should i run a bigger tire???

[elr658]

Your mechanic is correct.

[NukeImYerFodder]

I'm no expert, by no means, but it seems to me that if you change the tire to a different size then it would only be wise to make sure to change the rim as well that is designed to take that particular size of tire.

[zedx11]

there are differences in profile from one brand/manufacturer to another, they can even be the same size and have a different profile. some are more rounded and some are more pointed. find reviews on tires before this thread completely confuses someone.

[jimboy61]

Does this tire make my rim look large? ( ...as a chick would say)

[esornivram]

the tire mfg's spec the proper width of rim to tire profile
some allows wider tires on rim size than others
when you increase the ratio. from an 170/60 to an 180 /55 the proflie changes, some offer an wider tire but in the same profile
the curve of the tire is as important as the width
and flater profile cause the motorcycle to take more effort to lean over
resulting in slower reaction time to changes
its not all the contact patch, but an compromise between traction and handling,
larger tire gets less mileage due to increase frictional resistance and weight
heavy tires takes more to roll, as well as higher MOE(moment of enertia)
wheels r also measure by this, the lower MOE the less HP it takes to roll
http://www.avonmotorcycle.com/us/en/default.asp
http://two-wheels.michelin.com/2w/fr...103637&lang=EN

[metric sprocket]

Originally Posted by neebelung

True, and true.

In layman's terms, the way it was explained to me by my mechanic (when I was going to opt for a wider tire) is this: The wheel is still going to be the same width, so when you *pinch* a wider tire into a smaller wheel, you're basically making it "bow" out more, essentially making your contact patch narrower. You actually LOSE traction and handling, not gain it.

I agree you lose,traction handleing and change gearing. Ron

[paul-s]

Originally Posted by NYcruiser

Not true

ditto my 12 came with a 200 i put a 190 on it.those big tires weigh to much think of a gyro effect. bst carbon rims at the top of my list.

[Kawlison]

If you started reading this thread from the beginning answer you started with erroneous reasoning. You can't divide weight of bike plus rider by the psi of the tire to get contact patch size. Weight divided by pressure does not equal area regardless of the shape. Put eleven square inches down on a piece of paper and see how close that matches your tire's patch size.
Another misguided comment had to do with the "wider is worse" theory. Traction is increased with the size of the contact patch. Mileage may go down but not traction. Why do you think the largest high speed tires belong to top fuel dragsters that do the quarter mile in under 5 seconds and over 300 mph from a standing start? Of course eight(that's no lie) thousand horsepower is the beginning but a smaller tire would be up in smoke in less than 5 seconds.
Another part of the thread that doesn't tell the whole truth is the "fatter tires are not any wider due to rim size" consept. Drop the pressure and you get a fatter contact patch. Pretty hairy to run that way but facts are facts. The correct way to go up in width is change to a wider rim.
Next is the observatinon, "I went up a size and it ruined my bike's handling. You can destroy handling by changing a good tire's pressure by just a few psi. You can also get a stock size tire that just doesn't work for your riding style. Too many viarables to blame everything on the extra width.
Next time you get an opportunity to talk to an owner of a new Corvette ask him if he would like to go back to the size tire they on Vettes in 1968.

[elr658]

My 11 second Galant VR-4 is still on 195/65 15s.
My 10 second 1260cc Kawasaki ELR is still on a 120/90 18. On CV carburetors.
My CB1100F is getting the CBR F3 swap with radials AND ProLink.


I crap on conventional wisdom. I am smarter than everyone else.

[capncalyx]

Originally Posted by Kawlison

If you started reading this thread from the beginning answer you started with erroneous reasoning. You can't divide weight of bike plus rider by the psi of the tire to get contact patch size. Weight divided by pressure does not equal area regardless of the shape. Put eleven square inches down on a piece of paper and see how close that matches your tire's patch size.
Another misguided comment had to do with the "wider is worse" theory. Traction is increased with the size of the contact patch. Mileage may go down but not traction. Why do you think the largest high speed tires belong to top fuel dragsters that do the quarter mile in under 5 seconds and over 300 mph from a standing start? Of course eight(that's no lie) thousand horsepower is the beginning but a smaller tire would be up in smoke in less than 5 seconds.
Another part of the thread that doesn't tell the whole truth is the "fatter tires are not any wider due to rim size" consept. Drop the pressure and you get a fatter contact patch. Pretty hairy to run that way but facts are facts. The correct way to go up in width is change to a wider rim.
Next is the observatinon, "I went up a size and it ruined my bike's handling. You can destroy handling by changing a good tire's pressure by just a few psi. You can also get a stock size tire that just doesn't work for your riding style. Too many viarables to blame everything on the extra width.
Next time you get an opportunity to talk to an owner of a new Corvette ask him if he would like to go back to the size tire they on Vettes in 1968.

but doesnt it make a difference that these dragsters and vettes arent leaning on the tires through corners? i would think that getting a bigger tire for a car would be a much different scenario than getting bigger motorcycle tires that arent meant for the rim.

[cruiserone]

oh boy
- let's go back to the times where the tyres were wooden and square !!

