Correct tyre pressure ?

[richard]

I purchased one of these cheap digital tyre pressure gauges from a local petrol station and when I tried it on the bike it was way out !! or so I thought. Having checked it out with the car and our local tyre service shop I found it was my ancient metal slide gauge which was at fault. On a regular 15 mile run I found the hill climbing improved and on a flat (as far as I can tell) run near home whereas I am normally registering 15.8 mph I was reading 16.5 mph. In future I will pay more attention to tyre pressures. well I guess I learn something every day.
Richard.
ps. I was under inflated by about 15 psi. I try to keep my Ezee Liv at 55 psi

 

[Ian]

Tyre pressure does have a big impact on the rolling resistance of the tyre, a tyre flexes far less at a high pressure, wasting less energy,meaning more speed, and in the case of an e-bike more range. The acceptable pressure range is normally marked on the tyre wall and because of the extra weight involved with an electric I like to run my tyres at the high end of the range.

Another factor affecting resistance is the tyre itself, knobbly mtb tyres have a particularly high rolling resistance where as the narrow slicks used by road racers have very low resistance. The Swalbe Marathon Plus tyres favoured by many e-bikers because of their resistance to punctures have noticeably less rolling resistance that the standard tyres on most bikes.

 

[flecc]

Richard, a few years ago I got cheeky and turned up at my local trading standards department with my two slide pressure gauges and asked for them to be checked.

To my surprise I was given red carpet treatment. A huge master gauge, pressure balancing tank and pump were produced and they ran through a complete sequence of tests at 5 lb intervals on both gauges, recording the precise variations at each level. They then raised certificates for the gauges, identified to each and showing all the correction factors, signed and stamped by trading standards. All in all an hour and a half spent on my gauges, and I had the feeling that they'd been waiting for years to have a chance to use their exotic equipment.

I've kept one gauge in store as my master, and that tells me that the digital gauge I now have is also very accurate.
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[richard]

You never cease to surpise me Flecc, however I corrected the tyre pressures on madame's Ezee chopper today with similar good results but while out on a test run whilst coming up a steep hill I couldn't help but think what a good bike the Ezee chopper would have been for our lady member in San Francisco, it's a pity they are still not made. Do you think anybody in the states would still have one in stock.
Richard

 

[flecc]

Yes, Nycewheels have them in stock on the link below Richard, and what's more, they give a choice of Li-ion or NiMh, the latter being perfect for hill climb work, and the Chopper being the ideal bike for San Francisco as you say.

eZee Chopper $1600
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[richard]

Well done Flecc, not being familiar with links etc ( I am Bee useless with computers ) do you think you bring that to her attention.
Richard

 

[flecc]

Have done in that thread Richard, and also made a couple of suggestions to get round those problems.
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