M6 guys with surviving 12-bolts inside!
04-22-2005 | 09:04 PM
#24
Banned
Joined: Mar 2005
Posts: 223
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Originally Posted by SUX2BU
I was going to get HUGE axles too but then i read Moser web site.
Should you be concerned about breaking an axle?
To achieve maximum performance you should use the smallest axle available that will safely handle the torque your car produces.
The torque rating of Moser Engineering Custom Alloy Axles are as follows:
30 Spline - 6,200 ft. lbs. (per axle)
31 spline - 7,000 ft. lbs. (per axle)
33 spline - 8,200 ft. lbs. (per axle)
35 spline - 9,600 ft. lbs. (per axle)
40 spline - 12,000 ft. lbs. (per axle)
Which axle size is right for me?
The way to pick your axles is so one axle will handle all of the maximum torque your car can produce. That way it is practically impossible to break an axle because you have at least a 200% safety factor.
Should you be concerned about breaking an axle?
To achieve maximum performance you should use the smallest axle available that will safely handle the torque your car produces.
The torque rating of Moser Engineering Custom Alloy Axles are as follows:
30 Spline - 6,200 ft. lbs. (per axle)
31 spline - 7,000 ft. lbs. (per axle)
33 spline - 8,200 ft. lbs. (per axle)
35 spline - 9,600 ft. lbs. (per axle)
40 spline - 12,000 ft. lbs. (per axle)
Which axle size is right for me?
The way to pick your axles is so one axle will handle all of the maximum torque your car can produce. That way it is practically impossible to break an axle because you have at least a 200% safety factor.
04-22-2005 | 10:06 PM
#25
When your talking about impact loading, you can't really compare the torque rating of the axle vs what rwtq the car is producing. The impact value is much higher. It's very difficult to quantify impact values. I design oilfield equipment, and what was use at work as a very rough rule of thumb is multiply the force x 20 and that will give you an estimate of the impact force. In this case, a car producing 400 ft-lbs would produce about 8000 ft-lbs of "impact" torque. Therefore, it might be just about time to upgrade to a 33 spline axle. my .02
04-22-2005 | 10:26 PM
#27
Originally Posted by Dragula
I think your refering to the Bernoulli's principle of hydraulics as it relates to fluids. That's much differnet than tires on a track.
wrong!
I think your refering to the Bernoulli's principle of hydraulics as it relates to fluids. That's much differnet than tires on a track.
wrong!
I think the're the expert, not you!
04-22-2005 | 10:39 PM
#28
Banned
Joined: Mar 2005
Posts: 223
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Originally Posted by Dragula
Then why would moser go thourgh the trouble of using 1st gear ratio and axle ratio in there calculation. No where did you take this into consideration in your 400 ft*lbs X 20 = 8000 ft*lbs calculation.
I think the're the expert, not you!
I think the're the expert, not you!
Ok, so according to Moser, a car that produces 500 ft-lbs of torque at the flywheel would produce 500*2.97*4.10*.85 = 5175 ft-lbs of torque. .85 being the drive train loss factor and 2.97 being the first gear ratio. Then, you would have to divide 5175 ft-lbs by 2 given that there are two axles. That gives you 2587.5 ft-lbs per axle. So you are saying that a 31 spline axle will hold up behind a motor producing 500 ft-lbs or torque!!!
Wrong!!
04-22-2005 | 11:02 PM
#29
Quote:
Originally Posted by Dragula
Then why would moser go thourgh the trouble of using 1st gear ratio and axle ratio in there calculation. No where did you take this into consideration in your 400 ft*lbs X 20 = 8000 ft*lbs calculation.
I think the're the expert, not you!
Ok, so according to Moser, a car that produces 500 ft-lbs of torque at the flywheel would produce 500*2.97*4.10*.85 = 5175 ft-lbs of torque. .85 being the drive train loss factor and 2.97 being the first gear ratio. Then, you would have to divide 5175 ft-lbs by 2 given that there are two axles. That gives you 2587.5 ft-lbs per axle. So you are saying that a 31 spline axle will hold up behind a motor producing 500 ft-lbs or torque!!!
Wrong!!
Originally Posted by Dragula
Then why would moser go thourgh the trouble of using 1st gear ratio and axle ratio in there calculation. No where did you take this into consideration in your 400 ft*lbs X 20 = 8000 ft*lbs calculation.
I think the're the expert, not you!
