Carbon Fiber Driveshaft FAQs
Below are some frequently asked questions about our carbon fiber driveshafts. Also, check out QA1's YouTube channel for tech, product and company videos!
It's a common misconception to rate a driveshaft by horsepower, because torque is all that affects the driveshaft. Our driveshafts have horsepower ratings listed because most customers have this info, so we list horsepower ratings of 750 to 2000 HP depending on the U-joint used. We do need torque ratings before we can recommend a particular driveshaft though.
While horsepower is the sheer power and speed produced by the engine, torque is actually more critical to driveshaft operation. Torque is the twisting force of the engine, which is what a driveshaft needs to withstand so it doesn’t lead to a failure. Torque ratings are what you need to look at when choosing a driveshaft.
This all depends on the length, the diameter, the tube structure, and the overall weight of the driveshaft. Because we design and wind our driveshafts in-house, we can work with you to ensure that we meet your specific needs and RPM requirements.
The weight savings depends on the diameter and wall thickness of each driveshaft. We’re approximately 70% lighter than a generic steel tube.
Will a rock or other debris ruin the driveshaft?
Companies that sell performance and racing parts design products to withstand common ways parts can be damaged. Some companies use a thin layer of surface protection on their driveshafts, while QA1 incorporates protection right into the carbon tube with our resin, so durability and toughness is built in throughout the wall. This resin, designed specifically for racing and street performance, helps deflect rocks and debris.
For example, QA1 displayed a used driveshaft at SEMA and PRI with over 1000 laps on it from well-known dirt racer Scott Bloomquist. Marks from debris were minor and were only seen when up close. Many circle track racers are amazed by how well their QA1 driveshaft holds up after racing all season on dirt tracks, so you know it can withstand dirt and debris on asphalt. Watch a video on Bloomquist’s driveshaft on our YouTube channel: https://youtu.be/2-Q-bEBq4w8
It’s hard to quantify impact, but QA1’s driveshafts are raced all over the country in dirt late model and dirt modified applications where dirt, rocks, mud, and other debris are constantly hitting the driveshaft, and they hold up very well. They’re not designed to support the weight of a vehicle balancing on a rock like rock crawlers do, but normal impacts from rocks and debris have not been an issue.
While care instructions for carbon fiber driveshafts often state to replace them if they’ve been dropped, that’s also generally listed in steel or aluminum driveshaft instructions and is not an indication of any sort of fragility on the part of carbon fiber. Like other materials, carbon fiber needs to be taken care of properly; it’s the same as any other equipment you wouldn’t want compromised. For example, if you dropped a brand-new $3000 billet crankshaft on the ground, would you use it? It may work, it may not – it’s ultimately up to the customer, but QA1 recommends replacing a dropped driveshaft to be safe.
At QA1, we dynamically balance our driveshaft assemblies on a precision balancer that can give us very accurate and repeatable results. We leave a flange on our tube yokes so that if needed, we can go in and mill this flange to remove material/weight. We haven’t had to do this very often. We first try to “shim” the U-joints left or right to bring the balance in. We can also make minor adjustments to the U-joint snap ring thickness to bring them into balance. We are so precise when it comes to balancing our driveshafts that we even consider the weight of the decal, which is added when the driveshaft is on the balancer and is placed where it will improve the balance.
Most companies will glue weights onto the tube or the tube yokes to bring their shafts into balance. We work very hard in our assembly to make a tube that doesn’t need additional weight added on, as most weights end up flinging off over time.
We put in extra time and focus on this area and worked with 3M’s Aerospace and Technology Division to find the best bond. We developed a proprietary bonding procedure that uses a high-strength structural adhesive. Many passenger jets are constructed with a very similar process. This is the strongest part of the entire assembly, and this bond is one of the reasons QA1 driveshafts are so strong and durable.
For the most part, we use 7075 aluminum for its high strength and stress resistance. Other materials are possible, including steel, 6061 aluminum, and others.
Around 3” to 4”, depending on the diameter.
Yes. Accelerated U-joint wear can be a result of extreme misalignment angles, and less consistent RPM can be a result. Dirt late models run about 25 degrees of U-joint angle, which is way more than recommended, but that’s what works for their cars.
It depends on the diameter of the tube, the U-joint size, and the tube yoke design. We can go up to about 25 degrees with one of our current designs.
Yes. We design them to flex a certain amount depending on the market. Winding our own tubes in-house gives us this advantage over many of our competitors in the racing and performance market.
With carbon fiber, you can design how much flex you need. Our engineers look at the application and what the driveshaft is being used in conjunction with. For example, we designed some of our circle track driveshafts to be softer than steel and others to be much stiffer. We found that driveshafts that allow increased twist under load had increased traction on slick tracks, while the stiffer options are better for tacky or rough conditions.
It depends on the resin and structural adhesive that’s used. We currently have one system developed with a maximum temp rating of about 200°F. We have developed another that is good to about 320°F.
It depends on if the shaft is in compression, tension, or bending. The design has to be changed for the different loading, but overall, it is usually much stronger than traditional materials.
No, we have not. It’s something we’re aware of and watch for, but we have not had any issues.
No, we have not had the need to do this yet. Corvettes and BMWs come with carbon fiber roofs in some cases and the manufacturer will paint them for UV protection. We can do this for applications if needed.