rjb wrote: ↑5 Jul 2022, 4:21pm
Some knobblies have a rotation arrow which is opposite for front or back.
And with good reason. If a tyre tread is designed to grip better in one direction then the forces at work on the front will be when braking and therefore opposite to the forces at work on the rear tyre when driving.
I've had more than one customer complain that I'd fitted one of the tyres the wrong way round and I've to point this out to them.
lettersquash wrote: ↑5 Jul 2022, 5:09pmand they look much better at shifting the water
I think that is a red herring since you have to be going something like 120mph to aquaplane on a pedal cycle. Admittedly, some tyres have a reputation for being a bit slippery in the wet - but those same tyres are found to be no problem at all by other riders - all due to materials and riding style..
Except in the case of MTB tyres, I am positive that direction of rotation makes no difference. Tyre manufacturers have even said that a light thread pattern is only there to satisfy fears of the rider. You do not have to go back very many years to find that NO tyres had directional arrows at all. Have construction and materials changed that much?
I think you will be perfectly ok on those tyres fitted either way around.
This has come up before. I recall that either Continental or Schwalbe said on their website that it does not matter for road use but may well in mud (with knobbly tyres). They added that they put direction indicators on road tyres because customers have come to expect them!
Cycle tyres are much narrower, rounder and run at higher pressures and slower speeds than car tyres, so water clearance is never a problem.
I guess like a lot of this it's suck it and see. I should also have said I intend some offroad stuff, mostly gravel, but I wanted my road sections to be fairly easy, so chose a slicker tyre (as well as starting with something very cheap to see how it went). Also, regarding weight, I should also say I'd be camping with another 5-10 kg of gear, and the bike weighs about 11 kg.
Supplementary question - I've never actually measured tyre pressures, and I'm not sure any of my pumps that have gauges (for the car) will work on this Presta valve setup. I'll probably use the rule of thumb method - does it feel firm enough to my thumbs, and how much is it deforming when I look down, as well as how much rolling resistance versus comfort there is.
Anyway, I might have to ask at the local shop why they don't match the picture, and if they've changed the design or sent the wrong thing!
I agree with Paulatic and others about rotating to the right. It's true that it probably doesn't make any practical difference though. The point is, as others have said, that, as the tyre rotates, surface water trapped between tyre and road should be driven away to the outside of the tyre. But that's about reducing aquaplaning, which is far less likely with bikes than with cars.
Whilst bikes are quite light, our tyres are also very narrow compared to those on motor vehicles (and we also only have two of them per vehicle), with much higher pressures (except with yours!!!) Apparently the aircraft industry did some research aimed at preventing the issue for planes. Extrapolated, it suggested that typical bikes would only be likely to aquaplane at speeds over 200 km/h. That possibility has therefore not worried me unduly, especially in utility riding.
Any loss of grip is likely to be caused by mixtures of oil and water, or wet metal surfaces, and so on. I think it was Richard's Bicycle Book that argued that damp roads were worse than deluged ones, because heavy rain washes away the oil dropped by cars, whilst light showers just produce a nasty, slippery, mix.
531colin wrote: ↑5 Jul 2022, 2:23pm
Has anybody ever found it makes any difference at all which way you mount tyres which DO have "direction arrows"?
I have never found any difference at all; I suspect that (like "dropped seatstays" and a lot of bicycle "design") the feature is there just to make you think somebody has thought about it.
I once read that some people intentionally mount tyres the wrong way round, as it improves braking performance. Not sure if there's any truth in it.
I've had MTB tyres that have 2 direction arrows one saying "front" & the other saying "rear". Presumably for better braking on the front & better drive on the rear.
Former member of the Cult of the Polystyrene Head Carbuncle.
Really not convinced it makes much difference, but the way I remember which way round to put a tyre on is by thinking of the impression tractor tyres make in mud. They always point back the way they came.