Ok, so according to Moser, a car that produces 500 ft-lbs of torque at the flywheel would produce 500*2.97*4.10*.85 = 5175 ft-lbs of torque. .85 being the drive train loss factor and 2.97 being the first gear ratio. Then, you would have to divide 5175 ft-lbs by 2 given that there are two axles. That gives you 2587.5 ft-lbs per axle. So you are saying that a 31 spline axle will hold up behind a motor producing 500 ft-lbs or torque!!!
Wrong!!
Hell by what your saying we all should have gotten 40 spline axles for a safety factor in your calculation.
All I've said is that your equation of 400 lb*ft. X 20 = 8000 lb*ft is innaccurate. Your justification for this reasoning is bogus.
A 31 spline axle should be able to hold the torque and ratios you've listed. Assuming it is set up correctly and maintained properly.
A lot of the axle breakage is not due to the axle, it's due to the setup. A weak axle housing will flex, if the housing flexes, your not only putting torsional stress on the axle, your also putting longitudinal stress on them. Therefor it can break.
04-23-2005 | 12:38 AM
#30
Moser 12-Bolt/4.10's/ Eaton HDPosi/33 Spline/Girdle/ABS/TCS/ About 7,000 Very,Very Hard Miles on it!!!! Whines like a SOB, but been doing that since new, besides the whining very happy with it!!!
Other Mods: Every Suspension Piece you can think of + 6-Point Cage, Stock Motor, Stock Clutch,Stock T-56/ Steel DS/ Nitto DR 275/45/17
Beat the hell out of it everytime it on the Road or Track/ Drag Racing and Autocrossing /Tire-Blistering Burnouts/Donuts / 100mph+ Freeway Runs/ you name it it has been through it
/ Only Problem was last weekend took the Stock Broken Tranny Mount off and put Poly Tranny Mount on, next day Cracked the Extension Housing on my T-56 
/ Hey something had to give, Car is Soooo Solid, Tranny is weakest link now/ Gotta replace Tranny Extension Housing and while Tranny is out, Putting Spec 3 Clutch and Flywheel in!!!
Norwalk last October: Dumping the Clutch at 6K, Wrinkling the DR's, and Pullin the Tires off The Ground Every Run
!!!! 12-Bolt sure is Tons of Fun!!!! 
Other Mods: Every Suspension Piece you can think of + 6-Point Cage, Stock Motor, Stock Clutch,Stock T-56/ Steel DS/ Nitto DR 275/45/17
Beat the hell out of it everytime it on the Road or Track/ Drag Racing and Autocrossing /Tire-Blistering Burnouts/Donuts / 100mph+ Freeway Runs/ you name it it has been through it
/ Only Problem was last weekend took the Stock Broken Tranny Mount off and put Poly Tranny Mount on, next day Cracked the Extension Housing on my T-56 / Hey something had to give, Car is Soooo Solid, Tranny is weakest link now/ Gotta replace Tranny Extension Housing and while Tranny is out, Putting Spec 3 Clutch and Flywheel in!!!Norwalk last October: Dumping the Clutch at 6K, Wrinkling the DR's, and Pullin the Tires off The Ground Every Run
!!!! 12-Bolt sure is Tons of Fun!!!!
04-23-2005 | 01:23 AM
#31
I am not a survivor.
425 rwhp 390 tq 6k clutch dumps on 28/12.50 et streets w/ 4.11 eaton posi and took several teeth off the ring gear. Switched over too 4.56 and spool and haven't had a problem since.
425 rwhp 390 tq 6k clutch dumps on 28/12.50 et streets w/ 4.11 eaton posi and took several teeth off the ring gear. Switched over too 4.56 and spool and haven't had a problem since.
04-23-2005 | 01:16 PM
#32
TECH Enthusiast
Joined: Nov 2004
Posts: 659
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From: Red Stick, LA
I am glad to see there are a few engineers here, but to calculate the "shock force" on an axle would be difficult (Break out the Math Cad). You have to figure out Friction of the tires and clutch as well. The clutch and tires may even need some DE to account for the bouncing of both. This would be very complicated, but could be done. I imagine Moser/Strange/Currie have a pretty good idea what you will need as far as axles go. Of course you could just use some pro stock stuff and not ever need to worry.
04-25-2005 | 10:56 PM
#33
Banned
Joined: Mar 2005
Posts: 223
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Originally Posted by Dragula
Before you put me on the defensive please explain your calculation.....
