Recent posts from the Hambini Blog

• Bicycle Wheel Aerodynamics, Which one is fastest!

  Posted: October 17, 2018

  |

  Categories: Wheels , Aerodynamics

  In terms of drag caused by a bicycle rider, the biggest loss is caused by the rider themselves followed by the wheels and frame.

  The drag caused by wheels is significant because of two fundamental reasons. The first is they hit the air first as they are the most forward part of the bike and second because they are rotating. The effective air speed at the top of a wheel/tyre is double the indicated speed of the bike.

  In the bike industry, wheel aerodynamic testing has generally been conducted by two groups of people - Wheel manufacturers and journalists. Wheel manufacturers will usually adjust tests to make their particular wheels look more favourable than their competitors in testing. This is usually achieved by a combination of adjusting speeds and angles. The reality is this type of test is not impartial.

  Journalists on the other hand tend to visit their local university and ask some clever boffin to conduct their testing for them and give them t

  Read more »
• Bottom Bracket Pressfit and Creaking- An engineering Opinion

  Posted: October 17, 2018

  |

  Categories: Bottom Brackets , Bearings

  If you are reading this you will have probably already come across the numerous posts by various individuals in Internet forums across the web.

  The issue of creaking bottom brackets has been blamed on the introduction of pressfit and directfit bottom bracket standards, where bearings either push directly into the bike frame or push into cups which are then pushed into the bike frame.

  General guidance varies from taking everything out and regreasing it to installing with extreme measures such as epoxy resin.

  Pressfit is not the problem and threaded is certainly not the answer...

  The reality is pressfit has nothing to do with creaking. There are many areas of a bike where bearings have a pressfit and there are no problems. For example, wheels, freehubs, pulley wheels and some headsets are pressfit yet they don't generally creak.

  The basic reason for the creaking is one of two reasons, either a poor fit or misalignment. Often, the two occur at

  Read more »