Heavy Duty Trucking Logo
MenuMENU
SearchSEARCH

Underinflated tires don't work very well

Regular readers of Heavy Duty Trucking may know me as The Tire Guy. I've written the magazine's tire feature every month for the past four years or so. I got a dose of my own medicine on Christmas Day, trying to take my motorcycle out for a rare winter spin

by Jim Park
January 4, 2012
Underinflated tires don't work very well

Riding a motorcycle on soft tires proves once and for all the negative effects of under inflation.

4 min to read


Regular readers of Heavy Duty Trucking may know me as The Tire Guy. I've written the magazine's tire feature every month for the past four years or so. I got a dose of my own medicine on Christmas Day, trying to take my motorcycle out for a rare winter spin.



I live near Buffalo, N.Y., not the kind of place you'd expect to do any two-wheeling around Christmastime. But we're having an odd winter this year. Temperatures have been hovering well above freezing since November. The mercury has dipped below freezing only a couple of times so far this season, so, on a rainy Christmas day with temperatures in the mid-40s, your scribe decided it would be a great day to get the bike out.

I mean, how often do we northerners get to ride on Christmas day?

Because of the wet roads, I decided to switch out my rear tire -- which was due for a change in the spring -- for a tire with more tread on it. I have a few parts bikes in the garage because parts for my 28-year-old Virago are getting hard to find. One of the tires is nearly new with lots of tread for slippery wet roads, and it's still on a wheel, so the change would be simple.

That tire had not been ridden in a couple of years, so I fully expected it to be a little soft. There's a 7-11 up the road from my house with a coin-operated tire pump, so I figured I'd ride up there and fill the tire before I tore off into the wilderness. It's a tubeless tire, and it was firm and still tight on the rim, so I figured it would get me the mile or so up to the corner store.

The bike barely rolled down my driveway. It labored in first gear, and nearly stopped when I shifted into second. Had I tightened the wheel too much? Were the bearings under too much load? Was the brake dragging? No, I had hand-spun the wheel before taking it off the stand. So what was dragging?

I nursed the bike up to the store, fished four quarters out of my pocket for the tire pump, and set to inflating the tire. The manual recommends 28 psi inflation pressure, but I had less than 10 psi in the tire -- about one-third the suggested pressure.

Topped up and saddled up, I wheeled out of the 7-11 parking lot like the wind. The drag was gone and the bike rolled along as smoothly as ever. Could a soft tire have made that much difference?

The sidewalls on a motorcycle tire are fairly stiff, and the tire didn't look visibly mishapened while I sat on the bike, but there was certainly something in that tire that didn't like running soft.

A few years ago, Tim Miller of Goodyear provided me with a quote about underinflated tires that resonated because I had been there. He said driving on soft tires was like walking barefoot on a beach with deep sand. Pushing the shifting sand aside with your foot requires energy, and that's why your legs get tired walking in deep sand. It takes some effort; like rolling a 400-pound motorcycle with a 200-pound rider on a tire with just one-third of its recommended pressure.

I'll grant you right now, my tire was severely underinflated, but it didn't look or feel underinflated. Much like a truck tire with 50 or 60 psi instead of 100 or so. You can't tell much by thumping a tire, but your engine would sure notice a difference, especially if several tires on the truck were under-inflated.

So, I'll call it a lesson learned -- the hard way as usual. A little more experience I can bring to my monthly tire column. And you, dear reader, can believe me or not. If not, you'll have to learn the lesson the hard way yourself.

If that's how you operate, take Tim Miller's advice and go for a walk on the beach rather than mine, trying to roll soft tires down the road.

Subscribe to Our Newsletter

More Blog Posts

Blurry truck driver at night.
On the Roadby Jim ParkJuly 9, 2024

Truck Driver’s Dilemma: Click, Twist or Swipe?

Whether 'tis safer to twist a knob or press a button than to swipe right then swipe down to scan the menu for your favorite playlist...? That's a question for the age.

Read More →
Volvo FH16 780 tractor.
On the Roadby Jim ParkJune 4, 2024

Even the Swedes are Doing Turnpike Doubles

The government doesn't seem to mind asking trucking to invest a trillion dollars toward a greener future. But they won't let us pull turnpike doubles making 30% less CO2. Which is insanity, says HDT's Jim Park in his On the Road blog.

Read More →
On the Roadby Jim ParkMarch 8, 2024

Is Your Recruiting Message on Point?

How does your recruiting and retention messaging compare with the reality at your company? Would your drivers agree with your own assessment? Jim Park explores those questions in his On the Road blog.

Read More →
Ad Loading...
On the Roadby Jim ParkJuly 25, 2023

You Can’t Blame Trucks for the Highland Rest Area Bus Crash [Commentary]

The causes of the Highland Park rest area crash go far beyond the parking shortage and the need for flexibility in hours of service — but those issues must be addressed, too, says Jim Park in his On the Road blog.

Read More →
On the Roadby Jim ParkMarch 2, 2023

Electric Trucks Seem Far Down the Road for Fleets Dealing with Today's Maintenance Challenges

While the push for zero-emissions trucks rings clear for regulators, advocates and even a small crowd of suppliers, ZEVs seem to have run out of steam down on Main Street, says HDT Equipment Editor Jim Park in his latest On the Road blog.

Read More →
On the Roadby Jim ParkJanuary 6, 2023

Guinea Pigs 2.0: Can Trucking Comply with a Near Impossible NOx Reduction?

The EPA’s Final Rule on NOx reduction will be incredibly difficult if not nearly impossible for trucking to comply with. Rather than endure another round of equipment failures, downtime and loss of customer faith, industry needs to rally ‘round the OEMs and seek a solution to this wrong-headed rule.

Read More →
Ad Loading...
On the Roadby Jim ParkDecember 6, 2022

Is Downspeeding Bad for Brakes?

Is there a connection between downsped drivetrains and increased brake wear? There shouldn’t be. Downsped fleets seeing increased brake wear are probably not letting the technology do its job, explains HDT Equipment Editor Jim Park.

Read More →
On the Roadby Jim ParkNovember 28, 2022

Dig for the Gold Behind CVSA’s Out-of-Service Numbers

Published out-of-service rates don’t mean much until you dig into the why. With brake problems consistently placing in two of the top five spots, maybe we’re missing something in brake maintenance, writes HDT Equipment Editor Jim Park.

Read More →
On the Roadby Jim ParkJune 22, 2022

Things That Go Poof in the Night

We’re in electric-truck heydays now. But like another famous heyday, the 1849 California Gold Rush, there will be a lot fewer winners than losers, says Jim Park in his On the Road blog.

Read More →
Ad Loading...
On the Roadby Jim ParkJanuary 7, 2022

Do Your Truck Drivers Know How to Descend a Mountain Grade?

Where do drivers learn mountain-driving techniques? It's sure not from the typical state CDL manual. Jim Park shares what he learned following a deadly 2019 Colorado crash.

Read More →