Sag and “Is my shock working properly?”

[STeveMcD]

OK, here we go.

2004 ST1300, 18k, new to me last October. I have NO IDEA whether the shocks have ever been touched or modified.

What I “feel” is that they’re stiff in the sense that I feel minor road imperfections as controlled bouncing in the front.

Not a problem and the bike behaves well on the road and at speed.

This morning, I measured static and dynamic sag

Static sag, from shock unloaded to carrying just the weight of the bike = 1.4375 (1 7/16”) = 36.5mm

Dynamic sag, with my 200lb carcass and after bouncing and letting it settle, 1.75in = 44.5mm

static sag % of travel = 36.6 / 117 = 31.2%
Dynamic sag % = 44.5 / 117 = 38.0%

The old (SS+DS)/2 /travel is (36.5+44.5)/2 = 40.5 / 117 = 34.6%

Does this seem reasonable?

PRE-ANSWER caveats - I am NOT INTERESTED in “take everything apart and rebuild it yourself to get to know your bike.” I am interested in others’ readings and the % of total fork travel that seems to be normal.

 

[STeveMcD]

Thanks for the reply. I’m going to look at the rear next, just to get a baseline

 

[mjc506]

You might get a better idea of fork condition by measuring 'stiction':

You might find it easier with a helper, but it's quite doable on your own.

Bike on side stand, pull on the bars to get as much weight as possible off of the front wheel, then gently ease the weight back on and stand the bike vertical. Measure travel/clearance between dust wipers and bottom of lower crown. Now, front brake on, push down on the forks, and slowly ease back up. Measure travel again.

The difference between the two numbers is a measure of how much static friction is present - the force any bump or undulation has to exert before the forks even begin moving. The smaller the better, <10mm is usually pretty good. Excess stiction can be down to dirty seals, bad fluid, worn/damaged bushings, fork misalignment (twist), bent tubes...

You can do the same with the rear too, but stiction is usually much smaller as the seal drag is only acting on a single small shock shaft, rather than two large ones!

 

[dduelin]

OK, here we go.

2004 ST1300, 18k, new to me last October. I have NO IDEA whether the shocks have ever been touched or modified.

What I “feel” is that they’re stiff in the sense that I feel minor road imperfections as controlled bouncing in the front.

Not a problem and the bike behaves well on the road and at speed.

This morning, I measured static and dynamic sag

Static sag, from shock unloaded to carrying just the weight of the bike = 1.4375 (1 7/16”) = 36.5mm

Dynamic sag, with my 200lb carcass and after bouncing and letting it settle, 1.75in = 44.5mm

static sag % of travel = 36.6 / 117 = 31.2%
Dynamic sag % = 44.5 / 117 = 38.0%

The old (SS+DS)/2 /travel is (36.5+44.5)/2 = 40.5 / 117 = 34.6%

Does this seem reasonable?

PRE-ANSWER caveats - I am NOT INTERESTED in “take everything apart and rebuild it yourself to get to know your bike.” I am interested in others’ readings and the % of total fork travel that seems to be normal.

The ST1300 fork sweet spot for rider or dynamic sag is about 36 mm. It appears you might have aftermarket springs and/or extra preload because the stock rider sag is normally far more than 44.5 mm. Under my skinny 165 lb in gear riding weight my stock suspension rider sag was 47 mm.

The ST is way undersprung for average American riders. I got my 2005’s fork working well for me with 16mm more preload on oem springs and running a 2:1 mix of Showa 5 & 10 wt fork oils to 6.7 wt.

 

[Igofar]

None of your measurements will mean squat if your preload adjuster unit is low or empty of fluid.
Unscrew your preload knob all the way, then count how many clicks it takes before you meet any resistance.
I'm betting your adjustment is empty, and your gonna find about 12 clicks before it even starts working.

 

[SMSW]

PRE-ANSWER caveats - I am NOT INTERESTED in “take everything apart and rebuild it yourself to get to know your bike.” I am interested in others’ readings and the % of total fork travel that seems to be normal.

Your bike is about 17 years old. Consensus here is that fork oil should be changed roughly every 20k miles. If you don't have a service history, you are sitting on a horny dilemma. To change the oil or not to change the oil, that is the question. Several of us have rebuilt the front forks with Race Tech's Gold valves - they make a huge difference over stock. I have said they spread the bumps out - sort of made them wider and lower while others who ride more aggressively than I have said the bike feels more planted and responsive. Putting them in of course means getting to know your bike more intimately than you want.

