Today’s bike parts are almost universally better than bike parts of 20, 30 years ago, but for each bit they function better, they look worse. Most bike riders live with it. Some work out little hacks to make old parts work with modern components. I wondered: Why not just take a modern part and give it vintage looks? If what was bad about a modern bike rear derailleur was that it was all black, why couldn’t I make it silver?

The bike that would be receiving this vintage-ized part is this , rescued from abandonment in the salt and snow for two years on a quiet Brooklyn side street.

When it was new, this bike had eight close speeds at the back, three wide at the front. In the years since the ‘90s, mountain bikers have switched to wide-range cassettes and close 1x or 2x chainrings. The old setup worked fine, but I figured this was a fun chance to try something new. Moreover, new 10-speed cassettes don’t actually take up any more space on the bike than old 8-speed ones, and fit right on this 1990s hub without any modification.

Also convenient is that while eight-speed stuff is starting to delve into the realm of “vintage,” 10-speed parts are for the most part “old.”

Buying a high-quality 10-speed mountain bike derailleur from a decade ago, say, a Shimano Deore XT RD-M786 SGS, doesn’t actually cost any more than what you’d spend on eBay buying a Deore XT rear derailleur from the ‘90s, and the newer one gets you 10-speed compatibility and a clutch to keep your chain from bouncing around on trails. The only problem is that the 1990s unit still looks generally the same as any derailleur from the 1970s on, and would look good on any classic frame. The 2010s one is completely anodized black, and only looks good on a modern build.

The Inspiration for this NaOH Adventure

I figured my quest was hopeless, until I saw this post from bike wizard ShredPortals, who made a modern Sram derailleur look like it was built to match the look of the vintage bikes he rides:

Well, after two days of work, a lot of back-and-forth trips to the hardware store for more drain opener crystals, I had pulled of my cheapo ShredPortals imitation, with a lot less polish and a great deal more pitting.

You see, NaOH (also known as caustic soda, lye, and purchased as either an oven cleaner in spray form or drain opener in crystal form) chemically dissolves anodization off of aluminum. If you submerge an anodized aluminum bike part in an NaOH solution, it will strip the color right off it.

The only trick is that NaOH also dissolves aluminum, so if your solution is too strong, or if you leave your part in the mix for too long, it will leave you with pitting, or worse, as I was about to find out.

Here is how it started:

And here’s how it ended up:

It’s beautiful! Or at least it’s as pretty as I could get it with the pitting some of the NaOH caused and from me not having anything finer than a 600 grit to sand it down with.

Now for all the hacks.

Everything That Went Wrong With The NaOH

My process for silver-ifying this derailleur was relatively simple. I would disassemble the derailleur as much as possible, strip each part individually, and re-grease and reassemble. I’d end up cleaning and refurbishing the derailleur in the process. I was stoked. I love taking things apart and putting them back together again!

The “putting things together again” eluded me after my first attempt. I left the cage plates in too strong of an NaOH solution (240g water, 96g Drano crystals) for too long (a couple minutes) and dissolved not just the anodization, but also the threads that mount the plate onto the body of the derailleur. It looked cool and reminded me of the but it didn’t work. I ordered a new spare plate.

The second time around I protected the main mounting threads with some putty, and was happy that they looked good when the stripping was complete. Somehow the mounting bolt came free from the plate, though (it’s a press fit) and I had to do some finagling to get it to screw in tight to the body of the RD.

The threads I forgot to protect were the little ones that hold the screw that keeps the main spring in tension – the little round guy with the phillips head on all these Shimano RDs. The NaOH ate what I guess is an M4 hole up to about an M5. I had to tap it and run a low-profile water bottle cage bolt in there I had lying around from some kit. It juuuuust cleared the guide pulley:

After a ride around the block I realized it impacts the chain in certain gears, and would get gunked up with dirt in a heartbeat, so I ordered a set screw from BoltDepot to replace it.

I also forgot to protect the inner cage plate threads, and turned an M5 hole for mounting the tension pulley into an M6. I couldn’t re-tap it because only an M5 bolt will fit through the tension pulley. (I guess I could have sourced an old Simplex or Suntour pulley, but they wouldn’t love a 10-speed chain. Forget it. I don’t even know why I know that.) What I had to do was throw a tiny nut on the end of the bolt, which is not quite long enough for comfort. I’ve ordered another longer bolt to take its place, and some more Threadlocker.

I was surprised at how much I enjoyed the process of stripping, sanding, sanding some more, using hex wrenches as tiny sanding blocks to get into the tightest nooks and crevices, filing a bit, sanding again, and polishing this little derailleur. It came apart and back together far easier than I expected () and it works better than I ever imagined.

It All Works And Is Surprisingly Backwards-Compatible

In another extremely cursed case of backwards compatibility in this setup is that Shimano’s 10-speed mountain bike shifters have , which just so happened to be exactly what I had lying around in my parts bin for this bike. My Deore XT shifters from 1987 click just fine through the first six gears of this 10-speed cassette, and the final speeds work if I switch to friction mode.

I think the look largely worked out! It doesn’t look exactly like the old derailleur, but it’s nice enough.

I thought this process was going to be a bit of a nightmare, and to some extent it was. I hated working with lye — thick rubber gloves coming on and off, masks, eye protection, all of this washing and cleaning and scrubbing and dissolving was a pain. If I did this over again, I would probably just spray each part down with oven cleaner. I was amazed, though, at how much I enjoyed cleaning up each part, sanding them (relatively) smooth, and re-assembling. I don’t think I’d want to do this for work (you can ), but I am looking for an excuse to do this job again.