Bruce Arnold
Well-Known Member
Detailed discussion on tire pressure. I'm no expert. This guy sounds like he has both knowledge and experience.
Interesting Video on Tire Pressure
- Thread starter Bruce Arnold
- Start date
tomjasz
Well-Known Member
- Region
- USA
- City
- Minnesnowta
A synopsis? It's too long!
Bruce Arnold
Well-Known Member
A lot of it was about racing, which doesn't apply to me, but it gave the background to understand why he has come to the conclusions that he has. A couple of items that do apply to the recreational/commuter cyclist like me: The psi number on the tire is not the recommended pressure. It is one-half of the pressure that will blow the tire off the rims they use in testing labs. The assumption being that if you stick with that, you'll never get close to blowing your tires off your rims. Good to know. Second, he said that a lot of people mistake the high-frequency vibrations of a tire that is pumped up pretty high with being speedy. The vibrations are fast, but the tire probably isn't attaining optimum speed. He said pump it up, and then bring it down one or two psi at a time until it feels smooth. That's the sweet spot. This is because of how tires flex when going over all the little bumps and holes in pavement. When it feels smooth, the tire is flexing well without losing energy unnecessarily. When you get those high-frequency vibrations, that's wasted energy that you feel.
This is contrary to the usual talk about rolling resistance, which assumes that the harder the tire, the less resistance.
But really, Thomas, find half an hour somewhere this weekend and watch the whole thing, there is so much information that is either useful or just darn interesting.
slayer1962
Member
I lasted 3 minutes 
elliot friedman
Active Member
2 more than myself
slayer1962
Member
26"4" fat tire bike gets 6 pounds in sand or snow and 20 lbs on the road
Bruce Arnold
Well-Known Member
Seems we have some people with little to no attention span! 
slayer1962
Member
Or some with too much time on their hands
handsslayer1962
Member
Bruce glad you can take a little ribbing. I am obsessive with a enough things in my life and understand if this is a passion you want every bit of information possible.
I bow hunt and fish and i am into everything i can find to help me. The bike for me helps me access more spots for my sports. I do mess with tire pressure but very basic, hard tires on the road ( 15 lbs ) and low pressure in the pinelands where there is a lot of sand ( 5 lbs) My basic adjustments make a lot of difference so i am sure on longer rides getting into the perfect pressures helps. I guess i am not a real bike guy its just a tool to enjoy my other sports. There is some hope though i have been riding on the road more and ordering stuff that helps me do that. Horn/ alarm, lock, new chainring , bags
I bow hunt and fish and i am into everything i can find to help me. The bike for me helps me access more spots for my sports. I do mess with tire pressure but very basic, hard tires on the road ( 15 lbs ) and low pressure in the pinelands where there is a lot of sand ( 5 lbs) My basic adjustments make a lot of difference so i am sure on longer rides getting into the perfect pressures helps. I guess i am not a real bike guy its just a tool to enjoy my other sports. There is some hope though i have been riding on the road more and ordering stuff that helps me do that. Horn/ alarm, lock, new chainring , bags
FRANKENBIKE
New Member
Hi, This is my first post as I am new to the forum;
I had been running at 16psi front and rear on 26' fat tired electric bike weighing 65lbs. have since up-graded my bike which now weighs 130lbs. (this is my second e-bike build)
And have bumped up the pressures to 18 psi front and 20 psi rear tire. To account for the extra weight and speed.
I am however currently upgrading the brake system from 2 piston to 4 piston and the rotor from 160mm to 203mm. Just to make sure I can stop quickly.
I am an old fart and only ride on bike trials / bike lanes.
I had been running at 16psi front and rear on 26' fat tired electric bike weighing 65lbs. have since up-graded my bike which now weighs 130lbs. (this is my second e-bike build)
And have bumped up the pressures to 18 psi front and 20 psi rear tire. To account for the extra weight and speed.
I am however currently upgrading the brake system from 2 piston to 4 piston and the rotor from 160mm to 203mm. Just to make sure I can stop quickly.
I am an old fart and only ride on bike trials / bike lanes.
... and what would be the pressure that will blow the tire off the rim in testing labs? It is not usually written on the tire.
slayer1962
Member
Frankinbike, that is some heavy e bike! battery and Motor?
Alaskan
Well-Known Member
That was fascinating. I have been in search of the perfect tire with the best protection, that rolls the fastest and is most comfortable. I think I may have found what will give me the best results. This video gave me a clear path forward to fine tune what I have set up and see how good it can be. Thanks. "optimization...the answer will be found by the person who takes the time to search for that balance point between too much and too little. Get out your notebook."
Bruce Arnold
Well-Known Member
Twice the pressure marked on the sidewall.
Handlebars
Well-Known Member
- Region
- Canada
I guess that my tires are different. Kendas, and they say "Min 40 Max 65 psi"
PaD
Well-Known Member
I’m confused.
Listening to what’s said in the video in first post I learn that a lower tire pressure is often giving a lower rolling resistance and wider is better too.
The lab test of different sized Marathons at different tire pressures performed by bicyclerollingresistance.com does not give that result. I first thought that maybe these lab tests are performed on a very smooth surface but the roller has a pattern.
Is the problem with the test the surface anyway?
The 32mm tire appeared to be constructed in a way and with materials that was different from the other sizes. Described in the linked test.
www.bicyclerollingresistance.com
Listening to what’s said in the video in first post I learn that a lower tire pressure is often giving a lower rolling resistance and wider is better too.
The lab test of different sized Marathons at different tire pressures performed by bicyclerollingresistance.com does not give that result. I first thought that maybe these lab tests are performed on a very smooth surface but the roller has a pattern.
Is the problem with the test the surface anyway?
The 32mm tire appeared to be constructed in a way and with materials that was different from the other sizes. Described in the linked test.
Schwalbe Marathon 32, 37, 40, 47 Comparison
Comparison of the differences in rolling resistance, puncture resistance, size and weight of the Schwalbe Marathon 32, 37, 40 and 47 mm touring bike tires
www.bicyclerollingresistance.com
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