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Tire Pressure – Stop Guessing And Read The Science
Tire Pressure – Stop Guessing And Read The Science
New discoveries about the relationship between pressure and performance indicate new directions for research and development.
Read the full story here
Comments
Either way I will be trying a (slightly) lower psi on my test ride and see how it works.
@jimmymstevenson weight, rim width, and tire width all come into play when adjusting your pressure. You have to be careful not to go so low to fear pinch flats. I'm assuming that Poertner is 170lbs and running 70psi. I'm 205lbs on 25mm tires and usually run 100-110psi however i will also be trying a lower pressure, maybe 90psi?
http://markcathcart.com/about/
What about latex tubes, any thoughts on that?
If you have only one pump, you can determine the error of that (offset or slope bias) and accurately compensate. But if you're lazy like I am, err on the side of less pressure. Most pumps are accurate to +/- 7 psi, so if you want 100 psi, pump it to 95 and you're going to be okay. Sure, you may be at 88 or 102, but missing on the low side is better than missing on the high side.
Tried 80 and feels fine. Looking forward to trials on the rail trail course where I can evaluate changes vs. net speed.
Great post/article!
https://www.facebook.com/sworrytrials/
https://www.facebook.com/OdetoLaz/
The various spreadsheets and calculators on the web give both higher and lower pressures for the rear tire, with www.biketinker.com being the closest at 6 psi less. All but the Vittoria app show VERY low pressures for the more lightly loaded front tire, 20 to 40 psi less. From my experience running the front tire at much more than 5 psi less than the rear results in very poor bike handling and also more of a tendency towards high speed shimmy.
Can you also address front tire pressure in the future.
Think of it like a car with a front engine or a mid engine (I'll leave out those idiotic beetles/911's). With a front engine, you'll likely want more pressure in the front tires than the rear for optimal traction and mileage (normally 35psi front / 32 psi rear for an unladen sedan). For a mid engine sports car, the front tires have much less weight, so the rears may be 32, and you'll put 28/9 in the front (my lotus, being under a ton, uses 28 rear and 25 front for cornering, a bit more for highway driving).
It's nice to read that someone else repeated his experiment with the same results but I believe Jan Heine and the BQ staff must be credited for being the first ones.
Pics of the Lotus, please!!!!!
1) Tyre
2) Intended Use
3) preferred handling characteristics
i) major understeer - think stunt drivers might be the only one interested in this - or prius drivers
ii) minor understeer - how most cars are designed
iii) minor oversteer - rear-drive road cars
iv) moderate oversteer - race cars, Jeremy Clarkson
v) major oversteer - Ken Block
For better handling in the miata, you'll need to run a few tests or ask a miata forum what they run. I have little experience with those. They're light, and 50/50 is good, so I'd look at 29-29 cold as a start and move up/down a psi from there. For that car, I'd shoot for a little loose in the back end with the tires cold.