Performance Driveshaft

[Silver03MM]

Has anyone replaced their driveshaft on their MM with a performance one? If so is there much of a difference?

[DEFYANT]

Has anyone replaced their driveshaft on their MM with a performance one? If so is there much of a difference?

Search the forums. Lots of answers there.

Dennis is having a group purchase on the MMX driveshaft.

[Rider90]

Just get yours rebalanced and save some $$$

[LVMarauder]

+1 to Rider90, go to a reputable driveline shop and get it balanced, run to 137 and no problem, with 4.10's. $50 vs $500

[O's Fan Rich]

And a Metco Driveshaft loop while your at it....

[DEFYANT]

There is the delema.

My research here says this:

For sustained high speed driving, like over 100mph for along time, a MMX driveshaft is in order.

For the occasional blast to 140 and back down to cruising speeds, 75mph, the rebalance is ok.

Question is, what do you intend to do with your car and how much do you want to spend?

Since money is an issue, I may be going with the rebalance to hold me over for a while.

Question for the masses:

I've been running 4:10s for 18 months with NO vibrations at any speed. Suddenly, I recently developed a vibration at 90+ mph. Why?

[Rider90]

And a Metco Driveshaft loop while your at it....
^^ what he said. It's cheap insurance.

[RF Overlord]

I've been running 4:10s for 18 months with NO vibrations at any speed. Suddenly, I recently developed a vibration at 90+ mph. Why?Charlie, that's exactly how it happens. I'm not saying you definitely have a problem, but you might want to check the tailshaft bushing and seal carefully.

Part of the driveline critical speed issue is that it's perfectly possible to have NO vibration, then all of a sudden you have a bad tailshaft bushing and/or seal. This is because the flexing in the driveshaft ISN'T an issue of balance, it's one of stiffness (insert tasteless joke here). The DS can be perfectly balanced in all axes, yet it will still flex at the resonant rotational speed. Anyone who had a vibration with their stock DS (with 4.10s) and found that having it rebalanced cured the problem actually had an out-of-balance DS and is still subject to the same potential critical-speed issue.

Let us know what you find...

[SergntMac]

Two different issues, completely different.

If you think your drive shaft is out of balance, get it balanced. That's a very simple problem with a very simple answer.

However, like Charlie said, if you're doing any serious high speed driving over an extended period of time, replace the drive shaft with the appropriate performance part, or, you will be replacing transmission tail shaft seals and pinion seals, possibly bearings as well.

When the factory driveshaft gets to a certain rotational RPM (above 6000 RPM), the composite metals in the drive shaft start to come apart. It bulges in the center, and whips at the ends, and no balancing job anywhere can prevent a drive shaft from reaching it's harmonic break point.

That's the short story...Google your query and read the years of research by Ford engineers. It's not new, and it's not a problem. Just depends on where you step into the conversation.

[Tallboy]

Charlie, that's exactly how it happens. I'm not saying you definitely have a problem, but you might want to check the tailshaft bushing and seal carefully.

Part of the driveline critical speed issue is that it's perfectly possible to have NO vibration, then all of a sudden you have a bad tailshaft bushing and/or seal. This is because the flexing in the driveshaft ISN'T an issue of balance, it's one of stiffness (insert tasteless joke here). The DS can be perfectly balanced in all axes, yet it will still flex at the resonant rotational speed. Anyone who had a vibration with their stock DS (with 4.10s) and found that having it rebalanced cured the problem actually had an out-of-balance DS and is still subject to the same potential critical-speed issue.

Let us know what you find...

As usual, RF nailed it. Balancing a stock driveshaft will do just that-ensure proper balance. It will not cure the "whip" [think of a jump-rope], if that's what is occuring. No problems here, but I'm on 3:55 gears.

[LVMarauder]

I agree with defyant too, IF you are going to do extended high speed driving do the MMX but for the occasionaly romp to insanity and strong posibility of jail time rebalance should be ok. =)

DEF- Dont know why you all of a sudden have vibration, maybe sign of pending rear end or tail shaft failure?

