[508] Automatic gear knob dimensions

[the-termin8r]

Hi all,

I have a bit of an odd favour to ask of anyone with an automatic 508. Could you measure the dimensions specified in the image please? "A" is from the spine to the furthest-forward point of the protrusion on the top. "B" is from the approximate centre-line of the mounting shaft to the same protrusion.

The shape of the one on my C5 means that when the car's in park there's almost no space between the knob and radio fascia. That in turn means that I can't actually leave anything in my DIY cup holder. My thinking is that if the 508's knob is significantly smaller I might have enough clearance but I don't want to spend money on one only to find that it's also too big.

Cheers.

[mickthemaverick]

Just a bizarre thought Rob, can you spin the knob round 180 so the straight spine is toward the radio?

[the-termin8r]

I had that idea too, I'd have to pull it off and see. Though with that being said, if it's anything like the knob on my previous manual it'll need the jaws of life. I don't want to put repeated unnecessary strain on the mechanism. I'll see if I can find any videos that show the mount in detail.

[the-termin8r]

For anyone in the future, A is ~57mm and B is ~32mm. I ended up buying one from a breaker. Annoyingly, despite fitting on the shaft of the X7, it's still too big for my purposes. So a total waste of 24 quid. Mounting the original backwards is also a no-go because the shaft is keyed.

[the-termin8r]

Ok, so things might have gotten a little out of hand. After the initial failure, I decided to tear the knob down in an attempt to flip the mounting channel by 180 degrees so that I could mount it backwards. Well, it turns out nothing inside this thing is symmetrical, it's all keyed. Even all the bits on the "outside" of the mounting channel are keyed.

Construction-wise it's actually quite disappointing. It's almost entirely plastic and is a combo of clipped, screwed, and double-sided-taped together. The "metal" surface on the top plate is actually a plastic panel with some kind of metal foil covering it to give the metal feel. I don't even know if the leather is real. In comparison, the knob of my old manual X7 was a solid lump of metal wrapped in real leather. Though I suspect the cap with the gate map was the same sort of plastic / metal-foil affair. Can't speak to the construction of the auto knob on the X7 but it feels built solidly enough.

It wasn't in the cards, but I guess I'm now designing and printing my own custom gear knob that'll fit LOL. I'll probably share the designs when I finish it, but they're unlikely to be useable for most people. It'll basically use the mounting channel I got out of the 508 knob and printing something to fit over that. The issue is that the channel can't be sourced on its own. The only way to get it would be from a gear knob. I have no clue if all PSA cars with that channel have the same "outer" features that the custom knob would fit over and I doubt the AliExpress knock-offs are designed in the same way as well.

Either way, here are the few teardown photos I took:

[myglaren]

Ridiculously complex for such a simple and utilitarian item.

How about one of these simple yet tasteful items

[the-termin8r]

Different mount unfortunately. The stock mount is a plastic sleeve with groves and clip points that's glued on to the main shaft (as seen on this Mk1 C4). Additionally, I want something that will blend as much as possible into the interior. An 8-ball would stick out like a sore thumb and in general I'm not a big fan of that kind of gimmick/novelty kind of trim/accessory. I'm effectively aiming for a narrow black cylinder with possibly a domed top.

[myglaren]

That wasn't a serious suggestion. I think the snooker ball thing is seriously tacky.

[the-termin8r]

Ok, good, you had me worried there. I'm not good at detecting sarcasm in text and there are people who unironically think they look good. LMAO

[mickthemaverick]

Any use? https://www.ebay.co.uk/itm/304743021360

[the-termin8r]

I was looking at those ones but they looks like they have the same sort of protrusion as the 508 one (I don't think a 4mm saving will be enough) but also nowhere to zip tie the gaiter. I'd rather not spend any more money on another failed experiment.