I came off

[Yellow Saddle]

And compared to roads in Europe, the roads in the UK are a disgrace.

Book a holiday in beautiful Costa Rica.

 

[ianrauk]

Book a holiday in beautiful Costa Rica.

No thanks.

 

[EasyPeez]

But, if you have a contact patch of 200mm^2 on your 28mm (wide) tyre and a contact patch of 150mm^2 on your 20mm wide tyre and you corner over a tiny slick of oil of 100mm^2, you will have 100mm^2 in reserve on the large tyre and just 50mm^2 on the narrow tyre. Should the 50mm^2 thus just not be enough to keep traction, you will slide on the narrow tyre but not the wider tyre.

But have a careful look at the scenario. It is pretty unlikely and probably far-fetched.

Thanks, this is helpful and insightful, as was the rest of your post. In relation to the extracted section, and recognising that the specific example scenario is unlikely, do the same principles not also apply to the much more likely scenario of cornering on a wet road surface? You'll have to forgive my scientific naivety here, but what I'm getting at is, isn't there a theoretically definable (assuming all variables of speed, rider weight etc were factored in) breaking point at which a cornering tyre will slip on a wet road? And wouldn't one of the affecting variables in this equation be size of contact patch? Ergo a greater contact patch on a wider tyre would mean the 'breaking point' at which the tyre lost traction would be less easily achieved? This may be nonsense, I'm just trying to better understand in layman's terms how this works.

The wider tyre will NOT give you better traction

Something I don't think your post touched on was pressures. I've heard it said that lower pressures = more grip. Is this a myth? If not, then doesn't the fact that a wider tyre can be effectively run at 10-15psi lower than the narrower tyre mean that actually it could give better traction?

 

[col.kurtz]

I was thinking the same thing, a lower pressure should equal a greater contact patch with the road, giving you more grip. The trade off I suppose is less responsive turn in?.

 

[Johnno260]

I was being sarcastic, EU roads in the most part seem better than ours.

In general I think our roads are in the worst state I can remember, they should be in a better state than they're currently (in my opinion)

Potholes this year have cost me a set of bike wheels, and two alloy car wheels, in all circumstances I couldn't avoid the hole without causing a bigger accident, so from my point of view the roads are in a sorry state.

 

[S-Express]

And compared to roads in Europe, the roads in the UK are a disgrace.

There are good roads and bad roads in every country, just like there are here. Except Malta - where the roads are universally terrible.

 

[Yellow Saddle]

Wouldn't it be more positive to aim for good cycling surfaces for all, not justify poor ones because other people have worse.

Yes, Adrian, obviously it would. However, each time there is a broken spoke reported, it was because of the poor state of the roads. The two are not related. Each time someone gets a puncture, it is blamed on the poor states of the road. It isn't. Pinch flats excluded.
My remark about third world countries with bad roads was just to attempt to get some perspective.
However, I bet that many complaints here about a pothole is just that a complaint. Very few people report them. Our council has fixed every single pothole I reported within days. I catch people out when they complain and said the council did nothing. I ask them for the complaint reference number so I can follow up. My offer is not taken up.
I sense a lot of whining about things but not a lot of participation and understanding. Do you know anyone who has ever attended a council budget meeting in order to get an understanding of the finances and priorities of the budget?

 

[Johnno260]

This year I gave up reporting as they had been reported and had cones/spray paint around them but not much was done for weeks.

Also I gave up trying to claim back on damages as my first attempts were so utterly stressful I couldn't face it, Kent and E.Sussex councils seems to make things hard so you give up.

I have attended my Parish Councils meetings, they're funny to be honest, the week after getting approval for a mobile phone mast on Parish land they spent a chunk of the money from the mast on giving the clerk who was the chairmans wife a pay rise! I sorta gave up on local government after that!

 

[raleighnut]

Thanks, this is helpful and insightful, as was the rest of your post. In relation to the extracted section, and recognising that the specific example scenario is unlikely, do the same principles not also apply to the much more likely scenario of cornering on a wet road surface? You'll have to forgive my scientific naivety here, but what I'm getting at is, isn't there a theoretically definable (assuming all variables of speed, rider weight etc were factored in) breaking point at which a cornering tyre will slip on a wet road? And wouldn't one of the affecting variables in this equation be size of contact patch? Ergo a greater contact patch on a wider tyre would mean the 'breaking point' at which the tyre lost traction would be less easily achieved? This may be nonsense, I'm just trying to better understand in layman's terms how this works.


Something I don't think your post touched on was pressures. I've heard it said that lower pressures = more grip. Is this a myth? If not, then doesn't the fact that a wider tyre can be effectively run at 10-15psi lower than the narrower tyre mean that actually it could give better traction?

IMO the thing is once you have lost traction on a wet road you're very unlikely to get it back.

 

[EasyPeez]

IMO the thing is once you have lost traction on a wet road you're very unlikely to get it back.

I agree but I'm not sure how your point relates to my questions? Sorry if I'm being dim!

 

[Yellow Saddle]

Thanks, this is helpful and insightful, as was the rest of your post. In relation to the extracted section, and recognising that the specific example scenario is unlikely, do the same principles not also apply to the much more likely scenario of cornering on a wet road surface? You'll have to forgive my scientific naivety here, but what I'm getting at is, isn't there a theoretically definable (assuming all variables of speed, rider weight etc were factored in) breaking point at which a cornering tyre will slip on a wet road? And wouldn't one of the affecting variables in this equation be size of contact patch? Ergo a greater contact patch on a wider tyre would mean the 'breaking point' at which the tyre lost traction would be less easily achieved? This may be nonsense, I'm just trying to better understand in layman's terms how this works.

