Kumho rear tire air pressure?

[Peter Aawen]

.....(Is there a point where too little pressure might become dangerous?)

Yes, there is Bob! But there's no specific or 'set limit' - whatever the particular pressure is in your circumstances may vary a fair bit depending upon a whole lot of things, including the construction method of the particular tire itself, the width of the rim it's mounted on, the tire's size & profile, the thickness of the sidewalls &/or the tread material, the number & size/dia of the wires/cords of the plies in the tread & sidewall, and a whole bunch more!! :dontknow: All that said, on modern tires fitted to rims like our Spyders run, & especially when the weight loading on the tire is as low as it is under our Spyders, the 'bead seating fail pressure' is generally fairly low! :sour:

Back some years.... well, actually closer to a few decades now, the 'brief' for radial tires was to never drop your pressures below about 12-14psi or you risked unseating the bead & rolling the tire off the rim; but over the last 20 odd years, that level has been moved somewhat lower as tire design & construction methods have given manufacturers greater ability to make tires that retain their shape & bead seating with faaaarrrr greater ability than was originally possible!! Lower profile tires especially call for this, but the methods & construction techniques that help keep the bead on ultra low profile tires seated during high speed & high load cornering and even during rapid acceleration or braking have shown to provide such gains in performance, handling, wear, & traction that they've bled over into just about all road vehicle tires; hey, we can even get 'Run flat' tires now that won't unseat the bead even when the tire is blown; but as I mentioned earlier, there's no specific set level that applies to all tires or all conditions.

Still, those simple 'tools' that have occasionally been mentioned (like 'the 4psi rule') can help YOU to determine what pressure is optimal for whatever tires you are running on YOUR Spyder, so that YOU can then make a reasonably informed decision on what pressures to run &/or about whether you want to increase or lower your pressures to suit your needs or feelings about how & what you want from your tires or for your tires to do for you. Sure it might take a little bit of effort to work it out & then keep fine tuning it, but if you want optimal performance &/or wear, traction etc, you might just need to make a little bit of effort! And I'd like to think that by this stage of the tire pressure discussion you are just a little bit aware that by varying your pressures much from the 'indicated optimum' you will be compromising some aspect of the balance of traction, ride, wear, & handling etc provided your tires! But it's YOUR CHOICE, & YOUR DECISION about what pressures you run & about what you want from your tires!

Me, I'm happily running 14-18psi up front & 16-20psi in the rear of the (non-Kenda) car tires that I run under my Spyder (car tires that happen to be Kumho btw!); just as I'm happy with the significantly improved ride, handling, traction, & wear I get from those tires - 30,000 plus km of waaaay better performance in every respect (even from the rear tire!) instead of the less than 5000km of marginal performance I got from the Kendas AND the car tires I run happen to be cheaper too!! Why wouldn't I be happy! :thumbup:

 

[Bob Denman]

Peter,




:clap:

 

[blacklightning]

It was sort of a random thought: we used to use sheet metal screws to keep our ATV tires in place. We were running about 5 psi, a LOT of horsepower, and the most extreme conditions possible! nojoke

We could spin the tires on the rims with a quick spin of the throttle... and those tires were designed to run at super low pressures! :shocked:

This same concept was followed when using drag slicks on my brothers race car. Very low tire pressure, sticky tires, and lots of horsepower. Screws were a must.

 

[blacklightning]

I keep a close eye on my front tires and check them especially before longer rides. But the back is so difficult to get to, that I have it all checked when taking it in for serviced and go with their recommendations. After that, I look to see that they are round and not flat on the bottom or squatted a lot. If I feel no adverse affects in the handling or wear, then I am good.

 

[Fatcycledaddy]

I keep a close eye on my front tires and check them especially before longer rides. But the back is so difficult to get to, that I have it all checked when taking it in for serviced and go with their recommendations. After that, I look to see that they are round and not flat on the bottom or squatted a lot. If I feel no adverse affects in the handling or wear, then I am good.

That is why I purchased the FOBO system from Lamont. I love that all I have to do is look at my phone and check tire pressure and temp at any time. Makes it easy to check for that 4psi rule Peter was referring to. I also love the fact that it warns me if any pressure goes below or above the limits I have programmed in. Money well spent!

Before I ride, check pressure and temp, stop for gas or food, check pressure and temp, shut down for the night, check pressure and temp.
No more laying on the ground trying to reach through a sprocket to get at the valve stem for me!!:yes::yes:

 

[BLUEKNIGHT911]

PSI AND BEAD - RIM

Question: How much does the air pressure in the tire affect it's ability to remain seated on the bead of the wheel? :dontknow:
(Is there a point where too little pressure might become dangerous?)

