Wide VS Narrow Tires (Pizza Cutters to Wide)

[trailhunger]

Some whack advice being tossed around here. Pizza cutters in a monsoon is a huge mistake:

1. Smaller Contact Patch = Higher Contact Pressure
Narrow tires put the truck’s weight over a smaller footprint. While this helps “cut down” into snow or soft terrain, in heavy rain the smaller footprint can’t channel away as much water per rotation, making it easier for the tire to lose grip and ride on top of the water.
2. Less Water Evacuation Capacity
Most hydroplaning resistance comes from tread pattern + channel volume.
A 255-wide tire simply has less tread width to evacuate water than a 275/285-wide tire running the same pattern. At highway speeds, water can build up faster than the narrow tire can push it aside.
3. Higher Ground Pressure = Earlier Lift-Off in Standing Water
Think of it like a water ski: higher pressure means it will “plane” sooner if the tread is overwhelmed. This is why very narrow, high-pressure tires (think compact spare tires) are especially risky in wet conditions.

The OE specs win, moderate, C rated. Although I do agree all you lead foots slow the fck down. Esp at a school zone. I live right by one, trucks agro as f during commute hour

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[GDTRFB]

This is exactly why I wish a 265/75r17 tire existed

 

[Goriders]

I went wider than OEM AT tires for summer and narrower winter tires for winter. Both worked awesome for what I wanted. I just matched the diameter and bought a full spare.

 

[izzy]

Think of it like a water ski: higher pressure means it will “plane” sooner if the tread is overwhelmed. This is why very narrow, high-pressure tires (think compact spare tires) are especially risky in wet conditions.

I just want to drop a little bit of data in

https://www.tirerack.com/tires/test...N1u6DtQAXgIvFQ2dyLtTrfy9UJbBq4z2aD5Ff64Sswn7M

Wider tires have a harder job to do than skinny tires because they have to move more water out of the way of their wider contact patch. They also have to move that water further from the center of the tire to the edge. How efficiently the tire moves water is dependent on it's tread pattern though so there's plenty of tires that are just inherently bad in the wet, irregardless of their size.

You can hydroplane on any tire in the rain if you're going fast enough. We're talking about 1" difference in treadwidth here between 275/70/17 and a 255/75/17 too so it's kind of a moot point. But ultimate Tire Rack says "In the wet, a narrower tire is generally faster than a wide one"

Tl;dr

Don't speed in the rain and replace your tires at 4/32.

 

[Briscoelab]

This is actually true and why bicycle tires don't need tread at all to be safe in the wet. The PSI of the contact patch surface area is so high the water is squished away.

This is actually true, despite what most would think. A bicycle tire on a road bike essentially cannot hydroplane. However, the other comments regarding lateral grip do come into play and are a separate issue from hydroplaning. A 23-25mm slick road tire will definitely let loose in a wet corner at pressures most would have used with a narrow tire like that, if pushed too hard. But even that is complicated, as it's usually related to contaminates on the roadway (ie oils) that come up early in a rain event or that are just there from normal use, and not necessarily the water. In the pouring rain (or extended rain) bicycles can corner VERY fast with no issues (because the contaminants are washed off the surface by that point).

A bicycle tire with some small tread pattern and/or a wider width will corner better in the wet (at a given PSI) in the real world. Slipping because of small gravel pebbles, concrete dust, dirt, etc plays a big roll here and a couple extra mm width or a minimal tread can impact corning in these situations. But in the bicycle context the real advantage of the wider tire is the ability to run lower pressure in general, which gives reduced real world rolling resistance, more wet weather grip, and substantially more cornering grip in any situation. Even Grand Tour teams are nearly exclusively running 28-32mm tires on their typical road race bikes (with time trial bikes sometimes using 25mm class tires still). Another fun aside, bikes can out brake and out corner cars and motorcycles on fast technical mountain descents in the dry or wet (due to amazing brake performance relative to system weight and the inability to hydroplane when straight line riding/braking). But... I think we've gotten a bit off track here ;)

 

[Brent@ANParts]

I find myself enjoying narrow tires more and more, probably due to the rolling resistance and better fuel economy, but I enjoy the steering feel around town a bit more.

 

[trailhunger]

This is actually true, despite what most would think. A bicycle tire on a road bike essentially cannot hydroplane. )

lol yea okay. You watch this to the end and tell me a cyclist can’t hydroplane.

If pizza cutters are your thing you do you but they can’t evacuate any better at the most critical situations. Water treads are generally wider sipe patterns. The original aqua tread was wide as f.

 

[Briscoelab]

lol yea okay. You watch this to the end and tell me a cyclist can’t hydroplane.

If pizza cutters are your thing you do you but they can’t evacuate any better at the most critical situations. Water treads are generally wider sipe patterns. The original aqua tread was wide as f.

That rider absolutely did not hydroplane. The specifics of someone on a time trial bike that was documented to have overinflated tires for the conditions, who rode into a lake is so far outside the subject of this tread as to be hilarious honestly

The first crash they just lost control and slipped, the second was much the same, but with more drama because of the amount of water involved. The second crash was largely caused by 2 things: 1. The tire losing lateral grip when the turned the wheel slightly and 2. The lateral pressure exerted on the deep section carbon wheel by the lake they were riding through when they turned the wheel to the side... which of course caused a feedback loop making everything worse. Also: 3. time trial bikes' riding position is very front weight biased which made but #1 and #2 worse and caused them to unweight the rear end of the bike as the deceleration shifted their weight further forward. As they were breaking with that weight shift and the side pressure on the front wheel from the water, they lost the rear end completely.

Thanks to work stemming from the aircraft industry research on hydroplaning and tire profiles we actually know a lot about how and when actual hydroplaning occurs. This has been scientifically studied ad nauseam that a bicycle, even in a race situation can't achieve speeds required to cause hydroplaning given: Tire pressures, the tire contact patch size, system (bike and rider) weight, and the rounded profile of bicycle tires (which is inherently different than car tires). A road cyclist would need to be approaching ~100mph before physics would allow them to actual hydroplane.

You can definitely crash in the rain though! There is much less traction on wet roads for cars or bikes. But slipping out or loosing lateral stability ≠ hydroplaning. Some fun reading if you're so inclined: https://www.sheldonbrown.com/tires.html#hydroplaning

The very extreme thought case showing this could be a train, not on a track but going down a wet road. Very narrow "tire", zero chance of hydroplaning, but absolute terrible lateral grip. This is also why trains don't hydroplane on wet tracks.

For cars or bikes there is a LOT that goes into wet grip that is way more important than hydroplaning to 99% of us. Car tire width definitely impacts wet grip and performance overall. Not arguing against that.

Back to vehicle tires I'm not a proponent of pizza cutters above all else. As mentioned earlier, my preferences lean toward a slightly skinnier width for a given height, but nothing massively outsize the norm. When I did get a very skinny tire for the height (255/85R17 or roughly a real 35x10x17), I wasn't a fan on road. Flip side is I also don't like 315 or 12.5" width in tires below a marketed 36" or 37" tire. Goldilocks is where most of us are gonna land and be happy.

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