Setting rear suspension sag via preload adjustment

Hey guys, After taking my first ride today I suspect my rear sag is off and want to tighten it up. I currently weight about 195 pounds and I am about to install the Honda saddlebags and trunk. I dont know what factory setting is best suited for(I have three threads above the top lock ring exposed).

What I have done in the past on my sportbikes is measure the fully extended distance(wheel off the ground) from fixed point on swingarm(near axle) and fixed point on rear seat cowl. Record this as measurement A. The have the rider fully geared up and sitting on the bike with full weight on bike in normal riding position. Give rear of bike one push down to consider sticktion then re-measure and consider this measurement B. The difference from measurement A to measurement B should be 35 to 40 millimeters.

Again I have used this on sportbikes in the past. Does anyone have different sag specifications for the NC?

I generally use 1/3. On a 6 inch travel, that is 2 inches of sag or 51mm. Your number would give a stiffer ride than mine. Given the role of a sport bike (high performance on relatively good roads) that is probably appropriate. I think it would be firmer than I would want for a bike in this service. It depends on your personal preference and use for the bike. You could certainly start there and see if you want it firmer or softer. My fine-tuning process is a test course which contains the largest bump I want to hit without bottoming the suspension at 50 mph. When I am happy with my "test bump" I am generally happy on the road.

The initial sag is just a starting point to get into the ballpark. Just knowing the sag puts you in a good position to optimize it. So many people just start cranking on it without even knowing their starting point.

Craigmri said:

Hey guys, After taking my first ride today I suspect my rear sag is off and want to tighten it up. I currently weight about 195 pounds and I am about to install the Honda saddlebags and trunk. I dont know what factory setting is best suited for(I have three threads above the top lock ring exposed).

What I have done in the past on my sportbikes is measure the fully extended distance(wheel off the ground) from fixed point on swingarm(near axle) and fixed point on rear seat cowl. Record this as measurement A. The have the rider fully geared up and sitting on the bike with full weight on bike in normal riding position. Give rear of bike one push down to consider sticktion then re-measure and consider this measurement B. The difference from measurement A to measurement B should be 35 to 40 millimeters.

Again I have used this on sportbikes in the past. Does anyone have different sag specifications for the NC?

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The target sag of 35 to 40 mm is good for the NC. I usually use 30-35 mm of sag as target but other street bikes I had did not have 6" of rear shock travel. Besides 30-35 mm another rule of thumb is 25% of travel and with the NC this is 1.5" or 38 mm.

dduelin said:

The target sag of 35 to 40 mm is good for the NC. I usually use 30-35 mm of sag as target but other street bikes I had did not have 6" of rear shock travel. Besides 30-35 mm another rule of thumb is 25% of travel and with the NC this is 1.5" or 38 mm.

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Dave

30-35mm on a bike with a 4 inch travel would be closer to 1/3 than it is to 25%. Also, the difference in 1/4 and 1/3 sag is only 1/2 inch. I think the key thing to remember is that it is a starting point. Start here or start there. Works either way. I can work with any starting point. The process after that is what gets you to what works best for you. Chances are we all end up with different final set-ups when we are all happy with our bikes.

Setting suspensions is like Goldilocks and the three bears...

Lee,

Yes, there were two rules of thumb in my post. One, 30-35 mm, is in all the sportbike suspension tuning manuals. The other is 25 to 33% of travel which might be more relevant with longer travel suspension like that of the NC700X or airheads. You did point out the most important thing - initial sag is just a starting point and depending on other factors and rider preferences it can be close or far from there.

Err...Hmm...., Lee,

Do we have to use first names to start posts from now on?

dduelin said:

Err...Hmm...., Lee,

Do we have to use first names to start posts from now on?

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Lol...yeah most of us know we are way out of you guy's league already ;-)

Kidding aside, better than you PMing each other, this way we learn a little every post.

(Sorry about making PM a verb)

dduelin said:

Err...Hmm...., Lee,

Do we have to use first names to start posts from now on?

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Nah. Drop it. Sounds like we are lecturing, which neither of us would EVER do!

Thanks for confirming my adjustment approach guys. While its obvious the suspension components on the NC are budget pieces, it makes sense to get the most out of them by getting the one setting we can adjust as close to perfect as possible. If after this I'm still not satisfied, will a stock shock off another Honda sportbike work on the NC such as a 600RR shock?

Craigmri said:

... If after this I'm still not satisfied, will a stock shock off another Honda sportbike work on the NC such as a 600RR shock?