I go through a pinon seal every six months, just had axle seals replaced as well , not sure if thats due to 4.10's or not.

[sailsmen]

Charlie, that's exactly how it happens. I'm not saying you definitely have a problem, but you might want to check the tailshaft bushing and seal carefully.

Part of the driveline critical speed issue is that it's perfectly possible to have NO vibration, then all of a sudden you have a bad tailshaft bushing and/or seal. This is because the flexing in the driveshaft ISN'T an issue of balance, it's one of stiffness (insert tasteless joke here). The DS can be perfectly balanced in all axes, yet it will still flex at the resonant rotational speed. Anyone who had a vibration with their stock DS (with 4.10s) and found that having it rebalanced cured the problem actually had an out-of-balance DS and is still subject to the same potential critical-speed issue.

Let us know what you find...

What he said, the short version is the DS bends at the higher speeds due to flex, it becomes a banana and causes vibration that can snap off the tailshaft housing.

This is why the Panther platforms come with a speed limiter.

[sailsmen]

"I go through a pinon seal every six months, just had axle seals replaced as well , not sure if thats due to 4.10's or not."

4:10's are not the cause, something is wrong.

[Joe Walsh]

Perfect solution, EXCEPT for cost, is a Carbon Fiber driveshaft.

VERY light and VERY stiff.

[LVMarauder]

"I go through a pinon seal every six months, just had axle seals replaced as well , not sure if thats due to 4.10's or not."

4:10's are not the cause, something is wrong.


Well ive done it three times now, once under extended. Axles two weaks ago. What could it be? The only reason I know its the pinon is when I come back from cali and park on my parents inclined drive way I get yelled at for dripping oil everywhere( and FLM tells me its the pinon) and when its level it does not leak at all. Im sure when its moving it does leak bc of pressure increase but only leaks standing on an incline. ideas? (Sorry for hijacking)

[DEFYANT]

"I go through a pinon seal every six months, just had axle seals replaced as well , not sure if thats due to 4.10's or not."

4:10's are not the cause, something is wrong.

Rear axel alighnment??

Bent tubes??

[SergntMac]

Rear axel alighnment??

Bent tubes??Nah...DS whip.

[sailsmen]

You might want to try marking your drive shaft and rotating it 180*.

Check your control arms to see if they are bent. I don't think the tubes could be bent.

Do you hear a whine from the gears? Try driving w/ the windows up no fan at nite when there is less back ground noise.

Do you drive over 100mph on a regular basis?

[LVMarauder]

rarely over 100 mph and zero noise from the rear end.

[jstevens]

I had mine exchanged with a balanced one at Alternative Auto.

Works great. A lot smoother at 120 than before.

[fastblackmerc]

"I go through a pinon seal every six months, just had axle seals replaced as well , not sure if thats due to 4.10's or not."

4:10's are not the cause, something is wrong.
IMHO.... I can see the transmission tailshaft bushing & seal being damaged by an out of balance driveshaft, but the pinion & axle seals?????? Something else is going on there.

[Dennis Reinhart]

Just get yours rebalanced and save some $$$


This will not cure the problem the Metal Matrix Drive shaft will, this is what the FHP is using in all the Marauders we did and they have cars clocked at over 155 MPH, the stock draive shaft is rated for about 125 MPH with 355 gears.

Drive line Critical speed
<HR style="COLOR: #d1d1e1" SIZE=1><!-- / icon and title --><!-- message -->What it is –
Every rotating object has a “critical” speed or resonant speed, which is a function of its design, mass and stiffness. This is when the driveshaft is whipping in the middle, rather than spinning on a true centerline. For a driveshaft, this is also called “first bending mode”, indicating the shaft actually bows out into a boomerang shape (on a micro-scale). This first mode bending speed is usually referred to in a driveshaft frequency.

