weighted shift knob?

[Austin David]

new Caterham, MX-5 transmission with what I assume is a not-quite-Miata shifter (at least, shorter than my NB MX-5 which AFAIK is the same transmission).

 

Should I use a weighted knob?  My stock knob is pretty heavy, and I'm making a new one because bored and whatnot.  Current iteration is about 40-50g, but I could fill it with tin or tungsten or something and get it much heavier, if it matters.

 

The innernets are relatively divided between "lighter is more agile" and "heavier is more smooth."  And of course, both are best.

 

What do y'all think?

[JohnCh]

Personally, I'd experiment to determine which I prefer.  Even if 9 out of 10 people here state they prefer the stock weight, if you prefer heavier, then that's the right answer for you.  Perhaps tape different amounts of lead weight to the stock knob and try it out?

 

-John

[Austin David]

the question is really "stock weight" or "less than stock weight", but I get your meaning.    I'll try a few different weights and see what works.

[JohnCh]

Ah, I misread that and thought the comment about making it heavier was referring to the stock knob not a new one you have already fabricated.  But yeah, experiment  

 

-John

[Austin David]

Yeah, trying to see if I need to pack it with $30 in tungsten powder, or melt down some lead, or beg some steel shot from the local armory.  Or something.  Having a target weight might help.

 

I'll see if I can get some cheap lead tomorrow...

[Austin David]

for the record: stock shift knob is 196g, my test unit was about 30g.

[MV8]

I like to use pool balls for shift knobs by drilling and epoxying an insert (perhaps a seven ball?) or rod with a bolt-on lever (like a ford application T5). Very comfortable for large hands. Adding weight to a shifter makes no sense to me. Most oem shifters are isolated by rubber in the shaft or mounting flange.

[Dave W]

Unless there is a vibration issue, I would concentrate on the size and shape that fits your paw. I put a relief in the side for the thumb and a small lip for better grip.

[straightcut]

WWCD?  What would Colin (Chapman) do?  Don’t overthink it; it’s a Seven, go light!

 

on a serious note, I replaced the worn plastic shift knob on my Tacoma 4x4 with a stainless steel shift knob, not because I needed the mass, but because I thought hewn from a stainless billet was more cool than worn plastic. I noticed nothing function-wise. Frankly, I think the “weighted shift knob” thing is pure marketing.  Part II, the metal knob is HOT in the summer and COLD in the winter.

 

Simplify and add lightness.

 

Mark

[inchoate]

it's a seven so lighter is better.

 

if you need to fiddle try some different shapes.  that was my winter lathe project a few years ago and the shift knob that ended up working best for me was pretty far away from where I started.

[Austin David]

I've always liked a small sphere, but the stock knob had a pretty deep inset "S" that feels weird.  And it's solid metal, so kinda warm in the summer and very cold in winter.

 

I've got a polished plastic sphere with the insert Lotus logo, it looks good and feels good.  I'll try packing it with lead to see if there's a useful difference with added mass.  I think the range will be about 30-250g without having to get too creative... 

[Alex-Ks1]

How odd 

[fastg]

I have one of the Gracing shifters I am not using, really tightens up the Miata shift, very well made piece. 

 

https://www.gracingshifters.com/

 

Graham 

[Austin David]

testing 2 models, shifting 3-4-3 in neutral.

 

unit A, 31.8g vs unit B, 136g.  Similar materials and construction; both ~ hollow plastic.  Unit B mostly filled with lead shot; it's loose, so this may also provide dampening (like a deadblow hammer)

 

Both work, unit B is "smoother" -- less notchy bouncing in/out of neutral.  No meaningful difference in the effort required to shift in/out of 3-4-3.

 

For the reference: a similar sphere made of water would weigh about 56g, so I assume a solid wood knob would be about 50-60g

 

[MV8]

Adding weight applies thrust pressure to the synchros and fork pads which isn't needed or desired beyond selecting the gear.

Edited January 10, 2023 by MV8

[Austin David]

again the internet is torn on this -- range is "don't do it" to "it makes no difference", but clearly there's an upper limit.  I don't necessarily think the Caterham setup is perfect in every way, but I figure as long as I don't make it heavier than the 200g stock knob (about 7 oz) I won't be creating any new problems.

[inchoate]

wasn't there a Porsche sports racer that had a gearshift knob made out of balsa for weight reduction?

[Austin David]

Google seems to think it was a 917.  Interesting.  I can get down to about 28-30g total, including the sleeve to cover the gap between the ball and the boot.  The 917 model seems to come in around 35g with the internal shank to hold it together.

 

Pretty sure I ate about 350-500g of dinner tonight.

Edited January 11, 2023 by Austin David

[speedwagon]

Am thinking that controlling the weight on the foot-feed would be of more importance.   john

[Alex-Ks1]

as this debate runs on .. no one has asked about a T-handle or a pistol grip shifter, I see it as If I can grab it and move it, it did its job.