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That would be a nice research project and might get a step in improvement without paying the $600 for an Öhlins or Wilbers. No need to limit it to Hondas though. Any single rear could be a candidate to evaluate. You'd have to match travel, spring rate, and length. Plus you'd have to assure you have enough radial clearance for any reservoirs and the shock body.

There ought to be plenty of new take-offs from people who have upgraded.

Beemerphile said:

That would be a nice research project and might get a step in improvement without paying the $600 for an Öhlins or Wilbers. No need to limit it to Hondas though. Any single rear could be a candidate to evaluate. You'd have to match travel, spring rate, and length. Plus you'd have to assure you have enough radial clearance for any reservoirs and the shock body.

There ought to be plenty of new take-offs from people who have upgraded.

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Thats what I'm thinking Lee. When I return from my Two week Nova Scotia tour in July I'll focus on it.

Craigmri said:

Thats what I'm thinking Lee. When I return from my Two week Nova Scotia tour in July I'll focus on it.

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Are you riding your NC on this tour?

Craigmri said:

will a stock shock off another Honda sportbike work on the NC such as a 600RR shock?

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I would be a little careful, and make sure to do your due diligence with this before a purchase from a "the usual suspects" sportbike donor.

Being as the NC has a purported 6" rear suspension travel figure, but the shock doesn't have 6" of actual travel; it may very well be that the linkage geometry of a CBR600RR allows it to use a shock with the same overall dimensions as an NCX, but have even less actual travel-leading to a nasty bottoming out potential.

Also, even if the dimensions were the same, and the travel appeared to be similar, and the linkage ratio was close, it could be that the spring rate is off enough to go beyond the boundaries of acceptable adjustment.

I was amazed by something like this when I changed the shock on my CBR125R. It doesn't use linkage in it's design, so I knew to go for a lengthier shock and what I estimated to be the correct lb/in spring rate. My calculations for the spring were so high that I thought I goofed up, and ordered a spring only a few hundred pounds higher than what the OEM (FastAce) spring was on the new shock.

I was still off by at least 300 lbs!!!

The spring I have on now, is a 900 lb/in rate, and is still woefully undersprung. A 1200 lb/in spring is what I originally thought, and ends up being the right one.

dduelin said:

Are you riding your NC on this tour?

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Dave,

We are trailering from FLA to Albany and riding to Nova Scotia from Albany.

Craig

OK measure sag at 54mm.....Thats before I even add my Honda saddlebags and top box plus gear. I need to find a spanner.

Found a spanner tool in an old motorcycle tool pouch I had. I had to do a little grinding on the tool to make it work.

I weigh 195 pounds. Initial pre-load adjustment was at 3 threads above the locking ring. I initially had 54 mm of sag. Most sportbike sag recommendations say 35-40mm if a good target.

After adjustment I have 9 threads above locking ring and have 38 mm of sag.

While I still dont have my Honda luggage installed yet(still awaiting its arrival) I decided to leave the adjustment here for now. I want a firm-ish ride but not teeth chattering.

Just took the bike out for a short spin to test it out on a bumpy-ish twisty road and like the setting MUCH more now. Before I used to feel this sort of pogo-stick type sensation. Almost as if the bike was bouncing forward and aft back and forth. Didn't notice any more of that.

After the hard bags get installed I'll recheck but I like the upper 30's for sag adjustment so far. Will be riding out to Madstad tomorrow so I'll get a really better chance to feel the difference.

For reference, I put the bike on center stand to check fully extended measurement. I picked a point on the swingarm in-line with the axle and a point on the seat cowl due north of axle and this was measurement A. Then, I took bike off centerstand and sat on bike and balanced myself with arm on workbench and had my helper make measurement using same two points to measure off of. This is measurement B. A minus B is your sag.

OK, I have all my Honda hard bags installed(Side cases and top case). I rechecked sag and it went from 38mm to 46mm.

Broke out the spanner again and ended up maxed out on adjustment and the sag is 39.6mm. I was shooting for something closer to 35mm because once I have my gear on and bags loaded it was going to increase sag but I just have no more adjustment. With locking ring locked down I count 10 threads.

I suspect this will be fine but if I begin riding with a passenger alot I will have to upgrade the rear shock.

Thanks for continuing to update us on this project, Craigmri. I'm interested in getting sag 'set up' myself.

Craigmri said:

I suspect this will be fine but if I begin riding with a passenger alot I will have to upgrade the rear shock.

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Or just the spring if you are happy with the valving.

Lee, I didnt even consider that option. After my Nova Scotia trip next month I'll have a pretty good evaluation of the bike and if I need to address it. You have a Progressive shock do you not? How does it compare in ride quality and performance to original and how much do you weigh?

Beemerphile said:

Or just the spring if you are happy with the valving.

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