Setting sag. Measure off shock or rear axle?

nexusfish

nexusfish

El Mariachi
G'day guys, have been playing around with a new bike that has an extremely progressive leverage ratio (YT Capra). Just got to thinking that I never measures sag on the shock on my dirt bike, but we all do it on mtbs. I've found 3% sag difference on the Capra results in a lot of actual sag difference as the leverage ratio starts at 3.6 and ends up at 2.

Does anyone measure sag off the rear axle and does the 25/30% rule stand in that case?
 
nexusfish said:
Just got to thinking that I never measures sag on the shock on my dirt bike,
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Well you probably should.. Static / free sag is the first thing you should do... And will also determine if you need heavier / lighter springs.
Next you'll tell me you never check your air pressures...:eek:
What would you use as a point of reference above the axle? On the moto it's fairly easy you measure to the mud guard.
 
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Axle is preferable imo. 30% wheel travel is a good starting point. Tape a long pole/something that doesn't flex onto the seat so that it reaches over the rear axle. Some bikes are such a pain in the ass to measure the shock correctly at the shock (V3 Banshee with a coil springs to mind).

Also a lot of people don't take into account the linkages progression and don't realise that 30% at the shock can actually be much more wheel travel putting them way too deep into the stroke. I watched a mtbtelly video (I think it was the Rune test) and he was saying that Banshee had gotten the sag figures incorrect but basically he didn't understand/comprehend the concept of the linkages progression giving what appeared to be too little sag at the shock (eg Titan is 17.8mm sag for 32% sag recommended. 32% of shock stroke is 20.8mm).
 
Surely shock is the most accurate way when your wheel moves on an arc though? Just rely on the manufacturer linkage calculated values and find a good starting point in mm on the shock.

But keen to see people's methods for measuring from the wheel.
 
kten said:
Axle is preferable imo. 30% wheel travel is a good starting point. Tape a long pole/something that doesn't flex onto the seat so that it reaches over the rear axle. Some bikes are such a pain in the ass to measure the shock correctly at the shock (V3 Banshee with a coil springs to mind).

Also a lot of people don't take into account the linkages progression and don't realise that 30% at the shock can actually be much more wheel travel putting them way too deep into the stroke. I watched a mtbtelly video (I think it was the Rune test) and he was saying that Banshee had gotten the sag figures incorrect but basically he didn't understand/comprehend the concept of the linkages progression giving what appeared to be too little sag at the shock (eg Titan is 17.8mm sag for 32% sag recommended. 32% of shock stroke is 20.8mm).
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Was that the Beta Test (previously bible of bikes) video?? They hated the Prime v3 as they said it was too sloppy, probably Because of incorrect sag setting.
 
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