Single Speeding a 29er Full Rigid - Lessons Identified
G'day all,
I thought that I would give my experiences of building my first Chinese carbon bike.
I had been toying around with the idea of building a single speed carbon bike as an experiment to see just how light a bike I could produce. After taking much flak from others about the perceived risks of Chinese carbon, I did a bit of research, and decided to take the plunge. I went with Yoeleo because of the quick responses to all of my initial questions from ‘Leo’, the quality website, and their qwerky youtube videos (with the pretty Chinese girl!).
The frame that I ended up with is the YCMSF05
http://www.yoeleobike.com/29er-carbon-frame-for-mountain-bike.html . Because this was an experiment, I also went with a rigid fork, with an idea that if I run tubeless 2.25 tyres at 30 psi or less, I’m part of the way towards the cushioning of a “fat bike”. OK – a fairly slim fat bike. So this was never going to be an all mountain, rocky boulder strewn descent type of bike, but one for fire trails and the developed single track here in Canberra used for international 24 hrs races. (I’ve had a number of concussions over the last 35 years of riding, so I’m not a fan of jumps per se...)
How does it ride? - To cut a long story short, I was 4th in the Open single speed category in a recent 50 kms (~30 miles) cross country race with 500+ competitors. (I should point out that there were only 7 entries in the single speed category!) I was the only full rigid rider in the race...
Since having the full rigid single speed, I’ve ridden over 650 kms (~400 miles), all dirt, and as of a few days ago, did over 9,000 feet of climbing in 4 rides towards the 29,000+ feet Strava ‘Everest’ climb challenge (the remainder of the climbing was completed on my cyclocross).
Oh, and the frame, handlebars and rigid fork take a thrashing, as I weight over 220 lbs in lycra... (not a pretty look!!)
So firstly – my Chinese carbon is meeting my expectations, and far exceeding those of the detractors...
My order from Yoeleo cost me $1,425 USD, and comprised of:
• YCMSF05 - 29er hardtail frame
• Y-F-MTB-29 - rigid fork
• MTB-H2 Integrated handlebars
• Y-W29-23.5-30C-881 - 30mm / 23.5mm clincher wheelset, with aerospokes and Novatec D881SB D882SB Hubs (these are the 4 in 1 that I wanted for flexibity to reuse for bike N+1 – a planned dually with a potential thru axle)
• CFSP02 - Seat post
To create chain tension to ‘single speed’ the bike, I used the “Beer Components” eccentric bottom bracket. This necessitated that I ordered the frame from Yoeleo with a BB30 in lieu of a BSA.
Things would have worked out fine up until the point where I was having a chat in my LBS, and saw that they had a pile of SRAM XX cranksets for half price. Being a 24mm spindle, I was assured that the SRAM XX would work within the BeerComponents EBB30. That’s when I discovered the difference of the 24mm SRAM GXP and 24mm Shimano HollowTechII (which really is what the EBB30 was compatible with). A change of bearings in the EBB30 by the LBS to work with the GXP system has never given me full satisfaction—there is a little lateral slop. None of the other four LBS could offer a solution. It has been fine to ride, but a little frustrating to know there is the 0.5mm slop. The next disaster was that the big ring that came stock with the SRAM XX actually would grind into the chainstay on all but the most extreme rotation of the EBB30—meaning that the whole point of the eccentric bottom bracket (its rotation to obtain the chain tension)—was negated. So it was onto chainreactioncycles.com to order a smaller chain ring. Of course, the SRAM XX is a 120BCD (probably the largest bolt hole diameter of any MTB crankset), so the smallest ring I could get was 37T.
Fitting all of that gave me about 150 degrees of rotation of the EBB30 before I was within 3mm of the ring grinding the chainstay (the minimum tolerance I was comfortable with). I changed out the original Shimano 10 speed chain that I was going to use to a meaty 1/8” Gusset Slink Half Link Chain (in black of course!). I went with a half link chain to get more adjustment ability, and also to carry my weight when I stomp on the pedals climbing (being a single speed and all!). The chain is over 400 gms (0.9 lbs!!) in weight, but gives me confidence when stomping about on the pedals when I’m over 10 miles from a road (ie, a long walk back). That being said, I always ride with a heavy duty chain breaker and a few spare links in the tool container on the frame...
The weight? In the original photo, running tubeless, and with the original Shimano 10 speed chain and no bottle cages (also carbon of course!), it weighed 8.7 kgs (19.2 lbs). She is a little heavier now with the half link chain and tool container, but not much.
I aim to maintain a matt black (UD) style on N+1, N=2, ... bikes as well.
I will be replacing the SRAM XX crankset with a Shimano XT (104BCD), with an aftermarket 30T chain ring in the near future (the SRAM XX to go to the N+1 project – a dually).
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