What it does –
The energy stored and released through the deflection of the driveshaft through the resonance creates lateral and vertical accelerations of >10g at the problem frequency, which results in broken transmission extension housings, cases and causes moderate to severe vibration at highway speeds (> 70 mph), particularly with axle ratios numerically higher than 3.27:1. This energy release, when compounded by excessive driveshaft imbalance (some is good, too much or too little is not), companion flange run out/imbalance and excessive driveline angles provides the driver with excessive vibration and boom and tortures the driver and driveline components in general.

Because of this, most vehicles have a speed limiter to prevent from entering this mode and causing damage to the driveline.

Some detail –
As mentioned above, the driveshaft rotates at a certain speed based on rear axle ratio; tire size and road speed, but is independent of engine speed (unless you have a vehicle such as a Porsche 944 or C5 Corvette which utilize torque tubes and transaxles, in which case the driveshaft turns at engine speed).

The factors governing driveshaft critical speed include its material properties (i.e., Bulk Modulus of Elasticity which is roughly analogous to material stiffness), diameter, and length and to a lesser degree, wall thickness.

The only factor you can really modify to affect critical speed is material choice. Length is package-dictated, and diameter is usually constrained by driveline tunnel space as well. The answer then becomes a bit simpler – replace your steel shaft with an aluminum or MMC (metal matrix composite) shaft. Both offer reduced weight, which is key in this frequency range. MMC offers the additional bonus of additional damping and stiffness over a typical aluminum alloy.

As mentioned above, at the frequencies in question, a change in rotational mass has a greater impact on resonant frequency than a change in stiffness does, partly since it is easier to reduce mass than increase stiffness (adding stiffness almost invariably means adding mass -- a vicious circle), but particularly since resonant frequency is equal to the sqrt (k/m), where m is mass and k is stiffness. Here m is a stronger function being the in the denominator of a square root. So you can see that as “m” gets smaller, the resonant frequency “f” gets much bigger.

The use of an aluminum shaft provides a dual purpose – increasing critical speed out of the operating range AND directly reduces the rotational forces since those rotational forces are governed by:

F = mr w**2
Where w is rotation speed, m is the mass and r is the radius at which it is spinning.

This means that a 50% reduction in rotational mass results in 50% less rotational force. So, when a driveshaft rotates out of true, due to run out of the shaft itself or due to trans output shaft or axle companion flange run out, the reduced mass * the radius of gyration (i.e., run out) product is smaller than for the same conditions with a steel shaft.

This becomes important not only at critical speed, but at more normal operational speeds where the effects of run out and mass imbalance are more evident than those of resonance:

For a typical Fox or SN95 Mustang, driveline critical speed is around 95-100 Hz. Using stock tires we have the following:

225-60R15, 225-55R16, 245-45R17 all rotate at 812-820 revs/mile at 60 mph.

This give is 13.5 Hz wheel frequency at 60 mph, and assuming a 3.27 axle, we then have:

812/60*3.27 or 44.25 Hz , driveline frequency.

So, 100/44.25*60 yields a driveline critical VEHICLE speed of 135 mph. A good rule of thumb states that the objectionable driveline forces will start becoming significant at 70% of resonant frequency, so for the case of the 3.27 axle, the boom and vibration may be felt beginning at 95 mph.

Typically, 3.27 axles don’t provide the driver with much to complain about; it is 3.73 and above which create the concerns. Using a 3.73, we find that

13.53*3.73 gives 50.5 Hz wheel frequency at 60 mph (substantially higher than the 3.27)

And the critical VEHICLE speed then becomes

100/50.5*60 or 119 mph.

Taking 70% of 119 mph equals 83 mph, certainly a speed at which some Mustang drivers experience occasionally.

For a 4.10 axle, the “70% speed” is 76 mph!

Compounding this problem are factors like transmission output shaft run out, imbalances and run outs from components such as the reverse sun gear, driveshaft, companion flange and pinion pitch line run out (a torque induced run out created when the pinion tries to crawl up the face of the ring gear involutes).

