Trying to Lower my bike 1/2 Inch without buying Parts

[the Ferret]

Certainly not a suspension expert, but it seems to me the adjusters change the amount of compression of the spring, therefore the compressed spring length. An uncompressed spring would have a given length, if you compress that spring, the actual spring is the same length, but in it's compressed state with the gap between the coils getting smaller due to compression, the measurement between upper and lower shock eyes would be less, wouldnt it? There would also be less suspension travel left before coil binding would occur. On a straight wound spring i would think the feeling would be the same, but on a progressive wound spring, the feeling would be stiffer I would think. Just trying to think it through.

Heck, I dont mess with suspension, I just ride the darn things the way they come lol.

Btw being a short guy, I have to buy boots with vibram soles for riding, both for height and for traction ...or bikes with really low seat heights which is why I bought my 21 model instead of a previous year model.

 

[670cc]

Certainly not a suspension expert, but it seems to me the adjusters change the amount of compression of the spring, therefore the compressed spring length. An uncompressed spring would have a given length, if you compress that spring, the actual spring is the same length, but in it's compressed state with the gap between the coils getting smaller due to compression, the measurement between upper and lower shock eyes would be less, wouldnt it? There would also be less suspension travel left before coil binding would occur. On a straight wound spring i would think the feeling would be the same, but on a progressive wound spring, the feeling would be stiffer I would think. Just trying to think it through.

A simple way to view this is, take a coil spring that compresses 1 inch per 10 pounds force. Stand the spring upright on the floor and place 20 pounds on it. The spring compresses 2 inches. Now slip a block of wood under the spring to raise it’s bottom off the floor. Did the spring compress more? No, it just raise the weight upward by the thickness of the block. Is the spring stiffer or softer? No, the spring rate is the same. In this case the weight is the sprung motorcycle weight, and the block is the preload adjuster.

Until you hit a restriction, like the end of shock or linkage travel, moving one end of the spring with the adjusters just makes other end move. There is no compression change.

 

[WingMan71]

If the adjuster changed the spring length, then the shock was against the travel limit. Did you make this measurement with you on of off the motorcycle? If you were sitting on the motorcycle at some mid suspension travel, not against any stops or restriction, it is impossible for the adjuster to change the spring length. If you move one end of the spring, there is no more force on the other end than there was before (bike and rider weight unchanged), so the other end of the spring moves, too, keeping the length the same with no difference in compression.

Bike on the center stand with back wheel off the ground. Measured the total length of the spring from top of top coil to bottom of bottom coil. 8.5" before the adjustment, and 9" after the adjustment. Not sure why you believe that the spring can't be compressed. The bottom of the spring sits on a cup that's fixed. If it wasn't fixed, and offering resistance, the adjusting rings would do nothing.

Bike has not been back on the ground since I made the adjustment. Going to move the forks up in the triple tree 1/2" before I put it down and take a ride to see how it feels. I'll report back.

After that... I'm tapping out.

 

[the Ferret]

Interesting conversation for those of us that that don't fiddle with this stuff.

 

[670cc]

Bike on the center stand with back wheel off the ground. Measured the total length of the spring from top of top coil to bottom of bottom coil. 8.5" before the adjustment, and 9" after the adjustment. Not sure why you believe that the spring can't be compressed. The bottom of the spring sits on a cup that's fixed. If it wasn't fixed, and offering resistance, the adjusting rings would do nothing.

Bike has not been back on the ground since I made the adjustment. Going to move the forks up in the triple tree 1/2" before I put it down and take a ride to see how it feels. I'll report back.

After that... I'm tapping out.

With the back wheel off the ground, the spring is fully extended at the limit of the shock travel. The other end of the spring can’t move. You may have misread my explanations, as I always make a point that the spring is not against a stop or restriction. Yes, in this case, of course the length of the spring will change, because you are decreasing or increasing the force of the spring against the stop. But the length measured on the centerstand is irrelevant because, hopefully you don’t actually ride the motorcycle with the shock topped out, as it is in this case.

