Axels...?

[formercrewguy]

I'm sure this has been discussed before, but here goes.

Are gun drilled axels stronger than solid?

[wisdirtfan]

No just lighter but I'm sure many guys will argue with me.

[MasterSbilt_Racer]

No just lighter but I'm sure many guys will argue with me.

It comes down to material. The lack of a middle has little effect on strength.

[mab475]

Wrong it has everything to do with strength. I have seen many gundrilled axels come apart on the RR. The weight savings is almost all static because with the center being drilled it losses virtually no rotational weight. I'd rather have reliability and finish a race.

[Matt49]

I get the reliability side of the argument but with regard to weight I see the savings being more in the unsprung mass category than the rotational mass category. As mab475 stated, the mass is too close to the center to decrease the moment of inertia by much.

[mattworx]

im just spit balling but it has everything to do with traction that no one talks about. there are many different axel materials and for one reason to allow twist so you don't brake traction .a solid axel has very little twist and will brake the tires traction and they don't normally brake .the gun drilled do brake but you give that up for bite and weight at least that's the way I understand it

[Matt49]

I don't know for sure but I'm betting that there is very little axle twist (regardless of axle material and construction) in slick track conditions on dirt. Meaning I think the torque required to twist the axle far exceeds the amount of torque that would slip the tire.
I understand the theory behind all this but let's think about. Assuming the axle is acting like a torsion bar, it is basically just storing the energy but it still has to go somewhere. It eventually has to be released right? With a solid spool, the only place to release it is back to the tires. Even if it worked (the axle twist) you're just delaying the inevitable. Which I think would benefit in high traction situations but I don't think it is much of a play in dry slick conditions. I could be crazy.

[mattworx]

yep under stand what your thinking not that your wrong but this is how I look at it .as you get back on the throttle the axel DOES twist and as its energy is stored like you said it is then realest in time .not at the moment you have the least traction (its the shock factor on the tire patch to ground ) allowing the tire to maintain grip . mark your axle with a straight line ,we all do and when it stays twisted its time to replace it .that there tell me the axle is a torsion bar its flexing until the material finally fails. solid axles flex less so they don't maintain grip as well on a dry track . can someone explain why im write or wrong or if its all in my head.

[hpmaster]

I have seen a gun drilled axle "unwrap" or uncoil, it wasn't pretty and was a bear to try to take apart and salvage parts too. Don't know who made that "gem". Still use them.

[Matt49]

SCD,
Very interesting. I won't ask how much was too much but I would be interested in seeing torque numbers on some of these axles. The KERA stuff appeals to me from an engineering standpoint but I guess I just feel like in slick conditions it wouldn't be as big of a big play. But I won't let a feeling get in the way of real data if it exists. I guess if people see me changing out axles at the race track, the cat will be out of the bag on this one :-)

[MasterSbilt_Racer]

Wrong it has everything to do with strength. I have seen many gundrilled axels come apart on the RR. The weight savings is almost all static because with the center being drilled it losses virtually no rotational weight. I'd rather have reliability and finish a race.

The material in the center provides little rotational stiffness. Just look at the equations. Gun drilled axles break and splinter all the time. They have a higher case hardening and are brittle.

[mattworx]

I new the answer to my on question on axle just don't have any # to back it up other then R&D on the track .just wanted to see if anyone else did. I don't now if there is any data out there but I sure no it works using different axels .engineering is great but just because on paper it works or doesn't work that don't mean in real life it will or will not work .people that relay only on # will never get to there full potently because you never have all the data needed to come up with the answer

[Matt49]

I don't change mine anymore I found the right combo for me.

Im sure you can produce the real data for the rest of us simpletons.

I wasn't implying anyone was a simpleton. Simply saying that it would be nice (and informative) to see some torque numbers on the axles. I'm sure they could be tested just like a torsion bar.

[Matt49]

This: "engineering is great but just because on paper it works or doesn't work that don't mean in real life it will or will not work"...is only a partially true statement.
If it works on paper and doesn't work in real life (or vice versa), your engineering is flawed. In most cases meaning not all variables were taken into account.
It blows my mind how often people think that things in the physical world are somehow mystical and cannot be explained by the underlying mathematics. Math is the language of physics. I'm not saying that on-track testing isn't valuable but in order to understand the "why" behind something working, you have to dig a little deeper. "Why" is the question that takes everything to the next level.
Different schools of thought I guess...

[Matt49]

I understand HOW it works. But do you think the folks at Stangeoval figured all this KERA stuff out by trial and error? You're right, it isn't rocket science. It's pretty simply really but it's nice to have some data to put the information to real use. I'm not asking anybody to produce it, just saying it would be nice to see.

I actually had some strange ideas about axles, rotating weight, etc. that were somewhat counter-intuitive at first but maybe worth sharing. We all agree that decreasing rotating weight decreases overall moment of inertia. But in trying to control traction in slick conditions, could this be a bad thing? In other words, would having a larger moment of inertia act like free traction control by "dampening" the torque of the engine? Something to think about.

