Are your tires over inflated?

Can you imagine training for nearly a year for a ironman and finishing your swim only to find your bike in the transition area with a flat?

Bicycle pump

That is exactly what happened to quite a few triathletes at an ironman event a few years ago.

I heard a story from a customer about an ironman triathlon a few years ago. While the swim was going on many tires on bikes in the transition area were exploding because of the intense sun beating down on the tires and expanding the air inside. Every few minutes there was another loud blast. Boom, Boom. If you have never heard a high pressure road tire explode it sounds just like a shotgun blast.. Can you imagine the surreal setting of the transition area of 800 bikes?

The reason that they had this problem at all is because many of the riders likely pumped their tires to the maximum rating of the tire. Then when the air expanded and BOOM.

Tire pressure is often overlooked but critical aspect of how your bike handles.  Higher tire pressures generally have lower rolling resistance and greater resistance to pinch flats.

So why not pump your tires to the max on every ride?

The higher pressure makes the bike feel fast but may actually be slowing you down!
If the tire is too hard it will have a tendency to vibrate and bounce which increases rolling resistance and makes for an uncomfortable ride.
Where as if the tire is too soft you will increase rolling resistance and greatly increase your chances of pinch flats.

The number on the sidewall of the tire is the maximum pressure

The manufacturer always prints the max psi on the sidewall of the tire. This is not a recommended pressure it is the maximum.

So how to you determine the ideal pressure?

There is no single simple answer because there are so many variables. Rider weight, riding style, road surface, tires, the list goes on. The best way is to do some testing in other words trial and error.

Here are some basic guidelines for pumping up

  • Inflate your tires before every ride with your floor pump
  • Smaller riders 120 and less should be between 90-110 psi
  • Larger riders 170+ should be between 100-130psi
  • Front tire should be around 5psi less than rear
  • If the road or course is exceptionally smooth increase the pressure 10psi or more
  • If the road is wet drop pressures 5-10 psi
  • If you will be doing hard cornering or long descents drop pressure 5-10 psi
  • Never inflate your tires over the manufactures maximum recommended tire pressure.

What tire pressure do you run in your tires?

Need help determining what pressure range is right for you? Ask a question here.

Comments

  1. lamarshall says

    Thank you for this! Especially interesting is the recommendation for lower pressure in the front–never heard that before.

  2. DaveKrentz says

    Me neither. I wonder if it’s because the rear wheel takes more force from your pedalling.@lamarshall

  3. BicycleLab says

    More weight and more side to side force. Your rear wheel has approx. 60 % of the weight so needs a little more pressure to have the same drop or tire flex. @DaveKrentz @lamarshall

  4. h2odog says

    I am running Scwalbe Delta Cruisers 700x35c on a Linus Roadster 8 speed. I am 170 lbs. The PSI on the tires are 35-65. What would be ideal?

  5. BicycleLab says

    If you are doing mostly smooth road I would start with close to the max on the rear and slightly lower in the front. @h2odog

  6. says

    I am about 280lbs, I ride a Specialized CrossTrail on everything from dirt to asphalt. The Max PSI is 85lbs, this is what I fill the tires to, should it be less for me?

  7. BicycleLab says

    @Reasons2Ride I would just pup the tires to the max. You could try lowering slightly but you may get pinch flats. Do you get a lot of flats?

  8. Oddsox says

    I recently bought a Kona Dr. Good with Continental City Ride tires, 32×622 and it reads 80 max. Woke up one morning and the tires were dead flat. Guessing you can’t let them sit too long or the bad roads have slowly knocked the air out. I’m 125lbs and again, ride very bad city roads.

    thanks in advance!

  9. treedawg says

    I had my tire explode in the sun however it wasn’t over inflation but plastic rim tape that melted causing the tube to blow out into the spoke holes. I have since switched to fabric tape

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