After adjustment, when you set the bike down on it’s suspension, in some mid point of suspension travel, the laden spring length will be the same as before you made the adjuster ring change, because the motorcycle still weighs the same. However, the motorcycle ride height will have changed, which I believe was your goal in the first place.

 

[the Ferret]

The motorcycle ride height will have changed.

The unladen motorcycle ride height will have changed (higher), but also the laden ride height (lower)...correct?

 

[670cc]

The unladen motorcycle ride height will have changed (higher), but also the laden ride height (lower)...correct?

No. Motorcycle weight compresses fixed spring rate by x distance. Motorcycle weight plus rider weight compresses spring further, x+y distance. Motorcycle and rider weight act upon the spring in the same way, at the same point. I believe the progressive action of Honda’s ProLink linkage makes the distance non-linear, but the direction is still the same.

 

[the Ferret]

ok I'm going for a ride now on my stock suspension and try not to think about this lol.

 

[dduelin]

Bike on the center stand with back wheel off the ground. Measured the total length of the spring from top of top coil to bottom of bottom coil. 8.5" before the adjustment, and 9" after the adjustment. Not sure why you believe that the spring can't be compressed. The bottom of the spring sits on a cup that's fixed. If it wasn't fixed, and offering resistance, the adjusting rings would do nothing.

Bike has not been back on the ground since I made the adjustment. Going to move the forks up in the triple tree 1/2" before I put it down and take a ride to see how it feels. I'll report back.

After that... I'm tapping out.

What he said is true. Adding or removing preload does not change the length of the unladen spring. With the bike on the center stand and you dropped the adjusting rings 1/2" the spring did measure 1/2" longer but when the bike is on it's wheels again the spring will be 8.5" as before and the seat to ground measurement will be 1/2" lower than before adjustment. All the adjustment did was lower the ride height which was your desire. The shock will be more prone to bottoming as it is operating 1/2" lower in its designed travel.

You are light and self-described ride "easy does it" so losing 1/2" of shock travel probably won't matter but it would for heavier riders.

 

[Rydinon]

You are light and self-described ride "easy does it" so losing 1/2" of shock travel probably won't matter but it would for heavier riders.

How about when he goes over freeway blacktop expansion humps? Or a RR crossing at an elevated speed? On a smooth road, lowering the preload makes no difference, the problem is when the bike hits a bump and there is not enough suspension travel to absorb the shock. I thought the suspension on my ST was uncomfortable when I hit both those freeway bumps and RR tracks, and I was not bottoming the forks or shock. For the record, those asphalt bumps I dislike were a good 2" tall, some higher, but they just milled them all flat and repaved.

 

[WingMan71]

With the back wheel off the ground, the spring is fully extended at the limit of the shock travel. The other end of the spring can’t move. You may have misread my explanations, as I always make a point that the spring is not against a stop or restriction. Yes, in this case, of course the length of the spring will change, because you are decreasing or increasing the force of the spring against the stop. But the length measured on the centerstand is irrelevant because, hopefully you don’t actually ride the motorcycle with the shock topped out, as it is in this case.

After adjustment, when you set the bike down on it’s suspension, in some mid point of suspension travel, the laden spring length will be the same as before you made the adjuster ring change, because the motorcycle still weighs the same. However, the motorcycle ride height will have changed, which I believe was your goal in the first place.

Yes, my original goal was to reduce the ride height. Rain forecast for the next couple of days, so it may be a while before I get a test ride.

Not sure I'm understanding what you said, but I will certainly not be riding the bike with the "shock topped out". Why?

No shock designer would permit adjustment of their shock beyond the allowable range limited by the mechanical design of the adjusters themselves. Whether the adjusters be the stepped collar type or threaded rings like ours, there is a designed limit to the movement of those adjusters that is a safe range which will not allow the shock piston rod to bottom out our top out in the shock body. In the case of stepped collars, there are only so many steps on the collar, all within the allowable safe range to operate the shock. In the case of our threaded adjusting rings, the threaded section on the shock body limits the travel of the adjusting rings to only the designed threaded area. Setting the adjustment anywhere within these designed mechanical limits is safe to ride with that shock.

