Welcome to the Hambini Engineering website. This website started off as my place on the internet for me to detail technical aspects of bikes, cars and my love of engineering. This is largely in conjunction with my YouTube channel where content mainly involves bikes and cars.
Recent posts from the Hambini Blog
Update, more wheels added 06 July 2019
Update, more wheels added 06 September 2019
Precursor - The critics and those with a vested interest
I have added this section to the start of this blog post. The method this test uses is called transient state and it is used when aerodynamics are constantly changing. This is difficult to explain in detail in one blog post so I have linked to a youtube video.
In short, the wheel companies are exaggerating their power savings and testing using methods THAT ARE INAPPROPRIATE FOR ROAD USE. If they tell you otherwise, they are categorically lieing and I would be more than happy to prove that in a court of law.
The important part of the video is embedded below and this shows the difference between airflow that exists in the real world, airflow that manufacturers test
I do not usually write this type of post but I wanted to clear a few things up. I am an engineer by training and one of my weaknesses is I am unable to articulate myself as well as I would like. This is mainly because English is not my native language. There have been a lot of negative words exchanged between myself and FLO cycling about their wheels and I wanted to clear a few things up.
My engineering is Genuine
A key fact that seems to have been glossed over is when a set of FLO wheels was originally tested, the results were kept private and I went to lengths to contact FLO cycling to inform them that their wheels had performed badly. I waited a number of weeks and received no reply. I took the view that as a comparative nobody in the cycling industry they did not really care. So I proceeded to publish the results on my blog.
At this point FLO got interested – they did not want the negative publicity a
The aerodynamic performance of wheels often grabs the headlines and the marketing budget but the reality is the hubs and the bearings within them will have more of a performance differential for the average cyclist. As an example, the power differential between wheels of an equivalent depth at speeds of less than 35km/h will only be 1-2W, the difference in bearing friction can easily exceed that.
Wheel hubs and freehubs account for around 60% of the rotational friction in a bicycle drivetrain. The remaining friction is from the pedal bearings, bottom bracket and pulley wheels. The total amount of friction is small but a cost effective marginal gain.
The term rotational drag has been used of late to describe the amount of power required to spin a wheel up to speed. This loss is a significant aerodynamic loss of about 25 to 30 percent. Rotational drag is not the same as frictional drag which comes from the mechanical components.