms using the crank puller.

Unscrew the bottom bracket (left side is usually reverse-threaded on English-thread bikes).

Clean the shell, grease the threads.

Install the new BB, making sure it’s the right spindle length and shell width (e.g., 68mm x 113mm).

Reinstall the cranks.

Do you want me to help figure out the exact size BB you need too? You can either measure the old one after removal or I can guide you based on the crankset type. 🚲✨

A few messages back and forth (omitted for length considerations) before it asks me for a picture of the crankset.

Got it — from this new photo, I can see the crankset more clearly. It looks like a Suntour XCM or similar vintage-style triple crankset, which often pairs with a square taper JIS bottom bracket.

Given that it’s a triple crankset (3 chainrings):

Bottom bracket shell width: Likely 68mm (common on road/touring bikes from this era).

Spindle length: Typically 113mm or 118mm for triple cranksets like this.

For a Suntour setup like this, 113mm is usually a good starting point — it keeps the chainline more centered. If you want a bit more crank arm clearance from the frame, 118mm works too.

👉 Recommended bottom bracket:

68mm shell width x 113mm spindle length (square taper, JIS)

Brands like Shimano (UN300 or UN55), Tange, or Token are reliable options.

Would you like me to find a compatible bottom bracket online or walk you through the installation next? 🚲✨

We'll find out this weekend whether we're one step closer to AGI or I wasted 50 bucks on Amazon.

68mm shell width x 113mm spindle length (square taper, JIS)

Did you, um, measure those things? I'm not saying the robot is wrong in this, but both of those could be measured precisely enough with a tape measure (or calipers if you've got em) to be pretty sure you're getting the right thing.

But like, why would I do that when I can just ask computer?

More seriously, it's hard to measure my old bottom bracket without being able to take it out, right? Or is there something I'm missing? My understanding was that if I bought a bottom bracket that was slightly wider it may change my pedal width and I'd just have to adjust my derailleur.

Barring a short spell, ChatGPT has never used nearly as many emoji during a chat with me. Is there something in your instructions or memory?

Definitely not instructions or memory. I hate emojis. There doesn't seem to be any commonality to when it throws in dozens of emojis; that specific conversation had random work-related questions, random discussions about biology and then a lot of questions about bike bottom brackets. Every answer was full of emojis.

Jesus Christ, BB replacement has been such a pain for me. I too had a square taper, but purchased one of the incorrect depth to start. The manufacturers don't even list what you have anymore since they use interchangable suppliers, and my budget hybrid bike had one that failed after a measley 2,500 miles which is absolutely pathetic for such a basic component.

Between the opaque nature of diagnosing it and the need for specialized tools, it's the bike repair job that gets the biggest thumbs down from me.

If you haven't checked out the park tool videos on YouTube yet for these things, do. They're awesome at least.

Yeah, at this point I've spent as much on tools for taking out a square taper and fixing all the other shit wrong with my bike as I would have buying a new beater off craigslist. I'm down to the cups and they're so rusty they may as well be welded to the frame. My wife is not amused.

In my defense, we got a (relatively, for our area) lot of snow this year and half an inch of snow induces such panic in the populace that a fleet of plows immediately dump a metric ton of salt on every road. Now that spring is here, I've replaced the chain, cassette and derailleur. FML.

Park Tool videos are solid. I really like RJ The Bike Guy too for his videos showing how you can do the same work without specialised tools and why you should save yourself a lot of trouble and just spend the money on the right tool, even if it's not the pro spec Park Tool version.

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