Will it change the way the shock performs and the bike handles? Sure. But, all adjustments within range are safe or the manufacturers wouldn't allow it.

 

[dduelin]

Yes, my original goal was to reduce the ride height. Rain forecast for the next couple of days, so it may be a while before I get a test ride.

Not sure I'm understanding what you said, but I will certainly not be riding the bike with the "shock topped out". Why?

No shock designer would permit adjustment of their shock beyond the allowable range limited by the mechanical design of the adjusters themselves. Whether the adjusters be the stepped collar type or threaded rings like ours, there is a designed limit to the movement of those adjusters that is a safe range which will not allow the shock piston rod to bottom out our top out in the shock body. In the case of stepped collars, there are only so many steps on the collar, all within the allowable safe range to operate the shock. In the case of our threaded adjusting rings, the threaded section on the shock body limits the travel of the adjusting rings to only the designed threaded area. Setting the adjustment anywhere within these designed mechanical limits is safe to ride with that shock.

Will it change the way the shock performs and the bike handles? Sure. But, all adjustments within range are safe or the manufacturers wouldn't allow it.

Shocks will bottom out or top out when the right (wrong) bump or hole is encountered regardless of where preload is adjusted. The manufacturer has no control over rider operation and conditions encountered. A fork or suspension can also top out when the springs are too weak for weight of rider and cargo. How so? A heavy rider might have to wind in excessive preload to get rider sag in the recommended range, usually 25 to 33% of total travel, but when the bike is unloaded the excessive preload moves the ride height to the top of designed travel. Unloaded could be when the bike is parked but also when the moving motorcycle tops a hill, a rise, or when rebounding from a sharp harsh bump. The relationship of rider sag to unladen sag
indicates if the spring rate is correct for the rider.

All this is rather pedantic to our discussion but is information found in any in depth suspension tuning guide.

You lowered the seat to suit your need and you are a light rider that intends to ride easy. I wouldn't worry too much about it.

 

[the Ferret]

Still trying to wrap my head around this..so if the bike was sitting on it's tires (not on the centerstand), and you twisted the adjuster rings either up or down, would it have any effect on the unladen seat height? would it make the ride softer or stiffer? What are the adjusters for?

I know..... how can a guy that has owned 32 street bikes, raced motocross for 10 years, ridden for 58 years and approx 800,000 miles on the street, ridden thru all of the lower 48 states, 2 provinces of Canada and 5 countries in Europe, and worked in bike shops for 17 years not know this stuff? I have no answer for that. They build them, I ride them...as is lol.

 

[670cc]

Still trying to wrap my head around this..so if the bike was sitting on it's tires (not on the centerstand), and you twisted the adjuster rings either up or down, would it have any effect on the unladen seat height? would it make the ride softer or stiffer? What are the adjusters for?

I know..... how can a guy that has owned 32 street bikes, raced motocross for 10 years, ridden for 58 years and approx 800,000 miles on the street, ridden thru all of the lower 48 states, 2 provinces of Canada and 5 countries in Europe, and worked in bike shops for 17 years not know this stuff? I have so answer for that. They build them, I ride them...as is lol.

If the bike is sitting on it’s tires, and is normally sprung such that it has compressed the springs somewhat under it’s own weight, then when you turn the rings or collar one way or the other, the seat height will go up or down. The spring rate is unchanged; the ride is neither firmer or softer.

The adjusters are so you can set the sag, or position the bike so there is the desired amount of suspension travel above and below the laden ride height, so that topping and bottoming the suspension is minimized. This way you best utilize the available suspension travel. If desired results cannot be obtained with the adjusters, you may need (a) different spring(s).

 

[the Ferret]

The owners manual mentions nothing about sag that I saw, it only says this


"Adjusting the Rear Suspension

Adjusting the suspension requires a pin spanner. We recommend that you have your vehicle serviced by your dealer.

Spring Preload:

You can adjust the spring preload by the adjuster to suit the load or the road surface. Use the pin spanner to turn the adjuster.