Combine these factors and the already marginal NVH resulting from proximity to 1st bending (critical speed) and the NVH becomes absolutely agricultural.

The aluminum shaft minimizes the contribution from companion flange run out and the driveshaft’s own run out, directly due the lower mass. The pinion is free to pitch +/- 20 degrees and adding in any run outs of the companion flange or driveshaft at the pinion end results in the driveshaft mass having a large eccentric path to wobble about. It is this path times the mass of the driveshaft, which gives the characteristic boom and vibration at highway speeds.

Thus, as Newton predicted, as mass decreases so will the forces. That is why an aluminum shaft is your friend when coupled to 3.73s.

One side note: that great big mass on your pinion nose, fondly named by driveline engineers after the appendage on a male moose, is tuned to 45 Hz, the frequency at which the 2nd order forces created by u-joints as they rotate, force the pinion to bounce or pitch up and down and shake you by the seat of your pants and create an uncomfortable boom in the car. Once again run outs and imbalances will modulate this 2nd order driveline phenomenon to make it worse, so the moral is, LEAVE THE MOOSEB-, uh, DAMPER ON the pinion nose!

Another item: you CAN expect more axle noise when using an aluminum shaft however, which does not necessarily mean the pinion depth or side shims are incorrect, or that the gear cutting process is flawed. It just means that the aluminum shaft is more willing to “bend” circumferentially, torsionally and in a double hump (2nd bending) much more easily than a steel shaft.

Recall my prior statements at the very beginning about aluminum stiffness vs. steel? Picture a piece of sheet metal ducting. Bend it and it makes a WA-WA sound. That is pretty much what a driveshaft does, but at a much higher frequency – higher than even the dreaded “critical speed” of 100 Hz.

Axle noise will occur from about 350 Hz all the way through 500 Hz, sometimes even higher than that. The energy comes from the teeth meshing at the pinion/ring gear interface. This energy is transmitted to the driveshaft (and suspension components) and makes them deflect in the same sense as a piece of sheet metal goes WA-WA. Aluminum is less stiff than steel and takes less energy to deflect it, so it is far more inclined to make your axle go WOOOOO as you drive down the road at 45-70 mph.

Assuming again a 3.73 axle ratio, which has 11 teeth on the pinion and 41 on the ring gear, the axle noise frequency is calculated as (at 45-70 mph):

815/60*3.73*11 or 557 Hz at 60 mph.

This means the WOOO you hear at 45 mph is about 418 Hz and the WEEEEEE you hear at 70 mph is way up there at 650 Hz. You can’t SEE the driveshaft is bending and breathing and twisting, but it is telling you that precisely that is occurring.

So, now armed with this information, you now understand the basics of your vehicle’s driveline.

Information provided by JW
<!-- / message --><!-- sig -->

[younga1]

Do I need to replace or balance my driveshaft prior to exploring the top end w/o the speed limiter??

http://www.texasmile.com/

Don't want to be stupid but also don't want to spend $500 just for a one time event.

Thoughts???

[Dennis Reinhart]

Do I need to replace or balance my drive shaft prior to exploring the top end w/o the speed limiter??

http://www.texasmile.com/

Don't want to be stupid but also don't want to spend $500 just for a one time event.

Thoughts???

No you do not need to replace the drive shaft to run the car over 125, for short periods. What you need to understand is that the issue is not balance its the metal the OEM drive shaft is made of and at high speeds above 125 MPH its reaching its critical dive line speed, the drive shaft flexes or resonates, this is transfered to the transmissions rear tail shaft, but if you plan on running periodic or constant high speeds or have gone to 410's the MMDS is very good idea, the FHP had three cars walk out the rear tail shaft bearing on three cars before going to the MMDS.

[sweetair]

This will not cure the problem the Metal Matrix Drive shaft will, this is what the FHP is using in all the Marauders we did and they have cars clocked at over 155 MPH, the stock draive shaft is rated for about 125 MPH with 355 gears.

