Setting Suspension Sag

[julian]

Fitted Ohlins and am setting sag. Do I need to set preload to ZERO to work out initial figures?

Measuring values with preloads pre-set from the box (R=16mm and F= 18mm) yields the following:

Static sag= F1 - F2 = 7mm (should be 15-30mm)
Ride height = F1 - F3 = 19mm (should be 35-50mm)

Static sag = R1 - R2 = 20mm (should be 10-20mm)
Ride height = R1 - R3 = 42mm (should be 25-40mm)

So it looks like rear (oversize 160 spring) is at top end of recommended limits and front (std) is right out of limits (or is this anomoly of telelever or me being 100kg?).

Er, what next ......?

[Archie]

Looks like you should take some preload off the front and add some to the back.

Or just sit on the petrol tank.

Alan

[Gromit]

Julian - I managed to get the sag on mine set pretty much bang on the mid point of the Ohlins recommended settings, so I'd expect you should be able to even with the heavier spring. Takes a bit of fiddling around (which is a nause it has to be said) but it'll get there in the end.

[julian]

so when you take the reference settings do you do it with or without preload or doesn't it matter?

[Gromit]

Julian - when I did the sag on my rear Ohlins, I wound the preoload adjuster until it is 'loose' and has no effect. At that point, I took the sag reading from a spot on the bevel box directly above where the wheel 'spindle' would be. That was a base line from which I just added preload until the sag was in the middle of the Ohlins recommended settings. The no-preload setting will obviously give you the largest sag, but what I did is get the bike on the centre/workshop stand so the rear wheel is off the floor. Measure the distance, then push the bike off the stand and measure again (static sag).

Doing the front was a bit more tricky as you can't adjust the shock in situ. I just wound up the preload adjusting rings 3mm 'harder' and did the old cable tie thing on the fork leg to check sag. Seemed to work out about right, or near as dammit.

Hope that info helps - even if it is from someone who works by trial and (lots of) error

[andrew s]

Julian,

It doesn't really matter as it is the difference between unloaded sag and static sag which should be about 10mm (but if you wind all the preload off then you know you have it right). It is good to do the loaded sag as well that way you get it right for your weight on the bike, do you know how to do this.

Loaded rear sag should be between 25 to 35mm. I did not mess with the front preload. Left the Wilbers preload which was set to my weight at the factory.

Hope this helps, sometimes it is better to explain in person.

Andrew

[julian]

Thanks chaps.

Turns out that preload was set to zero on the rear, so adding 16mm (as recommended) positions it at 26mm of the 25-40mm range vice previous 42mm. Because the stiffer spring is fitted then less preload is required, say 10mm which = 32mm bang in the centre of the range.

Haven't got my head round the front yet.