Road America PCA: Video Thread
09-10-2013, 01:41 PM
#61
Nordschleife Master
Thanks guys. When I saw that impact was unavoidable, I tried to steer the car to the the right a bit to give myself more room (wall goes away right), but was aware about the danger of hitting the gravel going sideways.
Yes about the tensionners
And agree about J class... but have lots of $$ invested in the cup box (purchase and repair; big mistake in hind sight), so not an easy one.
Yes about the tensionners
And agree about J class... but have lots of $$ invested in the cup box (purchase and repair; big mistake in hind sight), so not an easy one.
09-10-2013, 01:46 PM
#62
Rennlist Member
Wow, sorry Francois :-(
"only" 40MPH is a hard impact still and you should be happy to be OK.
Crap happens, you will fix it and thanks for posting.
Its a loss but could be a lot worse.
"only" 40MPH is a hard impact still and you should be happy to be OK.
Crap happens, you will fix it and thanks for posting.
Its a loss but could be a lot worse.
09-10-2013, 02:21 PM
#63
Three Wheelin'
I don't know a lot about those parts on water cooled cars, but I have experience with a stub axle/hub failure on a 911. Actually my wife was driving. In 25+ years, I have only seen this happen once, but I checked in with quite a few friends and racing contacts (with pro experience dating back through the 60's) to get perspective.
In our case, the failure occurred under load in a long left hand corner. The wheel departed and tore up the quarter panel and rear bumper on the way. The brake caliper was knocked off of the control arm and the rotor broke into pieces.
As the wheel sailed off into the sunset, it knocked the oil line off of the tank and many quarts of oil hit the track. On the way, some oil hit the headers, so there was a fire as well.
In any case, with a failure like that shown, it might be a good idea to check in with folks whom have vast experience with the configuration you are running to better understand potential causes. If the part was timed out, so be it. But I have not heard of this on those cars. I would want to know as much as possible and share as much as possible with others.
In our case, we were unable to determine for sure whether the hub broke first or the stub axle broke first. There was some concern that the nut was not properly torqued, but I seriously doubt that cause.
I replaced the parts with good used pieces which were cracked checked before installation. And I have resumed the policy of paint dotting the rear axle nuts-- to me it is a worthwhile practice.
And yes, I have seen them move, even when properly torqued.
I am glad the accident was not much worse in this case.
In our case, the failure occurred under load in a long left hand corner. The wheel departed and tore up the quarter panel and rear bumper on the way. The brake caliper was knocked off of the control arm and the rotor broke into pieces.
As the wheel sailed off into the sunset, it knocked the oil line off of the tank and many quarts of oil hit the track. On the way, some oil hit the headers, so there was a fire as well.
In any case, with a failure like that shown, it might be a good idea to check in with folks whom have vast experience with the configuration you are running to better understand potential causes. If the part was timed out, so be it. But I have not heard of this on those cars. I would want to know as much as possible and share as much as possible with others.
In our case, we were unable to determine for sure whether the hub broke first or the stub axle broke first. There was some concern that the nut was not properly torqued, but I seriously doubt that cause.
I replaced the parts with good used pieces which were cracked checked before installation. And I have resumed the policy of paint dotting the rear axle nuts-- to me it is a worthwhile practice.
And yes, I have seen them move, even when properly torqued.
I am glad the accident was not much worse in this case.
09-10-2013, 02:55 PM
#64
Burning Brakes
I don't know a lot about those parts on water cooled cars, but I have experience with a stub axle/hub failure on a 911. Actually my wife was driving. In 25+ years, I have only seen this happen once, but I checked in with quite a few friends and racing contacts (with pro experience dating back through the 60's) to get perspective.
In our case, the failure occurred under load in a long left hand corner. The wheel departed and tore up the quarter panel and rear bumper on the way. The brake caliper was knocked off of the control arm and the rotor broke into pieces.
As the wheel sailed off into the sunset, it knocked the oil line off of the tank and many quarts of oil hit the track. On the way, some oil hit the headers, so there was a fire as well.
