Quote:
Originally Posted by AlphaKilo ![O.T.](https://www.team-bhp.com/forum/images/smilies/Off Topic.gif) So essential I understood only thing from your post:
"The worse the road condition, the best one's chance of braking" - Hurray! Any politician will be happy to hear my conclusion.
One serious question to you: Why do the rear tyres of tractors have such huge treads? Why are they outwards like spikes rather than inwards like in other road vehicles? (it would be really hard to drive the tractor on smooth tarmac (well if you can find one such road anywhere in India))
a. Because they are mostly used in slush environment where grip needs to be ploughed
b. some other technical reason behind it
c. Just for fun dude!creativity!!looks cool |
![O.T.](https://www.team-bhp.com/forum/images/smilies/Off Topic.gif)
Tractor rear tyres are big and have huge treads because:
1) Bigger diameter tyres means more ground clearance.
2) A tractor has to pull a plough which is as high as 21 inches deep inside the soil, so you can understand how high the pulling force is required. Its not similar to towing a vehicle on plain road. The forces involved are very high and severe in nature.
3) The deep treads sink deep in soil and then when the tyre rotates its like the treads push a chunk of soil back thus creating traction. The difference between on-road tyres and tractor tyres is smilar to two rotating pulleys in contact with each other and two gears in positive contact with each other respectively.
Some more tractor tyre facts:
a) Indian tractor tyres are filled with 70% water to ballast them additional weight.
b) Additional ballast weights are also added to increase the tractor weight.
c) 15% Wheel slip during farming is considered a normal practice. Thus tractor tyres dont last long inspite of being made up of hard rubber.
I really did not understand your question regarding inward and outward spikes and neither I am any tractor tyre expert to answer your exact query.Sorry for that, all I know is that there are lot of complex soil mechanics taken into consideration for deciding the same.
Also as per the link attached above thanks for reminding me that its the amontons law of asperities.
To confuse more:
Torque (T)= Force (F) X Radius (R) where R is radius of tyre transferring power and T is the torque at the axle.
Considering torque at the axle remaining the same which one would be better a scooter or a motorcycle to climb a hill-road and why?
For a scooter the force F will be more because of less tyre radius so a scooter should ideally be better to climb a hill. But practically its the motorcycle right! (This question was asked to me in my Final engineering Viva
![Big Grin](https://www.team-bhp.com/forum/images/smilies/biggrin.png)
)
Consolidating the above literature:
Actual Friction (leading to traction) is dependent to less or more on:
1) Nature of materials in contact.
2) Area of contact patch.
3) Adhesion of two materials.
4) Surface finish of bodies to a certain extent.
It seems Friction has its own ways of being dependent of many things but at the same time remain independent of many parameters at least in theory!