China Bike – A Carbon Rigid Single Speed 29er experiment

NOTE: At the request of some friends from MTBR, I’ve added a gallery of all of the pics I’ve taken regarding this build.

Backstory…

I’m taking the plunge. I have a few buddies who have single speed mountain bikes, and riding with them using 20+ gears when they only have 1 available just seems unfair.
Other reasons for this project are that I wanted to try buying a frame directly from the source (chinese manufacturer), instead of through 3-4 additional hands, and that it seems like a fun bike to add to my stable.

The Process…

I sourced the frame a mixture of ways: I knew I wanted to go carbon, and 29er if possible (greatly due to the fact that I love my Santa Cruz Tallboy frame). To get inspiration, I was reading a forum thread on MTBR.com looking for single speed bike info & pictures, and realized that buying the frame direct from the manufacturer was an actual possibility.

That led me to eBay, where I didn’t find a carbon 29er frame for sale on there, but within a listing for a 26″ wheel frame I noticed a seller put in a picture with text in it inviting people to inquire about a carbon 29er frame. I did, and eventually found my way to gotobike.com.cn. They have several carbon 29er frames available, and I opted for what they call the MTB854 (many pictures to follow). I chose them over competitors mostly because they also had a carbon rigid 29er fork available, and they had a 21″ frame option.

Costs & Parts…

Parts from China

MTB854 21″ Frame Geometry
As I mentioned before, one of the primary goals was to see what buying a frame direct from a manufacturer overseas was like. Since I do importing for a living, I had a fairly good idea of how it would work, but several things took place along the way I couldn’t foresee.
I ordered a 21″ frame. I sent probably around 10 emails confirming specs and stuff from the manufacturer. The components I ordered were easier to come by than the frame and fork. Once I found a company that had both the frame and fork in stock and available, I pulled the trigger. The manufacturer stated that they had a 3K, 12K, and UD weave available for all of the frames. Via email, Ally with gotobike.com.cn informed me that the only finish they had was 3K. No big deal to me, as all of the other components I had ordered were 3K (it’s a classic weave after all).
When the parts arrived though the finish of the frame was UD Gloss! Not a deal breaker by any means, but it was still different than stated in our agreement. I emailed them about it looking for a discount, but had virtually no luck. They told me they’d throw in a free water bottle in my next order. Ridiculous. I ordered some additional parts from them so we’ll see if it shows up.
Overall the parts from them seem to be great. The frame uses an integrated headset, and the brand is Token, which I’ve never heard of before, but according to their website, they make some nice stuff so we’ll see.
Below are some pictures and weights of the chinese procured parts from gotobike.

Lessons Learned…

USE FIBER GRIP on your seatpost. I made the mistake of forgetting to do this on my first ride, and broke my seatpost clamp bolt trying to get the smooth surfaces to bind.

The Finished Product – V1 – Chain Tensioner

All of the parts for the bike finally arrived. I had to wait for 4 weeks to get the cog and the chainring from Homebrew Components. I bought the SRAM XO crank purposely because it did not use a built in spider. I wanted a removable one so that I could run the spiderless chain ring.
It was very easy to swap out, and doing so provided a weight savings on of 160 grams. Even better it’s pretty looking ;).

For the mean time I’m running a Surly Singeator, which helps keep tension on the chain. It works really well, but I’m also going to be trying an alternative tensioning system in the next couple weeks, which brings me to part 2…

The Finished Product – V2 – Beer Components EBB

Since I’m new to the Single Speed MTB world, there were a few things that I had to learn about. The most important of which is chain line and chain tension. Chain line is an easy enough concept, and is even easier to accomplish with a good set of spacers.

Chain tension though, is a little more complicated, not because it’s a tricky concept to wrap your head around, it’s actually simple. What’s confusing is that there are enough was to accomplish tension it’ll make your head spin! Frames with Horizontal dropouts are the best option normally for a single speed setup because they are easy to create tension and super easy to adjust.
Since I opted to save some money buying my frame direct from the carbon manufacturer in China, I was limited to the dropout selection they had available, which in my case was a traditional vertical dropout that you would usually use with a geared setup.

Traditionally, if you have a vertical dropout, you’re going to be forced to use something like the Singlenator I used originally above. But, one of the coolest things about the frame I purchased is that the Bottom Bracket shell is made to the BB30 spec, which is a relatively new system that allows for the bearings to be directly pressed into the bracket, eliminating the need to have threaded BB cups that are made of metal, and therefore increase the weight of your bike.

The BB30 bottom bracket cup is larger in diameter then a threaded external bottom bracket, which allows enough space for an ECCENTRIC BOTTOM BRACKET! An Eccentric Bottom Bracket (EBB) allows you to “twist” the crank so that you can get tension in the chain at the bottom bracket, eliminating the need for a spring loaded tensioner in the rear.
The benefits of this are:

To my knowledge there’s only one company that offers an eccentric bottom bracket for a BB30 cup, Beer Components. I have one on the way, and as soon as I get my hands on it I’ll install it complete with pics.

much much more to come…