cheap stuff online

Theres some Conti Grand Prix S for sale on www.cecilwalker.com.au for under $60 a pair, free shipping within Australia.

Etxy

try probikekit.comindex.phpOpen ↗ $56 a pop which isnt bad or you
can try and haggle this price at your local bike shop...

23mm is perfectyl fine...not much rubber gets on the road with a 23mm and with 20mm its even
less...so I prefer 23mm (so do a lot of the pros in Europe)

hth

"Paul Jones" <"katpaul"@dodo.com.au(nospam)> wrote in message
"]news:[email hidden]...

Quoted message said:

Hello all!

Does anyone know what might be the cheapest place I can buy Conti GP3000 or supersonic tyres
on-line?

If the bill can be sent via money order that would be even better

Paul Jones

"Scotty" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

23mm is perfectyl fine...not much rubber gets on the road with a 23mm and with 20mm its even
less...so I prefer 23mm (so do a lot of the pros in Europe)

The area of the contact patch of a tyre depends solely on the pressure in the tyre and the force the
wheel is supporting - not on the width of the tyre. The area is (downward force on wheel)/pressure.
This just comes from the definition of pressure. Narrower tyres just deform their walls more to
achieve the same contact patch area as wider ones operated at the same pressure. This wall
deflection is a lossy process and is why the narrower tyre has greater rolling resistance as the
wider one when both have the same construction and pressure.

John Retchford

The conti's have a higher pressure rating in the 20mm size.

Would this make up for that deformation?

Paul

John Retchford said:

"Scotty" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

23mm is perfectyl fine...not much rubber gets on the road with a 23mm and with 20mm its even
less...so I prefer 23mm (so do a lot of the pros in Europe)

The area of the contact patch of a tyre depends solely on the pressure in the tyre and the force
the wheel is supporting - not on the width of the tyre. The area is (downward force on
wheel)/pressure. This just comes from the definition of pressure. Narrower tyres just deform their
walls more to achieve the same contact patch area as wider ones operated at the same pressure.
This wall deflection is a lossy process and is why the narrower tyre has greater rolling
resistance as the wider one when both have the same construction and pressure.

John Retchford

RE: TYRES

Have a box of IRC Paperlites available . These are the team versions from their Japanese factory as
used by the Alexia squad in Italy . Every bit as fast as Supersonics. Red sidewall/black tread
700x20mm, 200 gm weight , all important 220 tpi thread count for a supple ride .Foldup kevlar bead.
Half price.....just $29 each.

Also 23mm kevlar belted Vittoria Courier training/racing tyres only $18ea 25mm Maxxis Detonator the
best training tyre around at $24ea Clement tubulars $39 ea.

PLUS much more..... email me at: [email hidden]

www.idealcycles.com

John Retchford said:

"Scotty" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

23mm is perfectyl fine...not much rubber gets on the road with a 23mm and with 20mm its even
less...so I prefer 23mm (so do a lot of the pros in Europe)

The area of the contact patch of a tyre depends solely on the pressure in the tyre and the force
the wheel is supporting - not on the width of the tyre. The area is (downward force on
wheel)/pressure. This just comes from the definition of pressure. Narrower tyres just deform their
walls more to achieve the same contact patch area as wider ones operated at the same pressure.
This wall deflection is a lossy process and is why the narrower tyre has greater rolling
resistance as the wider one when both have the same construction and pressure.

John Retchford

"Paul Jones" <"katpaul"@dodo.com.au(nospam)> wrote in message "]news:[email hidden]...

Quoted message said:

The conti's have a higher pressure rating in the 20mm size.

Would this make up for that deformation?

I can't quantify these effects (it is very difficult). But we can learn something from simple
physics and materials science.

The tension force in the tyre wall is proportional to the tyre width and to the pressure.
Continental's literature states that the carcase construction for the 20, 23 and the 25 mm models is
the same (for the GP3000), so the wall stress (i.e. resistance to bursting) is also proportional to
the width and the pressure. So we can put 23/20 times the pressure into the 20 mm tyre as the 23 mm
tyre and have the same wall stress. Does this result in less rolling resistance? I doubt it. I
understand that the narrower tyre working at the higher pressure is slowed more by road roughness.
Remember, too, that we are dealing with small changes in very small forces here. My son and I
estimated the rolling resistance of a bicycle with high pressure tyres on a smooth floor to be about
2 newtons.

What is your application for these tyres? Unless you are racing successfully at the very highest
level there are many more fruitful things to be concerned about than the fine detail of tyres -
working on the engine for example. My advice is to forget about 20 mm tyres, buy 23 or 25 mm ones
and don't pump them up so hard that your teeth rattle. Tyres provide practically all the
"suspension" of a road bicycle.

John Retchford