Evo 1100 rear shock - possible upgrade? - Page 5

chris.p · 14-06-2021, 02:17 PM

I think an easier way would be to say, "Static Sag" i.e. the sag the bike has with no rider on board, i.e. it's own weight. and "Rider Sag" i.e. the sag when a rider is sat on the bike.

I personally always set the "Static Sag" first, as this gave you the bikes ideal measurement's then I would do the "Rider Sag" and use the Ohlins sheet to work out whether I need softer springs or harder springs.

Remember that "Preload" only alters the ride height of the bike, not how far the suspension will compress.

"Compression" only slows down or speeds up the springs compression.

"Rebound" is the Opposite of Compression, it slows down or speeds up the extension (rise) of the suspension.

By sticking to those simple rules you can not go far wrong.

Once you go past those workings you enter the realm of a wizard's black art of suspension, oil thickness (Weight), Pistons, Oil shims, bypass shims, Air gaps etc the list is endless and you will fry your brain.

bigredduke · 14-06-2021, 02:34 PM

Can of worms duly opened!

Right, with the help of Mrs BRD & daughter I have the following measurements:

R1 = 571mm, R2 = 560mm, so static sag is 11mm
R3 = 530 so sag with rider onboard is 41mm which is 1mm outside of the Ohlins parameters so I conclude that the spring is just over the limit for my bulk. Do you agree?

If I reduce the preload slightly, will the R1 figure increase slightly because the rear wheel will drop or have I got that completely wrong?

slob · 14-06-2021, 02:57 PM

no adjustment should change R1, reducing preload should increase both Static Sag & Ride Height (Rider Sag)

bigredduke · 14-06-2021, 03:05 PM

Quote:

Originally Posted by slob

no adjustment should change R1, reducing preload should increase both Static Sag & Ride Height (Rider Sag)

Thanks Rob

I think I've got it the wrong way round! I backed off the preload & rider sag increased by 9 mm to 50mm, so if I increase the preload it should reduce (possibly)!

Luddite · 14-06-2021, 03:15 PM

Quote:

Originally Posted by bigredduke

Thanks Rob

I think I've got it the wrong way round! I backed off the preload & rider sag increased by 9 mm to 50mm, so if I increase the preload it should reduce (possibly)!

Yes! If you increase the preload so that your rider sag is below 40mm, then your static sag will probably be just below the 10mm recommendation. But, as long as you have at least 5mm static sag, it'll still be safe to ride on the road.

bigredduke · 14-06-2021, 04:38 PM

Update!
I increased the preload by 4mm from standard. I don't know if that is considered a lot or a little?

I took it out and whereas before, I felt as though I was rather 'perched' over the front end & constantly sliding forward into the tank, now it feels a bit more 'relaxed'. Steering feels a little slower but the rear feels settled and comfortable. Interestingly, the front suspension feels a little harder and less forgiving now than when the OEM shock was fitted, I don't know why that should be. I need to check the sag on the front next to see if it is within recommended parameters.

I also need to check the rear static sag again to check that it hasn't gone AWOL as a result of the changes!

Luddite · 14-06-2021, 03:06 PM

Quote:

Originally Posted by bigredduke

Can of worms duly opened!

Right, with the help of Mrs BRD & daughter I have the following measurements:

R1 = 571mm, R2 = 560mm, so static sag is 11mm
R3 = 530 so sag with rider onboard is 41mm which is 1mm outside of the Ohlins parameters so I conclude that the spring is just over the limit for my bulk. Do you agree?

If I reduce the preload slightly, will the R1 figure increase slightly because the rear wheel will drop or have I got that completely wrong?

Adjusting the preload won't affect the length of the shock at full extension - whether you have zero preload or it's wound fully in, the R1 figure won't change.

That spring sounds just on the soft side of ideal, but it'd be perfectly safe to use on the road. Get it set up at JWR and see how it feels on the road. If you're not constantly bottoming out and it doesn't feel 'wallowy' you shouldn't need a stiffer spring. A lot depends on your riding of course - I favour compliance over bumps as I'm not a particularly aggressive rider but if you're flinging it into bends and powering out on plenty of throttle, you're probably going to want the next stiffness up on the spring (120N/mm).

bigredduke · 14-06-2021, 04:43 PM

Quote:

Originally Posted by Luddite

I'm not a particularly aggressive rider but if you're flinging it into bends and powering out on plenty of throttle, you're probably going to want the next stiffness up on the spring (120N/mm).