[trugudguy]

Originally Posted by Plato

I'm completely sober, so why doesn't this sound right to me

It seems the shape and diameter of a m/c tire would have some bearing on the contact patch. Take the 800a vs the 800b, at the same front tire pressure it still seems the 800b would have more front tire touching the road. Maybe I'm thinking to much of the flat car tire

Quote:
Originally Posted by bikeaholic
There's a lot of confusion about why we use such big tires. It's commonly believed that a bigger tire has a bigger contact patch. This is incorrect. An ST1300 fueled up weighs about 700 pounds; the rider is about another 200. The tires are at about 40 psi. So, 900 pounds divided by 40 psi is 22 square inches. If the weight is equally distributed on the two tires, each tire has a contact patch of 11 square inches. That's it, tire width and diameter never entered into the calculation. A narrow tire will have an 11 square inch contact patch that's long and narrow; a wide tire will have an 11 square inch contact patch that's short and wide. If you drop the tire pressure to 20 psi (popular for on/off road bikes) then your contact patch doubles in size. If you find yourself in snow or rain, raising the tire pressure will shrink your contact patch and help you push through to the road.



Plato, I'm with you! It looks to me like 900lbs divided by 40psi may equal 22 but it's 22 lbs of weight per square inch of tire. I dunno...

[mklmtrskl]

stick with the size your bike comes with, they did the research and found the best one, they have more time then we do trust them, also the tire is made to fit the wheel, when you put a wider tire on the sam wheel you change everything, the cotact patch wil not be the same on a wide tire on the same wheel because it doesn't fit the wheel, the bike will never handle better because of a wider tire, it's not possible, we dont need wide tires to stick to the road like a car, we need a constant contact patch at all angles, when you put a wider tire on a wheel han should be on it you actually have less rubber on the road at certain angles. Stick with your stock sizes!!!!!!!!!!!!!!!!!!!!!!

[vn2kbob]

Seems like most 1000cc sport bikes limit their rear tire size to 190 while the 600's limit their to 180. If there were anything more to be gained from going wider than this, you'd see it on AMA bikes, MotoGP's and the like. Those sizes above are at the point of diminishing returns for handling and traction. My VN2K has a 200 tire, the Yamaha Raider a 210 but guys, anything wider than that does affect the amount of effort required to lean the bike of a verticle rotating axis due in part to its width and especially weight. All just my humble opinion.

[wireguy]

Originally Posted by nathan600r

The size of your rear doesn't affect your the way handles. Most tires have the same contact area. An oval is still an oval no matter how wide it is. It still comes togther at a point. Center of gravity and weight distribution are the keys to a good handleing bike. My friend has a lowered 650 front and rear. That thing handles like a dream, it can almost go circles around my ninja and my GPz.

if you run a fat tre on a narrow rim it piches the tire and gives a narrower patch.a narrower tire on a wier rim gives a flatter profile which is good for hauling *** in a straight line but sucks in a corner.a rear tire that is too wide no matter what the profie looks like will also overpower a narrow front tire in a corner.

[tely]

Originally Posted by nathan600r

The size of your rear doesn't affect your the way handles. Most tires have the same contact area. An oval is still an oval no matter how wide it is. It still comes togther at a point. Center of gravity and weight distribution are the keys to a good handleing bike. My friend has a lowered 650 front and rear. That thing handles like a dream, it can almost go circles around my ninja and my GPz.

650R ???? how did he lowered it? im intrested in getting one in the near future, but am afraid because i am short and alot of people have told me that when they lowered it, it didnt handle the same and had to put it back the same way and shave the seat or find other ways.

Please let me know....

[NCDave]

Did they lower the rear tely? If they only dropped the forks to lower the front, then that would affect the relative angles. if they dropped the rear as well, the angles should remain. I think......

On top of that, how much would the handling actually change for an "average" rider. Most of us probably don't ride to limits that it's a factor. Many of the shops do this type of change. you know that if the manufacturer or the shop felt it was unsafe they wouldn't do it for legal reasons.

[rbentnail]

I've been trying to remember where it was, because I'm a dope and didn't bookmark it, but I saw not too long ago a company that made lowering links that were actually turnbuckles. I thought it was a great idea b/c they were adjustable from 1-4" simply by turning. No links to change after the initial installation. Anyone else remember seeing them?

[tely]

Originally Posted by NCDave

Did they lower the rear tely? If they only dropped the forks to lower the front, then that would affect the relative angles. if they dropped the rear as well, the angles should remain. I think......

On top of that, how much would the handling actually change for an "average" rider. Most of us probably don't ride to limits that it's a factor. Many of the shops do this type of change. you know that if the manufacturer or the shop felt it was unsafe they wouldn't do it for legal reasons.

Hey Dave!...that is exactly the reason I was asking, because where I bought my motorcycle in Palmetto Kawasaki they dont do any kind of changes to the motorcycle for legal reasons...and i know the 650r is a little high for me and I just wanted to know if it could be adjusted without any problems to the handling. Because Ive read a few pros and cons...so i am a little confuse about it....and about riding to the limit, for sure that is not a problem with me...i ride once in a while due to getting home late from work and I hate riding here in Miami....is crazy!

[cabledawg79]

So what is the biggest tire i can run on my 08 meanie without any mod to the rear?