Hell by what your saying we all should have gotten 40 spline axles for a safety factor in your calculation.
All I've said is that your equation of 400 lb*ft. X 20 = 8000 lb*ft is innaccurate. Your justification for this reasoning is bogus.
A 31 spline axle should be able to hold the torque and ratios you've listed. Assuming it is set up correctly and maintained properly.
A lot of the axle breakage is not due to the axle, it's due to the setup. A weak axle housing will flex, if the housing flexes, your not only putting torsional stress on the axle, your also putting longitudinal stress on them. Therefor it can break.
Hell by what your saying we all should have gotten 40 spline axles for a safety factor in your calculation.
All I've said is that your equation of 400 lb*ft. X 20 = 8000 lb*ft is innaccurate. Your justification for this reasoning is bogus.
A 31 spline axle should be able to hold the torque and ratios you've listed. Assuming it is set up correctly and maintained properly.
A lot of the axle breakage is not due to the axle, it's due to the setup. A weak axle housing will flex, if the housing flexes, your not only putting torsional stress on the axle, your also putting longitudinal stress on them. Therefor it can break.
Back to the formlua, I know it's overkill in that it overestimates the amount of impact force. The reason for this is that the equipment I design, it pays to overestimate the amount of impact force to produce a safer design. I have made dozens of designs using this very simple formula and have never had a failure yet. As someone else pointed out, it is very hard to predict the impact force of a complex system such as a drivetrain. But again I was just trying to illustrate the phenomenon of IMPACT LOADING. Sorry if I'm talking above your head. I am through with this thread!!
I think you are taking this a little to seriously Red Just my .02....................
04-29-2005 | 09:59 AM
#36
Seven ring and pinions in 9 thousand mi,bolt on car full suspension max impact loading
with 6200 clutch dumps.Keeps loosing pinion bearings and hurtind the gears.Solid pionion spacer did not help this one.
with 6200 clutch dumps.Keeps loosing pinion bearings and hurtind the gears.Solid pionion spacer did not help this one.
04-29-2005 | 08:06 PM
#37
i'm on my 4th year with my moser 12 bolt,33 splin,eaton and 4.11's. i have the ram 910,26x11.5x16 m&h racemasters and i luanch with a dump at 6,000-6,500rpm's. i have some gear noise but she has been holding togeather great.
04-29-2005 | 08:34 PM
#38
I've been running my Moser 12 bolt with 30 spline axles for close to 4 years now. I've suffered through leaks, a few axle bearings and had to replace the gears due to a shop screwing up my pinion gear in the process of fixing a pinion seal leak. The posi needs to be rebuilt due to one wheel peel, but it still is holding together.
04-30-2005 | 09:04 AM
#39
I never said that my calculation was accurate. As a matter of fact, if you re-read my post it says that it is a very rough estimate. I also never claimed to know more about designing differentials than Moser. Of course they are the experts. And I am sure that the ratings of the axles are accurate. What I am simply trying to illustrate that there are probably more to the calculations than simply the torque of the motor, the gear ratio of the 1st gear, and the gear ratio of the differential. You cannot tell me that there are 8,000 ft-lbs of torque on the axle due to the motor alone! There is a little thing called IMPACT LOADING that has quite a significant effect on whether or not you have enough splines in your axles or not. Guys running M6 transmissions can tell you all about this. If you don't believe me, try taking a Mechanical Engineering course in Statics and Dynamics for Engineers. And by the way, good luck on that.
Back to the formlua, I know it's overkill in that it overestimates the amount of impact force. The reason for this is that the equipment I design, it pays to overestimate the amount of impact force to produce a safer design. I have made dozens of designs using this very simple formula and have never had a failure yet. As someone else pointed out, it is very hard to predict the impact force of a complex system such as a drivetrain. But again I was just trying to illustrate the phenomenon of IMPACT LOADING. Sorry if I'm talking above your head. I am through with this thread!!
Back to the formlua, I know it's overkill in that it overestimates the amount of impact force. The reason for this is that the equipment I design, it pays to overestimate the amount of impact force to produce a safer design. I have made dozens of designs using this very simple formula and have never had a failure yet. As someone else pointed out, it is very hard to predict the impact force of a complex system such as a drivetrain. But again I was just trying to illustrate the phenomenon of IMPACT LOADING. Sorry if I'm talking above your head. I am through with this thread!!