Drive line Critical speed

<HR style="COLOR: #d1d1e1" SIZE=1><!-- / icon and title --><!-- message -->What it is –
Every rotating object has a “critical” speed or resonant speed, which is a function of its design, mass and stiffness. This is when the driveshaft is whipping in the middle, rather than spinning on a true centerline. For a driveshaft, this is also called “first bending mode”, indicating the shaft actually bows out into a boomerang shape (on a micro-scale). This first mode bending speed is usually referred to in a driveshaft frequency.

What it does –
The energy stored and released through the deflection of the driveshaft through the resonance creates lateral and vertical accelerations of >10g at the problem frequency, which results in broken transmission extension housings, cases and causes moderate to severe vibration at highway speeds (> 70 mph), particularly with axle ratios numerically higher than 3.27:1. This energy release, when compounded by excessive driveshaft imbalance (some is good, too much or too little is not), companion flange run out/imbalance and excessive driveline angles provides the driver with excessive vibration and boom and tortures the driver and driveline components in general.

Because of this, most vehicles have a speed limiter to prevent from entering this mode and causing damage to the driveline.

Some detail –
As mentioned above, the driveshaft rotates at a certain speed based on rear axle ratio; tire size and road speed, but is independent of engine speed (unless you have a vehicle such as a Porsche 944 or C5 Corvette which utilize torque tubes and transaxles, in which case the driveshaft turns at engine speed).

The factors governing driveshaft critical speed include its material properties (i.e., Bulk Modulus of Elasticity which is roughly analogous to material stiffness), diameter, and length and to a lesser degree, wall thickness.

The only factor you can really modify to affect critical speed is material choice. Length is package-dictated, and diameter is usually constrained by driveline tunnel space as well. The answer then becomes a bit simpler – replace your steel shaft with an aluminum or MMC (metal matrix composite) shaft. Both offer reduced weight, which is key in this frequency range. MMC offers the additional bonus of additional damping and stiffness over a typical aluminum alloy.

As mentioned above, at the frequencies in question, a change in rotational mass has a greater impact on resonant frequency than a change in stiffness does, partly since it is easier to reduce mass than increase stiffness (adding stiffness almost invariably means adding mass -- a vicious circle), but particularly since resonant frequency is equal to the sqrt (k/m), where m is mass and k is stiffness. Here m is a stronger function being the in the denominator of a square root. So you can see that as “m” gets smaller, the resonant frequency “f” gets much bigger.

The use of an aluminum shaft provides a dual purpose – increasing critical speed out of the operating range AND directly reduces the rotational forces since those rotational forces are governed by:

F = mr w**2
Where w is rotation speed, m is the mass and r is the radius at which it is spinning.

This means that a 50% reduction in rotational mass results in 50% less rotational force. So, when a driveshaft rotates out of true, due to run out of the shaft itself or due to trans output shaft or axle companion flange run out, the reduced mass * the radius of gyration (i.e., run out) product is smaller than for the same conditions with a steel shaft.

This becomes important not only at critical speed, but at more normal operational speeds where the effects of run out and mass imbalance are more evident than those of resonance:

For a typical Fox or SN95 Mustang, driveline critical speed is around 95-100 Hz. Using stock tires we have the following:

225-60R15, 225-55R16, 245-45R17 all rotate at 812-820 revs/mile at 60 mph.

This give is 13.5 Hz wheel frequency at 60 mph, and assuming a 3.27 axle, we then have:

812/60*3.27 or 44.25 Hz , driveline frequency.

So, 100/44.25*60 yields a driveline critical VEHICLE speed of 135 mph. A good rule of thumb states that the objectionable driveline forces will start becoming significant at 70% of resonant frequency, so for the case of the 3.27 axle, the boom and vibration may be felt beginning at 95 mph.

