DO WANT

[OreoGaborio]

http://thekneeslider.com/stellan-ege...lds-a-slugger/

Slugger

[ilikenapalm]

The bike is almost as ugly as the dude who built it.

[PainfullySlow]

Sorry Pete, that is a face only a mother could love...and he is horribly crossed up on it :-p

[Jim]

and i thought it was going to be a picture of me

[Ductard]

I know very little about motorcycle geometry...but is it correct to say that thing has a huge rake angle (waiting for somebody to make a dirty joke outta that).

If so, how would that affect handling? I read on wikipedia that "all else remaining the same, altering rake alters trail"

...and from what I can tell, the front suspension is set up more like a backwards swingarm than forks.... any idea what that would do?

Oh, and a picture of this thing popped up in the corner of the page that was on...


http://thekneeslider.com/buell-super...y-tpj-customs/

What a beautiful 'tard.

[soofle616]

I know very little about motorcycle geometry...but is it correct to say that thing has a huge rake angle (waiting for somebody to make a dirty joke outta that).

If so, how would that affect handling? I read on wikipedia that "all else remaining the same, altering rake alters trail"

...and from what I can tell, the front suspension is set up more like a backwards swingarm than forks.... any idea what that would do?

Oh, and a picture of this thing popped up in the corner of the page that was on...


http://thekneeslider.com/buell-super...y-tpj-customs/

What a beautiful 'tard.

No, it does not have a huge rake angle. What you're seeing as rake is the angle between the clipons and the wheel but with a swingarm front end that angle is irrelevant. All the front end geometry is set up at the wheel hub at the front of the swingarm. Rake and trail are determined by those parts and have nothing to do with the relative position of the hand controls and the wheel.

As for what the swingarm itself does, it separates steering and suspension action so the two can act under ideal conditions at all times. The swingarm and the upper control link keep the front wheel at the same rake and trail regardless of chassis angle. During hard braking or hard acceleration, standard forks compress or extend, altering the angle of the chassis an shortening or lengthening the rake of the front end which affects the steering's response to rider input. Knowing this and knowing how things are affected, good riders use that change to their advantage. With a swingarm, hard braking will compress the front end but steering geometry will not change so steering response will be exactly the same regardless of hard braking, hard acceleration or constant speed cruising.

[Ductard]

No, it does not have a huge rake angle. What you're seeing as rake is the angle between the clipons and the wheel but with a swingarm front end that angle is irrelevant. All the front end geometry is set up at the wheel hub at the front of the swingarm. Rake and trail are determined by those parts and have nothing to do with the relative position of the hand controls and the wheel.

As for what the swingarm itself does, it separates steering and suspension action so the two can act under ideal conditions at all times. The swingarm and the upper control link keep the front wheel at the same rake and trail regardless of chassis angle. During hard braking or hard acceleration, standard forks compress or extend, altering the angle of the chassis an shortening or lengthening the rake of the front end which affects the steering's response to rider input. Knowing this and knowing how things are affected, good riders use that change to their advantage. With a swingarm, hard braking will compress the front end but steering geometry will not change so steering response will be exactly the same regardless of hard braking, hard acceleration or constant speed cruising.

Thanks for the info. That's what I was looking for. I'm trying to understand how the swingarm compressing doesn't have the same effect as the forks compressing. The forks compress linearly (along the angle between the clipons and the hub), but with the swingarm the wheel would still move closer to the frame along an arc....so how does that not "alter the angle of the chassis?" ...and by your explanation of front end geometry, wouldn't the hub and front of the swingarm change relative to each other as the swingarm rotates (thereby changing front end geometry through the stroke)?

Also, I'd imagine that the steering occurs by "tilting" the wheel relative to the horizontal vs. what a fork typically does (some combination of tilting and "turning" the wheel relative to the direction of travel). If so, wouldn't that reduce/eliminate *some* of the problems with mid-corner steering inputs (that it binds the bike up because the wheels are pointing in different planes along the direction of travel)?

On another note....wouldn't you think of this:

....so the two can act under ideal conditions at all times....

more like this:

...so the two can act under constant conditions at all times...

You alluded to this in your post - I'd call myself a *decent* rider, and I definitely notice / use the side effect that trail braking the front makes it easier to tip in...prolly to my advantage too that on exit the forks lengthen and reduce the impact of any *accidental* input I might be putting into the bars...

[OreoGaborio]

I know very little about motorcycle geometry...but is it correct to say that thing has a huge rake angle (waiting for somebody to make a dirty joke outta that).

If so, how would that affect handling? I read on wikipedia that "all else remaining the same, altering rake alters trail"

...and from what I can tell, the front suspension is set up more like a backwards swingarm than forks.... any idea what that would do?

Oh, and a picture of this thing popped up in the corner of the page that was on...


http://thekneeslider.com/buell-super...y-tpj-customs/

What a beautiful 'tard.

