A few weeks ago, I wrote about driving to Connecticut to score a very well-priced Recaro office chair (if you don’t know, that’s a Recaro car seat on a rolling office-chair base) that was upholstered in the same orange spectrum fabric as the two Recaros in Bertha, my ratty 2002. The seat isn’t mint, but it’s in pretty nice overall condition, and it’s certainly far better than both of Bertha’s two tattered ones.
As I said in the piece, my original thought was that I’d pull off the rolling base and use the seat to replace Bertha’s badly worn driver’s seat, but once I saw how flawlessly the orange spectrum fabric matches the color of the walls and the drapes in my dining room/office, I realized that it’ll likely remain a home furnishing—and that’s okay.
f course, the joke is that while $250 is a great price for an intact Recaro orange spectrum seat, I never would’ve spent $250 for an office chair.
However, even with that probable future, there was still one thing about the seat that bothered me: It was missing its tilt-adjustment knob. What was there instead was a snapped-off plastic nub held on by a 10-mm bolt. Yeah, the plastic trim surrounding it was also missing, but if you’ve been reading my work for decades, you know that I’m a function-first kind of guy; I don’t care about the trim, but even for use as an office chair, the tilt should be adjustable.
There should be a knob there.
My first thought was, “No problem. I’ll just order a plastic knob from McMaster-Carr.” I and many others have long held that McMaster has the best website on the planet, full of so much database-specifiable detail and reference material that it’s simply astounding. A quick look revealed that “comfort-grip through-hole knobs” would probably be the place where I found the knob of my desire.
You want knobs? I got yer knobs right here, pal.
Of course, I needed to specify the hole size and threads. I unscrewed the 10-mm bolt from the Recaro and pulled off the snapped-off plastic knob nub (say that five times fast). And that’s when I saw the problem: The form-factor of the shaft that the knob needs to slide on is very specific. It’s circular, but has the sides squared off.
Hmm.
While this shape makes perfect sense for a knob that you don’t want to slip, the knob choices on McMaster don’t show anything like it. And venturing out into the great big bad web wasn’t productive, either; success in Internet searching is still pretty dependent on having the correct search terms, and “square-sided shaft” or “flat-sided shaft” produced images of things with keyways or one flat side, but not two.
I measured the dimensions as 1/2-inch for the rounded portion and 3/8-inch for the flat-sided area, but that wasn’t helpful, either. That is, even if those are the dimensions of some standard form-factor, searching for those dimensions with words like “shaft” or “knob” wasn’t a magic handshake.
Plus, it turns out that the knob is more complicated than that. The original knob is actually a two-piece assembly. The inner piece is the part with the squared-off hole, and has been NLA for decades. The outer piece—the thing that looks like a knob—snaps over the inner piece. Our friend Dave Varco—the man behind Aardvarc Racing and the upholsterer and seller of E21 320i Recaros—sells a 3D-printed version of the long-unavailable inner piece for $35 plus $6 shipping on eBay as well as off his website. The photos below are courtesy of Dave. You can even see different versions of knobs for circular and squared-off shafts in the exploded parts diagram. Even though my seat is a Recaro seat and not a BMW Recaro seat, it looks like it’s the same part.
Pieces #11 and 12 show the knob and the “support for adjusting wheel.”
The 3D-printed piece Dave Varco sells.
Now that I knew that there was a source for the inner piece, I set out to look for the outer knob that snaps over it. Its part number, 52 10 1 875 826, is still available; BMW dealer list is about $30. But while I was glad that there was a click-and-buy solution for both pieces, the idea of spending what would total about $80 for a two-piece tilt adjustment knob for a $250 Recaro seat with a rolling office chair-base that I never planned to use as an office chair, but now was using as an office chair, set off my cheapskate alarm. Put another way, if you’re like me (and let’s hope you’re not, but I think we’ve established that you probably are), you can appreciate that there’s a part of me that, when I get a good deal on something, I hate to “pollute the deal” by having to spend non-deal prices on other things that are needed to make the deal item fully functional. Like an $80 seat knob.
So I began to look at other alternatives. While poring over lots of images for seat knobs on eBay, I stumbled upon this:
Could it be?
Yes, Volkswagen part 191881671 for a Mk2 Corrado (Febi part 15950) is a one-piece knob that sure as hell looks like it has the square-sided hole that I need. Further, when I searched for these part numbers, I found reference to not only Volkswagen, but to Recaro, since the seat the knob is for was apparently produced by them.
Multiple vendors on eBay and Amazon had these knobs, but all of them were in eastern Europe. At least they were inexpensive. I picked the one that showed the real photograph above with the real Febi box, $9.65 shipped from Latvia.
I was in no rush. Click. Buy. Smile.
A few weeks later, the knob arrived. It so clearly looked like what I needed that I jammed it right onto the seat’s shaft.
Front…
…and the all-important back. The edges of the squared-off hole are a little mangled from my overly enthusiastic test fit.
It was a tight fit, which I thought meant that it, well, fit.
Success—sort of.
However, when I pulled the knob back off, I could see that the flat-sided hole is in fact slightly smaller than the shaft on the seat, and what I thought was a very snug fit was actually the plastic deforming. It’ll be fine for set-and-forget use on an office chair (and a quick trip the hardware store will get me an Allen-head bolt that’ll fit in that tiny hole), but were I to install the seat in a car, I think that the more frequent tilt adjustment and the vibration might cause it to fail.
I could add the Recaro Seat Knob Episode to the long list of examples of my being penny-wise and pound-foolish and needing to buy the same part twice, but the cost here was so low and the immediate problem so completely solved that instead I think I’ll file this one under “no harm, no foul.”
But I still never would’ve spent $259.64 for an office chair with adjustable tilt.—Rob Siegel
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Rob’s newest book, The Best of The Hack Mechanic, is available here on Amazon, as are his seven other books. Signed copies can be ordered directly from Rob here.
