Airless tires, what do you think ??

[Dozerboy]

You don’t need a sidewall to have a stiff tire on a airless tire.

They have been around 15+ years in the AG and construction industry. We used them on projects that we where tearing up tires on and normal tires on other. We had issues with excessive tire hope when we where putting the tire under a height load situation on airless tires. Due to the ribs flexing and springing back.


Sent from my iPhone using Tapatalk

[Lonnie]

I corner too fast not to have a thick sidewall.

I see SUVs with custom 26-inch wheels and low-profile tires on them that look like rubber bands because they have virtually NO side-wall. I cannot imagine what the ride-quality in those vehicles is like (talk about WAGON WHEELS) OR what it takes to stop that rolling diameter inertia from 75 MPH or what the handling is like in a rain storm. I laugh because the rims expose the VERY small stock OEM brake discs and calipers (at least in perspective scale to the gargantuan rim).

[Desertnate]

I`ve wondered the same thing when I see those, but I doubt the 20 or 22`s OEMs mount on new vehicles are much better. My XL rated, 18" summer tires with 40-series sidewalls are pretty stiff. I couldn`t imagine running even less sidewall. The ride would be pretty choppy unless the dampers were really soft.

Most people probably don`t even think about or understand unsprung weight. Those massive wheels are really heavy and there is absolutely no performance gain. When I finally bought a set of summer wheels/tires, I saved about 3~5lbs per corner over the OEM wheel/tires. It`s not much, but I can actually feel the difference when swapping them out each year. A little less weight can do amazing things for the handling.

[Coleroad]

Most people probably don`t even think about or understand unsprung weight. Those massive wheels are really heavy and there is absolutely no performance gain. When I finally bought a set of summer wheels/tires, I saved about 3~5lbs per corner over the OEM wheel/tires. It`s not much, but I can actually feel the difference when swapping them out each year. A little less weight can do amazing things for the handling.

Amen brother

[Coatings=crack]

I see SUVs with custom 26-inch wheels and low-profile tires on them that look like rubber bands because they have virtually NO side-wall. I cannot imagine what the ride-quality in those vehicles is like (talk about WAGON WHEELS) OR what it takes to stop that rolling diameter inertia from 75 MPH or what the handling is like in a rain storm. I laugh because the rims expose the VERY small stock OEM brake discs and calipers (at least in perspective scale to the gargantuan rim).

Depending on the type of wheel you can loose weight or stay the same in weight thus being able to stop the same or quicker. Most stock wheels are made cheap as possible while still being sturdy (heavy). I went from a 18’ to a 20’ and they were lighter.

Modded suspension too to get better cornering. Same with those big SUV wheels. Unless their getting cheap not much difference in rotating mass. With those Lo pro tires the definetly ride rougher but still better than most cars.


Sent from my iPhone using Tapatalk

[Accumulator]

We don`t mind the harsher ride from low-profile tires, but the roads are just too bad and replacing/repairing wheels and tires got old.

There are higher-profile tires that have stiff sidwalls, but the ones I`m familiar with have some real shortcomings (e.g., Goodyear RSA ).

Yeah on the unsprung weight...the steel wheels on the Crown Vic weigh a ton and swapping them for alloys would improve some things dramatically (did on the last one). But it`s nice to have one vehicle that can simply go anywhere we want to go without having to worry about damaging a wheel or a tire (or being too low), well...two vehicles like that, counting the old Tahoe (75 series tires).

Same thing with suspensions...we don`t mind stiff, we simply need more ground clearance to be able to get around without scraping. The cars that couldn`t be used like normal vehicles were swell with their track day-level handling, and they sure looked neat, but they were so impractical that we simply don`t miss them. I`ll probably say the same thing about the S8 if/when I get rid of it, I never use the thing any more because it`s too extreme for running errands, even though it`s almost Camry-like-practical compared to so many cars. Heh heh, back when I had the Mallett, they assumed their customers would just replace the front airdam regularly!

[Dan]

Depending on the type of wheel you can loose weight or stay the same in weight thus being able to stop the same or quicker. Most stock wheels are made cheap as possible while still being sturdy (heavy). I went from a 18’ to a 20’ and they were lighter.

Modded suspension too to get better cornering. Same with those big SUV wheels. Unless their getting cheap not much difference in rotating mass. With those Lo pro tires the definetly ride rougher but still better than most cars.


Sent from my iPhone using Tapatalk

You certainly can get big wheels that are light, but most aftermarket wheels are big and heavy. It really varies by car, but some sportier cars actually come with some pretty light wheels. I know because I`ve priced out replacement and had to look at wheels north of $500 each to be lighter than the factory ones.

[The Driver]

You don’t need a sidewall to have a stiff tire on a airless tire.

Sent from my iPhone using Tapatalk

That was my point, you need some flex under extreme loads. The point over having a lower tire pressure (Besides the heat/expansion issue) when tracking is so when under load the tire shifts and puts more rubber to the road when pulling hard lateral G`s. You NEED give, otherwise, you`ll slide right off the track.

[Desertnate]

I think the break-even point for a passenger vehicle is around 19" before they start getting heavier.

My car comes with 18" wheels. When I was looking for my summer wheels, the significant weight savings was found by going down to 17". I could have made some crazy weight savings by going smaller. Finding a 19" wheel which was lighter than my OEM 18" was rather difficult. Most were equalt to, or heavier than OEM, but there were a few (very few!) very expensive wheels available from reputable brands. Going up to 20" and the wheels were all much heavier. I had no intentions to go over 19", but it was entertaining to look at 20"

In the end, I stayed at the OEM size and saved weight for a reasonable cost from a highly reputable brand. At my local autocross the only fast cars running anything over 18`s were those who had to go larger due to brake clearance issues.