Since you don't want to take the bike apart yourself, I suggest you make an appointment with @Igofar and ride over to his place for a learning experience that will knock your socks off (even if you have motorcycle boots on). I doubt you will find anyone who is his equal. Otherwise, take it to your local mechanic, and after he screws things up, you can ask us for more help.

There are good mc mechanics out there. Since there are comparatively few ST's, and these bikes are so reliable, few of the techs have worked on enough ST's to become familiar with them. Your standard bell curve applies to these mechanics, the thin near end is the really gawd awful group, the middle chunk is the standard incompetent group, and the far right end (as thin and small as the near end) comprises the good guys. I know a good guy, but you are as likely to use him as Larry (Igofar).

Larry, you can stop reading here. Larry is so far off my bell curve as to make a joke of comparing him to other mechanics. Read the reviews here of his work by other guys (I've never had him work on my bike, but I have availed myself of his white courtesy phone). First, he lets you watch. Second, he explains EVERYTHING he does to your bike. Third, he is teaching you about your bike. Fourth, he goes over your bike from stem to stern and will show you what is out of adjustment or tolerance, and then proceed to fix it via #'s 1,2,& 3. How many shops let you watch them work on your bike? How many have the sign, "Labor rates: $50/shop hour; If you watch: $100/hour; if you ask questions, $200/hour." Sure that is sometimes facetious, but most places won't even let you watch from outside the shop. Insurance issues my bottom.

 

[dduelin]

Thanks for the reply. I’m going to look at the rear next, just to get a baseline

By all means get the baseline. To save time, the 900# stock spring in the rear suspension is inadequate for your riding weight. If the preload adjuster is working perfectly and has resistance from the first couple of clicks (there are 36 total) there is 10 mm of total preload adjustment available. Like Igofar said it's likely yours will have no resistance for 12 clicks or more. It's common to have lost much of the original preload travel. The preload adjuster can be serviced but the spring rate is simply too soft for riders over 160 lbs or so in riding gear.

If there is enough preload travel available for you to get 36 to 40 mm of rider sag then you get off the bike and measure static sag it will likely be topped out with 0 to at most 5 mm of sag which indicates the spring rate is inadequate for your riding weight.

 

[STeveMcD]

Your bike is about 17 years old. Consensus here is that fork oil should be changed roughly every 20k miles. If you don't have a service history, you are sitting on a horny dilemma. To change the oil or not to change the oil, that is the question. Several of us have rebuilt the front forks with Race Tech's Gold valves - they make a huge difference over stock. I have said they spread the bumps out - sort of made them wider and lower while others who ride more aggressively than I have said the bike feels more planted and responsive. Putting them in of course means getting to know your bike more intimately than you want.

Since you don't want to take the bike apart yourself, I suggest you make an appointment with @Igofar and ride over to his place for a learning experience that will knock your socks off (even if you have motorcycle boots on). I doubt you will find anyone who is his equal. Otherwise, take it to your local mechanic, and after he screws things up, you can ask us for more help.

There are good mc mechanics out there. Since there are comparatively few ST's, and these bikes are so reliable, few of the techs have worked on enough ST's to become familiar with them. Your standard bell curve applies to these mechanics, the thin near end is the really gawd awful group, the middle chunk is the standard incompetent group, and the far right end (as thin and small as the near end) comprises the good guys. I know a good guy, but you are as likely to use him as Larry (Igofar).

Larry, you can stop reading here. Larry is so far off my bell curve as to make a joke of comparing him to other mechanics. Read the reviews here of his work by other guys (I've never had him work on my bike, but I have availed myself of his white courtesy phone). First, he lets you watch. Second, he explains EVERYTHING he does to your bike. Third, he is teaching you about your bike. Fourth, he goes over your bike from stem to stern and will show you what is out of adjustment or tolerance, and then proceed to fix it via #'s 1,2,& 3. How many shops let you watch them work on your bike? How many have the sign, "Labor rates: $50/shop hour; If you watch: $100/hour; if you ask questions, $200/hour." Sure that is sometimes facetious, but most places won't even let you watch from outside the shop. Insurance issues my bottom.

You want me to ride from Massachusetts to Arizona to have my forks looked at?

 

[STeveMcD]

By all means get the baseline. To save time, the 900# stock spring in the rear suspension is inadequate for your riding weight. If the preload adjuster is working perfectly and has resistance from the first couple of clicks (there are 36 total) there is 10 mm of total preload adjustment available. Like Igofar said it's likely yours will have no resistance for 12 clicks or more. It's common to have lost much of the original preload travel. The preload adjuster can be serviced but the spring rate is simply too soft for riders over 160 lbs or so in riding gear.

