Q – which one of the following is true regard skidding of tyres (braking), or, are they both true.
1. Skid marks are not made by temporary melting of the road surface
2. The brakes cause the wheels to lock, which in turn causes the road surface to melt
1. Skid marks are caused by abrasion rubbing a layer of rubber off the tyres.
For proof, note that skid marks occur on concrete as well. Not only does the concrete not melt, but it is the wrong colour for the skid marks.
That’s always been my argument, Moll, but I keep getting told I’m wrong.
I’ve never even heard the idea of the asphalt melting. I’ve always known them to be rubber rubbed off on the road.
it’s not called “laying rubber” for no reason.
mollwollfumble said:
1. Skid marks are caused by abrasion rubbing a layer of rubber off the tyres.For proof, note that skid marks occur on concrete as well. Not only does the concrete not melt, but it is the wrong colour for the skid marks.
each skid mark costs the owner thousands of miles of driving rubber.
roughbarked said:
mollwollfumble said:
1. Skid marks are caused by abrasion rubbing a layer of rubber off the tyres.For proof, note that skid marks occur on concrete as well. Not only does the concrete not melt, but it is the wrong colour for the skid marks.
each skid mark costs the owner thousands of miles of driving rubber.
i think when it comes to skid marks, saving their own life trumps ‘thousands of miles of driving rubber’…
stumpy_seahorse said:
roughbarked said:
mollwollfumble said:
1. Skid marks are caused by abrasion rubbing a layer of rubber off the tyres.For proof, note that skid marks occur on concrete as well. Not only does the concrete not melt, but it is the wrong colour for the skid marks.
each skid mark costs the owner thousands of miles of driving rubber.
i think when it comes to skid marks, saving their own life trumps ‘thousands of miles of driving rubber’…
Well, without the rubber, their life is more at risk for more thousnds of miles of driving than it would be without wasting the rubber.
roughbarked said:
stumpy_seahorse said:
roughbarked said:each skid mark costs the owner thousands of miles of driving rubber.
i think when it comes to skid marks, saving their own life trumps ‘thousands of miles of driving rubber’…
Well, without the rubber, their life is more at risk for more thousnds of miles of driving than it would be without wasting the rubber.
how is hitting the brakes to avoid hitting something ‘wasting the rubber’?
and hitting something now is less risk than driving on less rubber?
you are confusing wheel lock-up under brakes with doing a burnout.
stumpy_seahorse said:
roughbarked said:
stumpy_seahorse said:i think when it comes to skid marks, saving their own life trumps ‘thousands of miles of driving rubber’…
Well, without the rubber, their life is more at risk for more thousnds of miles of driving than it would be without wasting the rubber.
how is hitting the brakes to avoid hitting something ‘wasting the rubber’?
and hitting something now is less risk than driving on less rubber?
You shouldn’t be waiting until the last minute and wating rubber. You shoud be driving to the conditions.
Boris said:
you are confusing wheel lock-up under brakes with doing a burnout.
yes he was.
roughbarked said:
stumpy_seahorse said:
roughbarked said:Well, without the rubber, their life is more at risk for more thousnds of miles of driving than it would be without wasting the rubber.
how is hitting the brakes to avoid hitting something ‘wasting the rubber’?
and hitting something now is less risk than driving on less rubber?
You shouldn’t be waiting until the last minute and wating rubber. You shoud be driving to the conditions.
lol
then again if you wheels lock up maybe buy a newer car with abs.
;-)
how was the OP confusing them?
If you’ve ever seen a tyre with a flat spot after a lock up it’s obvious it’s the rubber being torn off the tyre rather than the road being melted.
I’ve never heard of anyone suggesting that skid marks are melted road.
pommiejohn said:
If you’ve ever seen a tyre with a flat spot after a lock up it’s obvious it’s the rubber being torn off the tyre rather than the road being melted.I’ve never heard of anyone suggesting that skid marks are melted road.
yes you have. it was mentioned here.
it might happen with a truck with multiple axles where there is more chance of the multiple tyres causing enough friction to melt the road surface. or not.
pommiejohn said:
If you’ve ever seen a tyre with a flat spot after a lock up it’s obvious it’s the rubber being torn off the tyre rather than the road being melted.I’ve never heard of anyone suggesting that skid marks are melted road.
since the rubber eventually wears/washes off the road surface leaving no trace, it’s not the road surface that melts.
(it takes a reasonably long burnout in the same spot to melt the tar)
Boris said:
it might happen with a truck with multiple axles where there is more chance of the multiple tyres causing enough friction to melt the road surface. or not.
