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Re: 26R Spinners, RH thread on right?

PostPosted: Wed Apr 29, 2020 5:49 am
by Andy8421
abstamaria wrote:
3A6EDD5B-7C47-45ED-B4CB-81C4B774C84F.jpeg
Either Shelby or Chapman is wrong.

I drilled a hole on one of the ears of each spinner to put locking wire, when I was racing the Elan. I removed the wires now that the Elan is retired to street use. Still a good idea perhaps. (Photo below taken at the local sports car club gathering in Manila this February, pre-lockdown.)

Andy

From the various stories and quotes I have read, it is believed that Shelby got it the wrong way round on the Cobra. Hence I guess the need for lockwire.

Re: 26R Spinners, RH thread on right?

PostPosted: Wed Apr 29, 2020 7:21 am
by Panda
I have been running my 26R replica for 3 years in competition only. I fitted as per the bulletin lists and have never had a problem with loosening. That is rh thread on left hand side.
Alan P.

Re: 26R Spinners, RH thread on right?

PostPosted: Wed Apr 29, 2020 8:43 am
by Andy8421
Panda wrote:I have been running my 26R replica for 3 years in competition only. I fitted as per the bulletin lists and have never had a problem with loosening. That is rh thread on left hand side.
Alan P.

It would seem you have been lucky, though I guess over the short distance of a race it probably doesn't matter.

Re: 26R Spinners, RH thread on right?

PostPosted: Wed Apr 29, 2020 8:49 am
by geni
ne serait 'il pas plus simple et précis par un dessin de montage et serrage des 4roues !
cela aiderai beaucoup a mieux comprendre toute ces explications qui se contredises
enfin un avis que nous partageons

Re: 26R Spinners, RH thread on right?

PostPosted: Wed Apr 29, 2020 8:52 am
by alan.barker
Cher Geni,
En Anglais svp :wink: :wink:
Alan

Re: 26R Spinners, RH thread on right?

PostPosted: Wed Apr 29, 2020 9:30 am
by geni
wouldn't it be simpler and more precise by a drawing of assembly and tightening of the 4 wheels!
it will help a lot to better understand all these contradicting explanations
finally an opinion that we share
I use google translation" !

Re: 26R Spinners, RH thread on right?

PostPosted: Wed Apr 29, 2020 10:37 am
by vstibbard
My 26R is set up same as Alan's and when new it ran in 12 hour races... it never lost a wheel and nor was it lock wired!
Modern GTS model Porsche's are the same. One thing to be aware of is you only ever grease either the thread or the contact face of the spinner, never both.
V

Re: 26R Spinners, RH thread on right?

PostPosted: Wed Apr 29, 2020 11:00 am
by Andy8421
geni wrote:wouldn't it be simpler and more precise by a drawing of assembly and tightening of the 4 wheels!
it will help a lot to better understand all these contradicting explanations
finally an opinion that we share
I use google translation" !

Geni,

As with most things, there is a lot of nonsense posted on the web on this subject. I am no expert, but I do have an engineering background, and I have done some research on this subject for my own edification.

From the best I can tell, the dominant effect that comes into play is 'mechanical precession' which I linked to earlier. All of the postings on the web about inertia of the the spinner, the wheel moving under braking and acceleration are written by people who don't really understand what is going on.

The direction of precession is driven by the relative diameters of the two fittings - in our case the male spinner has a smaller diameter than the wheel, in the case of the Rudge-Whitworth spinner, the female spinner is bigger than the wheel.

For the spinner to self tighten, fit the right hand threaded fittings on the right hand side of the car for the Elan and any other car with a male spinner. For cars with a female Rudge-Whitworth spinner (pretty much the rest of the world) the opposite is true, fit right hand threads to the left hand side of the car.

I think the 26R sheet linked to above was written by someone who didn't understand how the effect works. There are stories about Chapman having to educate his design team as they didn't understand it properly.

I am more than happy to be corrected - so please feel free to put me right.

Re: 26R Spinners, RH thread on right?

PostPosted: Wed Apr 29, 2020 11:09 am
by abstamaria
If it’s any comfort, the Cobra guys are are also grappling with the issue.

http://www.clubcobra.com/forums/all-cob ... wrong.html

http://www.the289register.com/phpBB3/vi ... 0&start=30

Re: 26R Spinners, RH thread on right?

PostPosted: Wed Apr 29, 2020 8:02 pm
by tvacc
The idea is so when you brake, the nuts tighten. I think this is common sense. At least that is what I have always been told.

Re: 26R Spinners, RH thread on right?

PostPosted: Wed Apr 29, 2020 10:22 pm
by Panda
I just happened to see Jay Leno's magnificent Elan restoration video. The car was built by Jim Hall and I noted he removed the lhf wheel by turning the spinner anticlockwise. With his great racing history and achievements, I am sure he knows what he is doing!
Alan P.

Re: 26R Spinners, RH thread on right?

PostPosted: Thu Apr 30, 2020 12:48 am
by Davidb
Or not...

Maybe he just read the "Handling and Maintenance Notes" that came with the new old stock body that Jay found in England that nobody had noticed for 55 years!

Re: 26R Spinners, RH thread on right?

PostPosted: Thu Apr 30, 2020 2:03 am
by bitsobrits
alan.barker wrote:When i first visited New Zealand in 2013 i went to "Southwards Open day" Paraparaumu .
There were a few Lotus Elans including a +2. The owner said he had rebuilt the car and i said he had fitted the Hubs the wrong side. He had put the Anti Clockwise Spinners on the right hand side (driver's side NZ) :?
IMG_3519.JPG

Alan


Wouldn't that be correct for the southern hemisphere? Coriolis effect or something like that. :mrgreen:

Re: 26R Spinners, RH thread on right?

PostPosted: Thu Apr 30, 2020 6:13 am
by Andy8421
tvacc wrote:The idea is so when you brake, the nuts tighten. I think this is common sense. At least that is what I have always been told.

Tony,

I think that falls into the 'old wives tales' bucket. Couple of problems with this argument:

- If you brake gently, but accelerate hard, does that mean the rear wheels will eventually fall off?

- Why do female taper Rudge-Whitworth spinners (Jags, Ferrari, MG etc) do up the opposite way to Lotus with a male taper?

My money is still on the mechanical precession effect.

Andy.

Re: 26R Spinners, RH thread on right?

PostPosted: Thu Apr 30, 2020 6:28 am
by Andy8421
abstamaria wrote:If it’s any comfort, the Cobra guys are are also grappling with the issue.

http://www.clubcobra.com/forums/all-cob ... wrong.html

http://www.the289register.com/phpBB3/vi ... 0&start=30


Thanks for the links, some sensible arguments there. The Cobra guys have an interesting problem. It seems that some Cobra wheels are fitted with a Jag type Rudge-Whitworth spinner, some (Halibrand?) with a Lotus style spinner.

Not only can't they agree which way to do them up, they can't seem to agree whether the two types should be done up differently, or the same. The fact that some owners are having to resort to using lockwire on what supposedly was the wheel / spinner combination used in racing means that somebody is doing something wrong. I find it hard to believe the pit crew fitted lockwire after each wheel change in a race.

I am still of the belief that male taper (Lotus) has the right hand thread on the right of the car, female taper (Rudge-Whitworth) has the right hand thread on the left of the car.

The implication for the Cobra guys is that if you change the type of spinner, you need to swap the hubs over to the opposite side of the car. Not sure that argument will sell well over on the Cobra forum.