Mercedes GP W02

[siskue2005]

Nascar has been using this stuff for long time now, scrabs reported on this at Malaysian GP

[feynman]

You sure?

Last I saw NASCAR lightly glued the 5 nuts onto the rim, to keep the nuts in place when torquing up. When taking off, the old nuts fly-off everywhere, but that doesn't much matter, it's about getting the new wheel on fast.

[bill shoe]

Ahh, yup, Mercedes wheel nuts have pretty much already been covered. Thanks for feedback.

[The FOZ]

Which will be fine as far as it goes, but if they do ever have a nut problem they are up the creek. Instead of grabbing a spare nut from the spare gun and losing a second or two, they now have to unbolt all the wheels, and send a committee back into the garage to rummage about and find whatever spare set of (used) extra tyres they have available.

If the nut is now integrated with the rim, and the rim is fixed to the tyre, and the tyre allocations have to run in sets ... first time it sticks, it could get messy in a hurry.

Integrated is hardly the word to use - it implies that the nut (and it's function) is PART of the rim. Clearly that's not the case. This is a nut that is held in place with a retention clip that keeps the nut in place, but allows free rotation.

I've never seen a cross-threaded wheel nut, so quite likely the teams already have a method of avoiding that problem sorted out. This system would be no different, and it's entirely plausible that the nuts can be yanked off with the right sort of motion and a loose nut put in it's place should that ever occur.

Not forgetting that they're equally likely to strip the thread on the car, and I've certainly *never* seen that happen.

Not if they use a softer metal on the nut than the spindle...which I do remember Steve Matchett saying a time or two.

Come to think of it, though...we do see an awful lot of loose wheels, could that be from cross-threaded nuts?

[beelsebob]

Not forgetting that they're equally likely to strip the thread on the car, and I've certainly *never* seen that happen.

Not if they use a softer metal on the nut than the spindle...which I do remember Steve Matchett saying a time or two.

Come to think of it, though...we do see an awful lot of loose wheels, could that be from cross-threaded nuts?

Heh, fair point indeed!

[feynman]

I had always assumed the nuts to be made of sacrificial material.
Chew up a nut in a pitstop, force it off and screw on another ... in terms of materials choice, you surely don't want to be anywhere near the probability of stripping a hub, that'll put a definite crimp in your pitstop time, changing a car corner.

I also assumed this is why the wheels still regularly take the opportunity to try and clear the catch fencing, despite all the extra nut retention mechanisms added ... the nut has been forced on at an angle, stripped out clean, and is not fully seated so the retention clips can't hold it, and is just waiting for turn 1 and a chance to shed its load.



Anyhow, as for the Merc wheel, rims are still homologated at season start, no? So I guess the rim remains the same and it is a captive nut and tunnel inserted into a standard wheel.
Whether this tunnel alignment mechanism is entirely sufficient to prevent stripping, and therefore allow you to run the risk of mating nuts to rims to sets of tyres, I don't know.

[marcush.]

this is not really a matter of soft vs hard in the context of nut and hub thread.
It´s a matter of material pairings and surface finish as well as coatings and lubricants.
Galling is a nasty thing and Titanium,alumium and ni alloys are prone to galling and surface fretting...-you can weld these simply by surface friction or in the case of Ti simple contact may be all that is needed.

To me the wheelnut area is one of the big areas where racing is in the stoneage of things and seemingly the teams are working more on the symtoms and not on the
problem itself.
To retain a wheel by a threaded nut is to me a bad idea ,considering you need to change wheels three or more times per race as quick and reliably as possible.

[PlatinumZealot]

So how else are you going to get that mechanical advantage to hold the wheels on?

Are you thinking of some type of reverse collet like mechanism?

[hollowBallistix]

So how else are you going to get that mechanical advantage to hold the wheels on?

Are you thinking of some type of reverse collet like mechanism?

Could you use something like a Drawbar system that's used in Machine Tools Spindles ?

[marcush.]

I thought about some kind of hydraulic locking combined with a bajonet coupling.(place the wheel and turn a ring to secure the wheel to the hub -fixation ring snaps into position -parts interlocked.-Add hydraulic pressure -available in the car anyways -and volila you got a redundand system - and it takes No time to thread on the part -plus you can only release the gun when the wheel is in it´s secured position ,plus you don´t have the insecurioty of not correct preload on the nut - I´m not entirely sure if you are allowed to do things completely without threads though..
There are hundreds of possibilities to secure the wheel to the hub safely .A thread does not feature very high in my list.

[rdr]

there is a misconception in this :You run the engine rich to cool it not to be quicker ..So leaning out the mixture will not hurt your performance but cause overheating,right?
So why did they not ask him to go slower because the car was overheating???

I don´t get this.

marcush, can you explain this?

My theory is that in cooler conditions they used blown diffuser to more extent.
Consequences were short on fuel with two cars.

[ForMuLaOne]

Engines can be cooled by richer mixtures. But there will be a point from where you lose power. If you want to lean the engine, you will increase temperatures, especially exhaust gas temperatures. Using exhaust temperatures for mixture setting can be done by leaning the engine until EGT reaches the peak. It will decrease by leaning quite far wich results in power losses. Therefore you would run it on the highest EGT the system is capable of, but on the rich mixture side of the peak. if you want to run save temperatures AND normal fuel consumption, you have to slow down.

[marcush.]

Mercedes is ,to my understanding not really blowing the difusser at this time as they blow the upper surface of the floor ...maybe the added mass airflow leads to a virtual elongation of the difusser -I don´t know.
they burn fuel in overrun conditions with retarded ignition ,something that surely contributes to engine heat buildup.
So maybe you are right they could not use this feature after a certain point in the race.
But still the official wording was lack of fuel ,not overheating issues.If it were temps -Rosberg would not have been fuming at the end of the race like he did.
He clearly had the impression the car was quick enough to win.Not a single word about having overheating issues.He was told to conserve fuel and his statement was not :the car had reduced performance because oif the maps he had to use but :
he had to shortshift and coast ...
I understand that this will help the temperatures as well but why not stating we had temperature issues instead of :we had not enough fuel on board to run at that speed?

[xpensive]

In all honesty, I admit to have been stunned by Mercedes sheer pace in China, guess that even I can get things completely wrong at times, though it's not veryu often.

Hats off JET.

[Formula None]