Lean angle

[Dendrob]

Even if you're the type to take full advantage of the amount of lean your tyres have to offer, do you find that if you scrub the rear tyre to the very edge, the front tyre is not scrubbed to the very edge?

It's as if the two wheels are experiencing different lean angles to get around the same corner.

Is it coincidental that the width of a tyre has an effect on the lean angle? A wider tyre needs more lean angle to get around a given corner, assuming all other parameters are the same. But the front and rear tyres, especially on a modern bike, are dramatically different widths, yet they both have to carry the same motorcycle around the same corner. The theory seems to tell us that the rear tyre needs more lean angle than the front.

So, is this what happens and if so, is it an explanation for the different amounts of sidewall scrubbing I mentioned at the beginning?

You know the lean angle-ometer they have on screen sometimes in motogp. I assume that represents the main frame portion of the bike, including with it the rear wheel. But what if there were two lean angle-ometers, one on the mainframe and one on the forks. Would they be always showing different readings and never the same? Except when the bike is perfectly vertical.

[Wicky]

I'd guess when naturally counter steering around a corner the front tyre would be angled slightly more upright, plus front & rear tyres have different profiles.

[Dendrob]

I'd guess when naturally counter steering around a corner the front tyre would be angled slightly more upright, plus front & rear tyres have different profiles.

I'm definitely with you on the counter steering thing and would go further and suggest that even steering in the "right" direction would lead to different angles being set up between rear and front wheels. Any movement of the handlebars from "dead ahead", when incorporated with leaning the bike must result in a slightly different lean angle from front to rear with respect to the ground, I guess. Whether this is the reason for the front tyre never seeming to scrub to the edge when the rear does, I don't know? What do you think?

True, front and rear may have different profiles but doesn't this just manifest itself as different "effective" widths anyway, and as such doesn't really change what I've put forward? Is the radius of torus the right term? Dunno, all food for thought.

Cheers.

[bigtwinthing]

like i said you need to get out more and stop asking questions. if the back tyres Fatter more touches the ground and wears etc. it aint rocket science!!! if you put 2 tyres on the same size they wear almost equal.

[fabiostar]

has some posts on this thread disappeared?.. im near sure i posted on it?

[adyf]

If your front is less scrubbed than the rear ya ain't trying hard enuff , but be warned attempting to correct this fault may result in a hedge interface.try not to outthink it just do what I do and use the 'force'.

[Dendrob]

I take on board the advice guys, thanks.

Getting back to the subject and with respect to the fact that a wider tyre demands more lean angle, how do we reconcile the apparent dichotomy of two tyres of differing widths attached to the same bike?

[Dendrob]

has some posts on this thread disappeared?.. im near sure i posted on it?

Sorry, it's probably me who's confused the situation. I commented on a thread at the top of the list, on a very similar topic. I confess that what we were talking about got me thinking of the topic in the op of this thread. Apologies, I'm flitting!

[Jamoi]

Front & Rear tyres have a different profile.

[Dendrob]

Front & Rear tyres have a different profile.

So even though the front tyre is substantially narrower than the rear one, once the bike is leaned over the profile of the front tyre gives it an effective width (from the theoretical centreline of the bike) roughly equal to that of the rear tyre?

[KermitLeFrog]

Front & Rear tyres have a different profile.

So even though the front tyre is substantially narrower than the rear one, once the bike is leaned over the profile of the front tyre gives it an effective width (from the theoretical centreline of the bike) roughly equal to that of the rear tyre?

You are over-thinking it again. It depends on the tyre. My Storm has BT016's front and rear. The front is a higher profile tyre than the rear and the edges will never get used. The Yam has Pilot Powers front and rear. The front is a low profile tyre and both front and rear get used to the edge.

[fabiostar]

Front & Rear tyres have a different profile.

So even though the front tyre is substantially narrower than the rear one, once the bike is leaned over the profile of the front tyre gives it an effective width (from the theoretical centreline of the bike) roughly equal to that of the rear tyre?

You are over-thinking it again. It depends on the tyre. My Storm has BT016's front and rear. The front is a higher profile tyre than the rear and the edges will never get used. The Yam has Pilot Powers front and rear. The front is a low profile tyre and both front and rear get used to the edge.

very true. tyres are different, on the storm i had a supercorsa sticky sumthing or other and it was scrubbed to the edge, now i have a maxxis sticky thing and iv tried very hard and cant get it near the edge..

[StuartWags]

never really put much thought into it myself

[Dendrob]

Front & Rear tyres have a different profile.

So even though the front tyre is substantially narrower than the rear one, once the bike is leaned over the profile of the front tyre gives it an effective width (from the theoretical centreline of the bike) roughly equal to that of the rear tyre?

You are over-thinking it again. It depends on the tyre. My Storm has BT016's front and rear. The front is a higher profile tyre than the rear and the edges will never get used. The Yam has Pilot Powers front and rear. The front is a low profile tyre and both front and rear get used to the edge.

I must admit I stick with Bridgestone.

When you say higher profile do you mean the aspect ratio?

[Dendrob]

Thanks guys for the input.

What are your thoughts on the other part of my op? How a tyre of a certain width demands a certain lean angle and yet the front and rear tyres are substantially different widths. What is happening here?