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Dunlop Road Smart 3 tires AKA tire thread #2372-106A
- Thread starter nickrides
- Start date
This guy is really easy to listen to. Thanks for this link!
Interesting comment at around 1:30 and 5:20.
ncpbmw1953
Member
And God help you if you ever go down on that stuff. I can imagine leather might hold up a bit longer but synthetics will probably shred very fast. On the flip side traction should be better as long as the chip is bound hard which it normally seems to be. I rode out to Newport from Eugene a few years back and that didn't seem to be chip seal at the time.
With a smaller contact patch due to the "valleys" between the chips inherent in this type of roadway, the traction would be reduced as compared to smooth asphalt. The same reason slick tires provide more dry traction than treaded tires.
You're right that falling off on a "tar and chip" surface would likely shred one's gear, and then one's self, in short order!
pglaves
#13338
I absolutely disagree. Which grips rubber better: a smooth metal yardstick or a wood rasp?
stooie
Member
Interesting topic!
Our tire engineer friends breakdown tire grip into the categories "chemical grip" and "mechanical grip"
Chemical grip is a function of how sticky the rubber is. This is the primary grip for a warmed up racing slick on smooth asphalt.
Mechanical grip the force generated by the tire conforming to the irregularities of the road surface. This may very well be enhanced on the right chip seal surface.
i'd like to see data. I'm guessing that the optimal grip is a racing tire on a smooth surface. After that we get into the possible combinations of tire compounds and tread patterns on smoother and less so asphalt and varying chip surfaces that might give all kinds of results.
Where the irregular chip seal surface might provide an advantage in on a rainy surface as it might drain a bit better.
I think I'm going to stick with my plan to ride conservatively enough on the streets to not find out. I'll confine my testing of my limits and those of the tires to the relatively low speeds of the kart tracks when I go to play, oops, I mean "train", there.
Please be careful as you conduct your own experiments on this issue!
akbeemer
SURVIVOR
The traction on chip seal can be great. It is akin to riding on sand paper..... until you encounter a patch where the gravel has been pushed into the slurry leaving a nice patch of quite slippery and hardened tar. Essentially a tar snake on steroids and especially exciting when wet. Then there are the places where lose gravel builds up; also a heart accelerator.
akbeemer
SURVIVOR
I have an old tire I would like to cut in two. Which side of my saw blade should I use? Smooth edge down or tooth edge down? Which would be the hardest to push with my old arthritic shoulder?
I suggest that you hold the blade and beat the tire with the reciprocating handle/motor/battery assembly. This may pinch a little.
I respect your opinion.
At the same time, why are drag strips smooth? And how soft would a tire needs to be for the road to be able to mechanically impress itself into the rubber itself?
akbeemer
SURVIVOR
Chip seal would not stand-up to the force of a powerful drag racer running wide slick tires. It would be particularly vulnerable in hot temperatures when the tar softens. Great effort goes into laying down a thick layer of tire compond on the starting line area to enhance traction. The tire compound is quite sticky, especialy when warm. It would be difficult if not impossible for the cars to buildup the layer of compound on an irregular surface such as chip seal, so ultimately chip seal would have less traction than a smooth asphalt track that is well prepared (not typically found on public highways). Also, even minor bumps or undulations in a track can cause wheel hop which will greatly diminish traction; I think chip seal is more prone to such flaws. I'd bet a dollar to a donut that a car on a fully cured, well maintained chip seal road would have better traction off the starting line than an equal car on a fully cured, well maintained asphalt road (that was not prepared with a coating of tire compond).
pglaves
#13338
Fundamentally tires gain adhesion by one of two methods. Knobby tires are designed to allow the knobs to engage downward into soft surfaces, think snow, mud, sand, and to an extent gravel. Typical traction on pavement is achieved by the minute irregularities in the pavement - think grains of sand but not loose of course - pressing into the relatively softer rubber of the tire.
Drag racing is a peculiar subset where soft slick tires adhere to what is in effect a rubberized surface. Rubber does not slip very well on rubber, especially when the surface of one of the rubber elements has been heated to or almost to its melting point by tire burnout. Where there is smoke there is heat, if not fire.
https://www.google.com/search?client=firefox-b-1-d&q=how+does+a+tire+grip+the+road
Drag racing is a peculiar subset where soft slick tires adhere to what is in effect a rubberized surface. Rubber does not slip very well on rubber, especially when the surface of one of the rubber elements has been heated to or almost to its melting point by tire burnout. Where there is smoke there is heat, if not fire.
https://www.google.com/search?client=firefox-b-1-d&q=how+does+a+tire+grip+the+road
I think you're making my point for me. The minute irregularities are much more numerous in fine-grain asphalt than in coarse chip surfaces. I also get your point on drag racing surfaces. I was going to the extreme.
pglaves
#13338
There are three pertinent variables. How many little points, how sharp are the points, and how deeply into the rubber do the points penetrate. Traction is a result of all three.
lightweights 
Chipseal varies region to region as material used varies...and temps of roads and tires...and speed, which includes how one operates the throttle from a dead stop.
I learned to ride on oyster shell roads on a coastal barrier island ...when compacted and broken down not so bad... fresh laid shells were brutal to encounter with tires and jeans or Birdwell surf shorts and Chuck Taylor hi- tops. Have the scars and stories and some of my best schooling of avoiding get-offs!
Tire comparisons are fun but I can mount three sets of same tire on same three models and the results are all over the map with one guy bragging and one in total meltdown.
Chipseal varies region to region as material used varies...and temps of roads and tires...and speed, which includes how one operates the throttle from a dead stop.
I learned to ride on oyster shell roads on a coastal barrier island ...when compacted and broken down not so bad... fresh laid shells were brutal to encounter with tires and jeans or Birdwell surf shorts and Chuck Taylor hi- tops. Have the scars and stories and some of my best schooling of avoiding get-offs!
Tire comparisons are fun but I can mount three sets of same tire on same three models and the results are all over the map with one guy bragging and one in total meltdown.
pglaves
#13338
See Post # 15, this thread
