Promax Hf-2 bmx cranks



The HF-2 cranks are Promax’s top-of-the-line crank offering. Hollow-forged from 6061-T6 aluminum, both crank arms are hollow so they are super stiff, yet lightweight. The crank arms spin on a beefy 24-millimeter spindle permanently fitted into the drive-side arm.

With a 104-millimeter BCD four-bolt spider, they come in a variety of beautiful anodized finishes.

Available in anodized red, blue, gold and black with laser-etched graphics in 170-, 175- and 180-millimeter lengths. Now also available in 172.5 and 177.5 in black only. Bottom bracket sold separately. Meets or exceeds ENBMX standards. MSRP: $299.99

Chainline: 43
Q-Factor: 167

170-PX-CK13HF170: 768 grams/27.09 ounces
172.5-PX-CK13HF172: 819 grams/28.9 ounces
175-PX-CK13HF175: 838 grams/29.5 ounces
177.5-PX-CK13HF177: 858 grams/30.3 ounces
180-PX-CK13HF180: 877 grams/30.93 ounces

Tech Tip:
When using Promax HF-2 or CF-2 cranks, DO NOT use any spacers between the BB shell and and the BB cups. This will effectively shorten the spindle length.

Our cranks are BMX-specific and have a single-speed BB spindle designed to work with standard 68mm BSA BB shells. The spindle width is standard and should fit any and all 68mm BSA BB shells with external BBs without any additional BB spacers between the bearing cups and BB shell while maintaining a 43mm chainline and 167mm Q-Factor. 

The spacers are meant to be used only when using an MTB-style crankset meant for a 73mm wide BB shell with a our BB and a 68mm BB shell BMX frame. Make sense? For example, if you were using an XTR crankset with a standard BMX frame and our BB. 

Our cranks are designed to fit 68mm BB frames. The spindle length was determined for this, too. 

Using the spacers with our cranks on a standard 68mm BB shell can do several things. 

1. Create incorrect chainline/alignment. 

2. Prevent the left arm from clamping correctly to the spindle as the spacers effectively “shorten” the spindle length. 

We do not recommend the use of spacers with our cranks when used on BMX or other frames with a standard 68mm wide BB shell. However, I have seen many riders do this, with no apparent problems. I also have seen problems. 

Some BBs made by other companies are wider than standard and cause similar fit issues