Duration of test: May 2010 - present

Cost: £55

Options: Most sizes and colours.

Spec: 7075-T6 Aluminium. Weight: 84 grams (28t)




Spline drive system

Fit and forget


Can’t think of anything, maybe price?


Tree Bicycle Co are a small BMX component company who tend to do things differently. An example of their innovative thinking is their spline drive sprocket. While many associate spline drive with Profile Racing, Tree were in fact the first company to use the spline system over the traditional crank bolt to tighten a sprocket.

For some reason I’ve always had trouble with sprockets. They have never stayed straight (even when I didn’t bash them) and the bolt often came loose. One of my trails friends praised his Tree sprocket and the spline concept seemed like an ingenious solution to the standard (in my eyes) flawed system so I bought this.

When I took the Tree sprocket in my hands I was impressed. No wonder the price is high. The sprocket is really thick but light due to an incredible amount of machining to take off every bit of unnecessary material. It weighs no more than the average sprocket and crank bolt. Fitting was a breeze. It is advised to grease the splined interface but I found that out after it was installed. For the first time ever I had even chain tension rather than the usual tight spot; this is the first sprocket I’ve had that is completely straight.

After the first few pedal strokes I noticed how solid my drivetrain felt. There is absolutely no flex. Nearly two years later and I have nothing bad to say about it. It hasn’t worn despite running various chains and somehow it is still 100% straight. I’ve even sprocket cased a 6foot spine, twice, and it hasn’t damaged it in any way. The only reason why it looks battered in the photo is because of my smooth DIY spray jobs. Every time I’ve had to dissemble my cranks the sprocket has come off without problems.

I’m baffled as to why the spline system isn’t standard. The majority of BMX cranks run on 48spline spindles and there are no advantages to the bolt clamping system. It’s one less part to come lose, power isn’t lost through flex and it just works. It’s the sprocket equivalent of internal headset and pivotal seat posts, except the majority of companies and people haven’t realised it yet. The price is high but in the long run it’s a bargain; it will outlive probably any other sprocket out there.

If you need a new sprocket then look no further.

Tree Bicycles Co. website

Review date: March 2012

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