Rim-To-Tire Fit

[Hellion]

I am currently looking at all that the rim and tire world has to offer for our karts. I've narrowed things down to the quintessential classic go kart tires:

4.10/3.50-4
4.10/3.50-5
4.10/3.50-6

These all have the same section-width but there are different width rims that these tires will fit. For instance, the 5" Azusalite comes in 3", 3.5" and 4" widths but what is optimal?

Generally, with kart tires, you want the rims to be 1/2" to an inch wider than the tires, I.E. 4" rim, I'd use a 3.50 tire, 4.5" rim, I'd use a 4.10 tire, -Rickracer

As long as the hole in the middle of the tire is the same size as the wheel diameter, it will fit. Now, the profile, is another story altogether. 6" wide tire on a 5" wide wheel will look like a "beefy" tire. But if you put a 5" wide tire on a 6" wide wheel, it will shorten the height a tad, and sorta round out the corners/sides a little, like a racing kart slick. I have 6" wide slicks stretched onto 8" wide wheels. And 10" wheels even... Basically, the width of the tire and wheel affect the looks of the assembly. Tall and square or a tad shorter with rounded corners to help slide into a turn..... I'm going rounded. Tall and square shoulders dig in and cause flipping.... Can cause flipping...... Just my penny........ (too broke to offer the 2 cent version...) -firemanjim

This handy chart (for automobile tires) shows that the middle and right options are in the 'danger zone' but experience has been showing us that the right side option has been do-able for many years, at least in the automotive world, where the tires are the same width or even narrower than the rim. I will say this with the caveat that the latter practice (in the extreme) is mostly adhered to by the "tuner" or "ricer" crowd and like many things they do, may be ill-advised.

What can we get away with on our kart wheels?

Is there any detriment or performance benefit to using a 4" wide rim with a 4.10" wide tire (basically with both widths the same)?

P.S. I'm looking at using the slick tires that have a square profile and are not rounded at full inflation. I desire to keep the tire's profile intact.

 

[bob58o]

I tried an advanced search for Tire / Rim fit and this was all I found. Wish I could be more help. Sorry.

 

[itsid]

Now, the chart you attached is pretty much valid throughout all rim/tyre sizes.
The danger in picking the wrong rim or tread width is that
sideloads (fast tight corners heavy vehicles) are able to unseat the beads
popping the airseal (deflating the tyre and all the nasty effects that follow)

but it's also about proportion.. a kart tyre is much smaller than a car tyre typically and
with that it's more forgiving when it comes to rim width
especially wider rims on tubed tyres are very raely an issue;
since even if the bead unseats in a fast tight corner;
it will not pop the air seal thanks to the tube and it'll reseat as soon as you pull straight again.
It'll not be nice (wobble and actually causes increased wear on the tyres)
but it'll not be catastrophic at all.

Anyways.. karts are light, the wheels have small diameters, and even if the section height is a tiny bit large... there's no need to be overly concerned about rims being too wide

if you do not head for extremes that is... (9" wide tyre on 3.5" rim will likely fail .. even fail to mount)

But a 4.10 sits as nicely on a 3" (bulgin out slightly) as it'd sit on a 4" rim (as if drawn with a straight edge)

nothing will happen, especially not on tubed or perfectly pressurized tubeless wheels on a lightweight go kart.

It's all about the look you want

'sid

 

[Hellion]

Well, we do know that the tire in column A, "Proper Fit" is the norm for the way most tires are designed. The tire sidewall curves moderately inward to meet the rim on both sides and that's the way it is with most passenger car, lawn and garden and go kart tires.

I think that with the "rim too wide, tire too narrow" option, the tire is in a state of distortion and it's being forced out of its natural shape and this sounds like it is quite detrimental to the tire, to its integrity and to its longevity. True?

In other words, the sidewall is supposed to bulge out slightly from the rim. That's the way the tire is molded and it appears that way even when in new, off-the-rack condition.

But the gist of my inquiry is: does having the tire the same width as or narrower than the rim add any stiffness or sidewall strength to the tire?

 

[itsid]

Well "some" tyres are molded to bulge (I indeed think MOST are) but all?
I can't tell..

easiest thing to find out if distortion is all bad:
have the tyre standing upright (no rim, no tube) measure top and bottom bead distance and use the average to determine the rim width it's the least distorted by...
Now clamp the bead slightly until the inner (as in towards the hub, not the inside) faces of the bead are perfectly horizontal...
measure again to find the rim size it's actually designed for.
you see a difference?

Anyways.. for cars it's the size the tyre guy tells me.. for kart.. it's what I have laying around that fits

sidewall strength is only regulated by the section height, shore of the rubber and the psi the tyre/tube is filed with.
it's the direction of the forces applied that make a difference if the tyre gets mounted to a rim it shouldn't sit on versus the grip it's bead has against the rims collar.
(if the bead sits at a nasty angle it loses contact obviously.. )

'sid

 

[chancer]

Good questions.
Only thing I can add is that the 4.10-3.50 tires are available in "Slick" at MFGsupply.