Directional tread patterns - myth or fact
- Thread starter eklimek
- Start date
eklimek
New Member
Thanks for the reference. I scanned the work and found the following.
"The only reason that grooves exist in a tread is to aid traction in the presence of contaminants like water, snow, mud, ice, etc. If it weren’t for road surface contaminants, a tread pattern would be unnecessary and no one would want to undertake the difficult task of obtaining even wear and quiet operation from a patterned tread. "
Page 272
"Maintaining good wet traction requires that water on the road surface be expelled from under tire tread elements and that the boundary layer remaining after the gross water layer iis expelled be broken so that intimate contact is achieved between the tire tread and the road. Expelling the gross water layer depends on having both an appreciable groove vol ume in the tire and having voids present on the road surface, termed macro-texture. Often the road surface macro-texture will be worn away over time."
Page 319
"In aquaplaning the thickness of the water film is greater than the height of the asperities and water has to be squeezed out of the contact area. As a point on the rubber surface moves through the contact area it sinks through the water film until it makes contact with the tips of the asperities along the contact patch (see figure 11.15). This a function of the water height above the asperities and to the speed vf of the vehicle. With increasing speed the point at which dry contact is made moves further along the contact patch reducing thereby the extent of dry contact and hence the friction. When the speed is so high or the sink time is so long that even at the end of the contact patch (of length l) the water cannot be removed, then all frictional contact is lost and with it the steering and braking/accelerating capability of the vehicle. With a tread pattern, the contact width is reduced to the rib width and the aquaplaning speed increases dramatically, provided the water level is such that the void volume of the tread pattern is not completely filled."
Page 435
"Water is mainly removed towards the sides. Hence longitudinal ribs with short lateral channels are required to provide short drainage distances towards the sides and thus to increase the critical aquaplaning speed of the tire. To optimize the removal of water, diagonal ribbing and directional tread patterns are employed. A modern high performance tire can no longer be mounted in either direction on the rim. Attention has to be paid to mounting the correct side-wall towards the outside in order to achieve maximum water drainage."
Page 458
"The only reason that grooves exist in a tread is to aid traction in the presence of contaminants like water, snow, mud, ice, etc. If it weren’t for road surface contaminants, a tread pattern would be unnecessary and no one would want to undertake the difficult task of obtaining even wear and quiet operation from a patterned tread. "
Page 272
"Maintaining good wet traction requires that water on the road surface be expelled from under tire tread elements and that the boundary layer remaining after the gross water layer iis expelled be broken so that intimate contact is achieved between the tire tread and the road. Expelling the gross water layer depends on having both an appreciable groove vol ume in the tire and having voids present on the road surface, termed macro-texture. Often the road surface macro-texture will be worn away over time."
Page 319
"In aquaplaning the thickness of the water film is greater than the height of the asperities and water has to be squeezed out of the contact area. As a point on the rubber surface moves through the contact area it sinks through the water film until it makes contact with the tips of the asperities along the contact patch (see figure 11.15). This a function of the water height above the asperities and to the speed vf of the vehicle. With increasing speed the point at which dry contact is made moves further along the contact patch reducing thereby the extent of dry contact and hence the friction. When the speed is so high or the sink time is so long that even at the end of the contact patch (of length l) the water cannot be removed, then all frictional contact is lost and with it the steering and braking/accelerating capability of the vehicle. With a tread pattern, the contact width is reduced to the rib width and the aquaplaning speed increases dramatically, provided the water level is such that the void volume of the tread pattern is not completely filled."
Page 435
"Water is mainly removed towards the sides. Hence longitudinal ribs with short lateral channels are required to provide short drainage distances towards the sides and thus to increase the critical aquaplaning speed of the tire. To optimize the removal of water, diagonal ribbing and directional tread patterns are employed. A modern high performance tire can no longer be mounted in either direction on the rim. Attention has to be paid to mounting the correct side-wall towards the outside in order to achieve maximum water drainage."
Page 458
o1marc
Over 1,000 Posts
deviant said:
All the tires that failed were on the left rear of the car. I believe RB pulled out of testing due to a rule understanding that only 2 year old cars could be used and not current cars. One team ran testing with a newer car and caused a big controversy due to it.
