DeLorean wrote:Crazyswede wrote:Luke and I discussed the whole monster rear axle idea at one point and we wondered what the danger would be. As in right now when you hit something hard you bend the rear axle. Well if the rear axle is indestructible do you run the risk of tearing the whole axle out of the car or severely damaging the axle mounts thus rendering your car undriveable? The car was a little squirrelly with axle as it was but it was still moving since the axle gave in.
I have discussed similar with an old time saab racer that lives in palmerton, PA who insisted the same thing about the front control arms. he is a big fan of "just strong enough" so that the items that are attached to the car will bend and break before the car itself does. I guess there is logic to that?
Yes I agree, thing is that one something is strengthen it transfers loads to another location, that know needs to be strengthend, which repeats the cycle over and over.
The idea is to get a component reliable enough to do the job for a given time, just like tires or brake pads, they work great for awhile then need replaced, same holds true for other parts, they can be taken off inspected and then dealt with as needed.
I recall talking with Murray Thomas of TAD when Henry Joy was rallying a Mitusbishi EVO in the mid to late 90's, we were at Rim of the World Rally and Henry was having an enormus failure rate of drive axles on this event, lots of small jumps, sand and turning-sometimes at the same time, these failures had caused him to loose the lead.
I said to Murray, "whats your maintance schedule on the car?" He said, "it breaks we replace it." I said, "that's an exspensive way to loose!"
Murray said, "it's hard to know the life span of parts like axles." I agreed, however I said, "thing is we are here at Rim, axle breaking is going to happen, that's a given. I know axles are exspensive but you still have to buy them either as spares or repalcements right?" Murray agreed. "So get several sets, change them out at major service, that would be 3 sets for this event. Then when you go back to the shop inspect them, magnaflux, dye, what ever it takes. Log what axles were used for what event or even what stages-some stages are harder on things then others. This will help give you a life cycle of the parts. Thing is, Henry would be much happier with the car reliable and winning events then leading and breaking out, the monies going to be spent either way and if you explain what you're doing he'll be on board."
I brought this up because it shows the tires were getting better grip, via suspension, tire compounds, the LSD tightened up, and that more torque from the modified engine created more loads on the axles. Even thou these were factory competition axles they were still the week link, if they had been stronger then more likely the wheel bearings would have failed. Which would mean that the wheel hubs would then need to be stronger/larger to carry a bigger bearing, which is even more costly.
It shows that loads transfer and one can keep chasing part after part trying to get everything super strong and heavier but pushing the load further down the line, and that finding a simple balance is both effective and less costly.
Does this make sense?
IMHO,
Sean Tennis
But getting carried away and making it heavier than neccessary seems silly.