Typically, 3.27 axles don’t provide the driver with much to complain about; it is 3.73 and above which create the concerns. Using a 3.73, we find that

13.53*3.73 gives 50.5 Hz wheel frequency at 60 mph (substantially higher than the 3.27)

And the critical VEHICLE speed then becomes

100/50.5*60 or 119 mph.

Taking 70% of 119 mph equals 83 mph, certainly a speed at which some Mustang drivers experience occasionally.

For a 4.10 axle, the “70% speed” is 76 mph!

Compounding this problem are factors like transmission output shaft run out, imbalances and run outs from components such as the reverse sun gear, driveshaft, companion flange and pinion pitch line run out (a torque induced run out created when the pinion tries to crawl up the face of the ring gear involutes).

Combine these factors and the already marginal NVH resulting from proximity to 1st bending (critical speed) and the NVH becomes absolutely agricultural.

The aluminum shaft minimizes the contribution from companion flange run out and the driveshaft’s own run out, directly due the lower mass. The pinion is free to pitch +/- 20 degrees and adding in any run outs of the companion flange or driveshaft at the pinion end results in the driveshaft mass having a large eccentric path to wobble about. It is this path times the mass of the driveshaft, which gives the characteristic boom and vibration at highway speeds.

Thus, as Newton predicted, as mass decreases so will the forces. That is why an aluminum shaft is your friend when coupled to 3.73s.

One side note: that great big mass on your pinion nose, fondly named by driveline engineers after the appendage on a male moose, is tuned to 45 Hz, the frequency at which the 2nd order forces created by u-joints as they rotate, force the pinion to bounce or pitch up and down and shake you by the seat of your pants and create an uncomfortable boom in the car. Once again run outs and imbalances will modulate this 2nd order driveline phenomenon to make it worse, so the moral is, LEAVE THE MOOSEB-, uh, DAMPER ON the pinion nose!

Another item: you CAN expect more axle noise when using an aluminum shaft however, which does not necessarily mean the pinion depth or side shims are incorrect, or that the gear cutting process is flawed. It just means that the aluminum shaft is more willing to “bend” circumferentially, torsionally and in a double hump (2nd bending) much more easily than a steel shaft.

Recall my prior statements at the very beginning about aluminum stiffness vs. steel? Picture a piece of sheet metal ducting. Bend it and it makes a WA-WA sound. That is pretty much what a driveshaft does, but at a much higher frequency – higher than even the dreaded “critical speed” of 100 Hz.

Axle noise will occur from about 350 Hz all the way through 500 Hz, sometimes even higher than that. The energy comes from the teeth meshing at the pinion/ring gear interface. This energy is transmitted to the driveshaft (and suspension components) and makes them deflect in the same sense as a piece of sheet metal goes WA-WA. Aluminum is less stiff than steel and takes less energy to deflect it, so it is far more inclined to make your axle go WOOOOO as you drive down the road at 45-70 mph.

Assuming again a 3.73 axle ratio, which has 11 teeth on the pinion and 41 on the ring gear, the axle noise frequency is calculated as (at 45-70 mph):

815/60*3.73*11 or 557 Hz at 60 mph.

This means the WOOO you hear at 45 mph is about 418 Hz and the WEEEEEE you hear at 70 mph is way up there at 650 Hz. You can’t SEE the driveshaft is bending and breathing and twisting, but it is telling you that precisely that is occurring.

So, now armed with this information, you now understand the basics of your vehicle’s driveline.

Information provided by JW
<!-- / message --><!-- sig -->WOW now that's a lot of info there. Was there a group buy on a MMC shaft ? Did I miss it?

[DEFYANT]

WOW now that's a lot of info there. Was there a group buy on a MMC shaft ?YES Did I miss it? NO

It was posted in this thread towards the end:

http://www.mercurymarauder.net/forums/showthread.php?t=28274

[Hotrauder]

I just posted it in its own thread to hopefully draw some more attention to this GB. Sign up and lets get it going. dennis:beer:

[Svashtar]

People are mentioning $500, and I don't have my figures handy but I'm sure I paid $325 for my MMX DS in Sept. '04 from Dennis. That would be a big jump if it's 5 bills now. But, hell, that's almost 2 years now.

