On Bike Tyre Pressures and Seat Heights

A bit of Knowledge is a Good Thing! As you can see I have been doing some thinking about my bike ie should I upgrade and were exactly the 3kg savings are made that $3000 can get me.

Turns out about 2kg of it will be in the frame and components and 1kg in the wheels of which 400g is in tyres and tubes alone!

I started looking into bike resistant forces to see the affect of dead and rotating mass (yes I know mass is best out of the wheels but being an engineer i wanted to understand things better) and I found a calculator from Analytic Cycling that included tyre pressure in calculating rolling resistance and found rolling resistance increased compared to 120 psi for 90 psi and 60psi by 2.5% and 5% respectively. A friend of mine Gray recently questioned my choice of running 110psi .... Hmmm ... perhaps there is something in this ...

My approach has been ... hmmm this is hard enough and go ride but this morning I pumped the tyres just prior to departure (both were hard but 60 psi!). But wait there is more

I also looked at my seat height (suggested by Annette) and used the fit calculator from Competitive Cyclist which gave me some crazy numbers but that might have more to do with the sloppy measurements I made ... but it did recommend something higher.

I did raise my seat by 4cm above my old rule of thumb method of the heel on the pedal.

It did feel much better from a quick test ride and with the correct tyre pressures I think the two improvements helped me drop 30 minutes off my best riding time on a ride from Cronulla down to Bald Hill and back sort of proved it. I don't think I have amazingly improved by 10% with no training!

The sad part of this story is that it means until something breaks I cannot justify a new bike :>

Thanks to my friends for prompting me to understand things better :>

Why being a Weight Weenie is Wonderful

I not only admit I am a weight weenie ... but I embrace it. I have just spent three hours looking at the weight of my road bike compared to someone "light" bike. I probably spent about double the time (which really means triple) thinking and researching about this issue. When you consider the exorbitant hourly rate I charge you would really wonder why I even bother.

I guess a few reasons ... I am a geek and I need the warm fuzzy knowing I am making the best decision.

To this end, I will attack this in three parts.

This being Part 1 where I will look at my bike compared to a "light" bike to see where and how significant the differences are.

Part 2 of my investigation will be looking at the bike resistant forces during rides to assess what is really important.

Part 3 will look at the biomechanics of riding faster (which is my root cause).

Part 1 - Component Weights

Item	"Light" Giant TCR Composite '02 (not OEM)	My Protour	Delta
Cost	$3500+ est	$0	$ for me
Bike	6854	11060	4206
Frame	1325	3236	1911
Components	3373	4709	1336
Wheelsets	2155	3155	960

Weights in the above table are in grams. I know these values don't quite add up but I am not chasing 40g on here any more then I am on my bike. Weights in the above table are in grams.

But I think the table has convinced me that yes I can make significant weight savings in my frame and componentry but there are only limited savings to be made in the wheelsets where the most benefit can be made. There is potential to save about 400g in tyres and tubes which I can implement next time I need to change.

Interim Conclusion
I don't think a smick new bike is my answer although it would be nicer then the cruel harsh reality I need to train harder (and smarter?). Some new go fast tyres and tubes will be on the cards and a lil more investigating as detailed above.