Yes, that's me, power-sliding out of bends with my knee and elbow down

bigredduke · 23-06-2021, 06:52 PM

Rode the bike to James Wood @ JWR suspension yesterday in Louth, Lincolnshire.

Strangely, before I fitted the new Ohlins rear shock, the front felt less harsh on bumpy roads (with the standard Sachs shock).

Afterwards, the front felt awful. On bumpy roads, it felt like riding an unsprung bicycle over corrugated iron sheets. The rear felt good however.

So James backed the front compression damping off by 2 clicks, then 4, which improved the ride considerably. The rear is very supple and comfortable over uneven surfaces (with a couple of turns off the preload). I have taken another 2 clicks off the compression damping at the front but have yet to ride it. I'll see how it feels over the Weekender. I prefer the suspension to be accommodating rather than harsh but obviously, I don't want it soft and wallowy. Looks like the standard settings on the rear shock are not far off for me.

It feels less 'perched' over the front than it did & more like I am sitting 'in' the bike rather than 'on' it.
Work in progress!

14-06-2021, 02:17 PM	#1
chris.p Gold Member Join Date: Mar 2004 Location: lincoln Bike: No Bike Yet! Posts: 876	I think an easier way would be to say, "Static Sag" i.e. the sag the bike has with no rider on board, i.e. it's own weight. and "Rider Sag" i.e. the sag when a rider is sat on the bike. I personally always set the "Static Sag" first, as this gave you the bikes ideal measurement's then I would do the "Rider Sag" and use the Ohlins sheet to work out whether I need softer springs or harder springs. Remember that "Preload" only alters the ride height of the bike, not how far the suspension will compress. "Compression" only slows down or speeds up the springs compression. "Rebound" is the Opposite of Compression, it slows down or speeds up the extension (rise) of the suspension. By sticking to those simple rules you can not go far wrong. Once you go past those workings you enter the realm of a wizard's black art of suspension, oil thickness (Weight), Pistons, Oil shims, bypass shims, Air gaps etc the list is endless and you will fry your brain.

14-06-2021, 02:34 PM	#2
bigredduke Nothing to see here Join Date: May 2005 Location: brough Bike: M1100evo Posts: 1,546	Can of worms duly opened! Right, with the help of Mrs BRD & daughter I have the following measurements: R1 = 571mm, R2 = 560mm, so static sag is 11mm R3 = 530 so sag with rider onboard is 41mm which is 1mm outside of the Ohlins parameters so I conclude that the spring is just over the limit for my bulk. Do you agree? If I reduce the preload slightly, will the R1 figure increase slightly because the rear wheel will drop or have I got that completely wrong?

14-06-2021, 02:57 PM	#3
slob . Join Date: Jul 2003 Location: East London Bike: Multiple Monsters Posts: 9,713	no adjustment should change R1, reducing preload should increase both Static Sag & Ride Height (Rider Sag)

14-06-2021, 04:38 PM	#6
bigredduke Nothing to see here Join Date: May 2005 Location: brough Bike: M1100evo Posts: 1,546	Update! I increased the preload by 4mm from standard. I don't know if that is considered a lot or a little? I took it out and whereas before, I felt as though I was rather 'perched' over the front end & constantly sliding forward into the tank, now it feels a bit more 'relaxed'. Steering feels a little slower but the rear feels settled and comfortable. Interestingly, the front suspension feels a little harder and less forgiving now than when the OEM shock was fitted, I don't know why that should be. I need to check the sag on the front next to see if it is within recommended parameters. I also need to check the rear static sag again to check that it hasn't gone AWOL as a result of the changes!

23-06-2021, 06:52 PM	#9
bigredduke Nothing to see here Join Date: May 2005 Location: brough Bike: M1100evo Posts: 1,546	Rode the bike to James Wood @ JWR suspension yesterday in Louth, Lincolnshire. Strangely, before I fitted the new Ohlins rear shock, the front felt less harsh on bumpy roads (with the standard Sachs shock). Afterwards, the front felt awful. On bumpy roads, it felt like riding an unsprung bicycle over corrugated iron sheets. The rear felt good however. So James backed the front compression damping off by 2 clicks, then 4, which improved the ride considerably. The rear is very supple and comfortable over uneven surfaces (with a couple of turns off the preload). I have taken another 2 clicks off the compression damping at the front but have yet to ride it. I'll see how it feels over the Weekender. I prefer the suspension to be accommodating rather than harsh but obviously, I don't want it soft and wallowy. Looks like the standard settings on the rear shock are not far off for me. It feels less 'perched' over the front than it did & more like I am sitting 'in' the bike rather than 'on' it. Work in progress!