Thursday, September 8, 2011

Competition 4x4 has begun manufacturing tire carrier spindles

Previously we purchased all our 1-1/4” and 1-3/4” diameter spindles through another manufacture for a couple reasons. One, they were fairly cheap due to our quantity price break on large purchases. Two, they were easy to order and arrived in a couple days, so we didn’t need to worry about manufacturing another product in our mix.

However, over the last year the prices have steadily increased to the point that they have doubled in price. We even received word from the manufacture today that there will be another 6% - 18% increase on current prices! We also started receiving some spindles that would come bent upon arrival of the threads would be smashed during shipping. Well, we have had enough!

Two weeks ago we began manufacturing the spindles on our CNC lathes. They are produced from the same material as our previous provider and to the same dimensions. There are a few added benefits to our customers now that Competition 4x4 produces the spindles. One, we control the process and therefore are able to machine each item to exact specifications at a higher rate of quality. Two, we are able to save money and therefore pass the savings onto the customer by not raising prices on our tire carrier hinge kits as we would of needed to do with our previous provider. Three, we are able to provide quicker turn-around times and hold a more level quantity on hand.

The only drawback is that the previous manufacture provided a load rating of 1000 lbs. on the 1-1/4” spindles and 1750 lbs. on the 1-3/4” diameter spindles. Although we are machining the spindles from the same material to the same specifications, we have not conducted fatigue stress testing on the tire carrier spindles and therefore cannot advertise an exact load rating.

Why haven’t we conducted fatigue stress tests on the spindles you ask? The answer is bling-bling…as in money, lots of money! There is only a few metallurgical testing companies we found (most in California) that seem to have enough brains to properly setup the spindles in a jig and provide fatigue stress tests. They first have to do a compression test to see how much static load the spindle can bear before it snaps or shears off. They then take a percentage of that load and begin a fatigue stress test scenario (involves applying pressure and then releasing and repeating) over one million cycles! If it survives one million cycles, then it definitely deserves that load rating.

It’s unclear if the current manufactures on the market are providing a load rating of 1000 lbs. and 1750 lbs. for a fatigue stress scenario or compression in static load. The price for each test is around $7K - $8K. And since we will have 3-4 types of spindles to be tested and each in two material types = 6 – 8 spindle types. Some may need multiple tests to find the correct load for one million cycles. Calculate that all up and were looking in the ball park of…a lot of money!

At this time, were just not going to spend that kind of money on testing a spindle that we know uses the same material and specs. We will however test other spindles in the future that we plan on using, especially those with different materials (for example, 4340 chromoly – post heat treat).

We will most likely first provide a static load rating – how much a spindle can hold with continuous pressure until breaking - opposed to a fatigue stress test.

Until then, just know we are using the same materials (A36 HR) so as not to deviate from the other manufactures load ratings. However, for insurance reasons, we cannot claim the same ratings.

Any questions? Feel free to contact us or check us out online at

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