Thanks for the info. That's what I was looking for. I'm trying to understand how the swingarm compressing doesn't have the same effect as the forks compressing. The forks compress linearly (along the angle between the clipons and the hub), but with the swingarm the wheel would still move closer to the frame along an arc....so how does that not "alter the angle of the chassis?" ...and by your explanation of front end geometry, wouldn't the hub and front of the swingarm change relative to each other as the swingarm rotates (thereby changing front end geometry through the stroke)?

Also, I'd imagine that the steering occurs by "tilting" the wheel relative to the horizontal vs. what a fork typically does (some combination of tilting and "turning" the wheel relative to the direction of travel). If so, wouldn't that reduce/eliminate *some* of the problems with mid-corner steering inputs (that it binds the bike up because the wheels are pointing in different planes along the direction of travel)?

On another note....wouldn't you think of this:



more like this:




You alluded to this in your post - I'd call myself a *decent* rider, and I definitely notice / use the side effect that trail braking the front makes it easier to tip in...prolly to my advantage too that on exit the forks lengthen and reduce the impact of any *accidental* input I might be putting into the bars...

Ya coulda saved everyone a lotta time & head shaking if you just said....

FRONT SWINGARM???

[TrackRat]

Duc,
Check the video:
http://www.isrbrakes.se/products/ns2/

[Ductard]

Ya coulda saved everyone a lotta time & head shaking if you just said....

Yes, reduced headshake and lap times are advantages of the front swingarm.

Or we could just call it the "front-butt"

But thanks for the feedback, Pete. I'll stop asking technical questions and limit myself to unfunny one-liners.

[soofle616]

Thanks for the info. That's what I was looking for. I'm trying to understand how the swingarm compressing doesn't have the same effect as the forks compressing. The forks compress linearly (along the angle between the clipons and the hub), but with the swingarm the wheel would still move closer to the frame along an arc....so how does that not "alter the angle of the chassis?" ...and by your explanation of front end geometry, wouldn't the hub and front of the swingarm change relative to each other as the swingarm rotates (thereby changing front end geometry through the stroke)?

Also, I'd imagine that the steering occurs by "tilting" the wheel relative to the horizontal vs. what a fork typically does (some combination of tilting and "turning" the wheel relative to the direction of travel). If so, wouldn't that reduce/eliminate *some* of the problems with mid-corner steering inputs (that it binds the bike up because the wheels are pointing in different planes along the direction of travel)?

On another note....wouldn't you think of this:
more like this:
you alluded to this in your post - I'd call myself a *decent* rider, and I definitely notice / use the side effect that trail braking the front makes it easier to tip in...prolly to my advantage too that on exit the forks lengthen and reduce the impact of any *accidental* input I might be putting into the bars...

The swing arm moves along an arc, yes. And as a result so does the wheel. However, the rake is not defined by the position of the swingarm but rather by the steering hub located inside the wheel. The pivot angle of that hub determines rake and the pivot angle is determined by the relative positions of the pivots of the swingarm and link arm. Those two elements independently move in an arc but the lengths are designed such that regardless of where in that arc they are, the pivot angle of the hub remains constant (relative to the ground).

Steering occurs in the same way that it does with forks, it's just that the pivot location has been moved from the headstock on the frame to the hub inside the wheel. The wheel itself moves just as it would with forks.

Ideal and constant can be used interchangeably in that context. Good riders use the changing geometry of forks to their advantage but that does not change the fact that the bike is behaving inconsistently depending on the situation. The fact that some riders can work with that and use it advantageously just means that there exists a bandaid to this inconsistent behavior. Ideally, things should work the same way all the time so that the rider is not required to compensate for the bike doing something different.

[jwm2k3]

and i thought it was going to be a picture of me

They dont call you 'The Slugger' for nuthin...

[OreoGaborio]

I thought it was "Lil slugger"?

[Jim]

it's like a Tic Tac. lemme freshen your breath

[Ductard]

The swing arm moves along an arc, yes. And as a result so does the wheel. However, the rake is not defined by the position of the swingarm but rather by the steering hub located inside the wheel. The pivot angle of that hub determines rake and the pivot angle is determined by the relative positions of the pivots of the swingarm and link arm. Those two elements independently move in an arc but the lengths are designed such that regardless of where in that arc they are, the pivot angle of the hub remains constant (relative to the ground).

Steering occurs in the same way that it does with forks, it's just that the pivot location has been moved from the headstock on the frame to the hub inside the wheel. The wheel itself moves just as it would with forks.

Ideal and constant can be used interchangeably in that context. Good riders use the changing geometry of forks to their advantage but that does not change the fact that the bike is behaving inconsistently depending on the situation. The fact that some riders can work with that and use it advantageously just means that there exists a bandaid to this inconsistent behavior. Ideally, things should work the same way all the time so that the rider is not required to compensate for the bike doing something different.

Oh...it all makes sense now. I'll check out the video that Trackrat posted, but I think I think I get it now.

Guess I've been watching too many Batman movies.

[PhilB]

That's extremely cool. Not exactly an aesthetic triumph, but I love what he's done with it.

PhilB