Hi all. So finally I’ve decided to build a year-end bike for my self – amidst this pandemic we all deserve something better. Been in road bike since 2015, and MTB with 2 years experience and always curios on what discipline is needed for riding a fat bike. (hUGE TIRESS)
What I got is this Norco bigfoot frame and my question, is it okay for me to use a flared drop bars and use Shimano GRX as groupset or is it better to go with the usual flat bars and install it with Shimano Deore XT?
1. For a Fatbike to be truly useful, you need to live where it is cold and snowy enough for enough months of the year. Your trails must also be groomed in some way because it is quite difficult to ride in deep unpacked snow. If you live in the southern two-thirds of the U.S. or anyplace where it is mostly dry, a Fatbike doesn’t get enough use to be worth buying.
2. Unless your trails are very well groomed, you want to put on the widest tires possible.
3. Snow, ice, and mud pile up on a front derailleur rendering it useless. It is best to use a 1x drivetrain.
4. Pedalling those big heavy tires through deep snow requires a very low gear. With standard 1x Mountain bike cassettes with a largest cog of 50-52 teeth you will likely want a 26-28 tooth chainring.
5. Unless you intend to use your Fatbike on dry trails, a suspension fork is not needed. I don’t think suspension forks help much on when riding on snow.
TinyBubbles, it is time to begin experimenting! Fatbikes are a blast for any time of year in any temperature. I ride my Mayor year round along with three plus bikes.
Do you need a wide range cassette? Perhaps. It is personal preference. For example, I run a 28T chainring with a 36-11 cassette, in the Rocky Mountains, in 10° weather or 90° weather. It goes up, it goes down in elevation and doesn’t require 16′ of chain to do it! Short cage RD serves nicely and keeps my bike’s junk outta the dirt, snow, mud etc.
Snow/sand… Tires in 4.5-4.8″ range do better than 3.8/4.0. Tire pressure! Lower than you expect… For snow/sand, you want them to squish down some when you get on the bike. The intent of fat is a comfortable ride with massive flotation for loose/soft conditions. This is very different from any other discipline in that max pressure might be 12 PSI for dirt trails. Minimum pressure might be 3 PSI in powder over groomed. In snow, the tire flattens out and makes a larger footprint to limit sinking in, sand is similar. On tarmac, you air em up enough that they don’t flatten out but carry you with a slight compression with 5% rim drop under load.
I refer to tire compression in terms of rim drop % since no two riders are the same weight. PSI is less meaningful with rider weight and the silly low pressures a 4.8 requires vs. 23mm or 2.4 might require.
I run a carbon fork without drama 12 months a year. A suspension fork is an option but not a requirement. Keeping weight under control with a fatbike can improve fuel economy!
Hell, you can live in Florida and a fatbike would be awesome on the beaches, just sayin’. It isn’t a federal offense to ride a fatty on a 90° day on a nice sugar sand beach! They work in high and low temps.
Drivetrain, 1x is preferred for simplicity as well as reliability.
I prefer a flat bar for the fat bike just because the big wheel acts like a heavy gyroscope. It makes the most difference if you are on tight singletrack. Most of my riding is between close trees. If you are on wide groomed trails or beaches it is probably less important.