Tech Question on the CV change and lost 90 mins

Setting aside the "super power" argument for a while:

RG (actually, Johnny - while RG was working on the Hummer) said they lost the CV boot, and then subsequently the CV joint when the Fesh Fesh/sand entered the CV and chewed it up.

I understand that completely - what I don't understand is how can Team Speed prevent that next year?

I ask, because it looks like this ASO/cheating question has been satisfied....so, even if that didn't occur - we'd still have the CV joint issue.

Anyone techy enough to know about these things? Seems like those boots could rip at any time?

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Permalink Reply by AZBadseed on January 14, 2012 at 8:28am

The are susceptible to failure because they are "out in the open" on most IRS cars. It seems like the arms provide a lot of protection for the outboard cv's on the hummer, but so many miles and cycles and crazy terrain that it is not an uncommon thing.
I have had several rip, tear, or come loose on my 3000 car. Ask 100 people with some IRS experience in the desert, you're bound to get 100 different answers.
The main problem is you don't know it's ripped from inside the car until the CV fails. The changing it is a hell of a chore especially in sand/fesh fesh/ silt, etc.
If you get lucky enough to see one ripped or torn or something, while looking at the car, or changing a tire you can repair it, with duct tape, or a leather boot, or something like that.
I've taped my axle to a CV before and continued on to finish a race 100 miles later.
I a can of Lectra-Clean, some grease and duct tape....ALWAYS in my car! Haha

Permalink Reply by ivanspeed on January 14, 2012 at 8:33am

change them daily...

Permalink Reply by FD REBEL on January 14, 2012 at 10:27am

Yes! If you can? And use "Swepco 101" grease it sticks like glue and has a ultra mega high pressure rating.

Permalink Reply by FD REBEL on January 14, 2012 at 8:36am

I have used that driveshaft set-up similar to the one on the hummer for MANY SCORE races. The CV is a highly modified 930 or 940 made to run at high angles and high horsepower, it is lubraicated by a very very high quality grease and protected by a boot made from rubber or leather if the boot fails dirt/water can get in and trash it fairly quickly. I have had boots fail and the CV has lasted 50+ miles before failing because the grease has done its job... until, it gets so saturated with dirt/dust it fails.

Now, when Fesh Fesh (silt) gets into a CV from a tear in a boot it is so fine (powdery) that is causes the grease to fail much earlier, it turns the grease into usless pancake batter!
My fix for the problem would be a rubber inner boot with a heaver leather one over the top... problem fixed.

Permalink Reply by Hyteq Redneq on January 14, 2012 at 8:54am

From a picture I saw of it (don't ask for a link, I didn't save it) they were using both a rubber inner boot and leather outer one. I suspect this was caused by a rock tearing through everything. The setup they have has to be pretty good, how many thousands of miles of Dakar has the Hummer gone through over the years. The only improvement I could suggest is to have a fairly heavy gauge mesh embedded in the leather boot.

Permalink Reply by FD REBEL on January 14, 2012 at 10:31am

Or make the boots kevlar imbeded......Ohoo..Hooo.. off to the drawing board for another patent.. Thanks for the idea...

Permalink Reply by Mark R on January 14, 2012 at 10:26am

robby saying if we just greased it we may have won. my veiw. if you just greased it it could have siezed up later locked the truck up spun and rolled it . Then he would not have won the next stage to prove them wrong! so changing it sucked and we lost but it could have been the better of two evils. just my 2c.

Permalink Reply by redlinetech on January 14, 2012 at 11:47am

I remember some company trying to market these "bootless" high angle CV joints a decade ago for off road racing. They look like 2 paired universal joints. No boot to tear. Some early 4WD TT trucks used them back then. Maybe RGM needs to take a look at those again?

Permalink Reply by redlinetech on January 14, 2012 at 11:48am
Permalink Reply by Chad Nuzman on January 14, 2012 at 1:23pm

Needs kevlar cv boots!

Permalink Reply by ivanspeed on January 14, 2012 at 5:21pm

for 2013
1.14 alternators for every stage and better protection from elements and cooling
2. new cv's after every stage
3.Tons of serpentine belts or switch to double v belt set up
4. spare tire strap set up new one
5.TEST TEST TEST

Permalink Reply by NIKAL on January 14, 2012 at 5:41pm

My understanding is the boot did not fail. It was the clamp that holds the boot on is what broke causing the boot to come loose. Because of the air inflation set up on the ProAm hubs, I cant be 100% sure how the CV is in the hub. But the standard midboard hub the CV can be tough to get out of the hub. I can see how changing the whole hub could be quicker.

And as far as RG making the decision to change the CV vs. just re-packing it is probably because he knew silt was in the CV and he still had another stage to do. Changing it on the side of the road would be better the trying to do the same job on some sand dune. If that CV was to fail it will almost for sure wipe out the axle. I dont know if they carry a spare axle in the car. That alone could cause a DNF.

My guess is only after being back at his pit and looking at the CV and the amount of dirt that might have been in it, did RG realize that adding grease would have been the better choice. But you cant race in hind sight and you cant always tell how much dirt might have got in the CV, and how bad it could have damaged the CV. You really need to tear the CV down and clean it to see how bad it was. All you can do is put this in the memory bank for next time.

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