McLaren Wheel Nuts

[marcush.]

clearly the pit stop system with the wheel nuts and how things are managed is a unsafe process for all teams.I´m amazed how professional teams get themselves into ever more complex process steps without erasing the root cause of the issue .
The MGP system relies on the Mechanic peressing a button as soon as the nut is fixed...hello ??? the mechanic has to work his fingers bloody to get it done as quickly as possible.The pressure on him is so high that :"HOT" stops under race conditions are always taking longer than practise stops...that does tell it all.mental stress is getting the better off the poor devils.

In a first step you need to make the wheel fixing a forced process -eg you cannot leave the pit when wheels are not properly tightened..a rather easy exercise methinks.

Second :you need a car positioning system ..the car slotting in too quick or too far is the first variable to get rid off the second one is get rid off the wheelgun being responsible for providing the clamping force -which is not under control -the wheel gun should only fix the wheel ,clamping force provided by the car -so mechanic just has to fit the wheel .
I had thought Formula 1 was about lateral thinking ...but it seems most of them are into optimising what they know -even if it´s a dog of an idea ....

[QLDriver]

Well, it would be possible to see electronically if the tyre was secured - a strain gauge somewhere on the stud would be able to sense the strain, and hence the load on the stud. If the load is within a certain range, you know the nut is developing the correct clamping force and it's safe to release.

[marcush.]

straingauges are immensely temperature sensitive...you need to cater for temps in calibration.in effect different temp=different strain by a huge margin...so the thing is not really fail safe...but a load cell should be a possibility ?
I still think the best would be a hydraulic lock provded by the hub .You engage the nut to pressurize the system giving full clamp and undoing the nut is relieving the hydraulic force.This could be even coupled with a mechanical interlock of the hub /upright engaging when the nut is opened ....so it would be impossible to move the car with a wheel not fixed properly.
as i understand you need a threaded nut by regs ,but i don´t think it is mandatory to have the theads being the sole provider of clamping force.

[QLDriver]

The problem would be that a hydraulic system would be both heavy and 'fail-unsafe' - you cut the hose/lose pressure and the wheel falls off.

The load cells I deal with (in a testing lab) are generally built with strain gauges these days - and it's not terribly difficult to correct for temperature anyway.

[you_nes]

Judging by the fact they had trouble on all three stops, with different gun men, I would say that their issue was probably damage to the threads on the hub. (I.E. not the fault of the operator or the gun.)

Of course it could have been caused by the operator during the first pit stop.

I also think that teams persevere with the "clamping force generated by a guy with a gun" approach because it offers the least unsprung/rotating weight. Any clamping system within the hub would be bulky and weight in this area is critical.

[strad]

It looked clear to me that the wheel nut had been cross threaded to which I have suggested a foolproof solution. A Higby thread.

[mzivtins]

Honestly, what are they playing at?

Not even HRT do this to their drivers.

To be honest, do we even get to see HRT's pit stops? I agree with your statement, but i wonder if we could be wrong?


Also someone mentioned asking the rear wheelman, Mclaren have stated that in 4 issues with the left rear wheel there have been 3 different wheel men... this tells me its a process issue not a human one at least.

[Crucial_Xtreme]

Interesting take on a possible cause of the McLaren wheel nut problem from Matt Somerfield:

I’m speculating somewhat here but McLaren have had left rear wheel issues in consecutive races firstly with Jenson at China and twice more for Lewis in Bahrain. Exhaust gas manipulation is still not an exact science and heat generation toward the rear left wheel could be to blame.

With both the China and Bahrain circuits being clockwise, heat generated by the exhaust that should be heading inbound over the diffuser could be drifting outbound toward the left side. As the car corners and the ‘Coanda effect’ drifts away slightly on that side of the car. The hub that the wheel nut goes onto is made of Titanium however the nut itself is made of aluminium. Aluminium’s thermal properties are much weaker than titanium however the nut could act as a heating sleeve expanding that region of the hub more quickly making it difficult to put the new wheel nut on.

Link--> FinalSector Bahrain GP Technical Roundup

[cheapracer]

Ask the left rear wheel gun man.

He seems to have a disproportionate amount of experience on this subject compared to anyone else.

Most tracks are clockwise. Most strain and heat is suffered by the left rear wheel compared to the other 3.

[marcush.]

The problem would be that a hydraulic system would be both heavy and 'fail-unsafe' - you cut the hose/lose pressure and the wheel falls off.

The load cells I deal with (in a testing lab) are generally built with strain gauges these days - and it's not terribly difficult to correct for temperature anyway.

i don´t get your reasoning ..a formula 1 car has a very sophisticated hydraulics system already on board and it seems pretty well understood and reliable....
I think hydraulic failures are nowadays less common than wheel fixation issues.
We don´t see mechanical brakes ,we don´t see mechanical steering ,no mechachanical dampers .I agree all these systems dohave their own reliability rating but to call it unreliable due to being hydraulics is more opinion than fact?

I did not say the wheel is relying only on the hydraulics I said the clamping force is provided by hydraulics.Loss of pressure -easily detected -and you could cut the fuel supply or let the engine die as soon as you detect it (with a logic behind it to erase the possibility of a failed sensor or cable) ....it would be entirely safe .
And weight ? I don´t think that is an issue to design without having a tinsmithvise bolted to each corner of the car.....

[strad]

I found this most interesting...after the incident Hamilton borrowed a page from Mikes book and said he would support the guy..BUT...He doesn't even know the team members,,,sad really

"I don't know who it is, but I will go and see the guy, try and lift him up.

[Crucial_Xtreme]

BBC's Gary Anderson on McLaren pit stop problems

[youtube]http://www.youtube.com/watch?v=3_91T_6u4Kw[/youtube]

[GrizzleBoy]

I found this most interesting...after the incident Hamilton borrowed a page from Mikes book and said he would support the guy..BUT...He doesn't even know the team members,,,sad really

"I don't know who it is, but I will go and see the guy, try and lift him up.

Given that three seperate people have been involved with the four successive wheel problems, I'm not really surprised he doesn't know exactly who out of all of them he needs to talk to.

[multisync]

Last year they had no problems at all at pit-stops (probably one or two, but not too many). This year, 4 GPs, and on three of them they had destroyed Lewis or Button's race.
It is stupid to change the wheel-nut system to improve half a second on a pit stop but it results on big errors. If something works, do not change it.


Trocola

Nonsense. It's called progress. If you don't like change you're following the wrong game..

If that progress means more problems and bad results, can we call it progress? Seems the opposite of it


Trocola

The course of true love never did run smooth. This like most delevopments will need adjusting once they fully understand what's going on, it will be a progression.. I note some are very quick to blame the wheel men...which is more a comment on them than those actually involved.

[myurr]

I found this most interesting...after the incident Hamilton borrowed a page from Mikes book and said he would support the guy..BUT...He doesn't even know the team members,,,sad really

"I don't know who it is, but I will go and see the guy, try and lift him up.

Unless he either didn't want to name and potentially shame him, or they rotate them on occasion so he didn't know which exact team member it was.