[The Driver]

You don’t need a sidewall to have a stiff tire on a airless tire.

They have been around 15+ years in the AG and construction industry. We used them on projects that we where tearing up tires on and normal tires on other. We had issues with excessive tire hope when we where putting the tire under a height load situation on airless tires. Due to the ribs flexing and springing back.


Sent from my iPhone using Tapatalk

Yup, probably the dumbest thing you can do besides run crazy camber to look "Cool" as it were. Personally I`ll never run a bologna skin tire, I know someone who is a paraplegic because they ran 20 sidewalls on 20 inch rims, wound up, blowing out, sliding into a tree at high speed. 35+ sidewall for me not anything lower.

[Accumulator]

That was my point, you need some flex under extreme loads. The point over having a lower tire pressure (Besides the heat/expansion issue) when tracking is so when under load the tire shifts and puts more rubber to the road when pulling hard lateral G`s. You NEED give, otherwise, you`ll slide right off the track.

I find it interesting how some high-perf vehicles handle so great with lower pressures since that`s so foreign to my experiences with the vehicles I usually drive and completely opposite of how it works with the vehicles I was trained in.

IME, sidewall flex in big heavy vehicles is undesirable because of the risk of rim-to-pavement contact. Beyond "undesirable" really, as it`s a life/death issue.

When VDI was testing the effects of psi diffs in Crown Vics they had to suspend testing around 35psi because the sidewalls were flexing so much that the rim was gonna touch the pavement (with predictably fatal results). Looking at the pix, it was a hair`s breadth from contacting. When you track/AutoX those kind of cars and/or SUVs like my (old) Tahoe, anything below 42psi is a handicap, and when hard use raised that 42 up to something really high, it was never a problem and they never lowered the pressure to compensate. I can`t imagine how high the pressures got in the Suburbans we were running (especially the armored one, that thing weighed a *lot*), never thought to check them after they heated up.

In my area, underinflated tires are responsible for countless rollovers...it happens *all the time*, especially with SUVs. When you see how the rim(s) gouged the pavement and the tire got peeled off, it`s obvious what happened. All those SUVs/CUVs on their roofs...on public streets with moderate speed limits too. The psi that give a comfortable ride and even wear isn`t high enough for emergency maneuvers.

[Desertnate]

I find it interesting how some high-perf vehicles handle so great with lower pressures since that`s so foreign to my experiences with the vehicles I usually drive and completely opposite of how it works with the vehicles I was trained in.

I think a lot of this comes down to how the suspension and the tire work together to keep the largest contact patch possible on the ground. With a large vehicle with tall, soft(ish) sidewalls, in order to keep the tire from squashing and rolling on the sidewall like you described, you`ll need to put quite a bit of air in the tire to ensure the the tire tread stays as flat as possible on the ground. Even at really high pressures, the tire is still going to flex due to the weight of the vehicle. In a smaller, lower, lighter, car the tires aren`t under nearly the same levels of stress and therefore, if you over-inflate them, they don`t deform properly under cornering loads and won`t get the needed amount of grip. It might actually make the contact patch smaller.

Example: Two weekends ago I was running in our local SCCA autocross. I ended up parked next to another, more experienced GTI owner on the grid. He and a couple other veterans of driving FWD cars were telling me how they could combat understeer by simply raising the rear tire pressure above normal levels. This made the tires deform/grip less and allow the back end to purposely slip around a bit and rotate quicker in turns.

Not sure if it would work in reverse for a RWD car, e.g. if an oversteer monster could be tamed by lowering the rear pressures and the raising the fronts to create a little more slip in the front.

[Dan]

I think a lot of this comes down to how the suspension and the tire work together to keep the largest contact patch possible on the ground. With a large vehicle with tall, soft(ish) sidewalls, in order to keep the tire from squashing and rolling on the sidewall like you described, you`ll need to put quite a bit of air in the tire to ensure the the tire tread stays as flat as possible on the ground. Even at really high pressures, the tire is still going to flex due to the weight of the vehicle. In a smaller, lower, lighter, car the tires aren`t under nearly the same levels of stress and therefore, if you over-inflate them, they don`t deform properly under cornering loads and won`t get the needed amount of grip. It might actually make the contact patch smaller.

Example: Two weekends ago I was running in our local SCCA autocross. I ended up parked next to another, more experienced GTI owner on the grid. He and a couple other veterans of driving FWD cars were telling me how they could combat understeer by simply raising the rear tire pressure above normal levels. This made the tires deform/grip less and allow the back end to purposely slip around a bit and rotate quicker in turns.

Not sure if it would work in reverse for a RWD car, e.g. if an oversteer monster could be tamed by lowering the rear pressures and the raising the fronts to create a little more slip in the front.

That`s part of the reason some cars have different pressure for different axles.

[RaskyR1]

Is that conjecture? Because I don`t see anything from Michelin that indicates that: https://michelinmedia.com/michelin-uptis/

This concept from Michelin has been around for 15 years or so.

You would also have major tire balance issues in states with freezing temps/snow if there were no side wall on the released version.

[Desertnate]

You would also have major tire balance issues in states with freezing temps/snow if there were no side wall on the released version.

That`s a great point I hadn`t even thought of!

I know how much my wheel well fill up with snow and ice, I couldn`t imagine that junk getting into the voids in that tire. Not only would it be a balance issue, but it would prevent the wheel from flexing properly as well. Those voids being open to the air would keep the tire from warming up too, so you couldn`t count on any sort of heat build up to melt anything that gets trapped. Some would break loose I`m sure through vibration on the road, but not all of it if things filled up and became really solid.