r04DiE
300km a week through London on a road bike.
No. Why?
How much pressure?
- Thread starter Glasgow44
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S-Express
Guest
Because a smaller contact patch does not necessarily equal less rolling resistance. There's so much more to it than that. In many cases, a tyre with lower pressure will roll better than the same tyre at a higher pressure. This is not new information, by the way.
CanucksTraveller
Macho Business Donkey Wrestler
- Location
- Hertfordshire
Paging @Fnaar to the pressure thread, that's Fnaar to the pressure thread, double entendre waiting, thank you.
r04DiE
300km a week through London on a road bike.
It's new information to me so perhaps I should apologise for my ignorance.
U
User6179
Guest
Have you any data to back that up? , all the data I have saw says the opposite!
http://www.bicyclerollingresistance.com/road-bike-reviews
S-Express
Guest
Data to back it up? I thought it was common knowledge. All things being equal, on a smooth surface, a tyre will roll better at high pressure. Which is why trackies tend to go for high pressures (ie 120+) and (conversely) why P-R riders tend to go for wider tyres at lower pressures. On a 'real world' road surface, with all its various imperfections, a lower pressure will allow the casing to deflect more, thereby enabling the tyre to absorb road shocks, rather than bounce over them. Bouncing obviously diverts the wheel upwards, rather than forwards.
A quick scan through google should be all you need.
U
User6179
Guest
That was not what you said though , you said
"a tyre with lower pressure will roll better than the same tyre at a higher pressure"
Which is incorrect !
S-Express
Guest
Except I preceded that statement with the phrase "In many cases" - maybe you forgot to read that bit?
r04DiE
300km a week through London on a road bike.
Well where is your evidence to support that this is true then? i.e. that it is commonly the case?
mark st1
Plastic Manc
- Location
- Leafy Berkshire
You'd have more luck with a brick wall tbh.
U
User6179
Guest
Ajax Bay
Guru
- Location
- East Devon
and @r04DiE
This article gives some useful arguments (if not data) on which @S-Express may be drawing (albeit with careless phrasing), and I recommend it to you. The main argument is that by running wider tyres at lower pressures you reduce the suspension losses in the rider/bike combo and thus real rolling resistance is reduced. On a smooth drum (ie the rollingresistance.com tests) rollingresistance reduces very slightly as the pressure on the same tyre is increased - but this higher pressure results in more, for want of a better word, 'bouncing' on rough surfaces (eg roads) which actually means a narrower tyre at higher pressure (to avoid pinch flats) is 'slower'. Edit: this may be @S-Express "in many cases' ie not on tracks.
At higher speeds (eg 45+kph) aero aspects may come into play, and wider tyres tend to be heavier (which may be an issue if lots of acceleration involved - as opposed to steady riding). It would be excellent if tyre manufacturers of the good road tyres (Michelin, Continental, Vittoria, Schwalbe et al) made 28s which measured 28 and 32s in the same 'road tyre' range, as opposed to the step across (ie not up) to the fastest but heavier 'touring' tyres eg M Supremes.
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S-Express
Guest
I already named one example - Paris/Roubaix. Maybe you missed that as well.Could you name one case ?
S-Express
Guest
I'm not drawing from anything in particular - I honestly thought this was a generally-known thing. I don't know any riders that don't already understand this stuff. Except some on here, clearly.
Here's an interesting article from Hunt, which does describe the issue better. https://www.huntbikewheels.com/pages/recommended-tyre-pressures
Let the post-rationalisation and cognitive dissonance commence...