If there is enough preload travel available for you to get 36 to 40 mm of rider sag then you get off the bike and measure static sag it will likely be topped out with 0 to at most 5 mm of sag which indicates the spring rate is inadequate for your riding weight.

This is an interesting comment. While I understand that the bike, like almost all bikes, is undersprung for American riders, the idea that “the spring rate is inadequate for your riding weight” may be technically correct, but my real, practical interest is in riding, not at the edge, but moderately sporting on 400-500 mile days.

I’m going to potentially break a cardinal rule here, but jeebus there seem to be a lot of really incontrovertible, absolutes already in thissimple thread. Let’s dial it back a bit.

 

[STeveMcD]

How many trouble free, fun miles have been put on these bikes by perfectly reasonable riders of many sizes without altering the internals of their suspension? I would guess “millions.”

 

[dduelin]

This is an interesting comment. While I understand that the bike, like almost all bikes, is undersprung for American riders, the idea that “the spring rate is inadequate for your riding weight” may be technically correct, but my real, practical interest is in riding, not at the edge, but moderately sporting on 400-500 mile days.

I’m going to potentially break a cardinal rule here, but jeebus there seem to be a lot of really incontrovertible, absolutes already in thissimple thread. Let’s dial it back a bit.

Well, you asked the question. Any suspension tuning guide will give you the relationship between static sag and rider sag as it relates to spring rate. Mathematics and physics are incontrovertible. The numbers do not lie. Presumably readers of such guides are prepared to understand the physics and make their own decisions if they want to pursue the indicated upgrades to an adequate spring rate. Most don't I suppose and ride the bike as it is. Nothing wrong with that and most riders do just that. It's a great bike and will serve you well as it is.

Maybe you want to hear "the spring rate is inadequate for my weight but it's OK for what I want to do and will do with this bike". Is that more of what you wanted to hear?

BTW, the fork travel is 108 mm, not 117 so your sag figures are understated a little.

 

[STeveMcD]

No, but saying it is inadequate is not the same as describing what the noticeable adverse effects of this are for 99.44% of riding situations.

I’m not trying to pick a fight, and I understand that there are fanatics on the site about almost every aspect of the bike.

To me, “inadequate” in normal use implies danger, seriously compromised performance.

 

[dduelin]

No, but saying it is inadequate is not the same as describing what the noticeable adverse effects of this are for 99.44% of riding situations.

I’m not trying to pick a fight, and I understand that there are fanatics on the site about almost every aspect of the bike.

To me, “inadequate” in normal use implies danger, seriously compromised performance.

Fair enough. Semantics is a bear.

There will be people that say go ahead and set up the shock with virtually no shock preload and damping and you will love the ride. That is a bike riding virtually on the bump stop under a 200 plus lb rider but people do it and love it. They won't be the type of rider that learns how to tune a motorcycle's suspension but I'm sure that they love riding their bike as much as anyone and don't really care the spring rate less than optimal.

 

[STeveMcD]

Food for thought.

https://www.cycleworld.com/story/blogs/ienatsch-tuesday/do-you-really-need-stiffer-suspension/

https://autoportal.com/articles/the-most-effective-motorcycle-suspension-settings-9088.html

 

[dtcoleman]

Hey Steve.
I have a 2004 ST as well. It had over 85K klms when i bought it in 2019. So bout 55K miles. I had a 2001 1100 earlier and it handled the corners better. Not sure if it had its forks rebuilt. I miss that bike. This 2004 was sloppy but comfy. To your point.
If you want to just ride then fine. No rebuilding required or costly upgrades.
This 2004 was sloppy as mentioned. However i didnt go for the Race Tech. Too expensive. I decided to go for Traxxion Dynamics and DIY. Less cost n a noticeable difference. And no more leaking fork seals. My case was while i was replacing seals . . .
The suitable fork upgrade was &119 USD. The rear shock was what it was.
Now it rides n corners like my 1100. Nice.
Dave

 

[TerryS]

I can offer an alternative suggestion. Rather than worrying about an absolute number for sag, take a look and see how much travel you are actually using during normal riding. Either put a zip-tie on a fork leg and see where the slider pushes it, or if your bike is less than perfectly clean, take a look at the where the clean stops and the dirt begins on the stanchion. The manual states full fork travel is 108mm, and the last 8-10mm is the hydraulic bottoming stop, so if you are seeing no more than 100mm then you are using all the available travel without bottoming out.

If you are using more than that, then you do need to look at how to prevent bottoming, more spring preload is one way, a set of stiffer springs another, or even just abit more fork oil can help.

