30 psi in frt tires

[Easy Rider]

LOL. You act like you're 8 years old.

You give him too much credit.
Responding to his posts just drags you into the mud too.

[Road-Kill]

Second generation Smart Cars weigh a minimum of 1653lbs. You can see this here.

They have a range of tire sizes, but their stock wheels and tires are similar to our fronts. Their recommended psi settings are 29 for the front and 36 for the rears. Here.

Close but still no cigar.
And you must remember you are missing a wheel which reduces traction even more.
additionally...they figure the weight as the "average" of additional passengers and cargo.
even those little Smart cars figure an average of passenger and cargo being 600-800lbs, something not close to a Spyder.

Show me a weight rating for a tire that not only shows close to a 1000lb car but missing a wheel, like a Spyder.

The Smart car is almost 1700lbs and has an extra tire, the math?
The Spyder is 33% lighter?
The Spyders missing tire reduces traction by 25%?

Any mathematicians out there wanna try to solve this math quiz?

[Easy Rider]

Close but still no cigar.

So......53 posts into the thread and I forget what your recommendation is for tires ?
The stock Kendra's ??

And what does the Slingshot use for tires ?
Yes, I understand that it is not IDENTICAL but close is often good enough........despite protestations to the contrary.

[Mazo EMS2]

Happy new year!!! Now, can we stop beating this dead horse and move on? Strop worrying about what everyone else does and ride your ride.

[tehrlich]

Close but still no cigar.
And you must remember you are missing a wheel which reduces traction even more.
additionally...they figure the weight as the "average" of additional passengers and cargo.
even those little Smart cars figure an average of passenger and cargo being 600-800lbs, something not close to a Spyder.

Show me a weight rating for a tire that not only shows close to a 1000lb car but missing a wheel, like a Spyder.

The Smart car is almost 1700lbs and has an extra tire, the math?
The Spyder is 33% lighter?
The Spyders missing tire reduces traction by 25%?

Any mathematicians out there wanna try to solve this math quiz?

I only put the Smart Car information up because it is the only thing close to what we are running.

But a nitpick in your math... our rear tire is bigger than the Smart Car tires. I'll let you work that through your HP calculator, but until you actually ride with car tires, you REALLY don't know what you are missing. Why do you think so many on this forum replace them?

Not science, but do a search on this popular forum. Look for anecdotal evidence of your claims. Look for actual claims of:

"holy s.....t.... my car tires are making me spin out on wet roads!" See what you find for us and report.

[Road-Kill]

I only put the Smart Car information up because it is the only thing close to what we are running.

But a nitpick in your math... our rear tire is bigger than the Smart Car tires. I'll let you work that through your HP calculator, but until you actually ride with car tires, you REALLY don't know what you are missing. Why do you think so many on this forum replace them?

Not science, but do a search on this popular forum. Look for anecdotal evidence of your claims. Look for actual claims of:

"holy s.....t.... my car tires are making me spin out on wet roads!" See what you find for us and report.

I was simply asking for the hard data, the math or any actual testing done.
I see none of that.
I see thread after thread of what people "think" is best.

[Warlock]

It's funny how a single thread can bring out the bad in all. No matter what you type, post stats,etc it will not change a persons mind. That is why I stated I like 17 lbs for me. Might not be what you like so run what you feel is right for you. So when people ask a question that doesn't know it's best to tell them to try different pressures until the find their sweat spot. JMO and I'm sticking to it
Happy New Year, David

[BajaRon]

Here is a poor boy's method of looking at tire pressures.

Get your tires up to operating temperature (hard to do this time of year in many locations so some of us may need to wait until summer).

Wet an area on your driveway. A foot or 2 is plenty. You don't want standing water. Just enough to be good and wet.

Drive over the wet spot and you will see your tire footprint in the dry area on the other side. Kind of like the old carbon copiers, if you can remember back that far!

If you are running too high a pressure the outer edge of the tread pattern will be light or missing. You should see an equal and complete tread pattern. This does not work as well for low tire pressure as it has to be extremely low for the pattern to show a problem.

This will not work on the rear tire if you are using Kenda's because of their weak tread area. Kenda's balloon out at speed, so whatever results you get at slow speeds will not translate to the real world. It will work fine if you are running a car tire because the tread area on a car tire is strong enough to resist ballooning at speed.

The front Kenda tires also have a weak tread area. But because of the narrow tread span the effects of ballooning are greatly reduced on the front tires. This is one reason the fronts last so much longer than the rear.

[waynerho]

How about 75 psi or even a 100 psi. They float better when crossing rivers with the higher PSI's right?

​Jack

Sorry, but with the added weight of all of that tire pressure, my mileage went to hell fast. Just too heavy!

I'll stick with 4PSI, thank you.

[missouriboy]

<snip>

The Spyders missing tire reduces traction by 25%?

Any mathematicians out there wanna try to solve this math quiz?

I'm no mathematician but think that last statement is not mathematically correct. Say a Spyder did have two rear tires, at the same total overall weight. The rear-end footprint would be doubled, but the downward PSI would be halved... an exact wash.

The total coefficient of friction (traction) would probably change some, but methinks nowhere near 25% (50% on rear axle...).

[Bob Denman]

I run 85 psi in the front tires...











...of my Motorhome!

