Choosing right fork for fatbike

Apr 2, 2016
There are a lot of different bike models on the market today. If you decide to upgrade your present bike with a carbon fork, it’s not always as easy as you might think, so here is detailed guide about this.
 
 
 
 
 
Axle to crown
 
 
An important measurement to consider is what’s called “axle to crown”. It’s all about geometry. You see: different bikes have different dimensions. If you tried to install a fork where the length from the axle to the crown does not match the length of the fork then you will be in trouble. Higher fork - and front end and bottom bracket will be higher too, and head tube angle will be slacker. Lower fork - conversely.
 
Sarma for now has:
 
 
 
 
 
 
 
Steerer 
 
 
 
The two most popular choices are ones with a tapered fork head and ones with a straight fork head. In order to figure out which one you need look at the head tube on the frame of your bike. If it is straight you need a straight fork head. If it tapered—like from 1 ½” tapered to 1 1/8”—then you need a tapered fork head. You don’t even need to measure. You can tell by looking.
 
 
Drop outs
 
 
 
 
Thru axle fork have better torsional rigidity and more relible, while QR forks is just all about simplicity.                                                               
 
Look at your wheels whether it’s QR or Thru axle and choose a fork with right drop-out. Also pay attention, your hub could be convertible. QR=>Thru axle or back. Just ask your supplier about conversion kit. 
 
 
Brake specific 
 
Historically first fat bikes used rear wheel for front and rear. But we know that front and rear hubs are different not only in length and free hub, but with specific of brakes. Rear hub has 15mm from disk brake place to end of flange, rather than front only 10mm. That’s why you have to pay attention to brake specific.
Rear specific uses only on “old school” bikes as Surly Pugsley. 
Almost all new fat bikes come with front specific brake on fork.
 
OLD (Over locknut dimention)
There are two major dimension - 150 and 135mm. Rock Shox changed a market there with 150mm hub for Bluto. Big players could change a whole market. And more and more bikes even with rigid forks come with 150mm hubs.