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1 Person Sag Setting Using Stands?


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I've searched and not seen an answer to this yet so...

 

I need to resetup my ZX6. Don't have anyone around to help me. I do have stands though. Rear stand and both a stem stand and a fork stand. Can I use these to do the sage settings?

 

I would assume the stem stand along with the rear stand will let me measure the fork extension. Then the fork stand will let me get the static sag and sag with me on the bike using a zip tie to measure the travel.

 

Not sure how to do the rear though. i need a way to raise the bike until the rear tire starts to lift, get that measurement and the use the rear stand & front stand to measure the static sag and the sag with me on the bike.

 

Am I close?

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You can use the front stand to measure the full extension of the fork. A centre stand would be great to measure full rear extension, but that's sadly missing from most bikes these days. But you need to get the rear pof the bike off the ground without touching the wheel or swingarm. You'll get close enough if you lift the rear as high as you can while a helper measure the distance between the rear axle and a point on the frame.

 

To measure sag, first put the bike down on its wheels and pump both ends and let it settle on its own. This is sag with bike alone. Now climb on the seat and repeat bumping. Front sag can as mentioned be measured with a tie strip, but you need a helper to measure rear sag. I usually sit on the bike and just use a finger against a wall to balance me and the bike during this as you will never get a perfect measurement no matter what you do due to sag. You can lift the bike on its suspension and let it settle slowly and measure sag, then compress the suspension and let return slowly and measure sag again. The actual sag should in theory be just the middle between the two values you now get. But fine tuning needs to be done at the track, trying to add or remove preload to see if the bike gets better or worse. Setting sag is just to get it in the ballpark.

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Just did the front suspension today - zoinks!

 

The bike was previously setup perfectly for me. Or at least I was really comfortable riding it and had the confidence to ride it at my ability level. Now...not even close. Under breaking the front end feels like it is all over the place and then once I lean the bike over it felt like the back end was trying to slide out. I basically backed all the way off b/c I wasnt comfortable.

 

Difference - I've put on 10lbs - joys of being a hot shot software developer.

 

Anyway - I took the measurements. Unfortunately I didnt have a metric tape so I had to use NASCAR units.

 

Forks fully extended are 4.5" from top of the fork bottoms to the bottom of the dust ring.

Me dressed in geans, t-shirt and running shoes + all my gear (helmet, back & chest protector, gloves and suit) = 2.75" first time

After maxing out the preload ajuster and then going back 1 turn = 3.25"

 

So the best I could get was 1.25" of sag which isn't too far from where you want to be (25mm = .98 inches)

 

I have not done the rear yet, I'll probably do it tomorrow night after work.

 

I now have a choice -

1. get bigger springs front & rear

2. bite the bullet and do what my trainer wants and lose the 10lbs by not stuffing so much food down my pie hole.

 

The two choices are not necassarily mutually exclusive. In fact I probably need to drop my bike off at the shop to have the suspension looked over b/c it seems odd that 10lbs would make that big a difference. Perhaps some fork oil has leaked out or there is something broken.

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Stock springing is typically good for up to about 15 stone/220lb/100kg so if you're over that then think about stiffer springs. Most sports bikes have pretty much the same suspension stroke so although you're really aiming for a certain % of travel, a certain number of mm wil also do. Not easy to set up sag on your own but if the spring stiffnesses are right then setting without the rider will end up in the right place. So for the front aim for about 15mm sag (bike only) which should give around 25-20mm with you on it. Same for the rear, 6-8mm bike only. Worth also checking the sag with you on it when you have a helper, and also worth noting the bike-only sag figures so you can do it on your own next time e.g. after forks have been rebuilt and all your settings have gone.

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  • 1 month later...

Not sure how to do the rear though. i need a way to raise the bike until the rear tire starts to lift, get that measurement and the use the rear stand & front stand to measure the static sag and the sag with me on the bike.

 

Am I close?

 

You're probably done, but FWIW, if your bike still has a kickstand, you can put the kickstand down and very carefully lean the bike over toward the kickstand until the rear wheel comes off the ground. Then measure from your pre-selected points. I've done this method by myself and its pretty quick and easy.

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  • 2 weeks later...

Well - turns out that the left fork had developed a small leak that I somehow missed! So all of this worry was...not entirely a waste: I did learn some new skills.

 

Anyway - bike has been in the shop getting all the suspension stuff freshened up. We are also going to raise the bike a bike to see if that helps me. The Duc is set up much taller than the zx6 and I really like how it handles. Hopefully all of this will get me back to my happy place so I can get on with the getting the knee down.

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