[BajaRon]

I'm no mathematician but think that last statement is not mathematically correct. Say a Spyder did have two rear tires, at the same total overall weight. The rear-end footprint would be doubled, but the downward PSI would be halved... an exact wash.

The total coefficient of friction (traction) would probably change some, but methinks nowhere near 25% (50% on rear axle...).

I have not done the math but I strongly suspect that you are correct. There are a number of factors at work here.

First, by going to 1 rear wheel you lose the stability that you gain with 2 wheels spread apart.

Second, you are replacing 2 narrow tires with 1 wide tire. While the total footprint may be a bit less with 1 wide tire. The overall traction coefficient may not be all that different.

Third, as mentioned. The pounds per square inch down-force will go down as the footprint area goes up which also affects actual traction.

I don't think it is as simple as 4 minus 1 = a 25% loss. I suspect that it is a much smaller percentage on our Spyders.

Interestingly enough. A stronger sway bar actually transfers some of the excessive down-force on the front, outside tire, to the rear wheel in a turn. This increases not only the traction at the front of the Spyder. But also increases the traction at the rear at the same time. Only in a turn however, as this is the only time a sway bar has effect on handling.

There are, of course, disadvantages to having only 1 rear wheel. But there are also a great number of advantages. everything is a trade-off.

[Road-Kill]

An easy method would be to mount a desired tire on your Spyder and with the parking brake "on" pull your Spyder with gauge attached.
Do this for several different brands and let us know which tires require more pull to break traction.

If we could come up with a known gauge that everyone could obtain we could ask everyone to do this test.

Since there are many who already have different tires mounted we could acquire this info and close this discussion to facts.

[Easy Rider]

I see thread after thread of what people "think" is best.

That's all that the people here have access to.

If the data you want even exists, it likely is not available to the general public........because some company paid for it and all of the results may not reflect favorably on the people paying to do the study.

[Easy Rider]

If we could come up with ...................

What's this "WE" stuff ??
If it concerns YOU that much, then go for it.
Let us know what you find out.

[Deanna777]

I run 19PSI in the front tires( Continental Contiprocontact's) on my 2014RTS-SE6.

I have not had any problems.

Deanna

[fjray]

This horse has been dead for some time now. It doesn't matter if your an educated pro or a seat of the pants type it doesn't make anybody's opinion better or worse than the next or right or wrong. Use what makes you warm and fuzzy and ride more and stress less.
I personally tried pressures all over the place and finally gave up on the spyder and moved on. The handling was never going make me happy or make the spyder something it's not.

[tehrlich]

Personally, I don't care what people are running for psi.

What I do care about is loud-mouth-know-it-alls hammering anyone that has a different viewpoint. Their claims of superiority aren't really backed up except by grandiose claims and emoji abuse.

This is really what keeps this stupid topic going.

[BLUEKNIGHT911]

Personally, I don't care what people are running for psi.

What I do care about is loud-mouth-know-it-alls hammering anyone that has a different viewpoint. Their claims of superiority aren't really backed up except by grandiose claims and emoji abuse.

This is really what keeps this stupid topic going.

To the " Newbie's " here, the above is what's known as a " HATE MONGERING " post ........ it is often used by people who have no factual knowledge about the subject they are referring to. So they resort to name calling and other vitriolic musings to compensate for this, and as far as " Hammering " people, it sure looks they are the ones doing all the Hammering etc. ..... Sad ...... Mike

[tehrlich]

To the " Newbie's " here, the above is what's known as a " HATE MONGERING " post ........ it is often used by people who have no factual knowledge about the subject they are referring to. So they resort to name calling and other vitriolic musings to compensate for this, and as far as " Hammering " people, it sure looks they are the ones doing all the Hammering etc. ..... Sad ...... Mike

Why do you think I was referring to you?

LOL

[BLUEKNIGHT911]

Why do you think I was referring to you?

LOL

My post didn't say it referred to anyone in particular ..... It was meant as an Informational post ..... OMG are you owning up to the fact that you are a " Hate Monger " ...................Mike

[jaherbst]

Jack

[Bob Denman]

Beating a Dead Horse.jpg

Can we move on to the oil and helmet fistfights now?

[Richardv]

Kenda's are "weak" only because they have a softer rubber tread....because the machine they support is lighter.(to maintain traction)
Car tires are stronger....... because the machine they support is heavier.
My stock Kenda tires are doing awesome. 15,000 rear and 20,000+ for the front.
No need to risk extending my breaking distance to save a few bucks (or risk an accident).
What I'm reading on the use of car tires is why dealers, car tire manufacturers and installers mandate a waiver be signed.

BTW....I keep my awesome Kenda tires at 19PSI front and 28PSI rear.

19 in the front cause I installed the Baja Ron sway bar which eased up on the steering effort.

"19 in the front cause I installed the Baja Ron sway bar which eased up on the steering effort." Since when does a sway bar, help in turning a steering....??????? !!!!! ..... this statement out of the mouth of an expert.....!!!!! wow

[Road-Kill]

"19 in the front cause I installed the Baja Ron sway bar which eased up on the steering effort." Since when does a sway bar, help in turning a steering....??????? !!!!! ..... this statement out of the mouth of an expert.....!!!!! wow

I said the same thing before I installed Baja Rons sway bar.
Contact him and he will explain how improving the angle improves steering.
Your response is "a bit" over the top but its ok.