I posted about this last year , here's the short version ...... My Michelin Hydro-edge rear tire was drivable at 8 psi, ... it did feel slightly squirrely, so I checked it and added air....... Everything Peter wrote is valid ,imho ...... Mike :thumbup:

 

[Grayfox]

I posted about this last year , here's the short version ...... My Michelin Hydro-edge rear tire was drivable at 8 psi, ... it did feel slightly squirrely, so I checked it and added air....... Everything Peter wrote is valid ,imho ...... Mike :thumbup:

I did what Blue Knight said and set my tires at 16 on front and 18 rear on my 2012rts. I thank it rides better and hugs curves better, thanks for the info

 

[BLUEKNIGHT911]

TIRE PSI THING

I did what Blue Knight said and set my tires at 16 on front and 18 rear on my 2012rts. I thank it rides better and hugs curves better, thanks for the info

I'm glad you like it ( only if you switched to CAR tires - right ) .... they will work better this way if it's wet .... annnnnnnnnd your ride will be more comfortable because they will help ABSORB road irregularities :thumbup::thumbup:............. Mike

 

[nealperkins]

So what is the recommendation for the pressure in the original Kenda's? (Other than get rid of them...)

 

[Peteoz]

So what is the recommendation for the pressure in the original Kenda's? (Other than get rid of them...)

18 and 28, Neal.

 

[nealperkins]

Well, that's what I've got.
Thanks

 

[malibu_dan]

Y'all make me want to wear out the Kendas so I can put some real tires on and get some traction to go with the new Elkas!

 

[AY4B]

I wore out my rear Kenda before it got to 4000. I wore out the Yokohama S at around 10,000 because I kept 28 pounds in it. Wore out the center. My second Yokohama, I'm running 20 and may take it down to 18 after reading this thread.

 

[spyderfish]

18 Pounds "All Around"

:yes: I'm the Mike ( of Mike and Peter ) and if you are using a car tire ( any brand ) you will be safer and enjoy the ride better if you lower the REAR psi to .. 18 ( cold ) .. I'm sure Peter will agree with this :clap:. I know this may seem too low, but remember that tire will increase at least 3 psi after about 3 miles of driving ....... Mike :thumbup:

Mike and Peter,

With you folks all the way on this one. Kumho Ecsta on rear, original OEM on front, 19K miles. Looking for traction, longevity is secondary. Everything I have read everywhere indicates that lower pressure increases traction, A LOT. Limited of course by tire damage due to underinflation and too much sidewall flex.

So, simple and easy, 18 pounds all around.

Spyderfish

 

[BLUEKNIGHT911]

REAR TIRE

Mike and Peter,

With you folks all the way on this one. Kumho Ecsta on rear, original OEM on front, 19K miles. Looking for traction, longevity is secondary. Everything I have read everywhere indicates that lower pressure increases traction, A LOT. Limited of course by tire damage due to underinflation and too much sidewall flex.

So, simple and easy, 18 pounds all around.

Spyderfish

:agree: The Kenda's because of their construction perform better at a higher psi than any car tire..... if you have very good alignment they will last like a car tire also....... Personally I'm not impressed with the Kumho , many here have reported that it's wet road abilities decrease considerably at about it's half -life point. Try 18 psi, ( rear ) I think you will like that for many reasons, ............ Mike :thumbup:

 

[JP58]

I will go with 18. Sounds like most here agree. I have the Michelin Premiers on my Nissan Sentra. Expensive but they get better traction as they wear do to the Sipes get wider as they wear is what they say.

 

[Bob Denman]

I wore my Kumho down to within a couple of hundred miles of needing replacement: it performed consistently for the entire 12,300 miles. :thumbup:
(The last 100 miles was in a rainstorm: no signs of hydroplaning, or loss of traction!)

 

[BLUEKNIGHT911]

HYDRO - PLANING

I wore my Kumho down to within a couple of hundred miles of needing replacement: it performed consistently for the entire 12,300 miles. :thumbup:
(The last 100 miles was in a rainstorm: no signs of hydroplaning, or loss of traction!)

Bob, I never investigated an accident below 15 mph that I attributed to " Hydro-planning " :clap::roflblack::roflblack::roflblack::roflblack:........ Mike :thumbup:

 

[Peteoz]

Bob, I never investigated an accident below 15 mph that I attributed to " Hydro-planning " :clap::roflblack::roflblack::roflblack::roflblack:........ Mike :thumbup:

Cheeky bugger

Pete

 

[wrb3004]

Question about 4psi rule

I never new about the 4psi rule until I read this thread. Since then I have read other threads about it and have also googled it and read some interesting articles.

Based on many discussions about tires and tire pressure I am running Federal Formoza's on the front at 15# and I am running a General Altimax on the rear at 20#.

After about an hour of driving the fronts read 16# and the rear reads 23#(per the FOBO). So the fronts rose about 1# and the rear rose about 3#.
I can drop the cold pressure on the rear to maybe 18# or 19# and see if I reach the 4psi but I'm not sure I could reach the 4psi rule on the fronts without going quite a bit lower than 15#. From everything I have read 15# seems to be a good number.

Thoughts on this? Thanks Wayne