Not Your Typical AirPressure Question

[HarleyToo]

So, I have read all the threads here and elsewhere about the critical nature of air pressure in a DS tire setup. How the range tends to be optimum from 28-32 PSI.

What I have not seen discussed is dealing with tempature on tire pressure and how adversely this effects the DS setup.

Based upon tempature and a whole host of other factors (but mostly heat and cold), if tire pressure is so massively critical how is it that you are dealing with the variations over a longer trip?

I have taken trips where I begin in 100 degree Texas heat and climb to 60 degree mountain overpasses and vice versa. Its not uncommon to see even a 20-30 degree swing and never leave Dallas, depending on the time of the year.

I have noticed pretty serious tire pressure changes in my truck tires based on these extreme tempature variations. Even just running on a typical hotter Texas day, the concrete heating and friction will increase tire pressure in pretty short order.

So, my question, is how is this not having an extremely adverse impact on a DS setup?
Are you having to get off and adjust pressure constantly?

It seems that this would be a very negative variable in the DS equation.

 

[idk]

Having ridden DS at 14,000' on Mt Evans, and through the Mojave in Summer, through Mt Glacier National Park, and 1,300 mile days in the South in August, I can say that it has not been a problem for me. As with any motorcycle tyres, check the pressures regularly and all will be well.

The tyre pressure with DS is no more or less critical than it is with a normal MC tyre, and there are no more issues with variations in ambient conditions.

 

[JRock]

I run 28 psi and it works fine.
The lower pressure gives a squash effect in turns, increasing the contact patch.

Since a car tire is designed for a 3 thousand + pound car,
it seems to handle the stress of expansion and contraction and the side loads just fine on an 800 pound bike.

Nobody with a DS tire constantly adjusts their tire pressure.
It would not be much fun to ride the bike.

Just my opinion.
I could be wrong.

 

[HarleyToo]

Seems like, in the course of a long ride, that 28 psi would become 34 psi with heating effect and cause it to get squirmy. Adversely, in cold climates, going from the relative warmth of a garage (lets say) to outside temps your 28 might become 26 causing a similar effect.

But, you are not experiencing this?

Again, not trying to nay-say, just trying to understand the dynamics before making the change.

 

[idk]

There is a reason that all tyre pressures, on cars and bikes, should be checked when they are cold, and the reason is because the pressures change when they warm up. It is the nature of tyres - they all do it, with one exception. That exception is if you run 100% nitrogen in your tyres - it doesn't change pressure with temperature changes. That is the reason that your air pressure should be 4 or 5 pounds greater if you are using 100% nitrogen. As for me, I use a 78% nitrogen mix.

It is a non-issue with DS v. MC.

 

[wiffmajig]

I agree with all above posts. Never had an issue with tire pressure. I check it every month or so. I normally run around 30psi in mine. I'm a big guy and the lower pressure feels a bit mushy in corners. You have to find out what feels best to you... Your weight, riding style etc.

 

[HarleyToo]

Thanks for the info guys.

 

[CanberraR3]

I'll have to call BS on it not being an issue with car tyres. If, as car tyre advocates say, tyre pressure is critical and finding that "sweet spot" is essential to comfort, handling and ease of cornering, then a 4-6 degree fluctuation would have a marked effect.

On the other hand, while many people using proper tyres have a pressure they prefer, I know from my own experience that there's very little difference between say, 36 psi and 42 psi in terms of handling. It most noticeably affects ride, unless you're really punting it through a lot of corners, in which case you'd want to check the pressure anyway. In fact, I don't really notice much difference at all unless pressure drops to 32psi and I've never checked to see how high it gets in the heat because it's never occurred to me to so. In other words, it makes virtually no difference to feel.

I'd say it's a huge issue with car tyres and another example of the misinformation that gets pedalled when facts, science and logic are introduced.

 

[idk]

I notice a 2 pound difference in my front tyre - which is a MC tyre - dropping from 41 to 39. The steering is heavier and the handling is noticeably different. Maybe you're not as sensitive.

Also, on my Enfield 2 pounds makes a huge difference. The factory specs on their pressures varies between 20 and 28 pounds, depending on whether it is front or rear, and how much load (number and/or weight of people on the bike) the bike is carrying. They are tubed tyres. If you were to try to run them at over 30 pounds then they become dangerous.

btw, I never said that it wasn't an issue with car tyres. I said "It is a non-issue with DS v. MC". If you were to read what I said, you would notice that I said that it is exactly the same issue with DS as it is with MC tyres. Tyre pressures should be checked regularly.

 

[CanberraR3]

A wise man has reminded me not to comment further.



“Never argue with an idiot. They will only bring you down to their level and beat you with experience.”

― George Carlin