rear shock tuning

Learned this trick for setting rear shock spring tension. Tie a rubber band around the shaft to determine if its bottoming.

Yep, old trick

Or a zip tie

I would think the stock Ikon 2" of travel on a street bike is adequate. Yes?
(asking for my setup)

I didn't like the idea of a hard plastic zip tie bottoming out against the oil seal.

2" may be enough travel for Commandos with their laydown shock angle because you're getting more travel at the rear wheel. But I don't think its enough for a shock that stands closer to vertical as on my feather bed (I did manage to lay down my shocks a little). 3" shock travel still seems like a better idea on a Commando if you arrange it so bottoming height is the same but extension height is increased and the bike sits at the same height with rider on the seat - you're just adding more extension height in case the bike bounces - everyting else being equal.

Also factor in sag when you sit on the bike. The rubber band works for determining that as well. How much travel have you got left when sitting on the bike? The rubber bumper can also compress.

Your average pot hole can be 2" or more. I've got a 5" pothole on the dirt road leading up to my driveway - that's where I test.

Good tip.
What spring pre-loads are most folks running on the stock shocks?

Your shock settings depend on how you are going to use the bike. There are three things - load, spring rate and damping. If you carry a pillion passenger on a bike which is set up for solo riding, you wull usually get too much oversteer. As the back of the bike goes down, the rake on the steering head increases, and that increases the trail. More trail gives you oversteer, less trail makes the bike more difficult to tip into corners. When you set up for solo riding, you need springs which are soft enough to allow the rear of the bike to squat and give you oversteer if you accelerate in the middle of a corner. That way, if you go in too hot, you can recover. Then the other consideration is damping. You need enough damping to stop the rear end of the bike from jumping as you ride down the road, it can make the bike feel twitchy and destroy your confidence. If you have too much damping, the rear end can pump down and become too solid. Then you lose grip at the rear tyre contact patch.
If you are trying to set up a bike for road use, you are at a disadvantage, because the conditions do not usually repeat. On a race circuit, you do the same things many times over, so it is easoer to detect differences as you change the settings.
When you road race, the suspension settings and gearing are often changed to suit the circuit. For tight circuits, soft suspension, low tyre pressures, and low gearing are usually better, but it depends on the ratio of straights to corners. If your bike is underpowered, you need to improve your cornering. 5 MPH in a corner can be worth 10 MPH down a straight And if you corner faster, you do not have so much to make up on the straights. When you get passed, it should only be towards the ends of the straights.

With my bike, when I wind up the spring settings, the rate of turn in corners as I accelerate, decreases.
I was watching a video of Mike 'Spike' Edwards riding a Ducati. It was running wide in corners, so he wound-up the rear suspension. It is easy to get it wrong.
You can make changes and can simply become more frustrated. Whenever I ride a bike for the first time, I get it into a fairly wide corner and grab a handful of throttle halfway through the corner. That way I can see what it does. If it is a left hand corner, it should self- steer left - not right.

You can also use a twist tie, easy off/on and thinner than a zip tie.

I found this guide for suspension setup tuning useful.

Gortnipper - That's all good advice but it can be difficult for some to analyze whats happening in a turn (more for racers). A couple things to remember is that too much compression damping harshens the ride and this is more important for street riding than for road racing. Keep compression damping on the light side. Next is spring say when sitting on the bike. You don't want to use up more than 1/3 of your Travel. I shoot for around 25%. Then balance your rear and front rebound damping speed. See this vid and the rebound speed at the end.

gortnipper said:

You can also use a twist tie, easy off/on and thinner than a zip tie.

I found this guide for suspension setup tuning useful.

Click to expand...

Sounds like pseudo-tech to me.

"If your rear compression is too soft, you will get too much rear end "squatting"". Compression damping will slow down the rate at which any squatting occurs, but after a second or so the steady state attitude of the bike will be the same regardless of the degree of compression damping.

"If your rear compression is too hard you will not get enough "squatting" and therefore may not get enough traction". The author seems to think that squatting is an indication of the amount of load carried by the rear wheel; more load = more squat. Load on the rear wheel, due to weight transfer, will occur regardless of what the suspension does or doesn't do.

ggryder said:

Compression damping will slow down the rate at which any squatting occurs,

Click to expand...

Agreed

ggryder said:

after a second or so the steady state attitude of the bike will be the same regardless of the degree of compression damping.

Click to expand...

Compression damping helps set the steady state. The attitude (geometry) of the bike thru a turn is partially regulated/moderated by damping.

ggryder said:

The author seems to think that squatting is an indication of the amount of load carried by the rear wheel; more load = more squat. Load on the rear wheel, due to weight transfer, will occur regardless of what the suspension does or doesn't do.

Click to expand...

Load at rear wheel does change with weight transfer. It also changes with a geometry change, which is expressed as "squat".

Tornado said:

Good tip.
What spring pre-loads are most folks running on the stock shocks?

Click to expand...

Only talking preload as that's all that was asked then the general rule of thumb is 1/6th to 1/5th of total travel at the front and 1/3rd of total travel at the rear loaded with regular rider. Zip ties are your friend as it a working centre stand that lifts one wheel off the ground. Adjust to the rule of thumb and then test drive to look for bottoming and topping out on your expected roads and adjust to suit, if you get bottoming and topping out on one end then you need stiffer springs.

What the guy in this video says about cornering is essentially correct for bikes which have neutral steering. If you get into a corner too hot, you will usually start to run wide. The usual response is to trail brake to gently lose speed until you are slow enough to start accelerating again. The changeoverr point from braking to accelerating, is a matter of judgement. When you start accelerating again, it is important that you don't simply start running wide faster. That is when the rear spring settings and steering geometry are important. On a neatral handling bike, when the rear squats, the bike usually steers in the correct direction and leans less. With my bike, I can enter corners in the middle of the road, and accelrate full blast right through the corners. In a race, that is very difficult to beat. It is the reason that road racing my Seeley850 is very easy for me, I raced my old Triton for about 12 years , back in the old days, and never knewc why Manx Nortons were so much faster in corners. If your bike is set-up right, it does not mastter if you get into a corner and start to run wide. For me, that has always been normality. Psychologically, if you are running wide in a corner really fast, the thought of accelerating more feels wrong. But it can be the only way to get around the corner without crashing. I go into almost every corner on a race track too hot. You get accostomed to doing it. My Seeley oversteers a lot when I accelerate and it stays more vertical, so I get better grip. Most road bikes and two-stroke racing bikes, have neutral steering If the rear does not squat when you accelerate, you will continue to run wide, if you are too fast in corners.

It was not until the last time I raced, and that was about 8 years ago - that I really got on top of my cornering technique. Every time I ran wide, when I accelerated, the bike came back under control easily. I then suspected I could blast right through corners from start to finish - it worked ! The bikes in the class in which I normally race are mainly 1100cc methanol fuelled CB750 Hondas. In a straight line, they are extremely fast. While the three leaders were ot on the ripple strip on full lean, I rode under and past them at full blast. When I was about 100 metres ahead of then. my fual line came off. But I had them cold - I was in front with all the tight parts of Winton Raceway ahead of me. They were done, I had them cold. and they knew it.. After the race, we were not talkng. I think that is funny.
It is a simple thing, but something I never suspected. I had ridden a Manx and knew how they felt, but I never really knew the reason. When you fit 18 inch wheels to a Manx, it really stuffs the handling.
If you need to counter-steer as you enter corners, you do not have enough trail to corner fast.