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Ride Height - datum points


BrianG

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Now I've gone and done it! I've gone and messed with two (2) variables at once just because it was easier than taking the thing apart twice to do them one at a time. I altered the shock preload and the shock length (Penske) at the same time, and got a sag change that was unexpected.

 

All that aside...

 

I want to know what the standard ride heights are, for each end, of the short-frame (2000) V-11 Sport, to define OEM frame attitude?

 

That is:

What front-end land mark is measured at what distance from the ground?

What hind-end land mark is measured at what distance from the ground?

 

I know what altering each does, I just need to know how to get back to the OEM starting point..............

 

HELP!!

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I can't help with the rear but maybe I can with the fork. You should see 18 - 24mm unladen sag, maybe a bit more if you have soft fork springs. I think your fork caps should be flush with the top clamp, but I'm not positive on that because I have a later model year.

 

Measuring unladen sag: Put a zip tie on your fork leg, stand the bike up straight and push the tie up against the fork seal. Next, raise the front of the bike so the fork is fully extended and measure between the zip tie and the fork seal.

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Guest ratchethack

Tom, Brian knows how to measure laden and unladen sags. This isn't wot he's asking about.

 

Not sure why factory issue ride height might be so important, Brian. I've raised my rear ride height to get better ground clearance and sharpen up the rake & trail without raising the fork in the triples, but who cares wot the starting point was on the ride height (as you know, it's dependent on spring rates, sags, and load anyway) if you find a height that you like better? Do you know how much you lengthened the shock? If not, take before & after eye-to-eye measurements, multiply the difference by 2 (the swingarm gives very close to a 1:2 ratio) and you've got the rear ride height change. I added 5 mm shock length on my custom order Wilbers, got +10 mm ride height at the rear. Made a surprisingly large difference to ground clearance, and stopped me dragging the side stand for quite awhile. :race:

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Tom, Brian knows how to measure laden and unladen sags. This isn't wot he's asking about.

 

Not sure why factory issue ride height might be so important, Brian. ...

 

You're sure you had the right answer to the question?

 

Hubert

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Tom, Brian knows how to measure laden and unladen sags. This isn't wot he's asking about.

 

Not sure why factory issue ride height might be so important, Brian.

 

Just call it morbid curiosity. I like to know what changes come from what adjustments, and I'd just like to know what OEM the starting point was.

 

 

 

(the swingarm gives very close to a 1:2 ratio) and you've got the rear ride height change. I added 5 mm shock length on my custom order Wilbers, got +10 mm ride height at the rear. Made a surprisingly large difference to ground clearance, and stopped me dragging the side stand for quite awhile. :race:

Good to know.....

 

 

 

I backed off the shock preload only 2 flats (about 1/4 turn) and (at the same time) lengthened the shock about 5mm, and I lost 10mm of ride height, net. (the 15 mm initial unladen sag increased to 19mm) This doesn't make any sense to me as I expected a net 0 ride height change....

 

The Penske allows for only 10mm length adjustment and I'm considering adding the remaining 5mm just to get back to where I started....... but I'd just like to know where that puts me from OEM rear ride height.

 

I might as well get the front datum as well since Traxxion Dynamics worked my forks and replaced the springs/spacers. This is less critical since I have 20mm of unladen sag, which puts me right for the unladen ride height at that end.

 

So Ratch, ol' buddy, ol' pal..... do me a favor and go measure the distance from the TOP of the rear axle NUT to something......... other than your garage roof! ;)

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Guest ratchethack
Just call it morbid curiosity. I like to know what changes come from what adjustments, and I'd just like to know what OEM the starting point was.

. . .

So Ratch, ol' buddy, ol' pal..... do me a favor and go measure the distance from the TOP of the rear axle NUT to something......... other than your garage roof! ;)

Happy to oblige, Brian. But since I've got a custom shock, stiffer than stock 95 N/mm spring, preload set to my own target sags, and the shock is 5 mm longer than OEM to start with. . .

 

Wot value this has in determining the OEM ride height starting point is beyond me. . . :huh2:

 

FWIW, here's my benchmark frame o' reference:

 

I get an unladen, upright & off the side stand, 16 1/4" center-to-center between spindle nut and the rear muffler hanger/frame mount bolt.

 

How's that compare with yours?

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Happy to oblige, Brian. But since I've got a custom shock, stiffer than stock 95 Nm spring, preload set to my own target sags, and the shock is 5 mm longer than OEM to start with. . .

 

Wot value this has in determining the OEM ride height starting point is beyond me. . . :huh2:

 

FWIW, here's my benchmark frame o' reference:

 

I get an unladen, upright & off the side stand, 16 1/4" center-to-center between spindle nut and the rear muffler hanger/frame mount bolt.

 

How's that compare with yours?

 

 

Got home late so I can't post my number right now, but my Penske is length adjustable, now set 5mm longer than stock with a 500 lb spring. (which gives me 15mm of unladen sag).

 

The point is, with sag where I want it, I get to dial in ride height at the rear, too...... just like you do. With your same-year bike my guess is that we should be in the same ball-park for attitude. I just wanted a friendly reference point.

 

Thanks for the effort.

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I backed off the shock preload only 2 flats (about 1/4 turn) and (at the same time) lengthened the shock about 5mm, and I lost 10mm of ride height, net. (the 15 mm initial unladen sag increased to 19mm) This doesn't make any sense to me as I expected a net 0 ride height change....

How strange.

From my understanding, without replacing parts, the Penske can be adjusted in maximum eye to eye length two different ways.

1. The method in the manual is to simply unscrew the eye. Mine does not have that option. The result of lengthening it at the eye five millimeters should not be what you observed. It should have raised the ride height.

2. The method I must use for my Penske is to unscrew the shaft from the lower perch. Lengthening it here has the side effect of reducing preload, so if you left the preload adjuster alone and just lengthened the shock, the preload would drop causing the bike to sag much further. Your number for drop in ride height seems to match what we should expect for that scenario, but I would have expected a much greater increase in sag.

 

FWIW, from a very vague memory, my OEM bike had something like 25mm unladen only, 50mm laden front sag and maybe about 15-20mm unladen 50-60mm laden rear sag. Before replacing the rear spring I set the rear up to about 5mm unladen and 35-40mm laden I wish I had taken notes...but that is all happily in the past.

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Guest frankdugo

from the workshop manuel--which is downloadable from this site---pauls links in classifides.front axel nut to rear axel nut 1471mm.ground to top of seat{where it touches tank} 800mm. ground to top of instrement cluster 1090mm

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Dave, is your Penske installed with the remote damper fitting forward or to the rear?

 

Mine is forward so that access to the rebound damper control is easy (at the rear).

 

This leaves the adjustable-length eye easy to access as well, and is how I lengthened the shock.

 

You are right..... something is amiss... and I suspect that it is my initial measurement....

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