A History of Sprockets

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6013 AL • 1/2” Thick • JAM Industries • 2002

2002 6013 AL 1/2” 6013 AL 3/8” These two sprockets were the start of it all for Tree. In the early 2000’s sprockets were getting more and more thick, but the teeth and spindle hole were still wearing out fast. These fat sprockets, Made by JAM Industries, fit in with early 2000’s sprockets, but the material and strong simple design set them apart. The 6013 was much stronger than the standard 6061 AL being used at the time. They came drilled for the optional bolt on bash guard. News of the sprockets spread like crazy, just by word of mouth and Tree sprockets were everywhere. In the end 6013 was too brittle and the elongated bolt holes would sometimes break.

6013 AL • 3/8” Thick w/guard • JAM Industries • 2002

The next incarnation of the sprocket is probably the style most people picture when they think Tree sprocket pre 2005. Production moved from JAM Industries and some of the next series of sprockets were manufactured by Arsenal (bmx company from the early 2000s) as well as a local St.Louis machinist named Jim Alexander. At this point the design is more refined and has the classic Tree sprocket look. We are using 5/16� 7075 T6 aluminum which is twice the strength of 6061, the sprocket bolt holes are shorter which prevents the blowouts, and the holes for the guard are threaded so the bolts thread directly into the sprocket instead of requiring a nut or threaded washer on the back side. These were made through 2003 into 2004.

All of our sprockets are laser etched now, but these were the first. Around 2004/05 we had JAM make us some more sprockets. These sprockets had a more hard edged look than our others, but it was still 7075 and had threaded holes for the guard. The new feature aside from the engraving is the offset teeth. Up to this point the sprocket had the teeth near the center of the sprocket. We moved the teeth all the way to the inside for better chain alignment and still do that on our sprockets today.

The next version of the sprocket came out about 2005. Sprockets were much smaller at this point , and guards were growing less popular, so we started focussing more on the smaller sizes and phased the guards out. The shape of the tooth was changed to make a really smooth pull on the chain. This era of the Original sprocket from 2005 to 2008 had the most changes in manufacturing. It was being manufactured by RNC, our local guy Jim, and Phil Wasson at Super Rat at different times. During our time with Phil, we began working on the Lite sprocket and once it was finished we discontinued the Original sprocket for 3 years making this generation the last until 2011 when we re-issued them to offer a mid range priced sprocket.

The Lite Sprocket

Starting in 2006 we started working on the Lite sprocket and it probably went through more testing and prototypes than any other sprocket out there. The idea for this sprocket was to make something lighter that you didn’t have to be careful with. The design was a natural progression out of the Original sprocket. Phil Wasson made all the prototypes for the Lite sprocket at Super Rat. The sprocket pictured is one from the first set of prototypes. The spoke design came from widening the gap between the material on either side of the bolt hole location of the Original sprocket. It was only the start. Functionally, it was light, and fairly strong, but not strong enough. The bolt hole location was blowing out. A spline drive idea was already in the works too. After a lot of testing and a lot of different prototypes the Lite sprocket was done. It was very light, incredibly strong, and the unique look caught on pretty quick.

Prototype Light Sprocket • Cryogenically Frozen to Align Molecules • 2006

The first spline drives we tested were broached directly into the 7075 instead of using the steel insert. These sprockets had spokes that tapered the opposite way as the production version with a slight recess that would later form the I-beam, and a bolt hole location that was not fully enclosed that could be used if we stripped out the splines. We had mixed results, some of us stripped the splines on a hard landing, and others road the sprocket hard for years with no stripping. The chance of stripping, especially after repeated installations of the same sprocket was too high so we had to make an insert.

Prototype Lite Sprocket • Spokes Tapered from Center • 2006

The first production version of the Lite sprocket still had the hole pattern near the spindle, but it also had much thicker tapered I beam shaped spokes. The I beam maximizes strength while cutting down on weight. the taper helped cut down on weight but keeping strength by having more material at the center of the sprocket and less towards the outside. We developed the flower shaped insert for the spline drive versions making the Lite sprocket the first 48spline driven sprocket. The spline drive set up made it easier to get good sprocket alignment and created a more solid feeling drive train. The sprocket bolt was eliminated. If you’ve ever broken a sprocket bolt, it’s like breaking a chain, and now it was no longer a problem.

• Lites being machined at Super Rat

•Columns of Lite and Original sprockets courtesy of Phil Wasson!

Version 6 added more strength to the Lite sprocket. The outer ring was made thicker, but with the I beam design it was hollowed out keeping it stiff, strong, and light. The holes around the spindle were removed. Around this time Phil was closing doors at Super Rat, we stopped production of the Original sprockets and moved production to the Chicago area with Mike Goetz.

Around 2009 we moved manufacturing of the sprockets to Chicago. They were made using a self fed CNC Lathe with live tooling. They came off the machine with a mirror finish. The quality was excellent, but Mike had a good shop and Aerospace companies pay more than BMX companies so eventually one of his clients bought him out and had him run the shop for them. After 7 years and no less than 6 manufacturer changes doing whatever we could think of to produce our sprockets in the US, we were without a manufacturer and behind on sprocket orders. We needed high quality, reliable, cost effective ,and easy to work manufacturer with so we sought out the best manufacturers we could find in Taiwan making 2011 the last year of having our sprockets made in the US.

After ten years the sprockets are still getting better. On thecurrent 2012 line we have updated the spline insert to be even more secure, and we have reintroduced the Original sprocket that put us on the map in bolt and spline drive versions.

What about the next ten? We’ll just have to wait and see. We’ll constantly be updating our products and bringing out new ones to help you find all the good times you can through your bike. Thanks for making ten years awesome!



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