On Wednesday, April 18, 2018 at 6:02:49 PM UTC+1, Joerg wrote:
Just received some 25mm Vee Rubber road tires and it says 7bar 100psi
max on the side. That's a bit low for my taste.

The Zafiro I have on there now says 100psi min and 130psi max which is
more up my alley.

By how much can a low max rating be exceeded? I like 100-115psi on my
road bike in back. On the front I won't exceed the max because a
blow-out would be nasty and that carries less weight anyhow.

--
Regards, Joerg

http://www.analogconsultants.com/

Is this some new California fad, riding offroad on narrow rubber? Whatever for? BTW, I have no problem with low- or zero-tread tyres because I ride mainly on tarmac, even in the narrowest lanes, but surely a mudplugger wants considerable mechanical grip.

There's a good reason not to blow up tyres over the max recommendation: It can get pretty nasty and expensive when overinflated tyres blow the rim apart. It is well worth reading Andy Blance, the designer of Sheldon's beloved Thorn bike, on tyre inflation: see page 36 at
http://www.sjscycles.com/thornpdf/th...a_brochure.pdf

I was a convert to comfortable suspension and inflation regimes already in my motor-racing days, and achieved the same results the same way in cycling: see
http://thorncyclesforum.co.uk/index....16360#msg16360
(which is an extended version of a reply I first made on RBT to a query by Pete Cresswell)
and read on in the ensuing very well-informed engineering discussion about ways of determining the optimum tyre inflation.

In fact, there are all kinds of really good reasons for inflating bicycle tyres to the lowest you can get away with short of snake bites. I run my bike on 60mm Big Apple Liteskins inflated to 2 bar, which is about 29psi and I had two flats in 8500km, by which time the tyres were perhaps half worn. One of those was a snakebite when I hit a pothole at the bottom of a hill at 51kph when the tyres at the end of the month-long reinflation interval were probably down to 1.5 bar, and the other was a nail I picked up by going into an industrial building site to ask the workmen to show me their battery-operated angle grinder (which is a threat to locked bikes).

AJ
Both flats happened right after I announced that in 10 years on Big Apples I never had a flat...