Edit: I re-read the OP and you seem to be talking about the shock. You can look at shock shaft to see how much travel is being used, or look for witness marks in the bottoming stopper.

 

[SMSW]

You want me to ride from Massachusetts to Arizona to have my forks looked at?

There are at least a few guys who have planned a long trip out west and scheduled service with Larry. I don't want you to do anything - that is your choice.

The chances of finding someone competent to work on your bike, given the experience of many posters here, are very slim. I also said it was unlikely you would ride to Cleveland, and while the guy who worked on my bike was pretty good, he really has more experience w/ Harleys and Goldwings - he read my manual before diving in, but he did some serious trouble shooting first. My first choice, a BMW/Honda dealer's top mechanic made a bunch of guesses and billed me $650, doing NOTHING of value to me. At least the independent mechanic solved my problem and charged less than the dealership. He also offered me a much cheaper way of solving my problem. Oh, and Larry will not only do your forks, unless you were to kick and scream, and then he might tell you to go elsewhere. I doubt he would look at a bike to fix one problem and let other problems go unattended.

You have asked some questions here, and have gotten answers from some very knowledgeable people. You don't have to do anything at all. Ride the bike as it is. Change nothing. Operate on a belief system if you will and ignore the facts, if you prefer. Suspension systems for cars and bikes serve a purpose - and that is to provide a safe, comfortable ride. The safety part comes from having enough travel and damping to make the vehicle controllable under a wide variety of road conditions (and off road). Yes, as you said, millions of miles have passed under the tires of bikes with inadequate springing and damping. But a lot of accidents have also been caused by suspension that was not sufficient for the rider/bike combination. Riding with springs undersized puts you right on the edge. By that I mean if you ride conservatively, on smooth roads, you will likely have no problems. If you push the speed up, and hit some potholes and/or rough pavement, who knows? I once rented a Ford Explorer and drove a number of the original pass roads in the Rockies. My wife and I were going downhill when we hit some washboard - I was not going all that fast, (guessing now, 25 or 30 mph) but the shocks could not handle the input, and the SUV was bounced sideways toward the edge of the road. I recovered, probably due more to dumb luck than skill, but this is my point. You hit rough road with a shock nearly bottomed out, the spring binds, and you lose control of the bike. YMMV.

 

[SMSW]

I read your links. The first mentioned highly skilled riders being able to deal with lightly sprung bikes. That is one way to deal with the situation. Its been said ad infinitum that a great biker can outperform ABS brakes. MCN also told us their testers made repeated runs under ideal conditions to come up with minimum stopping distances. ABS allows the rest of us non racers to stop almost as well as the pros. I suppose increasing your skill level to the point where you can deal with virtually any bike's suspension is a worthy goal, but you better work on concentration too, like those racers.

Your second link discussed properly set up suspension. Yup, all food for thought.

 

[STeveMcD]

This is my 3rd ST1300 and I’ve ridden 20k per year since 1998.

and yet, for not the first time here, I’m actually sorry I asked…

 

[STeveMcD]

I'll lay out my concerns as clearly as I can.

On one hand, I understand the thinking that everything should be torn down to its core and rebuilt to better than new and as close to perfect as possible.

On the other hand, I have never seen, anywhere, so many people insisting that there's so much wrong with a great motorcycle, almost as if it will wobble, bobble, dive and explode if I dare ride it without every conceivable "upgrade."

On the 3rd hand, there is almost never a discussion of the law of diminishing returns. "The enemy of great is perfect."

On the 4th hand, a lot of this is predictable as the bike's age, and the remaining group becomes smaller, more concentrated, and more convinced of the perfection of the hive mind.

I do not remember any of this from 14 years ago when I joined with my second ST1300 (also a 2004) and attended a few NESTOC events. Back then, it was loose, friendly and more suggestion rather than insistence oriented.

The "this is our way, we are right" dogma is incredibly strong here, and human nature tells us that when we're in the thick of intense group think, we cannot see it for ourselves. For me, it has turned from friendly advice sharing and simple enjoyment of one of Honda's all-time great motorcycles, into something aggressive and, frankly, offensive. It is NOT just semantics, it seems locked deep in the current core DNA of this site, VERY different than my first go 'round.

Finally, the strongest proof of my point would be a visceral urge to deny it and attack, as has already happened passive-aggressively with comments like "Operate on a belief system if you will and ignore the facts, if you prefer." and many others of similar ilk.

We all have free will to act as we please, but some things add to community building and some things don't.