Polo Bikes

lower

lower than 175psi...

120psi is plenty for a 700x23c.

I accept that for track but with the rapid changes of direction on imperfect tarmac, wouldn't lower pressure give better grip because of compliance? (sidewalls absorbing lateral shocks so that the maximum shock whilst maintaining grip is higher).

Yes & no. The Fortezzas work because the compound is nice & soft, I think.

Pfffffffffffffff!!!!

Not you, Bill...

lower than 175psi...

120psi is plenty for a 700x23c.

Yeah, but if the tire is rated to 200 psi, why wouldn't you bang in as much as possible?

Polo has a Scoble...

Not you, Bill...

Anyway, the long and the short of it is that no-one has been able to convincingly answer why some tires are more grippy, whether a smaller contact patch is more grippy than a bigger one etc etc. Probably because it's seriously complicated physics & also tire grip is serious trade secret stuff.

poscoble

Not you, Bill...

What? Is it my fault these guys can't read the writing on the side of their tires?

A fella's gotta do something to ease the passing of a long night at work.

Pfffffffffffffff!!!!

Not you, Bill...

<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

There's a million pedants on this thread, why pick on me?

Polobatron

Not you, Bill...

Buffalo Bill - 0pts

bigger patch is more grippy ennit, softer compound is more grippy too, more grippy will usually mean higher rolling resistance, depends if you want to go faster or turn more reliably I guess, I have giant tyres that everyone hates, so, obviously, I'm spouting shite

Not. One of the reasons tubs are superior to wire-ons is that you can put 150 240 psi into them.

.

forum 24 = 0pts

lower than 175psi...

120psi is plenty for a 700x23c.

shhhhhhh

Polo has a Scoble...

this

Bill = Part-time troll = Tried it, turns out it's not really my thing... wipes snot

Yeah, full-time for you.

TS Repped. Emyr on ignore.

Drunk troll is hungover...

bill=> I use **Michelin Wildrun'r 26x1.40 [B]tyres on my polo bike. **[/B]Top slick tyres, really light, and they grip really well ! 420grm. Not really expensive, but you don't want to use it on an only rear break bike. It wouldn't last long

every top slick tyres are lighter and grippier.

http://www.schuss-bike.com/product.php?id_product=1173&id_lang=1

Please show where all the light grippy 26" tyres are.

i ride a continental sport contact: http://www.conti-online.com/generator/www/de/en/continental/bicycle/themes/city/citytyres/sportcontact/sportcontact_en.html
probably the lightest you will get

bigger patch is more grippy ennit

not at all

softer compound is more grippy too

mostly true, softer tires often have higher frictional coefficients

more grippy will usually mean higher rolling resistance

not necessarily

Anyway, the long and the short of it is that no-one has been able to convincingly answer why some tires are more grippy, whether a smaller contact patch is more grippy than a bigger one etc etc. Probably because it's seriously complicated physics & also tire grip is serious trade secret stuff.

this is quite simple in theory:

that is: "maximum sideway friction" equals "frictional coefficient" multiplied by "force that is applied vertically to the ground".
the frictional coefficient is the only part where the tire influences this equasion. it does NOT depend in any way on: tire surface, tire pressure, etc. it is a value that is determined in experiments (!) considering the two materials that are in contact, and outer influences, like lubrication (eg. water). rubbercompound x and tarmac have a certain coefficient. rubber compound x and wet tarmac have another coefficient. and so on.

in reality, a bigger tire or less pressure and therefore a bigger surface might help you if there is debris on the court that makes you lose contact with the ground when you ride over it. but, as long as your tire is in contact with the ground somehow, surface doesn't matter for grip

if you want more grip you have one option. get another rubber compound. a bigger tire won't help (at least not in theory, thats for sure)

rolling resistance is even more experimental stuff than friction, i don't know enough about it to really beeing able to explain everything right. main thing is: rolling resistance increases exponentially as pressure gets lower. probably because: if you have lower tire pressure, your tire doesn't just roll in clean contact to the ground, but it gets warped constantly. this needs energy, which is then mostly transfered into heat.

hope my poor technical english ins't too confusing

Interesting, I've been keeping my tyres around 60 PSI (38 Marathon Plus), thinking it would help grip. So that's basically bollocks then...

hope my poor technical english ins't too confusing

Not at all, you've just explained yourself better than pretty much every native english speaker in this thread.