Sag on 3rd Gen

[93 VFR750 RC36]

I've just measured the static sag on my 3rd Gen. It's currently at 47mm. I've got 16mm of preload available.

I understand that I should at around 32mm sag, is that correct?

If I want to retain a level of adjustment, I imagine I should cut new spring spacers that are around 15mm longer than the current ones. This would give me the ability to adjust sag for track and road.

What sag should I be looking at front and rear on the road? on the track?

I'm up to Mallory Park on Thursday for my first track session after the rebuild and I'd like to start off somewhere sensible with my suspension settings.

Stew

[Guest]

I've just measured the static sag on my 3rd Gen. It's currently at 47mm. I've got 16mm of preload available.

I understand that I should at around 32mm sag, is that correct?

If I want to retain a level of adjustment, I imagine I should cut new spring spacers that are around 15mm longer than the current ones. This would give me the ability to adjust sag for track and road.

What sag should I be looking at front and rear on the road? on the track?

I'm up to Mallory Park on Thursday for my first track session after the rebuild and I'd like to start off somewhere sensible with my suspension settings.

Stew

It depends.

How much total travel do you have available? How much do you weigh? How hard do you brake going into turns? Do you prefer a harsh ride with little damping or something a little slower and smoother?

For the track you would probably like to have only 25 to 50% of your total travel consumed by both the static and loaded sag in order to have plenty of travel for hard braking without running the forks into the hard stops.

You could crank down your 16mm of preload and get your static sag down to 31 mm, then measure the loaded sag with you on the bike. It you still have over 50% of travel left then you would likely be fine for a first time track day.

When i raced in GP i liked to set up the RS125 toward the softer side with medium damping such that i had nearly 75% of full travel available and set the damping so that it was not a harsh ride--makes it easier to ride when you have one less thing to worry about. Whether it's a dirt bike or a street bike i would want to use the full suspension travel, or as much as possible. Damping is proportional to velocity and if the suspension is so stiff that there is little to no travel, then there will be little velocity, and therefore no way to develop any damping to smooth out the bumps. i.e. to keep the tires on the road.

Good luck and have fun at the track...

[93 VFR750 RC36]

Sorry, I may have got my terminology wrong, I was under the impression that static sag was that sag attained with the rider on the bike.

The unloaded sag on the front is 30mm and my loaded sag is 47mm. I just want to ensure that I'm not so far out that I start causing myself trouble when I hit the track tomorrow. If I dial out 12mm, I'll be at 35mm front sag which is within the "normal" quoted by several sources and then see how it rides.

However, any advice is welcome

Stew

[Guest]

Sorry, I may have got my terminology wrong, I was under the impression that static sag was that sag attained with the rider on the bike.

The unloaded sag on the front is 30mm and my loaded sag is 47mm. I just want to ensure that I'm not so far out that I start causing myself trouble when I hit the track tomorrow. If I dial out 12mm, I'll be at 35mm front sag which is within the "normal" quoted by several sources and then see how it rides.

However, any advice is welcome

Stew

You may already know this, but another thing to do is loosen the chain. The chain needs to be loose enough such that at full compression at "your" maximum rear travel you still have a little slack in the chain. A tight chain will bind the rear suspension and limit travel of the rear shock just like hitting hard stops in the front.

Are you about 16 stones?

[93 VFR750 RC36]

This isn't a first time trackday, just the first time since I rebuilt the bike with 0.95kg/mm Racetech springs, F3 internals and a Jamie Daugherty 929 shock.

Having built it up myself, I'm a bit more nervous this time around, although considering how softly sprung it was before, I probably shouldn't be. I'm 15 stone and that's a lot more than the stock springs are ideal for.

Got new Bridgestone BT-023 tyres front and rear, braided Goodrich hoses and EBC discs and sintered pads too.

Basically, it may as well be a different bike.

Ah well, I'll tell you how it goes when I get back.

Stew

[vfrcapn]

Here's a guide: http://www.sportrider.com/suspension_settings/suspension_setup/146_0402_suspension_setup_guide/preload_and_damping.html

25mm track, 30mm street.

Ohlins has some slightly different suggestions: http://www.ohlins.com/Checkpoint-Ohlins/Setting-Up-Your-Bike/Underrubrik_1/

[Guest]

This isn't a first time trackday, just the first time since I rebuilt the bike with 0.95kg/mm Racetech springs, F3 internals and a Jamie Daugherty 929 shock.

Having built it up myself, I'm a bit more nervous this time around, although considering how softly sprung it was before, I probably shouldn't be. I'm 15 stone and that's a lot more than the stock springs are ideal for.

Got new Bridgestone BT-023 tyres front and rear, braided Goodrich hoses and EBC discs and sintered pads too.

Basically, it may as well be a different bike.

Ah well, I'll tell you how it goes when I get back.

Stew

Begging your pardon, i misread your earlier post. That's the great thing about the US and Great Britian, we're two countries separated by a common language.

Not a bad guess on the weight, i suppose that mathematical computational device is not so bad after all...

i'm itching to get back on the track myself.

[93 VFR750 RC36]

I set the front sag at 35mm and rebound at 4 turns from full hard. I went to Mallory and had a blast (see post in 3rd Gen forum with pictures).

I love the new feel of the bike. The brakes still catch me out as they pull harder than the old ones and the braided hoses really improve feel.

The stiffer springing is BRILLIANT! I can now ride with no wallowing or any of that stuff I had before on stock springs. Both on the road up to Mallory (86 miles each way) and on the track I was really impressed.

Having spent 4 years off the bike, I was completely knackered (Brit expression) or totally done (Canuck) by mid-afternoon and had to give it a rest as I still had to ride home. So by the time I was feeling confident enough to start to push it and start getting my knee close to the ground, my body was giving up on me. Guess I need to get back in the gym and on the rowing machine.

What I can say is that I didn't quite like the transition from hard braking to turning in and could probably do with stiffening up the rebound a bit. However, that'll have to wait for another day to see if it gives me the feel I want.

I'm still buzzing and that's not just because of the induction roar (which is un-friggin-believable!).

Gotta cut some new spring spacers for the forks though. I've got very little pre-load adjustment left and I've only just got to where it feels OK.

Stew

[93 VFR750 RC36]

Oh ya, to Jamie Daugherty if you're passing through . . .

The 929 shock you rebuilt for me with a new spring is awesome! I have bumped up the rebound a bit but the rear end is now as solid as a rock and over all the bumps and surface changes at Mallory, the back end of the bike was totally settled.

So much so I completely forgot about it while concentrating on the front end.

Cheers fella, you'll get my vote again!

Stew