Even so, but my understanding with Silverstone was Pirelli was blaming teams for cutting the curbs, running the wrong camber for the tires, and running too low of air pressure. I may be wrong about my lack of support for Pirelli's stance. But, the tires failed after they punctured, which usually lends to an issue with the tire's structure. Ultimately, I think they came to the conclusion that steel with those tire compounds was an issue and Pirelli finally got through the F1 governing structure to change over to Kevlar, which runs much cooler. I guess what I'm saying in all the jabber, is that the issue is way more complex then simply being on backwards.
Maritime
Over 10,000 Posts
VonYinzer said:
I did once. I had a set of Avon Roadriders installed at a dealer once and they mounted the front wrong. I wasn't sure if it was a big deal or not a big deal so I called Avon Tyre, they told me the tread pattern on the roadrider was designed to shed water away from the back tire and being mounted backwards, would not harm the tire for grip or safety or even handling, but it would reverse the water direction and funnel it all to the rear wheel. and since I am not a pansey and ride it torrential rain to get places I went back to said dealer, told them and they re-mounted it correctly as the risk of hydroplaning was increased a lot. They have universal front/rear tires and have instructions to mount in one direction for front and the opposite for rear because of water shedding etc. This is the roadrider tyre only. I did not ask about any other model
Oh yeah and because of this I bought tire irons and now mount my own tires, I don't trust others to do it right anymore
eklimek
New Member
I remain unsure of the actual relevance of mounting unidirectional tires. It does seem consumers review mounting of directional tires as a check on the tire installers attention to quality. They typically have little visual indication if the tire is properly balanced or otherwise mounted.
This reminds me of a story. Van Halen in their first record contract in 1977 set a certain tone which celebrity contracts followed ever since. The stipulation in their performance contract was that the promoter remove all brown Smarties from the bowl in their dressing-room. This ensured the contract was read properly and suggested the myriad details relevant to the safety of the stage were also attended.
This reminds me of a story. Van Halen in their first record contract in 1977 set a certain tone which celebrity contracts followed ever since. The stipulation in their performance contract was that the promoter remove all brown Smarties from the bowl in their dressing-room. This ensured the contract was read properly and suggested the myriad details relevant to the safety of the stage were also attended.
ApriliaBill
Yeah...I'm old school.
o1marc said:
It was actually M&M's, in the contract.....
eklimek
New Member
My error. Smarties vs M&Ms.
It is a "telltale". It's like putting a hair on the carpet. If its still there after maid service, what does it mean?
en.wikipedia.org/wiki/Tell-tale
A tell-tale or telltale is an indicator, signal, or sign that conveys the status of a situation, mechanism, or system.
It is a "telltale". It's like putting a hair on the carpet. If its still there after maid service, what does it mean?
en.wikipedia.org/wiki/Tell-tale
A tell-tale or telltale is an indicator, signal, or sign that conveys the status of a situation, mechanism, or system.
eklimek
New Member
Hillsy, thanks for clarifying. I was not there. It has assumed a greater significance.
"According to David Lee Roth, this was listed in the technical portion of the contract not because the band wanted to make capricious demands of the venue, but rather as a test of whether the venue had actually read and properly honored the terms of the contract, as it contained other requirements involving legitimate safety concerns.[75] If the bowl was present, then the band members could safely assume the other, legitimate, items in the technical rider were being fulfilled to their satisfaction. Conversely, if the bowl was missing, or brown M&M's were present, then the band members would be within their rights to have the venue inspect the work, ask it be redone, etc.[76] Their concern for safety was real, as in their earlier tours, not only was equipment damaged, but several members of their road crew were nearly electrocuted, both due to inadequate safety and preparation on the part of the local venue."
"According to David Lee Roth, this was listed in the technical portion of the contract not because the band wanted to make capricious demands of the venue, but rather as a test of whether the venue had actually read and properly honored the terms of the contract, as it contained other requirements involving legitimate safety concerns.[75] If the bowl was present, then the band members could safely assume the other, legitimate, items in the technical rider were being fulfilled to their satisfaction. Conversely, if the bowl was missing, or brown M&M's were present, then the band members would be within their rights to have the venue inspect the work, ask it be redone, etc.[76] Their concern for safety was real, as in their earlier tours, not only was equipment damaged, but several members of their road crew were nearly electrocuted, both due to inadequate safety and preparation on the part of the local venue."
haha, cause the truth is spoken from the back of a pair of ass-less chaps.hillsy said:
