Solid Tyres

[DieselJake]

Why don't we all have them?

Started looking into solid push bike tyres to which I found companies have developed a compound which far outlasts regular tubed tyres in terms of wear, feeling the same to the touch, weighing the same and most importantly riding the same which baffled me as to why the same evolution has not been applied to car tyres. Early car rubber tyres were solid and the main reason they then had air inside was due to the cost of rubber and softer rubbers wearing easier but surely if they have invented a compound that offsets the latter and can be made cheaply (even if they were double most tyres cost that could still be classed as cheap if they last five times the mileage and perform as well) they could essentially be used for fast road use and/or longevity.

 

[fast-ferret]

Interesting topic I hadn't really considered solid tyres even for push bikes - owning a road bike this is interesting to me as flat tyres and annoying and also the fact that road bike tyres lose pressure over the weeks I don't use them (because I'm a bit lazy). But, no idea why we don't use them I'm afraid.

 

[Charlie Farley]

very easy, the two are very different and perform very differently under load conditions.
Pneumatic air tyres abilities can vary greatly depending on there construction , air pressure and what they being used for , so they become much more versatile compared to solid tyres.
Solid tyres are great but only suit certain applications and are not really that adjustable , whereas pneumatic tyres can used much more widely and are more suitable for applications that require varied working loads , such as lorries/cars/bikes etc .
The pressure can be increased or decreased to suit different loads/speed etc , that cant happen with solid tyres whatever the compound may be.
A solid tyre on a forklift is fine , try driving that forklift at speed down a road....i'm not saying solid bike tyres are going to be that hard etc but they wont have that ability to work the same and aswell as a pneumatic tyre.

 

[Charlie Farley]

Classic example is on a trials bike, when you need serious grip you let the tyre down as much as possible , it increases the footprint of the tyre and the ability of the tyre to grip, you'll never get that from a solid type tyre .
I could see solid tyres on push bikes used on flat smooth road circuits working as they would be smooth and free from defects but on a public highway, very doubtfull it would work very , but allways open to the idea .

 

[CarbonMike]

All the big corporations that manufacture tyre air would go bust....

And good luck trying to mount one on a rim.

 

[DieselJake]

Solid tyres are great but only suit certain applications and are not really that adjustable , whereas pneumatic tyres can used much more widely and are more suitable for applications that require varied working loads , such as lorries/cars/bikes etc .
The pressure can be increased or decreased to suit different loads/speed etc , that cant happen with solid tyres whatever the compound may be.
A solid tyre on a forklift is fine , try driving that forklift at speed down a road....i'm not saying solid bike tyres are going to be that hard etc but they wont have that ability to work the same and aswell as a pneumatic tyre.

Well that's where your wrong as certain compounds mimic the desired pressure so they can feel as soft or hard as you like. Not only that but they will maintain how they are desired to feel/act.

good luck trying to mount one on a rim.

Thought the same at first but in theory they could actually be easier to fit as theirs many different stable ways of mounting them but depending how it's done the removal would be allot more tricky (if they don't outlive the car that is).

 

[Charlie Farley]

A compound wont change in a few seconds or minutes the way air pressure can be, i'd like to see a airless solid tyre that can be as variable and versatile as a pneumatic tyre, if solid tyres were so good then they would have been mainstream before now on more types of wheel.

 

[DieselJake]

Should really look into things before commenting, reminds me of when you were talking about the weight of my diesel car when it's lighter than your petrol.

In terms of why they aren't mainstream... well that's what I'm trying to find out... only reason I can think of so far is cost.

 

[Charlie Farley]

It may be lighter but then its got less in it than my B7 and you have a B6 not a B7…..seems like you know all the answers anyway so why bother asking the question to start with.

 

[CarbonMike]

Rotational mass... solid rubber tyres are gonna be dam heavy the transmission loss would be phenomenal.

Theres many many MANY reasons why there not used anymore... all the geeky automotive engineers & science people that are waaaay smarter then me or you did some science and realised air filled is the way forward.

Thats pretty much the easiest way to answer this qeustion. Now lay off the drugs...

 

[CarbonMike]

Also have you fact checked your first statement...

Was the reason they decided on air filled due to the cost of rubber?? I think not...

Your assuming a compound has or is even possible to invent cheaply?? Which it isnt, as oil prices dictate the cost of tyre production.
.

What makes you think theyd last "five times" longer then conventional tyres???

Your comparing a bicycle tyre to an automotive tyre... its not the same despite doing the same job.

 

[Charlie Farley]

1. Why are most tires inflated with air instead of solids?

• Cars experience a lot of shock in terms of bumpers, pot holes, obstacles etc. If you used a solid material (Say rubber) you would experience every bump & obstacle in the passenger seat because solids are good conductors of vibrations (Just like conducting electricity), while gases are compressible and can absorb shock, byhaving a lot of empty space inside it to give and take, enabling a smoother ride
• The mass of a solid tire will be significantly higher than that of a air filled tire (No matter how light the material is). This will cause two significant problems. A solid tire would wear out much quickly than the one filled with gas, because the friction (Which is proportional to weight) of the tire with the ground, would be high. Second, more mass means more power consumed to operate, leading to less mileage and higher operating cost.
• And most important of all, the cost involved and the technology required to manufacture these solid tires would be very high, imagine all that rubber going in, if it is some other innovative material, the cost factor would spike higher. Imagine paying a fifth of the car's value just to replace 2 pairs of tires?

However solid tires exist and are used for specific applications like Industrial forklifts where the vehicle moves at relatively slower speeds (5-20 kmph) and carries materials weighing in orders of tons, which is nothing similar to what a car does. (Rubber tires would burst when subjected to so much pressure)

 

[LawrenceH]

If they were stiff enough to have a low profile and handle well you’d bend rims every time you went though a pothole.

 

[Charlie Farley]

I've said what I think, and i'm not going to get drawn into another messy post, i'm out of here.

 

[DieselJake]

Rotational mass... solid rubber tyres are gonna be dam heavy the transmission loss would be phenomenal.

Could easily be as light or lighter than conventional tyres, again different use case but scooters that come with inner tubed tyres are often replaced by solid (cheap so not the best quality unlike what the bike folk tend to go for) tyres and newer designs have involved the same but with holes in to reduce weight. Not suggesting holes could/should be in solid car tyres but it's an interesting concept and becides this if they've got solid bike tyres to the same weight as tubed tyres (without doing this) with a much better wear rate it's hard to understand why the same/similar logic can't be applied.

Your assuming a compound has or is even possible to invent cheaply?? Which it isnt, as oil prices dictate the cost of tyre production.
.

What makes you think theyd last "five times" longer then conventional tyres???

Cheap is relavent to the application and longevity is based on other modes of transport already in use (believe it or not five times wear rate is actually conservative).

If they were stiff enough to have a low profile and handle well you’d bend rims every time you went though a pothole.

Low profile tyres increase the possibility of alloys being cracked either way (unfortunately I know this too well) but the benefit of solid rubber would be no air escaping, I presume that's what was meant by bending as it's hard to picture alloys actually bending.

 

[CarbonMike]

If there so awesome & great pitch your idea to Mr Pirelli then.

Be sure to let us all know how well you got on...

 

[DieselJake]

It's not my idea but thanks for the support.