I have been studying on these but haven't come across some concrete reason yet
I have figured following Results of different tire size:
1. Front tire being thinner would induce yaw in the opposite direction which seems an unfavourable factor.
2.Thinner front tire would make the camber angle of the front tire slightly higher than the rear one(considering hypothetical 0 steering and caster angle) which should be able to generate slightly higher lateral force.
3. Because of the caster angle, camber angle of front tire is higher than the rear tire which requires the front tire cross sectional profile to be more circular. So if we increase the width of the front tire to match the rear one, fromt tire mass would significantly increase.
4.Steering effort is less with lesser width(though i am not sure about this one)
Could you please tell if i am going in the right direction??
Are there any other factors??
The front tire is usually but not always thinner than the rear tire:
https://answers.yahoo.com/question/index?qid=1006050819702
The main factors are probably weight distribution of the bike (the rear wheel carries most of the weight), traction for the powered wheel (greater contact patch for better traction), and maneuverability. The wheel you turn is best kept as light as possible, for maneuverability (reduce gyroscopic effect).
The front tire is usually but not always thinner than the rear tire:
https://answers.yahoo.com/question/index?qid=1006050819702
The main factors are probably weight distribution of the bike (the rear wheel carries most of the weight), traction for the powered wheel (greater contact patch for better traction), and maneuverability. The wheel you turn is best kept as light as possible, for maneuverability (reduce gyroscopic effect).
Hey Albert
Thank you for answering. Gyroscopic forces was a very important factor i was missing.
In addition: thinner front tires have a lower tendency to follow grooves or uneven road surface (easier to control).
Kind regards, Mario
Hey Mario
Thanks for your answer but sorry i could not get your point.Shouln't it be easier for a thinner tire to fall into grooves
Because of an increased width of the tire, the contact surface to the road is wider. If a groove is on a asphalt road with a certain offset from the tire center line, the force impact may have a larger offset, that impacts a momentum. In case of a thin tire, lets say infinite thickness, this momentum decreases (to zero in case of a tire thickness of zero). In this way, motorcycles with wide front tires may tend to a certain sensitivity regarding "following" grooves of uneven roads.
Anothere point, I would like to mention is, that the required side slope angle of the motorcycle during cornering increases with rising tire width. This is because the contact point of tire and road surface moves, when leaning the motorcycle in corners. This effect is influenced by both, front and rear tire shape.
Kind regards,
Mario
Hey Mario,thanks again for the quick reply.I understood the relation between grooves and tire width.
By side slope angle,do you mean roll angle(camber angle).Yes that is right,but if front width is smaller than rear one than it induces an opposite yaw angle which i guess counters this roll angle effect.
Could you also suggest some good study material for motorcycle dynamics.Currently i am just studying dynamics book by vittore cossalter
Yes, you are right with the roll angle influencing factors. The effect depends on the ratio of front- and back tire shape.
The book of Vittore is a good one. Here are some more books / book chapters that might support your work:
https://www.amazon.de/Twist-Wrist-Motorcycle-Roadracers-Handbook/dp/0965045013
http://link.springer.com/chapter/10.1007%2F978-3-211-76666-8_4
http://www.tonyfoale.com/
http://www.powells.com/book/racing-motorcycle-a-technical-guide-volume-1-9780951292921
https://www.amazon.de/Motorcycle-Design-Technology-Gaetano-Cocco/dp/8879111892
Kind regards,
Mario
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