In any case, with a failure like that shown, it might be a good idea to check in with folks whom have vast experience with the configuration you are running to better understand potential causes. If the part was timed out, so be it. But I have not heard of this on those cars. I would want to know as much as possible and share as much as possible with others.
In our case, we were unable to determine for sure whether the hub broke first or the stub axle broke first. There was some concern that the nut was not properly torqued, but I seriously doubt that cause.
I replaced the parts with good used pieces which were cracked checked before installation. And I have resumed the policy of paint dotting the rear axle nuts-- to me it is a worthwhile practice.
And yes, I have seen them move, even when properly torqued.
I am glad the accident was not much worse in this case.
In our case, the failure occurred under load in a long left hand corner. The wheel departed and tore up the quarter panel and rear bumper on the way. The brake caliper was knocked off of the control arm and the rotor broke into pieces.
As the wheel sailed off into the sunset, it knocked the oil line off of the tank and many quarts of oil hit the track. On the way, some oil hit the headers, so there was a fire as well.
In any case, with a failure like that shown, it might be a good idea to check in with folks whom have vast experience with the configuration you are running to better understand potential causes. If the part was timed out, so be it. But I have not heard of this on those cars. I would want to know as much as possible and share as much as possible with others.
In our case, we were unable to determine for sure whether the hub broke first or the stub axle broke first. There was some concern that the nut was not properly torqued, but I seriously doubt that cause.
I replaced the parts with good used pieces which were cracked checked before installation. And I have resumed the policy of paint dotting the rear axle nuts-- to me it is a worthwhile practice.
And yes, I have seen them move, even when properly torqued.
I am glad the accident was not much worse in this case.
09-10-2013, 03:18 PM
#65
Rennlist Hoonigan
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Across most cars, this is not an uncommon failure. You have all the stress risers of the spline, plus the cross holes for the cotter pin, plus the hollowed end. I've seen it in lots of Formula Fords, FC, Miatas, and Porsches.
09-10-2013, 06:20 PM
#66
Nordschleife Master
So now, what about the spindle (name?), the bolt on the outboard end of the lower control arms that connects to the knuckle? I don't think that it's removable, so should we replace the LCAs every couple of years? I've seen those fail as well.
09-10-2013, 06:46 PM
#67
Rennlist Member
The first two pics are your set up on the GT3
The stub axle is part of the axle itself and inserts into the splined hub.
The wheel bearing is pressed into the wheel carrier and the hub is pressed into the wheel bearing.
There is a retaining plate that holds in the bearing, but really it is the axle/stub axle that holds everything together and pre-loads the bearing.
That is why once the axle breaks, the hub can easily pull out of the wheel bearing.
The third picture is how Porsche use to do it with the separate stub axle assembly. They started using stub axles integrated with axle in the mid 80's.
The stub axle is part of the axle itself and inserts into the splined hub.
The wheel bearing is pressed into the wheel carrier and the hub is pressed into the wheel bearing.
There is a retaining plate that holds in the bearing, but really it is the axle/stub axle that holds everything together and pre-loads the bearing.
That is why once the axle breaks, the hub can easily pull out of the wheel bearing.
The third picture is how Porsche use to do it with the separate stub axle assembly. They started using stub axles integrated with axle in the mid 80's.
09-10-2013, 06:55 PM
#68
Rennlist Member
This is from the Dart Auto site.
http://www.dartauto.com/projects/por...-installation/
Shows the wheel carrier sans wheel bearing.
Damaged hub and new hub.
Looks like the inner race of the bearing spinning on the hub and grooving hub.
Bearing being pressed into wheel carrier.
http://www.dartauto.com/projects/por...-installation/
Shows the wheel carrier sans wheel bearing.
Damaged hub and new hub.
Looks like the inner race of the bearing spinning on the hub and grooving hub.
Bearing being pressed into wheel carrier.
