Which road surface has the most grip?

TCJBOLDIE

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Is it the noisy coarse one that has a lot of tyre noise OR the very smooth hot mix that is far quieter to drive over.
When you add water does one suddenly lose a bigger % of grip more than the other ?-/

PS I already know The Stigs answer ;)
 
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obi_waynne

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A good question! Thinking about it I would have thought that more noise = greater friction = more grip.

Smooth roads are lethal in the wet but probably work well in the dry with slick tyres.
 

thexav

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I'd say a smooth road gives more surface area in contact with the tyre so would offer better levels of grip.
 

TCJBOLDIE

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The Stig says the coarse surface.
But be very careful as over here some local authorities use pea gravel (water polished stones from dredging and not the crushed quarry stone Stig is referring to) and that while being noisy has very little grip when damp.
 

SLEEPER

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I don't think it's as simple as smooth or coarse It depends on the material itself Tarmac ,concrete ,ashfelt or something else , they are all different.
And do mean in the wet or dry or both ?

If you mean overall I do know the answer . It is the surface that is at RAF Marham which is a special ashfelt . It costs an absolute fortune to put down so it is not remotely practicle for roads but you did ask the question
Water is the main problem ( obviously) . Wet and grip don't go together.
The problem with most road surfaces is that they are not porous so have to be cambered . If they could be flat there would be more grip.
The special ashfelt at ?Marham is porous and this is obviously a huge advantage driven on it at just over 170 mph I can say that is the best surface I have ever been on by miles and pretty much everyone who was there agreed.
It is smooth by the way.
 

TCJBOLDIE

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I would think that Stig was referring to the normal everyday road surfaces one encounters and not some special type.
IIRC he said the coarse chip allowed the tread to sink into the voids/gaps affording better grip .
FWIW I would have opted for the smooth surface that would allow a greater surface area for the tyre to grip onto in the dry and the coarse in the wet.

Brian I asked the question as a thread starter and to help in a small way to keep TC alive and interesting :)
 

SLEEPER

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I would agree with smooth . The same way as slicks grip better in the dry because as you say more surface area of grip.
Of course a special surface is different but the fact that it is smooth not coarse tends to back up that thought.
 

HDi fun

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Degrees of smoothness are hard to define. On a molecular level a smooth surface is anything but. A perfectly smooth surface would offer absolutely no grip whatsoever.
 

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