Front shocks removal

[Kevcules]

Probably a better idea, but didn't someone else have this problem? Was there not a discussion about weighting one of the side cases? I cannot help but think the two problems are related - pulling to one side and fork problems.

What would cause a bike to pull to one side? The front and rear wheels being out of line - but our bikes have an axle that cannot be adjusted to twist the rear wheel (like a chain driven bike w/ rear wheel adjusters). Frame being bent - highly unlikely absent a crash. Could one dragging caliper cause this? I would think the hot rotor would be very obvious and pushing the bike w/ the engine off would be an instant giveaway that the brakes were a problem. Steering head bearings? Maybe. And out of balance bike? I've had over 10 lbs in a side case with nothing on the other side and not noticed a problem.

I did read something common about these bikes having a slight pull to one side when letting go of the bars. I already tried the re-alignment process, maybe I'll attempt it again. It's not a terrible pull, but it does definitely pull. I've also tested the theory on having weight on one side in the hard bags with no real different results.
I haven't noticed unusual heat from the rotors and my bike always moves easy after riding. In fact, I'm so aware of the SMC issue, I always move the bike backwards a little after a hard stop to test the rolling resistance. So far it always rolls easily.....

 

[CYYJ]

...I took a look through a few more Honda service manuals and it seems a bit random which way up the springs go. If the springs are referred to as having a "tapered" end that goes up, if the springs have a "tightly wound" end that goes down...

I have been trying to figure out the relationship between "tapered end" and "tightly wound end" - so, I measured the diameter of the spring. The "tightly wound end" (coils close together) is 35mm outside diameter. The other end, which I suppose one could call the "loosely wound end", is 39mm outside diameter. From this I conclude that the end with the smaller diameter - the tightly wound end - is the "tapered end".

My 2003-2006 ST1300 Honda Service Manual states to install the springs tapered side down which I've always done in my 2005.

That makes sense to me, because the spacer tube (spring collar) is 38mm diameter, and it seems logical that it should rest on the end of the fork spring that is 39mm diameter (that being the "loosely wound" and "non-tapered" end), even though there is a rather large washer (spring seat) between the spacer tube and the fork spring.

Michael

 

[Kevcules]

When i removed my springs , they were installed with the tapered end (coils close together) down, like your manual says. My manual though says that they should be facing up. (I included a picture of my manual in a previous post) So I installed them the way they came out, for one of the reasons you talked about Michael. The larger diameter coils should meet with the washer and spacer that is a similar sized diameter. Some have said that it shouldn't matter which way the springs go in as far as compressing the spring, because it should work the same either way.
I had tried a couple spacers made out of aluminum, but was warned that they may cause my oil to get contaminated with them ,so I went with a stainless steel spacer at a different length than stock. I read on here that a 1.5" stainless steel grab bar for a tub or shower was the same size needed and they were right!

 

[dwalby]

Some have said that it shouldn't matter which way the springs go in as far as compressing the spring, because it should work the same either way.

the difference is how much fork oil is displaced by the spring. Tight end down will displace more oil, and raise the level higher than using the other end down. If you fill the oil by volume then keep the tight end down. Come to think of it, if you fill by level then you do that with the spring removed, right?? If so, then that level is also determined based on the spring orientation given in the manual, so there's only one correct way to install the spring using either method of oil measurement.

 

[Kevcules]

Hello again guys. Resurrecting my old thread....

Still not happy with my front springs/suspension. I don't ride too much these days as my back doesn't like it, but when I do, the ride isn't as pleasant as it could be when going over rough roads. I see other heavy bikes slow to a stop at traffic lights and their front shocks compress 2-3 inches nice and fluidly. I even saw another ST stop at a light doing the same thing. The front shocks compressed 3 to 4 inches real easy.
My front end is really stiff and doesn't compress easily. It seems like after forcing them to compress about an inch or two, it feels like they are crunching together. They are far better now after the latest change in oil (7wt), more pre-load, replacing bushings (which weren't bad) and making sure to re-align the front shock tubes properly on assembly. I also have been greasing the tube under the dust seal to help with stiction. I'm still rolling up and over the little bumps though. No good....

I checked the Sonic site and they recommended .95kg/mm per my weight and other things they asked. My bike has stock .87kg/mm springs I believe. I've read on here that Sonic usually recommends high for some reason and that's the result I got also.

I'm thinking I want to try .90 kg/mm springs and inquired locally. My local shops only deal with RaceTech and Progressive so I'll probably try one of them.

Is there anyone who is my weight (170 lbs) who has tried the Race Tech or Progressive front springs and found they helped? I'm not going to do the valving just yet. Too expensive for me right now , but different springs are worth a shot.
What spacer length and oil level from the top , did you try?

This is going to be my winter project and will be started in the next 3-4 months. Just trying to understand and get prepared for the job.

Thanks

 

[CYYJ]

...Just trying to understand and get prepared for the job.

This post might be helpful to you: ST1300 Front Fork Overhaul: An Illustrated Bibliography

Michael

 

[dwalby]

My front end is really stiff and doesn't compress easily.

I bet you're a hit with the ladies.....

However, I'm not sure about the stock .87kg/mm spring rate you quoted, since they're progressively wound springs and I don't recall ever seeing a Honda published spec. You might want to go to an even lighter weight oil like 5W first. It may be that your limiting factor on travel has more to do with damping response rate than spring compression rate. Not saying I know, just a thought.

edit: going with lighter oil will definitely help on the quick bump transitions, spring rate has little or no effect on quick, small transitions.

Years ago when I first started riding my ST1100 I had the opposite issue, I wanted the front end to be less cushy, since I was used to firmer suspension from riding sport bikes. I'm also 170lbs, and kept the stock springs, but increased the preload to raise the ride height, and went with heavier fork oil (12.5 wt.). That gave it more of the sportier feel I wanted, maybe going back to 5 wt. would get you where you want to be.

not sure about the 1300, but the 1100 came stock with 5W oil, the Honda SS-7 oil.