09-10-2013, 09:01 PM
#69
Three Wheelin'
hey dude, thank goodness you were ok, could have been much worse.
my couple of thoughts:
1. to anyone even remotely going near a race track, you should be wearing full safety gear, firesuit, undershirts, hans, shoes, gloves always. always. that could have been sooooo much worse; if a fire broke out and you were just cocked a few more degrees clockwide, you could have been pinned;
2. the minute you hit, and hit that hard where you know you're not moving the car, switch off the power. if you have a fuel spill from your tank which is up front-ish, you dont want an electrical fire. if you think you can get out of there, and drive it back, then sure, keep it running. but id have turned off the juice in there,
3. put your visor down right away once you've hit the wall, again, you have no konwledge the car doesnt quickly get engulfed, or nasty smoke comes into the cockpit, but save your eyes and the air you breathe
4. lastly, i might have tried to turn it a smidge to get more of a glancing blow, but you're about right wiht the gravel possibly flipping the car. but, that said, once you have made whatever changes are possible and you are about to actually hit, get your hands off the wheel. guys break hands, wrists shoulders by trying to hold the wheel and it gets jammed at you hard and breaks bones. your hans and harnesses will keep you from moving. cross your arms over your chest real quick to ensure you dont break an arm whacking it about (didnt see center restraint net)....and just hang tight.
just stuff to think about. that could have been real ugly.
glad you were ok . thats most important.
my couple of thoughts:
1. to anyone even remotely going near a race track, you should be wearing full safety gear, firesuit, undershirts, hans, shoes, gloves always. always. that could have been sooooo much worse; if a fire broke out and you were just cocked a few more degrees clockwide, you could have been pinned;
2. the minute you hit, and hit that hard where you know you're not moving the car, switch off the power. if you have a fuel spill from your tank which is up front-ish, you dont want an electrical fire. if you think you can get out of there, and drive it back, then sure, keep it running. but id have turned off the juice in there,
3. put your visor down right away once you've hit the wall, again, you have no konwledge the car doesnt quickly get engulfed, or nasty smoke comes into the cockpit, but save your eyes and the air you breathe
4. lastly, i might have tried to turn it a smidge to get more of a glancing blow, but you're about right wiht the gravel possibly flipping the car. but, that said, once you have made whatever changes are possible and you are about to actually hit, get your hands off the wheel. guys break hands, wrists shoulders by trying to hold the wheel and it gets jammed at you hard and breaks bones. your hans and harnesses will keep you from moving. cross your arms over your chest real quick to ensure you dont break an arm whacking it about (didnt see center restraint net)....and just hang tight.
just stuff to think about. that could have been real ugly.
glad you were ok . thats most important.
Just to bring it back on video topic, here is the vid. Password: rennlist
https://vimeo.com/74200859
BTW, I wasn't spaced out at the end, just obeying instructions to stay belted until workers arrive. Thank God for HANS.
The explanation about the axle break causing this is of course speculation, but something external caused the lock up, because other factors are identical to previous laps (speeds, brake point, etc.).
https://vimeo.com/74200859
BTW, I wasn't spaced out at the end, just obeying instructions to stay belted until workers arrive. Thank God for HANS.
The explanation about the axle break causing this is of course speculation, but something external caused the lock up, because other factors are identical to previous laps (speeds, brake point, etc.).
09-11-2013, 12:53 AM
#70
Nordschleife Master
Doug - Thanks for the mechanicals. I guess that there wasn't anything holding the wheel on after all... I'm grateful that I dodged a bullet; could have been much worse on three wheels.
Steve - Thanks for the safety pointers. I did turn the car off, but without any urgency. I will know better going forward. Driving suit ordered; had to get it anyway for a Chump car race next month.
Steve - Thanks for the safety pointers. I did turn the car off, but without any urgency. I will know better going forward. Driving suit ordered; had to get it anyway for a Chump car race next month.
09-15-2013, 09:31 PM
#71
Rennlist Member
wow, sorry for your loss francois.
let me know if you need help of anykind
safety is really important, i didnt realised it until i smashed
now, im full cage, hans, bucket seat with head restraint. etc...
let me know if you need help of anykind
safety is really important, i didnt realised it until i smashed
now, im full cage, hans, bucket seat with head restraint. etc...
