Coming off of Travis’s For a Change series on the Hope Academy, we thought we’d share a kid’s bike for this week’s Readers’ Rides. Let’s check out Holden’s 2019 Diamondback El Oso Nino fat bike!
As a family we ride bikes. We ride for exercise, we ride for fun, and we ride to get around town. I will not drive my son, now seven, to school. Living in the mountains that means that during winter we ride on snow, so as my son began preparing for kindergarden, I began looking for a snow bike.
Here is Holden’s 2019 Diamondback El Oso Nino, with a few component changes to lighten the bike and make it overall more ridable for a child. I was able to grab one of these on closeout as the model was being discontinued. It is great that Diamondback was one of the few to offer a small frame size with large tires, but it wasn’t exactly spec’d in a way that made it easy for a small child to actually ride.
The stock components were all budget minded and heavy steel making the bike around 36 pounds. More challenging was the gearing. The crankset was a short enough, 152mm, but had a 40 tooth ring on it. Stock drivetrain used a 14-28 freewheel, making the bike difficult for Holden to pedal on flat pavement and impossible on any snow. When he was able to get rolling on slight downhills, the cheap cable pull disc brakes were too difficult for his child hands to pull effectively, especially with winder gloves on. Any actual fat bike trail riding on the weekends was out of the question.
To start, we put the bike on a diet with some basic alloy parts I had from past bikes. I ordered a shorter stem to bring the reach in and swapped out the post, collar, and handlebars. Tuned the brakes as best as could be done, and to address the gearing issue we pulled the crankset off Holden’s Cleary 16″ bike, which fit the stock square taper bottom bracket. This worked well enough for the first winter, but wasn’t ideal.
Changing brakes to inexpensive hydraulics was relatively easy to plan for. The hubs are six bolt already and the frame mounts are IS tabs that just needed some alignment persuasion from a large crescent wrench. The difficult part was the gearing due to the stock bolt on rear freewheel hub. There simply are not great options for freewheels so I began the search for a hub replacement. Diamondback lists the rear hub as 180mm OLD which must be some sort of typo, the frame measures 190mm. Sun Ringle still offers a hub with swappable end caps to fit 190mm QR, and it has an HG freehub body which is compatible with an abundant number of cassette options. Best of all, swapping the hub dropped over a pound compared to the original steel hub.
Shimano had recently expanded on their LinkGlide concept and introduced a wide range of Cues components including some shifters and brake levers designed for smaller hands, marketed as S-Reach. Overall I really like the cross compatibility and durability of the LG/Cues products, and the easier operation of the shifter made it the obvious choice for a kids hand wearing winter gloves. Because Cues uses an 11 speed width chain for all drivetrains, the crankset had to be rethought.
The stock square taper BB worked fine but I couldn’t find a short crankset that would take a small chainring narrow enough for the chain, they were all designed for older 8 speed chains. There are already few fat bike crank options, and fewer still that come short enough for a child. Race Face had just announced 160mm lengths for the Turbine would be a touch long, but manageable for a tall six year old. The Cinch system has the added benefit of many chainring sizes and a replaceable BB spindles so I could narrow the whole system using a shorter 170mm BB spindle to improve the chain line and helped the ride-ability for Holden while still having plenty of frame clearance.
Now with hydraulic brakes, smaller chainring, larger range cassette, tubes swapped out to TPU to drop another pound of rotational weight, the bike is super fun for Holden. Riding weight is now just over 30 pounds. It is the daily commute bike during the winter and a source of great weekend fun on the local fat bike trails.
Build Spec:
- Frame: Diamondback El Oso Nino, steel
- Fork: Steel
- Headset: Cheap, threadless, black
- Stem: MSW Trail 35mm
- Handlebar: Ritchey Comp alloy, cut down to 620mm
- Bell: Spurcycle compact
- Seat post: Thomson Elite, cut down to fit
- Saddle: Diamondback stock
- Brakes: Shimano UR405 levers, MT410 calipers, 160 rotors
- Crankset: Race Face Turbine 160mm length, 170mm spindle
- Bottom Bracket: Race Face BSA Cinch
- Chainring: Race Face 1x Cinch, 26 tooth
- Shifter: Shimano CUES SL-U6050-10R Short Reach
- Cassette: Shimano LG400-10 11-43t
- Derailleur: Shimano Deore RD-M5130 medium cage
- Rear wheel: Sun Ringle SRC hub 190QR, HG freehub body, DT spokes, stock rim
- Front wheel: stock, steel hub bolt on
- Tires: stock 20 x 4.0
- Tubes: Biketube Brand Heavy Duty TPU
- Pedals: Race Face Ride
We’d like to thank all of you who submitted Readers Rides builds to be shared here at The Radavist. The response has been incredible and we have so many to share over the next few months. Feel free to submit your bike, listing details, components, and other information. You can also include a portrait of yourself with your bike and your Instagram account! Please, shoot landscape-orientation photos, not portrait. Thanks!