driveshaftshop bolts, is it safe?

[White64Goat]

Not sure what you paid for that shaft, but is $10 bucks of bolts worth not replacing them?

[puma]

the problem is not the price, the problem is to find bolts that will actually do the job at least as good or better than those.

Are the regular bolts at a hardware store as good as these? Like kodyo said, these aren't standard bolts.

[mrk1]

mcmaster.com easy source for hardware, usually only 2 days away

[spitfire481]

I have 10k+ miles on mine with the stock bolts and every time I've taken it out none of them have ever shown signs of backing off. My car makes 400whp/355tq and I launch on drag radials so take it for what it's worth

[VacantSky]

I've got about 10,000 miles on my drive shaft on stock bolts with washers removed. As mentioned before that wouldn't fly in the aircraft maintenance world (c-130 mechanic here) BUT our maintenance schedule and rules are overly strict.
A nut that has all of it's threads engaged is what you should be looking for. Threads extending past that don't help a whole lot. Maybe keep the bolt in place if it loses torque and backs off a little, but by the point of all four doing that you would or *should* notice, and rectify the situation. I normally look at mine every oil change.

Torqued to spec with all nut threads engaged is ideal. But I personally will look into buying longer bolts for this particular item so I can run washers again. Any hardware store should have efficient bolts. Grade 8 would be fine. That's something Home Depot or Lowes keeps in stock

And somebody asked about the feel of the driveshaft? Well I get a little bit of transmission syncro noise echo'd through it when pulling away in first, and compared to the stock driveshaft? I'd say it's like running with the AC off vs on. Stock DS would be AC on, and alu DS would be AC off. Sure not a lot of difference but 11lbs of rotational weight is a lot. Combined with full NA bolt ons and an off the shelf stage 2 tune, the car feels amazing compared to stock.

[puma]

thanks guys, i have not found anyone saying they had probem so far so was looking for people who actually installed those to see what they did. thanks

I will take the washer off and see how much better it is.

[IceFyre13th]

Originally Posted by puma

thanks guys, i have not found anyone saying they had probem so far so was looking for people who actually installed those to see what they did. thanks

I will take the washer off and see how much better it is.

Translation:

I don't care if my drive shaft pogo's my car into the air, or to go to ACE Hardware and buy the correct parts to do the job right. I just asked the question to ignore the advice I have been given.

Good luck...............you were advised on what to do the right way but have chosen to do it the wrong way.

[wu_dot_com]

here is from a design perspective of bolts, and washers.

typically bolt / nut torque are selected base off of the nut / bolt yielding load (which ever one is weaker) and compare it to the fatigue / impact loads require to achieve long term reliability. When you torque up a bolt, all the clamping force are transmitted from the bolt thds to the nut thds. the idea of having a minimum of 1-2 thds expose beyond the nut is so that all the threads (bolt and nut) are engage. Therefore, all the stresses are evenly divided amongst the number of thds. in your situation, you are reducing the number of threads engage, thus the stress seeing per thd is higher than design. as a design practices, in order to achieve maximum fatigue life of any bolt, you will torque it close to its maximum material yielding limits. in simple English, if the design have minimum margin, applying the full torque to the partial thd engagement will result in thd yielding, thus compromising your clamping/ load/ shear/ torque carrying capability in high/ life vibration environment.


when the botl/nut is being torque up. the opposing loads (equal and opposite loads) are reacting on to the bolt face to clamp surface and bolt head surface. with the washer, you are spreading the clamping force over larger surface area. thus w/ washer per unit area of the clamping surface will see less of the load. this is sometime necessary because the surface of the clamp material may not be strong enough to resist the compression force w/o deflection or deformation. this will be specially critical when you bolt two dissimilar materials such as Steel and aluminum where the aluminum is typically softer.

last, take good care in corrosion prevention. Two dissimilar metals will cause galvanic corrosion. Make sure all faying surfaces are independently protected from each other if they haven’t done so at the manufacture. Simple paint will do the trick.

[puma]

Originally Posted by wu_dot_com

here is from a design perspective of bolts, and washers.

typically bolt / nut torque are selected base off of the nut / bolt yielding load (which ever one is weaker) and compare it to the fatigue / impact loads require to achieve long term reliability. When you torque up a bolt, all the clamping force are transmitted from the bolt thds to the nut thds. the idea of having a minimum of 1-2 thds expose beyond the nut is so that all the threads (bolt and nut) are engage. Therefore, all the stresses are evenly divided amongst the number of thds. in your situation, you are reducing the number of threads engage, thus the stress seeing per thd is higher than design. as a design practices, in order to achieve maximum fatigue life of any bolt, you will torque it close to its maximum material yielding limits. in simple English, if the design have minimum margin, applying the full torque to the partial thd engagement will result in thd yielding, thus compromising your clamping/ load/ shear/ torque carrying capability in high/ life vibration environment.


when the botl/nut is being torque up. the opposing loads (equal and opposite loads) are reacting on to the bolt face to clamp surface and bolt head surface. with the washer, you are spreading the clamping force over larger surface area. thus w/ washer per unit area of the clamping surface will see less of the load. this is sometime necessary because the surface of the clamp material may not be strong enough to resist the compression force w/o deflection or deformation. this will be specially critical when you bolt two dissimilar materials such as Steel and aluminum where the aluminum is typically softer.

last, take good care in corrosion prevention. Two dissimilar metals will cause galvanic corrosion. Make sure all faying surfaces are independently protected from each other if they haven’t done so at the manufacture. Simple paint will do the trick.

ok, i understand, what about the fact that the washer is the exact same size as the bolt head? What was their primary goal by putting a washer like that? Could it be beacause it is a little bit softer than the bolt itself so it crushes a little bit instead of streching the threads? Any idea?

I tried without the washer (which is like 1/4 thick) and all the thread are used this way.

[OICU812]

Don't use washer like you do with OEM and those bolts are fine.

[industrial]

Originally Posted by puma

ok, i understand, what about the fact that the washer is the exact same size as the bolt head? What was their primary goal by putting a washer like that? Could it be beacause it is a little bit softer than the bolt itself so it crushes a little bit instead of streching the threads? Any idea?

I tried without the washer (which is like 1/4 thick) and all the thread are used this way.

The washer in this case is mostly to prevent the turning surface from damage. I don't honestly see the purpose of the flat washer in this application since the bolt and nut are both pretty large and the surfaces they mount to are both very hard. That's why I was ok with just chucking the washers and using loctite. If you are really worried (like I was), just use some loctite red. Those bolts and nuts won't go anywhere.

[acj47]

I have the same issue on my DSS CF shaft, ordered and installed last week. So far DSS has been unresponsive to my request to help source longer bolts (no, just going to ACE Hardware is not acceptable to me).

EDIT: just heard back from DSS after 3 days.

[woode]

Originally Posted by kodyo

When we do bolting in industry, we try to have at least 2-3 threads above the end of the nut. What you have would not be considered acceptable.

This. I work on aircraft and I can tell you that would not be acceptable, and I know I wouldn't accept that on my car. Especially when you can buy longer bolts for just a couple bucks..

Anyone running nuts like pictured knowingly or advising that it is acceptable is incompetent and I would not listen to them.

[ZionsWrath]

Originally Posted by acj47

I have the same issue on my DSS CF shaft, ordered and installed last week. So far DSS has been unresponsive to my request to help source longer bolts (no, just going to ACE Hardware is not acceptable to me).

EDIT: just heard back from DSS after 3 days.

Well? WTF did they say, don't be a cock tease!