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Discussion Starter #41 (Edited)
The pressure on the axle on assembly is enough to make a difference. Enough so to cause brake drag by not allowing the axle to self align on the forks. I've tested it and found it to make a marked difference.

If your forks are 5mm off you have a much larger issue. In general they are usually .5-1mm or so. Not enough to make any noticible difference in suspension action but enough to affect alignment easily.

You talk about deflection at bottom out. The larger issue there is that your setup is allowing either fork to bottom at all. That is the larger issue. Not that one is bottoming .5mm before the other.

And in the post you quoted I was talking about geometry. The length of the fork above the lower triple is moot. You can add 8" to the top of the fork and it does not affect geometry. So taking a cap measurement means absolutely nothing in geometry settings. What you want to know is how much fork is sticking out the bottom. The part that actually effects rake and trail. To have consistent data the lower form length is what you need to be notating.
 

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I agree. Your free length of shorter leg is your "zero" for geometry. But how many people do you know that measure their geometry with the wheel removed? It doesn't matter because the longer leg will be drawn up to match when the axle is torqued in. And I also agree if you're bottoming out, you have bigger issues.

Even at a 1mm difference, the compensation (2005 stock 600) is .850kg. That's about one pound difference. When you're fully leaned over, the pressure on your tire is biased to one side or another to the tune of a couple hundred pounds. 1lb of differential load isn't going to flex the front end enough to cause brake drag.

Matching free length is just a wasted effort.
 

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Discussion Starter #43 (Edited)
I'm talking brake drag in general. Over all. Not when leaned over.

If you do as I illustrated when you come off track your wheel will still spin free.


If you don't your brakes will likely be dragging. Bad. This hurts top speed. It hurts brake performance due to heat builup. It can cause fade. And it can cause uneven pad deposition which can cause pulsing in the brakes as well as many other issues in fork action as the legs are not parallel

It is not wasted effort. I've
Tested it numerous times. I've also had high end race tuners agree with it. Fork alignment being parallel is parmount to proper fork action and brake performance. If you don't also align them vertically it is much harder to be sure they are aligned parallel when installing the wheel. The free fork WILL drag on installation. It WONT self align on the axle so it WILL be pinched inwards on assembly.

You feel free to ignore it if you wish. As I've said before. You seem to like to ignore common established practices of race mechanics far more knowledgeable than you or I.

I didn't make this up myself. It was formed through research and picking brains of guys who build AMA, moto2, motogp, and various other race machines.and guys who have been in the chassis business for a damn long time
 

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Discussion Starter #44
Also when leaned fully over it should be noted that suspension action itself actually plays a far lesser roll than chassis and tire carcass flex.
 

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Yes. And because of that I don't just pump the pistons out all at once. What I do is rotate the tire as I lightly tap the lever to bring the pistons back out slowly and more evenly.

But the Teflon frees them up enough that they more easily are retracted too
Nice to know, will keep that in mind before I gorilla pump pistons out again... :shifty
Thanks for your advices, once again! :cheers
 

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I'm talking brake drag in general. Over all. Not when leaned over.

If you do as I illustrated when you come off track your wheel will still spin free.


If you don't your brakes will likely be dragging. Bad. This hurts top speed. It hurts brake performance due to heat builup. It can cause fade. And it can cause uneven pad deposition which can cause pulsing in the brakes as well as many other issues in fork action as the legs are not parallel

It is not wasted effort. I've
Tested it numerous times. I've also had high end race tuners agree with it. Fork alignment being parallel is parmount to proper fork action and brake performance. If you don't also align them vertically it is much harder to be sure they are aligned parallel when installing the wheel. The free fork WILL drag on installation. It WONT self align on the axle so it WILL be pinched inwards on assembly.

You feel free to ignore it if you wish. As I've said before. You seem to like to ignore common established practices of race mechanics far more knowledgeable than you or I.

I didn't make this up myself. It was formed through research and picking brains of guys who build AMA, moto2, motogp, and various other race machines.and guys who have been in the chassis business for a damn long time
Once again, you assume I don't know what I'm talking about. I don't do anything you said and my front wheel spins free all the time. Your way is not the only right way. Forks out of alignment will cause drag on the axle during installation and cause the leg to be pulled in. That's why you bounce it, or otherwise release that tension. An ideal installation position does not equal an ideal functional result. You use simple green to clean, I use brake fluid. You use teflon on the pistons, I use brake piston grease. You spin the wheel and gently tap the brakes to slowly bring the pistons out, I use spacers to control the position. I assure you, 1-2 pounds of difference in the legs throughout the stroke is a lot better than a few hundred pounds at one point.

