2023 Build: FM10 Budget Carbon Aggressive Trail 29er

Follow along as I build up a FM10 frame starting from scratch. I will be tuning and mapping the suspension progression to build a 140mm aggressive trail 29er on a budget. It his my hope that this bike will do everything from Downhill to Park to Trail to XC.

FM10 Week One: Winter Planning

Every winter I get the urge to change things up and try a new frame to build up. I can usually find a 29er frame used for around $600 and then rebuild and buy up used parts to fill the build. I can usually fund the build mostly through parting out old bikes that do not get as much use due to a change in trails or riding styles. I try to only add money only for rebuild kits and consumables.

This year I decided it was the year to go new instead of old, taking advantage of the overstock in certain areas of the bike market. In December of 2023 I was able to get a FM10 (or SP-M10) open mold frame from Peter at SP-Cycles in China delivered to my door at under $600. In the used bike market at the time, any 29er used frame with similar specs was double that price.

With the luck I had had with my now five year old Icanbikes P1 Carbon frame buld, I was hoping the same from a frame that is currently almost half the price (the Ican P1 has increased in price over the last 5 years).

The goal was a very plush 140mm aggressive trail bike with a 64.5 degree head angle. I am going to base my build on the current model Fuel EX 64 (Gen 6) travel and head tube angle. A Gen 6 carbon Trek Fuel EX 9.7 costs $4,700. My goal is to build a bike for way less than half that with similar kit.

Compromises:

Compromises that go along with starting with a FM10 frame include a slack seat tube angle near 73.5 degrees, a shorter reach (460mm in L) and not as much room for a long dropper post (since the seat tube is a true 19″). Of course the big drawback is the lack of a big box brand lifetime factory warranty. As with all inexpensive frames, there are always compromises, but since I like my seat back, would rather the wheelbase be shorter, and can live with a 120mm dropper post for now, this frame will do.

If I was only building a park or enduro bike I would have went with the Status 140 for the longer reach. If I was only looking for an XC bike I would have built up an Ican S3. This bike would have to find the middle ground between the two.

Shock Choices:

The selling feature for the FM10 frame was the ability to utilize my 20 year old cabinet of 190mm and 200mm eye to eye shock rebuilds to help test and tune them. It was also exceptionally progressive in 185mm eye to eye trunnion format if I wanted to get a new shock. Cane Creek trunnion shocks are half price at the moment which is tempting. With this frame at 200mm eye to eye I could run a piggy back air shock for a super plush long travel XC feel. This would steepen the head angle to around 66.5 degrees if I used a 130mm fork for quicker steering.

In 185mm trunnion mode it would drop the bottom bracket, decrease the head angle to 64.5 degrees and shine as an aggressive trail bike. What about the progressivity of this frame and the possibility of a coil shock? Guess I will have to do the math!

So now the work starts, this week I will install a headset and fork and measure the suspension rates in different configurations in order to pick the shock that will work best.

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Click this link to get to the FM10 Build Page (work in progress)