Speedtech Performance ExtReme and AFX Spindle Design and Engineering Process

Ever wonder how a part like a forged aluminum spindle is made? What takes aluminum to that level of grain structure that produces a stronger, compact, lightwieght part? 

Many spindles are cast components typically formed by pouring molten iron into a sand mold and afterwards doing some finish machining to make a finished part. Since this process is relatively inexpensive, quick and easy to do it’s often the choice in a high production environment.  While a cast part is strong and ductile, the mold can experience some shift and therefore cast parts can can be inconsistent.  Because the metal is poured into the mold it’s not possible to compact the molecules tightly together maximum strength is not achieved. Manufacturing in this way is often done with more and heavier material, for example iron instead of aluminum. 

A forged part is a completely different concept, all Speedtech Performance spindles are forged from 7075 (T73) aluminum. The results is a spindle that is lighter than cast iron, stronger than cast iron as well as cast or billet aluminum.  Our forged aluminum spindle is ultra light, precision crafted and very tough.

The forging process for each of our spindles starts out in at an aerospace parts manufacturing plant in the USA. A length of 6″ round billet 7075 Alcoa Aluminum gets trimmed to specific lengths as seen at right. That section is then put in a large hydraulic press and under great force is compacted into a much more dense slug measuring less than 1/3 it’s original length. Once density is verified and passes inspection, things really start to heat up!

After compression, the billet slugs are then heated to over 800 degrees. The red hot slug is placed in a special forging hammer and then pounded several times with over 2,000 tons of force into a preliminary top and bottom mold. When the slug has achieved an acceptable shape it is then removed and dipped in an acid bath to remove any scale and impurities.

After cleaning, the preliminary shape is heated again to over 800 degrees and placed back into the hammer. This time a second, more refined mold will create the spindle’s final shape. With over 2,000 tons of force the spindle is pounded again and again until it matches the mold. Along with forming the final shape, this process compresses the material structure giving the forging strength that surpasses cast parts. Before moving to the next step each part is quality checked for dimensional accuracy.

Once cooled the extra flash around the spindle is trimmed off. The final process is heat treating, which involves heating the forging to 870 degrees for 2.5 hours. and then water quenched to 140-160 degrees F. After this cool down the tempering process starts by heating the forging to 225F for 7 hours and then 350F for 9 hours. This process creates an exact level of material hardness and strength to be classified T-73 grade Aluminum. Grain structure is quality checked and each individual part is checked by undergoing very thorough strength testing to ensure every spindle is fit for purpose.

Once checked in and inspected at the Speedtech Performance factory the forgings go to the machine shop.  One at a time each part is placed in a 5 axis CNC machine and all critical surfaces of the spindle are machined to exact specifications. The spindle is then assembled with genuine GM C7 Corvette heavy duty bearing and hub assemblies, and then packaged ready for delivery to you. At Speedtech Performance we are dedicated to enabling you to take performance to the ExtReme!  We are committed to providing our customers parts that are reliable and perform beyond our your expectations. Our forged spindles are a great example of this, and that’s why they’re number one in the industry.

Be sure to ask your sales rep about these different options to customize your frame to your needs.


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St. George, Utah 84790

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