Ah now usually what happens with trucks is that the trailers haven’t got steering wheels so in effect they are dragged around corners and can indeed push the bitumen and the under surface around. While they are also wasting rubber.
Boris said:
it might happen with a truck with multiple axles where there is more chance of the multiple tyres causing enough friction to melt the road surface. or not.
Nope. The tyre will certainly get hot enough to abrade away but it’s moving over the surface of the road and so no part of the road is going to get hot enough for long enough to melt.
I’ve seen it done with a stationary burnout though. Because the car doesn’t move the road surface can get hot enough to start to melt and then get torn apart.
stumpy_seahorse said:
(it takes a reasonably long burnout in the same spot to melt the tar)
By which time all the rubber has gone and the rim is starting to contact the road surface.
roughbarked said:
stumpy_seahorse said:(it takes a reasonably long burnout in the same spot to melt the tar)
By which time all the rubber has gone and the rim is starting to contact the road surface.
no
stumpy_seahorse said:
roughbarked said:
stumpy_seahorse said:(it takes a reasonably long burnout in the same spot to melt the tar)
By which time all the rubber has gone and the rim is starting to contact the road surface.
no
roughbarked said:
stumpy_seahorse said:
roughbarked said:By which time all the rubber has gone and the rim is starting to contact the road surface.
no
When it gets that hot the tyres are fraying like crazy, throwing bits of rubber everywhere.
no
stumpy_seahorse said:
roughbarked said:
stumpy_seahorse said:no
When it gets that hot the tyres are fraying like crazy, throwing bits of rubber everywhere.no
Actually they can do.
Do a search on Youtube for the Summernats burnout competition. The more powerful cars will literally blow the tyres to pieces.
Spiny Norman said:
stumpy_seahorse said:
roughbarked said:When it gets that hot the tyres are fraying like crazy, throwing bits of rubber everywhere.
no
Actually they can do.
Do a search on Youtube for the Summernats burnout competition. The more powerful cars will literally blow the tyres to pieces.
yes, they can, (my mates built the uy wash) but your standard road sot melting burnout won’t delaminate a tyre, only if you are intending too
in pommieland during summer we’d get little bubbles of tar on the road home from school. we loved threading on them to make them pop. mum hated us tramping tar through the house though.
Boris said:
in pommieland during summer we’d get little bubbles of tar on the road home from school. we loved threading on them to make them pop. mum hated us tramping tar through the house though.
Must have been a shock when you came here then.
probably it is true the bulk of the skid mark rubber deposition is caused by abrasive ripping of tyre material(call it macro-scale), but of the case of bitumen at the microlevel there’d be aspects of the rubber that stick, and they’re two oil based materials, and given the pressures involved no great increase in temperature of any substantial area of the bitumen is required to have some of the bitumen melted, or aspects of the oil compound melted and combined with the rubber, forming a bond.
so i’d say most of the bulk of the rubber material is ripped and abraded from the tyre, and that probably a minor part adheres to the bitumen road surface, and that the bond might be said to be pressure-induced and involve melting to some extent. It doesn;t have to get ‘hot’ anyway, just as a skaters ice skate can be said to melt the ice, though the usefulness of that analogy probably stops there.
lot of bitumen roads the exposed surface has had the tar compound fairly much completely worn away anyway, so if there’s any melting of bitumen it probably more applies to new bitumen surfaces.
can rubber fuse with stone/gravel at the surface boundaries of the stone/gravel and is the pressure alone with only transient increase more at the microlevel enough to call it melting? At the molecular level of the materials i’d think it probably could be said to do that.
still it is the tyre that does most of the ripping, ‘ablates’ may even be an appropriate word, given the tyre is a sacrifcial wearing surface, that provides grip and cushioning too (suspension).
so really the idea of thee bitumen ‘melting’ would come down to semantics over whether the bonds (rubber to surface) by whatever forces at whatever level – how they adhere – properly, or mostly involved what’d satisfy whatever definition of “melt”. Which’d come down to an argument maybe involving a technical meaning of “melt”.
CrazyNeutrino said:
Crazy man driving on rims
He got some weird looks when he went to his mechanic and asked for a rim job
roughbarked said:
When I was an ankle biter growing up in Wagga, I observed the same phenomenon. And the same result. Loved popping them.
Boris said:
in pommieland during summer we’d get little bubbles of tar on the road home from school. we loved threading on them to make them pop. mum hated us tramping tar through the house though.
Must have been a shock when you came here then.
:)