It was a good deal as far as I'm concerned and cheap insurance. I got the DS loop as well. I have 4:10's and DR's tune and drove it at sustained sppeds just one time, but that was 3 hours across the AZ desert between 100 and 115 the whole way and not a bobble. It was like it was on rails and quiet ones at that. I love this car...

Norm

[Dennis Reinhart]

People are mentioning $500, and I don't have my figures handy but I'm sure I paid $325 for my MMX DS in Sept. '04 from Dennis. That would be a big jump if it's 5 bills now. But, hell, that's almost 2 years now.

It was a good deal as far as I'm concerned and cheap insurance. I got the DS loop as well. I have 4:10's and DR's tune and drove it at sustained sppeds just one time, but that was 3 hours across the AZ desert between 100 and 115 the whole way and not a bobble. It was like it was on rails and quiet ones at that. I love this car...

Norm


I have never sold a MMDS for 325.00 I cant buy it that cheap I did sell them for 525.00 that is the normall price

[RF Overlord]

Norm, I bought mine almost 2 years ago as part of a group buy and paid $500 w/free shipping...or something really close to that...I've never seen it offered for even CLOSE to $325...

[Dennis Reinhart]

We now have five, so every one needs to call Jackie, today. At the time I place the COMPLETE order they should ship with in ten days. WE can let this run trough Friday if you like once I order 5 and they have been processed, any late comers will have to pay the MAP of 525.00

[SergntMac]

People are mentioning $500, and I don't have my figures handy but I'm sure I paid $325 for my MMX DS in Sept. '04 from Dennis. That would be a big jump if it's 5 bills now. But, hell, that's almost 2 years now.
Norm I bought my first MMC drive shaft from Dennis in October of 2002. It was 525.00 shipped then. The price has not gone up since then, but I'm sure his profit margin has taken a hit.

475. shipped? That's 50 bucks out of Dennis pocket on every sale...Snooze, you lose.

Thank you Dennis!

[Dennis Reinhart]

Again I thank the club for allowing me to be here, but the group buy is a good thing, I just want you all to know I cannot order these till we have all the orders completed with PO's # for dynotech so please give Jackie a call. And yes Mac I do not make a large proffit on these MMDS.

[Svashtar]

I bought my first MMC drive shaft from Dennis in October of 2002. It was 525.00 shipped then. The price has not gone up since then, but I'm sure his profit margin has taken a hit.

475. shipped? That's 50 bucks out of Dennis pocket on every sale...Snooze, you lose.

Thank you Dennis!
Sorry guys! Pulled my invoice and next to "MMDS" is $525 for sure. Should have known that figure was BS as I distinctly remember _missing_ the group buy and paying the regular price. Have no idea where I pulled that $325 from. (Well, you can guess but I'm sitting on it. :D Once I hit 50 this year the brain cells have started going fast.) Maybe the meziere pump? Very sorry for the misdirection.

If you can do that or better 2 years later that is a hell of a deal.


Norm

[max454]

btw , i just looked under mine and my driveshaft is like new and silver, so i guess its aluminium maybe ? the stock one if its metal should be black or rusted right ?

[SergntMac]

btw , i just looked under mine and my driveshaft is like new and silver, so i guess its aluminium maybe ? the stock one if its metal should be black or rusted right ?Yes, the OEM Marauder drive shaft is aluminum, but it's composition has it's limitations. It's good for the max speed with 3:55 gears and lower, but when you move up to 4:10-4:30 rear gearing, and remove the speed limiter (as many of us have) the drive shaft can exceed it limits as a rotating mass. Dennis has the solution for that in this group buy.

[younga1]

Dennis,

Thanks for your feedback (#24)!!! This will be a one time event for me. Don't plan to many ventures past the 125 mark.

I'll save the new driveshaft $$ and apply it towards a new helment just in case. (and because it is required for this event)