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 Measuring suspension sag one handed

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voulga77
paulbrice
lcjohnny
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lcjohnny
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PostSubject: Measuring suspension sag one handed   Measuring suspension sag one handed Icon_minitime1Thu Mar 31, 2022 1:15 am

Only so many times I could ask my wife and daughter to come out into a cold garage and look at rulers and tape measures......

So i have devised a hack to allow me to check sag and repeat the readings without hearing the words "what! again!!"

I used
Like a Star @ heaven 120cm (4') of light coloured ribbon
Like a Star @ heaven 2 x light weights e.g 22mm nut or 8mm ring spanner
Like a Star @ heaven 5cm (2") of masking tape
Like a Star @ heaven 3 different colour felt tip pens
Like a Star @ heaven a supporting wall close enough you can balance sitting on the bike

i put a 2.5cm piece of masking tape along the spindle of the front and rear indicators (on the side away from the wall) and marked a clear line along the top.  
I then cut the ribbon in half and knotted a small weight onto each 60cm (2') length.  At the front i knotted the other end of the ribbon to the brake caliper so that the ribbon hung over my mark on the indicator with the weight keeping tension.  At the rear i knotted the other end to the brake pipe into the caliper and then over the indicator same as the front.

Then
1) jack it up and mark where the ribbon crosses the line on each indicator front and back with one colour = fully extended
2a) off the jacks - support the bike vertical on its wheels, push the front down and let it rise then (with your free hand) mark where the ribbon crosses the line on the front indicator with 2nd colour = bike only maximum sag, then lift the bike and let it fall and mark the ribbon again = bike only minmum sag,
2b) repeat at the rear.
3a) Sit on the bike feet on the rests balancing against the wall stand suddenly (to push the bike down) and let it rise and (with your free hand) mark where the ribbon crosses the line on the front indicator with 3rd colour = bike & rider sag maximum, then put your feet on the ground, lift them back on the rests. let the bike settle and mark the ribbon again = bike & rider minmum sag,
3b) Sit on the bike backwards and repeat the above marking the rear ribbon.

take the ribbons off and measure the differences from fully extended to the average bike only sag and the average bike & rider sag
Then use adjustments, springs and spacers to correct your GRiSO's sag to the figures given by your favorite guru

the difference between minimum and maximum at each pair of readings shows stiction in that suspension system - if the shock bearings are good it should be minimal at the rear but i can't get mine less than 12mm at the front Sad.

Hope that helps someone


Last edited by lcjohnny on Fri Apr 01, 2022 8:14 am; edited 3 times in total (Reason for editing : spelling mistakes 2/10)

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paulbrice
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PostSubject: Re: Measuring suspension sag one handed   Measuring suspension sag one handed Icon_minitime1Thu Mar 31, 2022 5:30 am

Thanks Jon, good info (I've struggled with 1m metal rule and dubious reference points to measure from +leaning against the wall)......

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voulga77
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PostSubject: Re: Measuring suspension sag one handed   Measuring suspension sag one handed Icon_minitime1Sat Apr 02, 2022 7:54 pm

For "solo" sag measurments I use IKEA paper measuring tape...

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Bill Hagan
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PostSubject: Re: Measuring suspension sag one handed   Measuring suspension sag one handed Icon_minitime1Sat Apr 02, 2022 10:50 pm

lcjohnny wrote:
Only so many times I could ask my wife and daughter to come out into a cold garage and look at rulers and tape measures......


****

So ... how many times would that be?

Asking, of course, for a friend.  Wink

OTOH, my "friend" has a heated garage, so presuming the number would be higher. cheers

Bill

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lcjohnny
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PostSubject: Re: Measuring suspension sag one handed   Measuring suspension sag one handed Icon_minitime1Sun Apr 03, 2022 12:04 am

voulga77 wrote:
For "solo" sag measurments I use IKEA paper measuring tape...

I like that idea

but not the idea of queueing in IKEA affraid
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Buellbloke
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PostSubject: Re: Measuring suspension sag one handed   Measuring suspension sag one handed Icon_minitime1Sun Apr 03, 2022 12:29 am

I've used the wall technique on the front, though did eventually get my slipped disc girlfriend to come to my council garage and do all the measurement in one hit. Mates couldn't be arsed something to remember next time they need help.
Luv to see a video especially sitting in the bike backwards Shocked shows real determination that does Laughing

Cable ties around front fork leg tube and rear shock piston woulda sufficed though evidently rear shock is a f*cker to fit a cable tie to.

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guzziownr
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PostSubject: Re: Measuring suspension sag one handed   Measuring suspension sag one handed Icon_minitime1Sun Apr 03, 2022 12:53 am

I used a cell phone sitting on a stool for video, a meter stick for reference points, a pencil as a pointer.

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rick pope
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PostSubject: Re: Measuring suspension sag one handed   Measuring suspension sag one handed Icon_minitime1Sun Apr 03, 2022 4:20 am

Bill Hagan wrote:


So ... how many times would that be?

Asking, of course, for a friend.  Wink

OTOH, my "friend" has a heated garage, so presuming the number would be higher.   cheers

Bill

C'mon, Bill. we know your best friend is your wife. We're both pretty lucky......

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