Tyres - Warning - Accelera
Discussion
Mr2Mike said:
obob said:
They are really not. I've had all sorts of budgets and none of them have ever slid out at corners and roundabouts at 30mph. Pretty sure people are lying, exaggerating or drive like idiots.
They really bloody are. Some (not all) budget tyres are beyond terrible, and how they manage to get approval to be used in the UK is amazing.
Its clear some people post with no thought at all, wide tyres on snow! bit early for April fools surely.
I fitted Accelera tyres on my Sprint and have the video to prove it at Castle Combe on a damp day.
http://www.youtube.com/watch?v=BCsaH6LI9a0
The second Dolomite I catch is powered by a red top Vauxhall lump.
As you can see it is hopeless in the wet but no worse or better than the others.
When people complain about products I think they must be more accurate as to why as I have met so many people who cannot drive and blame the car.
I fitted Accelera tyres on my Sprint and have the video to prove it at Castle Combe on a damp day.
http://www.youtube.com/watch?v=BCsaH6LI9a0
The second Dolomite I catch is powered by a red top Vauxhall lump.
As you can see it is hopeless in the wet but no worse or better than the others.
When people complain about products I think they must be more accurate as to why as I have met so many people who cannot drive and blame the car.
Edited by trackerjack on Tuesday 24th September 23:19
trackerjack said:
Its clear some people post with no thought at all, wide tyres on snow! bit early for April fools surely.
I fitted Accelera tyres on my Sprint and have the video to prove it at Castle Combe on a damp day.
http://www.youtube.com/watch?v=BCsaH6LI9a0
The second Dolomite I catch is powered by a red top Vauxhall lump.
As you can see it is hopeless in the wet but no worse or better than the others.
When people complain about products I think they must be more accurate as to why as I have met so many people who cannot drive and blame the car.
Better tell the tyre companies they are wrong. And all those improved traction/braking & cornering measurements with wider tyres data is simply not to be trusted. How's your tyre development career going?I fitted Accelera tyres on my Sprint and have the video to prove it at Castle Combe on a damp day.
http://www.youtube.com/watch?v=BCsaH6LI9a0
The second Dolomite I catch is powered by a red top Vauxhall lump.
As you can see it is hopeless in the wet but no worse or better than the others.
When people complain about products I think they must be more accurate as to why as I have met so many people who cannot drive and blame the car.
Edited by trackerjack on Tuesday 24th September 23:19
PistonHeads. Being an expert matters.
........"Comparing winter and summer tires of the same size, winter tires are actually at a disadvantage in terms of cornering stability," explains Dr. Andreas Topp, Head of Winter Tire Development at Continental. "This is due to the softer rubber compound and fine siping of winter tires designed for driving on snow and ice. Fitting narrower tires further exacerbates this inherent disadvantage. In order to achieve the same level of cornering stability and steering precision as with summer tires, fitting wider winter tires is recommended.".................
"........Wide winter tires also offer advantages on typically wintry road surfaces. On compacted snow surfaces in particular, they offer more space to form sipe edges, fill deeper tire tread grooves with snow, and increase friction between the rubber and snow. The handling properties of a car fitted with wider winter tires are also enhanced on compacted snow surfaces............."
".............Wide-base tires even offer advantages in deep snow: Their cornering stability is better than that of narrower tires and their braking distances are shorter. Narrower tires only have the advantage when it comes to traction in deep snow. ................"
(The above quotes are from a Continental press release entitled "Warm Slippers for the Colder Season")
Kawasicki said:
Nice rally car. Everyone on PH is an expert. See comment below.
Not especially, it's only an Impreza but all rally cars use similar tyres on snow, whether compacted or not.I've read your quoted comments and it doesn't explain why such narrow tyres would be used if they are so inferior? Since you are an expert you can surely tell us?
Mr2Mike said:
Kawasicki said:
Nice rally car. Everyone on PH is an expert. See comment below.
Not especially, it's only an Impreza but all rally cars use similar tyres on snow, whether compacted or not.I've read your quoted comments and it doesn't explain why such narrow tyres would be used if they are so inferior? Since you are an expert you can surely tell us?
I haven't been involved in rally tyres, so I am not an expert, so the following is just my theory.
