Forum menu
You'd still be wrong, then.
prove it.
This is the internet. I don't have to prove anything.
Cynic-al is right
Its as simple as this:
Say you and the bike weigh 200lbs
Each tyre* is supporting 100lbs If each tire has 25 psi of pressure it must have a contact patch area of 4 square inches
Shape of the contact patch differs for different wheel and tyre sizes but the area doesn't as long as the weight the air in the tyres has to support remains fixed.
*the back tyre will have more weight on it on the front but the example still stands
Precisely.
I win.
[url=
explained...[/url]
So given the simple physics lesson Giant's claims have a very distinct whiff of shite about them.
Contact patch area for 26" and 27.5" has to be the same for the same rider with the same pressure in their tyres.
Contact patch length?
I'm not clever enough to work that out but if the tyres were the same width I can't see how the contact length would differ by 2 cm (a 33% increase!) when the difference in circumference of the wheels is less than 5%
I'm not clever enough to work that out but if the tyres were the same width I can't see how the contact length would differ by 2 cm (a 33% increase!) when the difference in circumference of the wheels is less than 5%
there will be a difference, theoretically, in "feel" a short wide contact patch will be different to turn compared to a long thin contact patch. Once you throw in rocks, roots, wheel diameter i doubt you would feel it in the real world.
I'm not clever enough to work that out but if the tyres were the same width I can't see how the contact length would differ by 2 cm (a 33% increase!) when the difference in circumference of the wheels is less than 5%
Nope, I can't make the maths work for that either. I can see that the length would increase, but can't make it jump by that amount no matter what assumptions are made.
When you increase from say a 2.1 to a 2.3 tyre on a 26" wheel you generally run it at a lower pressure, because of the increased volume?
I might be missing something here, but assuming you're running the same width tyre on a 26" and a 29" wheel wouldn't you run the tyre on the 29" wheel at a lower pressure because of the higher volume of the tyre, which in turn would give a larger contact patch?*
* this could be completely wrong.
Nope, I can't make the maths work for that either. I can see that the length would increase, but can't make it jump by that amount no matter what assumptions are made.
Fit a really narrow tyre and let all the air out 🙂 I doubt that Giant have made it up, but I bet they've made some very unrealistic assumptions.
For the record I have a 26" bike and a 29er and I've never felt this supposed increase in grip. The bike that grips best is the one with the grippier tyres. If they both have the same make/model of tyre fitted then it's the one with the lower pressure. Beyond that I really can't feel a difference in grip, but then again I'm not a particularly sensitive soul.