Position 1 to 2 decrease spring preload (soft), or turn the position 4 to 7 increase spring preload (hard).

The standard position is 3."


What would "adjusting to suit the road surface" mean, if not to mean a harder or softer ride? It even says "soft" for positions 1 & 2 and "hard" for positions 4 & 7

 

[Rydinon]

The owners manual mentions nothing about sag that I saw, it only says this

What would "adjusting to suit the road surface" mean, if not to mean a harder or softer ride? It even says "soft" for positions 1 & 2 and "hard" for positions 4 & 7

I'd interpret that to mean a rough road gets a softer ride, unless you want to vibrate your fillings loose. A hard ride choice makes no sense unless the damping is commensurate to handle compression and rebound, but Honda did not go into explaining that. Now we have to guess at what they mean.

 

[670cc]

The owners manual mentions nothing about sag that I saw, it only says this


"Adjusting the Rear Suspension

Adjusting the suspension requires a pin spanner. We recommend that you have your vehicle serviced by your dealer.

Spring Preload:

You can adjust the spring preload by the adjuster to suit the load or the road surface. Use the pin spanner to turn the adjuster.

Position 1 to 2 decrease spring preload (soft), or turn the position 4 to 7 increase spring preload (hard).

The standard position is 3."


What would "adjusting to suit the road surface" mean, if not to mean a harder or softer ride? It even says "soft" for positions 1 & 2 and "hard" for positions 4 & 7

“Suit the load” makes perfect sense. Since the stock components give you no way to adjust the spring rate, at least you can adjust the sag or ride height as a compromise to accommodate a higher load, such as carrying a passenger. “Suit the road surface”, on the other hand, means nothing to me.

Honda’s use of the words hard and soft might add to the public’s misconceptions of what the adjusters actually do. I guess the ride is hard if it bottoms or tops out, and soft if it doesn’t?

 

[670cc]

The owners manual mentions nothing about sag that I saw, it only says this


"Adjusting the Rear Suspension

Adjusting the suspension requires a pin spanner. We recommend that you have your vehicle serviced by your dealer.

Spring Preload:

You can adjust the spring preload by the adjuster to suit the load or the road surface. Use the pin spanner to turn the adjuster.

Position 1 to 2 decrease spring preload (soft), or turn the position 4 to 7 increase spring preload (hard).

The standard position is 3."


What would "adjusting to suit the road surface" mean, if not to mean a harder or softer ride? It even says "soft" for positions 1 & 2 and "hard" for positions 4 & 7

Upon additional thinking, I realized the Honda owner’s manual may just be dumbed down. My Zero DSR owner’s manual gives directions on setting the sag, and gives recommended measurements to go by. (Maybe Honda thought that level of instruction was too technical for the nice people riding Hondas). My Zero dealer set the bike’s front and rear suspension sag for me, per the manual, with me on the bike at the time I bought it new.

Regarding dumbing down the manual: My 2012 Honda owner’s manual tells how to remove and install the wheels, complete with the needed fastener torque specs. I see the latest NC models don’t event mention that in their owner’s manual. Maybe they dedicated more space for how to operate the instrument cluster.

 

[Rydinon]

Since the stock components give you no way to adjust the spring rate,

Honda’s use of the words hard and soft might add to the public’s misconceptions of what the adjusters actually do. I guess the ride is hard if it bottoms or tops out, and soft if it doesn’t?

Non stock, i.e. aftermarket components give you no way to adjust the spring rate. The spring rate is, (I think you said this too, in an earlier post) measured in pounds/inch or kg/mm. A given weight will compress the spring one inch (or kg compress it x-mm. This is a function of the spring's material and geometry and is fixed for a given spring (excepting variable rate springs, which might have two or three spring rates for different sections of the whole spring).

I was going to post something along the lines that you did re Honda not thinking NC buyers would be sophisticated enough to understand suspension basics.

 

[CamaroEric]

Easiest and fastest way to lower your bike 1/2" would be to let the air out of the tires

Exactly what I was going to say. At least there are like minded people here.