No.
Go and have a look at a few short videos on Youtube on friction for high school and university students. It is actually quite fascinating. Friction is NOT dependent on surface area so a bigger contact patch will not move the breaking point. This breaking point is where static friction becomes kinetic friction. It is not affected by surface area because if you use a smaller area (contact patch) under the same object, the pressure increases. As the pressure increases, so the friction increases. It is an almost linear relationship. That is the fundamental principle of friction. My example above was a very special case. What I did by greasing/oiling a piece of the contact patch was to decrease the effective size of the contact patch without increasing the area. A kind of cheating if you like. My explanation is wonky, come back to me if you don't get it. I'll try and think of a better analogy.
[/QUOTE]
Something I don't think your post touched on was pressures. I've heard it said that lower pressures = more grip. Is this a myth? If not, then doesn't the fact that a wider tyre can be effectively run at 10-15psi lower than the narrower tyre mean that actually it could give better traction?[/QUOTE]

I assume you mean tyre pressure, not downforce?

Lets start with the ideal situation - tarmac. Lower internal tyre pressure will increase the size of the contact patch but decrease the pressure between rubber and road and cancel out the effect of larger contact patch - as per above. The rule holds: friction is not dependent on area.

The non-ideal situation number 1) is for instance where a tyre has to grip on soft turf. Here the surface is softer than the tyre and the tyre knobblies penetrates the turf to find footing deeper inside and then relies on the strength of the turf for traction. The stronger the turf, the better the traction. If the turf is very strong, only one knobbly needs to penetrate and traction is upheld. If the turf is loose and weak, more knobblies will improve traction because there are more "spikes" in the ground, if you like. Now, if softer tyre pressure allows more knobblies to penetrate, then lower tyre pressure will increase traction. If softer tyres don't make a difference to the foothold of the knobblies in the turn, then softer tyres are futile.
Scenario 2: The tyre has to find traction on gravel strewn on hard tarmac. We know rubber will grip the gravel but as you apply brakes, the gravel will roll away from under the tyre and you lose traction. If your knobbly can straddle gravel and find contact with the tarmac underneath, then it has benefits. If the knobbly cannot straddle the gravel, then it doesn't have a benefit and the tyre may as well be slick. Now, if a different tyre pressure gives the knobblies a better chance of straddling/penetrating between the gravel, then it is good, otherwise not.
Finally, on rough road such as road with large stone chips or as MTBers call them, marbles, a hard tyre bounces so much that it is more in the air than on the road. Reducing the pressure will keep better contact and hurt your beehind less.

Chemically the two types of traction I've described here - rubber on hard tarmac and, rubber on soft surfaces, are completely different. The former invokes Van der Waal's weak force, the latter the shear strength of the substrate.

I don't think there is a blanket rule that softer tyres offer more traction than hard ones. This doesn't mean that you won't find applications where softer tyres work better - dragster racing for instance, but that is because a bunch of factors come together to create a sweet spot in the soft raange.

 

[MiK1138]

Phew! first of all I hope Roosters bruises are healing nicely, second I am still confused on whether to replace my Nobbly MTB tryes with a more Slick tyre for Winter commuting in a urban area

 

[Yellow Saddle]

This year I gave up reporting as they had been reported and had cones/spray paint around them but not much was done for weeks.

Well, your council acknowledged the reporting of the hole, agreed that it is a safety issue and attempted to make it safer with the resources at hand. Resources are not unlimited. You probably cannot afford to live in a council area where they have 25 workers permanently on 24-hour standby with all the equipment warmed up and read to roll at the first report of a pothole. Or if you could find such an council at an affordable rate, you would probably not like the fact that there are no street lights, irregular bin collections and no social services.

Councils are not perfect and our roads are not perfect. Therefore it helps to understand priorities by attending meetings and contributing. Obviously squandering should not be tolerated, but keeping your finger on the pulse should keep that at a minimum.

 

[Yellow Saddle]

Phew! first of all I hope Roosters bruises are healing nicely, second I am still confused on whether to replace my Nobbly MTB tryes with a more Slick tyre for Winter commuting in a urban area

Slick.

 

[mjr]

However, I bet that many complaints here about a pothole is just that a complaint. Very few people report them. Our council has fixed every single pothole I reported within days. I catch people out when they complain and said the council did nothing. I ask them for the complaint reference number so I can follow up. My offer is not taken up.

I report them - certainly more than I complain in public about them. The council responses to them the last few years ranges between canned responses (most of the time) through to silence, which was once followed by an admission of complete inability to find a 3m x 1m crater on the inside of a sharp bend on National Route 11!

I sense a lot of whining about things but not a lot of participation and understanding. Do you know anyone who has ever attended a council budget meeting in order to get an understanding of the finances and priorities of the budget?

but what's the point of going to the meeting, really? Nothing much interesting happens at most council budget meetings. It's all decided by the cabinet party long before that and then their ballast just waves it through. Sometimes opposition parties might make a few grandstanding amendment proposals but it's usually democracy theatre by that point.

The time to get involved is in the budget consultations which are starting in most places about now: visit your local county or unitary council website, look for consultations and say that you want 10% of the transport budget allocated to cycle routes including maintenance of roads that are key cycle routes. Go speak to your county or unitary councillor along similar lines.

I have attended my Parish Councils meetings, they're funny to be honest, the week after getting approval for a mobile phone mast on Parish land they spent a chunk of the money from the mast on giving the clerk who was the chairmans wife a pay rise! I sorta gave up on local government after that!

I'm pretty sure that if the chairman didn't declare a conflict of interest and excuse themselves, they should have been punished IMO.

Parish councils vary wildly and sadly the Vicar of Dibley wasn't as fictional as I might like, but they rarely have anything to do with cycling support beyond a few off-road routes and parking stands. District/borough/county councils tend to be a bit better-behaved, but local politicians are still mostly local people and some may be nobbers.