Also when leaned fully over it should be noted that suspension action itself actually plays a far lesser roll than chassis and tire carcass flex.
On the purely vertical axis maybe, but I assure you the total load is going straight up through your suspension causing the bike to squat because it's having to deal with two acceleration forces instead of one. At lean, the difference is where that force is introduced to the system. Straight up and down, it's centered. At lean, it's biased to that side.
 

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I bet you'd argue that Ohins is probably one of the best, if not the best motorcycle suspension company in the world. Right? Probably know more about suspension than the combined knowledge of everyone on this forum. Right?

http://ohlins.com/Products/MountingInstructions/MI_FGRT809.pdf

Their instructions have you level the top of the fork, not align the axle. Page 2, steps 3, 9, and 10 specifically. Go tell them they're wrong.
 

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Discussion Starter #48
This how to is for people who have brake drag and alignment issues. If you have neither then it clearly doesn't pertain to you :idea.

But to come on here and tell me it doesn't matter when it has been tested and prove that it CAN is equal parts ignorant and arrogant.

You say this way isn't the only way. Isn't you arguing it can't possibly be correct a bit hypocritical then?

Listen dude, you're clearly intelligent. But you tend to so over think thinks as to rule out the simple shit. All the way to the point you will argue in circles with time proven techniques because some theory in your brain thinks it may not work

It does. It's proven. :thumbup.

Occam's razor. ;)

To those reading, IF you find you have brake drag, this is how to will likely help alleviate one of the several issues that cause it. It in conjunction with my other two how too threads will almost certainly cure it.

Don'take it more complicated than it needs to be ;)
 

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Discussion Starter #49
I bet you'd argue that Ohins is probably one of the best, if not the best motorcycle suspension company in the world. Right? Probably know more about suspension than the combined knowledge of everyone on this forum. Right?

http://ohlins.com/Products/MountingInstructions/MI_FGRT809.pdf

Their instructions have you level the top of the fork, not align the axle. Page 2, steps 3, 9, and 10 specifically. Go tell them they're wrong.
I don't have time nor cause to read the manual. I have a long drive. But...

Both you and the ohlins installation are assuming that the forks are assembled "properly" in that they are the same length and built to the exacting standards

I make no such assumptions. This how to is far more general in nature and making those assumptions in a how to is irresponsible IMO. The how to is written as to get rid of as many variables as possible and make it as close to fool proof as possible for anyone with any forks
 

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Discussion Starter #50
Also to re-clear up muddy waters on otherwise simple processes (it almost seems it has become your mission to muddy up simple how to's with mostly irrelevant and obscure hypotheticals)....


If I am doing a caliper over haul I clean with brake fluid and assemble with proper lube on seals.

My use of simple green and Teflon spray is for intermediate cleaning in the pits. Not overhaul. Using brake fluid to clean between sessions/races poses the issue of then having to clean the brake fluid off to avoid pad contamination once heat is built and any leftover brake fluid may migrate.

Watch in a GP paddock. Between races calipers are cleaned with degreaser and water ;)
 

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One of the potential causes of brake drag can be attributed fork legs not being parallel during wheel installation. If the legs aren't parallel, as the fork compresses force parallel to the axle is created. This force causes the position of the axle to shift within the fork. Since the brakes are attached to the fork, the caliper shifts relative to the rotor causing drag.


Joe's process reduces the mechanical conditions that cause fork misalignment. Proper installation of the front wheel ensures proper alignment. Both statements are 100% true.
 

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I have been struggling with a lethargic front tire. wanted to say thanks for all the input on how to align the front end. I found Moto Joe's suggestions to be spot on. I was fighting a front end chatter in turn 3 but when I set the right fork leg and then aligned the axle to the left leg my chatter was drastically diminished. my wheel drag was less but still present after may realignments. I rebuilt the caliper that was the culprit with no effect. playing with the sequence of events I got the wheel to turn fairly well. it was not until after I crashed I got it to turn freely. I had the bike measured before I converted it to track only so I know the wheel drag was not due to anything being bent. but now the wheel turns much freer. anyway thanks to you all.
 

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Discussion Starter #53
Good deal man. Glad I could help

The combination of alignment, proper caliper maintenance and cleaning and a good bleed job as per my write up can work wonders for front end feel.
 

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Thanks! I just did a track day at Chuckwalla and it was hot! The last session gave me a lot of lever vibrations while trail braking.
 
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