Driveshaft Shop Carbon Fiber Shafts Explained

[Driveshaft Shop]

Were new to this site, but not new to Subaru parts. we will be posting up some info one the new products we have for the cars and how they have changed and evolved over the last few years.

Our Carbon Fiber Shafts are a bit different, due to the fact that we have decided to take our time and offer what we feel is the best shaft that we could make. Before we come out with a new product we will take the time to investigate, research and put our own spin on what's currently being done. Over the years we have done extensive research, always reading and collecting information about Carbon Fiber, but with all that was going on the time was never right, until now. This company was founded by my father Robert Rehak, along with my uncle Carl Weisane, back in the late 60's when a double cardan CV was considered "High Tech". I would think these gentleman would be rolling over in their graves by now, knowing that we were literally "gluing shafts together".


Over the years I have seen many failures of Carbon Fiber shafts and I have collected many samples, (too many to show) but there was one thing that stood out on all of them. A certain profile on the aluminum (or steel) part that was mated to the Carbon Fiber seemed to be very consistently showing up. When we decided to move forward with Carbon Fiber shafts last year, we wanted to wait until we had our custom balancer in place so we could accurately test the claims of what Carbon Fiber shafts had to offer.

The first thing to do was find suppliers for the tubing, glue and of course the u-joint ends (unless we were going to be making them). I contacted my friends Tony and Brian at Sonnax, whom I've worked together with over the years on several aluminum yoke designs, and asked how their new line of u-joint ends were coming for use with Carbon Fiber. In the past we had been using another manufacturer for aluminum ends and had trouble with more than our share of bad parts, namely some of the GTO 200mph shaft ends that had issues with the u-joint fitment. Sonnax has been supplying our ends for the weld together shafts for quite some time, and their quality was more in line with what DSS demands for our customers, so it was a natural choice to incorporate them in our Carbon Fiber line.


I then contacted our Carbon Fiber tube manufacturer and spoke in depth with the head engineer about critical speed, strength and run out. I found that the critical speeds that they were quoting to us were phenomenal, but after research of our own found some of it to be misleading. They were quoting the tube only and not taking into consideration the u-joint ends and mounting points, like the SAE standards for critical speed show. Still, they were much higher and offered some real benefits to a lot of the newer cars that we were having certain issues with. After this we spoke to the 3M engineers about different glues and bonding processes and moved on to putting it all together.


Back to the design, we were told by the tubing manufacturer that ends of the tube come un-machined (we had known this from the past) and it was up to us to put the profile on the outer diameter of the tube so that the glue would bond correctly. It was suggested that we put a thread pattern, or as we were told, lines like an old 33LP record (you do remember records right?) was the best way to get the correct bond. Now at this point is where DSS deviates from the rest of the crowd, as this is the very same profile that i had seen in every bond failure and was uncomfortable with this assessment of the correct way to bond.






Tony and Brian from Sonnax had said they were working on a new profile for the u-joint ends and sent over some prints for me to look at (which was very cool of them). I was thoroughly impressed, even my gut instinct was happy, so we decided on this design and moved onto the rest of the planning. One very interesting thing that I observed when inspecting various cut and broken bonded ends from the samples I had been collecting, was one of the ends we had cut apart from a current production Nissan 350Z. Take a look at the way the Nissan factory did their bonding. There are no ridges on this one and we couldn't get the tube off of the end at all. It was now a part of the end, and there was no taking it off period. Although the Sonnax design is not exactly the same, it has some very important similarities that made me feel better about our choice.






Glue and Curing. We could go on and on about how much time we have spent on this part of the equation, but I feel some things need to be kept inside of the magicians hat, so all we will say is that there are several ways to bond and cure the glue. We did not take the easy way out on this one. My son Frank IV will be graduating from college this year with a degree in Machine Engineering, and like me he has a real eye for details. I'm proud to say that between him and myself we perfected our bonding process. He will be bonding all of the Carbon Fiber shafts, and of course Matt, our head builder who moved down from NY with the company, will oversee every operation and balance them upon completion. Frankie's no stranger to the shop or cars as he has always been around as a kid growing up. Check out his High School senior project (you should have seen the principal's reaction to him asking about doing this for his senior project). It would hard for me to say he didn't get any help from the guys in the machine shop doing this, but i will say it was all his idea and execution.





So after all of this, we have researched, spoken about and done, it was time for testing. We assembled a few shafts and off they went to the destructive testing lab for some bench testing before we put the shaft in a real car. We prefer this method of new part testing first to make sure all processes are done correctly, with both shafts and axles. Testing went very well, in fact better than we could have hoped for. As you see in the picture below what actually broke was the u-joint cross, the tube and bond remaining fully intact. The torque spec for the u-joint was at about 2600 ft-lbs of torque, but all the test shafts broke right at 3100 ft-lbs (Neapco should be very proud of the performance of these u-joints).





on the Subaru WRX/STI Shafts we know a 3" shaft will have clearance issues on the floor boards, the other aftermarket shafts out now are made with a 2.7 tube that just a little close for our comfort. What we did was have a Custom High Modulus tube wound to be able to spin at 10,000 rpm and handle 1000lbs of torque (in awd) then we didn't like the steel ends the other company's were using so we decided to make our own. We are putting a Billet aluminum end on our shaft so this along with the custom tube makes it the strongest and lightest shaft to date. tested and ready to go. we thought you might like to see what goes into making what we have to offer..




p.s. this is an older post, we have been making them over over 2 years now, not a single bond failure and i have even seen a few transfer case shafts broken from this shaft. Frankie has moved on to making prints but we have a Gentleman Matt Hayes doing the fine work now keeping up the good service and excellent work.

[swift996]

Do you have an estimated price for this yet?

[GTM_Challenge]

Very interested in more details!

[charged86]

keep the price at 1000.00 you sell a boat load including me.

[Captain Insano]

And... Will this be available for the Automatic Trans cars?

Product looks great. Thanks for posting all the information.

[Calum]

Fantastic first post!

I've used your stuff in the past and even after about 250 times down the 1/4 mile and about 200,000 kms they were still in good enough shape that I was able to sell them for about half what I paid originally. The only problem after all that was a rip in one of the boots, caused when I crated the axles for shipping. Even your customer service was outstanding.

If/when I need to replace the axles/shaft, DSS will be the only place I shop at.

[Sportsguy83]

Just freaking AWESOME!!

Thanks a lot for sharing all of this!

[TRD_07]

Weight and price?

[PhastekSport]

Our customers have been very pleased with the service / products from DSS.

Glad to see that you guys will be supporting this platform.


Sent from my SCH-I605 using Tapatalk 2

[FT_Monk]

Based on my experience, I would not buy anything DSS. But of course that is just me.

[F1point4]

May I inquire if your organization will construct a sort of a driveshaft loop? This will most likely sway me in your favour.

Cheers

[swift996]

Originally Posted by FT_Monk

Based on my experience, I would not buy anything DSS. But of course that is just me.

Not trying to incite a war but do you compare to expand on why?

[tisb0b]

Always nice to see a new product coming to market with some proper R&D behind it. So I take it you guys will be offering an aluminium drive shaft along with the carbon fiber for our cars?

[AZFA20]

I was literally just looking on your site for more information about the CF driveshaft for this platform. I had heard you were working on one and I am super excited to see it is really happening. When will these be available and how much $$. Can't wait!