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Related question - I’m getting dedicated winter tires this year for my Tacoma… worth going narrower (245-75-16 vs stock 265-70-16… effectively the same diameter)? Better traction presumably by more concentrated contact patch. I guess some better mileage too. Maybe slightly cheaper. Any downsides?
Thx!
Better traction and handeling in soft snow or slush, but a smaller contact patch will also mean worse traction on packed snow or ice. Pick yer poison. If you can go with a bigger diameter, but skinner tire, thats probably your ticket?Quote:
Originally Posted by tang
Downsides include being called a "Wagon Wheeler" and looking kinda dumb, like a fat chick with skinny ankles. But hey, if you really need MAXIMUM TRAXXXXION!!!! then yeah, go for it. Point being, if you already have snow tires, and weight in the back of the truck, and you still need help keeping a Tacoma on the road better than the millions of your flat brimmed brethren, then you might want to go back to driving school or hire an Uber on snowy days.Quote:
Originally Posted by tang
So it’s settled? Driving in Oregon buy winter tires (studded or not) and don’t jong up our roads. Driving anywhere else, do what you want.
Got it, a trade off then. May stick to stock width as I’m more wary of ice. ThxQuote:
Originally Posted by californiagrown
Funny-ish, thxQuote:
Originally Posted by Name Redacted
Article with link to test video of comparative testing of different winter tire widths on the same car:Quote:
Originally Posted by tang
https://jalopnik.com/this-is-how-dif...1829942841/amp
Assuming the vehicle weigh is the same, and tire pressure is the same, and given that tires are relatively flexible, the size of the contact patch on a hard surface (plowed but icy road) will be the same regardless of width. The only difference between wide and narrow tires is the shape of the contact patch. It makes sense that the long & narrow patch is more like a bulldozer track, which is why tractors and heavy earthmoving equipment tires are narrow compared to their diameter.Quote:
Originally Posted by californiagrown
Naturally floating on deep snow is a whole different ballgame, see "arctic trucks".
Exactly. It is not a traction tradeoff to narrow up. It is a hard win for slush/soft and a wash for ice/pack.Quote:
Originally Posted by 1000-oaks
The only tradeoff is slightly shortened tread life (you have the same contact patch on the road but less total tread area around the tire) while getting slightly better gas mileage (lighter tire carcass). These effects are very small.
The effect in slush is HUGE. I ran that exact narrowing 245 vs 265 on 4runners to great effect.
Both 245/75/16 and 265/70/16 were stock sizes on the Tacoma. We used both sizes on Mrs C's 2005 Tacoma, and on her Xterra, though mostly used the 265/70. Didn't really notice any difference in snow performance or treadwear.
For me, price often drives that last decision.
How so? the fore-aft dimension of the contact patch will remain consistent, but the width of the contact patch (assuming proper inflation) would be wider with wider tires... meaning a larger contact patch.Quote:
Originally Posted by 1000-oaks
The contact patch also increases when you increase tire diameter, because the fore-aft dimension of the "squash zone" of the tire increases... same reason why 29er tires have better traction than 26ers.
So it would seem that wagon-wheeling would get you the best of both worlds- skinny width to cut through deep slush/snow and not get moved around so much by rutted snowy roads, but also an increased contact patch to benefit on hard/icy roads.
Probably the most comprehensive discussion on the skinny tire and Tacoma topic:
https://www.tacomaworld.com/threads/...-tires.529656/
A lot wrong here. And you’re arguing against yourself?Quote:
Originally Posted by californiagrown
In the first paragraph the wider tire has a bigger contact patch, but by the end it’s the skinnier one?
^^^ Thx, that's a great thread
In the first paragraph a wider tire (assuming same diameter) has the larger contact patch. In the last paragraph a larger diameter tire (assuming same width) has a larger contact patch, and so you can run it skinnier.Quote:
Originally Posted by J. Barron DeJong
Whats wrong? Legit curious.
So, OP is talking about different widths, but same overall diameter.Quote:
Originally Posted by californiagrown
To a first approximation, the area of the contact patch is a function of the tire pressure, not the tire geometry. (That’s less true as sidewalls become shorter, and carcass becomes stiffer, like in high performance tires.)
So, going to a narrower tire here, where the sidewall is quite tall is going to keep the size of the contact patch about the same, but the contact patch on the narrower tire will be longer/skinnier in comparison to the wider tire.
Going to large overall diameter tires can affect the contact patch in beneficial ways in certain applications (see: BTCC cars of the 90’s, for example), but OP isn’t looking to do that.
ahhh, so youre saying more sidewalk flex on the skinnier tires is the cause for increased contact patch.
To calculate the square inches of contact area for a flexible sphere such as a ballon or tire against a flat hard surface, divide the force (weight) exerted on that object by the internal PSI of the object.
So for a vehicle tire, the contact patch in square inches would be roughly ((vehicle weight)/4)/(tire psi). Diameter or width is mostly irrelevant (for the purpose of this discussion), which only effects the shape / orientation of the contact area.
No, I’m saying that if the sidewalls of the two tires aren’t very stiff, then the area of the contact patch is going to primarily be a function of the inflation pressure.Quote:
Originally Posted by californiagrown
So at the same pressure, the narrower tire will have (about) the same contact patch area, but since the tire is narrower then the geometry of the contact patch is going to be longer.
But you also have to consider if you’re going to run the same pressure: the narrower tire needs higher pressure to maintain the same load rating, so if you’re still going to fully load up the truck in the winter, you need the higher pressure to handle that. The narrower tire with high pressure would have a smaller contact patch. Is it shorter too?
If you’re not going to full load the truck in the winter, then you can get a away with running lower pressures, and lower pressure does increase traction:
https://youtu.be/-stzafBMCa4
Personally, I go narrower winter tires on our vehicles, and run lower pressures - and relatively lower in the rear - than in the all seasons. (We often have deep snow and slush here.)
Right.Quote:
Originally Posted by 1000-oaks
Tires aren’t actually perfectly flexible - and the degree of flexibility can vary widely - but this is a good first approximation.
Meh I wasn't impressed other than they seemed to have good wear life. Not great in the snow and not great in the summer either. Price was decent thoQuote:
Originally Posted by waveshello
Sent from my SM-G981U using Tapatalk
Tires are not spheres though. At proper pressure, they are cylinders.Quote:
Originally Posted by 1000-oaks
At proper operating PSIs, why can width of the tire be discounted?
If the tire is perfectly flexible, then the contact area is entirely dependent on the inflation pressure.Quote:
Originally Posted by californiagrown
20 psi in the tire and supporting 400 pounds? Contact area is 20 square inches.
Increase pressure to 40 psi, and still supporting 400 pounds? Contact area is now 10 square inches.
The shape of the contact area changes with tire geometry, but the actual area, not too much. Narrower tire has a narrower contact patch, but since the -area- of the contact patch is the same, it must be longer. (Again, assuming perfectly flexible carcass, and same inflation pressure.)
I feel like I have to run a studded, winter specific tire on my old XJ (I currently have Firestone winter force with studs added), and I also threw in 180 lbs of sand in the back. With that combo I don’t go sloppy slidey.
With my newer rig I have ABS and traction control, so I have been happily running all seasons on that, but I might get studded winters this year and swap out twice a year, cuz there’s a les Schwab here now.