Tag Archive for: dyno

dyno – design

I usually do what the voices in my partner’s head tell her to tell me to do.

For once, my own head had something to say: ‘Stop wishing you had a dyno and build one!  You’re a k’n engineer for Heaven’s sake!’   And so it started….

There are two types of dyno:  the inertia or rolling road  and the  break dyno (the break dyno is responsible for the term ‘Brake Horse Power’). There are pro’s and cons for both but the big plus for the inertia type is that it is the easiest and cheapest to build.  Other pluses: More closely replicates what the bike experiences on the road and results from pull to pull are more consistent and repeatable. Repeatablility is key when you are checking  whether your random fiddlings are having the desired effect.

The inertia dyno is comprised of two basic parts: a rolling mass that is accelerated by the rear wheel of a motorcycle and a software package that crunches the numbers to spit out torque/power curves.

Mr Newton worked out the relationships that are used by the software which in essence deals with the rate at which your motorcycle accelerates a mass of known polar moment of inertia.

There’s heaps of DIY dyno stuff on the web if you want to dig deeper,  here’s a couple:

DTEC inertia dyno design guide


The design is all but complete and I’ll be looking at design considerations in  more detail in the next blog..