Aren't rally snow tyres usually aggressively studded? Studs give a huge advantage for traction on ice, where non studded tyres will really struggle.
Traction of studs on ice is generally much higher than sipes on snow.
Large tyre slip from traction in competition polishes and heats the snow, forming fairly smooth ice on corner exits. The narrow tyre might give an advantage in cleaning away the loose snow and letting the studs engage ice. Traction is probably the attribute that is most optimised on a rally car tyre, drivers are skilled and they will find a way to generate acceptable lateral and braking forces, for instance using large side slip angles.
Normal drivers don't drive like this. When testing normal winter tyres we were not allowed to use the handbrake or to left foot brake, as this would favour a tyre that could not really give a benefit to the average driver.
A few years back I did 8 tests, 4 on a fwd car and 4 on a rwd car. The test was a snow covered hill climb, with the target being to get to the top as quickly as possible. Tyre width increased, everything else was maintained. The widest tyre was about 3% quicker to the top of the hill. It was also easier to drive. The results were very repeatable.
No one person knows it all in tyre development. It's not a great idea to make assumptions about how tyres work. That I am 100% sure of. Continental are brave to come out with a statement that many see as incorrect. They will have easily repeatable results to back that statement up.
Kawasicki said:
Sorry for the unstructured comments that follow, I'm tired and going to bed!
I haven't been involved in rally tyres, so I am not an expert, so the following is just my theory.
Aren't rally snow tyres usually aggressively studded? Studs give a huge advantage for traction on ice, where non studded tyres will really struggle.
Traction of studs on ice is generally much higher than sipes on snow.
Large tyre slip from traction in competition polishes and heats the snow, forming fairly smooth ice on corner exits. The narrow tyre might give an advantage in cleaning away the loose snow and letting the studs engage ice. Traction is probably the attribute that is most optimised on a rally car tyre, drivers are skilled and they will find a way to generate acceptable lateral and braking forces, for instance using large side slip angles.
Normal drivers don't drive like this. When testing normal winter tyres we were not allowed to use the handbrake or to left foot brake, as this would favour a tyre that could not really give a benefit to the average driver.
A few years back I did 8 tests, 4 on a fwd car and 4 on a rwd car. The test was a snow covered hill climb, with the target being to get to the top as quickly as possible. Tyre width increased, everything else was maintained. The widest tyre was about 3% quicker to the top of the hill. It was also easier to drive. The results were very repeatable.
No one person knows it all in tyre development. It's not a great idea to make assumptions about how tyres work. That I am 100% sure of. Continental are brave to come out with a statement that many see as incorrect. They will have easily repeatable results to back that statement up.
TL:DR Rally cars use narrow tyres to get through the snow and their studs into the ice. Sadly this doesn't apply to our winters. The difference between a 195 and 225 winter tyre is going to be negligible to the average driver in road conditions, this seems like a pointless argument.I haven't been involved in rally tyres, so I am not an expert, so the following is just my theory.
Aren't rally snow tyres usually aggressively studded? Studs give a huge advantage for traction on ice, where non studded tyres will really struggle.
Traction of studs on ice is generally much higher than sipes on snow.
Large tyre slip from traction in competition polishes and heats the snow, forming fairly smooth ice on corner exits. The narrow tyre might give an advantage in cleaning away the loose snow and letting the studs engage ice. Traction is probably the attribute that is most optimised on a rally car tyre, drivers are skilled and they will find a way to generate acceptable lateral and braking forces, for instance using large side slip angles.
Normal drivers don't drive like this. When testing normal winter tyres we were not allowed to use the handbrake or to left foot brake, as this would favour a tyre that could not really give a benefit to the average driver.
A few years back I did 8 tests, 4 on a fwd car and 4 on a rwd car. The test was a snow covered hill climb, with the target being to get to the top as quickly as possible. Tyre width increased, everything else was maintained. The widest tyre was about 3% quicker to the top of the hill. It was also easier to drive. The results were very repeatable.
No one person knows it all in tyre development. It's not a great idea to make assumptions about how tyres work. That I am 100% sure of. Continental are brave to come out with a statement that many see as incorrect. They will have easily repeatable results to back that statement up.
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