[Bubstr]

Excuse me if I am missing the point on stored energy of a solid axle and a gun drilled axle. When I went to school, over 45years ago, the stored torsional energy of a bar or tube had negligible differences. It was based off of bar diameter, and bar length.

If you lock one end of a Torsion bar and turn the other with a torque wrench, to a specific degree, then increase it to the net degree, you would have that value. If it seems much like a spring rate checker, your right. A torsion bar is nothing more that a straight spring, that would be dependent on diameter and length.

All this said, the axles ability to store energy would be based on diameter and length, not if it's hollow. Hollow would only have the durability effect, if all other things where equal.

If you where looking for this stored energy to overcome the slip angle tolerances of a tire, I believe you would have better luck, looking into tire sidewall composition, tire pressures and wheel width to overcome oscillation that comes with exceeding the tire slip angle. That is my thought on this.

As a after thought, reducing un-sprung weight would aid in oscillation control. Gun drilled axles would have some effect on this.

[Bubstr]

I understand HOW it works. But do you think the folks at Stangeoval figured all this KERA stuff out by trial and error? You're right, it isn't rocket science. It's pretty simply really but it's nice to have some data to put the information to real use. I'm not asking anybody to produce it, just saying it would be nice to see.

I actually had some strange ideas about axles, rotating weight, etc. that were somewhat counter-intuitive at first but maybe worth sharing. We all agree that decreasing rotating weight decreases overall moment of inertia. But in trying to control traction in slick conditions, could this be a bad thing? In other words, would having a larger moment of inertia act like free traction control by "dampening" the torque of the engine? Something to think about.

Wouldn't a gear change decrease or increase torque, with out a total loss of it if needed? Just looking at all the angles. I've seen people decreasing engine RPM to get to a lower torque number on their torque curve for corner exit and increasing RPM to overcome engine drag entering a corner. All said wouldn't a driver with a feather foot and good seat of the pants feel, overcome most of these things. It's darn hard to tune a car for someone that treats the go pedal as a on / off switch.

[mattworx]

do you all now why a engineer cant make a race car work perfect ? its because the driver and track conditions are always changing so the #s are always changing. so in the end it comes down to what works for me might not work for you. no matter what the #s are(because you don't have them all) R&D is as important as #s or even more so on dirt cars . this is true or there would be only one car and one setup

[Matt49]

Mattworx, did you miss the part where I said, "I'm not saying that on-track testing isn't valuable"?
You make it sound like I'm saying all racing is done in a notebook or on a computer. I'm not. But you are downplaying the importance of engineering which is critical to improving performance at high levels. That's why F1 teams employ dozens and dozens of engineers and spend millions and millions of dollars on in-house engineering. There's an old saying: "races are won in the shop". What do you think that means? R&D is about a lot more than track testing. It's about doing homework and understanding what is really happening when you make a change. The track testing should be the proof, not the guess work. There is a distinct difference between the two.

But moving on...

There are definitely two schools of thought on the gearing deal. There's the one that says gear up (higher ratio) as the track slows down to get back in your power band. Then there's the one that says gear down to tame the car on exit. Personally I say leave it alone and just wheel-spin your way up the RPM you want :-)
(That's supposed to be a joke for those of you that don't detect sarcasm)

[7uptruckracer]

Mattworx, did you miss the part where I said, "I'm not saying that on-track testing isn't valuable"?
You make it sound like I'm saying all racing is done in a notebook or on a computer. I'm not. But you are downplaying the importance of engineering which is critical to improving performance at high levels. That's why F1 teams employ dozens and dozens of engineers and spend millions and millions of dollars on in-house engineering. There's an old saying: "races are won in the shop". What do you think that means? R&D is about a lot more than track testing. It's about doing homework and understanding what is really happening when you make a change. The track testing should be the proof, not the guess work. There is a distinct difference between the two.

But moving on...

There are definitely two schools of thought on the gearing deal. There's the one that says gear up (higher ratio) as the track slows down to get back in your power band. Then there's the one that says gear down to tame the car on exit. Personally I say leave it alone and just wheel-spin your way up the RPM you want :-)
(That's supposed to be a joke for those of you that don't detect sarcasm)

I like the dual boxes with the secondary box having the retarded timing lol

[Matt49]

:-)
Or disconnect the secondaries...
Or move the throttle linkage down on the pedal mount...
I like the throttle linkage move. The powers still there when you need but you just have to want it a little more.
Lots of ways to skin that cat.

[7uptruckracer]

Extra effective when you forget to change your pedal stop lol

:-)
Or disconnect the secondaries...
Or move the throttle linkage down on the pedal mount...
I like the throttle linkage move. The powers still there when you need but you just have to want it a little more.
Lots of ways to skin that cat.