 

[dduelin]

I bet you're a hit with the ladies.....

However, I'm not sure about the stock .87kg/mm spring rate you quoted, since they're progressively wound springs and I don't recall ever seeing a Honda published spec. You might want to go to an even lighter weight oil like 5W first. It may be that your limiting factor on travel has more to do with damping response rate than spring compression rate. Not saying I know, just a thought.

edit: going with lighter oil will definitely help on the quick bump transitions, spring rate has little or no effect on quick, small transitions.

Years ago when I first started riding my ST1100 I had the opposite issue, I wanted the front end to be less cushy, since I was used to firmer suspension from riding sport bikes. I'm also 170lbs, and kept the stock springs, but increased the preload to raise the ride height, and went with heavier fork oil (12.5 wt.). That gave it more of the sportier feel I wanted, maybe going back to 5 wt. would get you where you want to be.

not sure about the 1300, but the 1100 came stock with 5W oil, the Honda SS-7 oil.

The stock Honda spring rate has been quoted as .87kg/mm by the reputable firm of Racetech. It's used in their spring rate calculator to benchmark or as a datum to compare other spring rates to. Honda never published the spec but it's easy to measure and I have no reason to distrust it. I got the results I wanted in my ST1300 by mixing the nominal 10 wt SS-8 with nominal 5 wt SS-7 to a 6.7 wt. Combined with 16 mm of preload I got results that worked for me.

 

[dwalby]

The stock Honda spring rate has been quoted as .87kg/mm by the reputable firm of Racetech. It's used in their spring rate calculator to benchmark or as a datum to compare other spring rates to. Honda never published the spec but it's easy to measure and I have no reason to distrust it.

OK, good to know. My point was if its a progressive wound spring, (which I think it is because the 1100 has them) then the spring rate isn't constant, whereas a figure like .87kg/mm would suggest that it is. So this must be their "approximation" to an equivalent single rate spring for the user to use in selecting replacement springs. My apologies if the 1300 does in fact have single rate springs, I don't own one.

 

[dduelin]

OK, good to know. My point was if its a progressive wound spring, (which I think it is because the 1100 has them) then the spring rate isn't constant, whereas a figure like .87kg/mm would suggest that it is. So this must be their "approximation" to an equivalent single rate spring for the user to use in selecting replacement springs. My apologies if the 1300 does in fact have single rate springs, I don't own one.

Yeah, I don't know how "rate" applies to progressively wound springs - whether it's the initial rate at the bottom left of the plot curve or the stiff rate further up the right hand side of the plotted rate curve. My sense is that it is the final rate, the stiff one, as that is a better comparison to the rate of straight rate springs the Racetech and other tuners favor.

 

[Bmacleod]

The stock Honda spring rate has been quoted as .87kg/mm by the reputable firm of Racetech. It's used in their spring rate calculator to benchmark or as a datum to compare other spring rates to. Honda never published the spec but it's easy to measure and I have no reason to distrust it. I got the results I wanted in my ST1300 by mixing the nominal 10 wt SS-8 with nominal 5 wt SS-7 to a 6.7 wt. Combined with 16 mm of preload I got results that worked for me.

As Dwalby states, I dont understand how they publish that one number. The ST1300 fork spring seems to be a "dual-rate" progressive spring (there a 2 types of progressive springs but the other type doesnt apply here). It should have a number like .87/1.10kg/mm (e.g.). Having a progressive spring helps with the issue of manufacturing a bike to suit a wider variation of rider weights. The problem with a progressive spring is unless it is suited exactly to the rider weight, you can "use up" the soft portion of the spring by adding more preload and end up starting out with a stiffer spring than desired.

Edit... Dave, I see you replied while I was typing, but I left my thoughts anyway. So you see how that number could be vague. If that is an average than it would make sense that the spring is likely stiffer in the bottom half. As you add preload, i would think you would move "half" forward in the scale. (I know, bad analogy, couldnt think of another way of wording the "half" reference)

 

[dwalby]

The problem with a progressive spring is unless it is suited exactly to the rider weight, you can "use up" the soft portion of the spring by adding more preload and end up starting out with a stiffer spring than desired.

Adding preload doesn't compress the spring more than with less preload. It only changes the ride height, or in other words, how far the fork compresses under the weight of the bike/rider at rest. Regardless of how far the fork slider moves to get to that point, internally the spring will be compressed by the same amount, where the spring force equals the weight of the bike being supported by that fork.

A heavier rider will use up more of the soft portion because the spring compresses further to counter the weight of the bike/rider, but for any given rider weight adding preload will not affect the amount of spring compression inside the fork.

 

[dduelin]

As Dwalby states, I dont understand how they publish that one number. The ST1300 fork spring seems to be a "dual-rate" progressive spring (there a 2 types of progressive springs but the other type doesnt apply here). It should have a number like .87/1.10kg/mm (e.g.). Having a progressive spring helps with the issue of manufacturing a bike to suit a wider variation of rider weights. The problem with a progressive spring is unless it is suited exactly to the rider weight, you can "use up" the soft portion of the spring by adding more preload and end up starting out with a stiffer spring than desired.

Edit... Dave, I see you replied while I was typing, but I left my thoughts anyway. So you see how that number could be vague. If that is an average than it would make sense that the spring is likely stiffer in the bottom half. As you add preload, i would think you would move "half" forward in the scale. (I know, bad analogy, couldnt think of another way of wording the "half" reference)

Adding preload doesn't move the spring rate up the Y axis of the spring's plotted rate. It still starts out at the soft rate even if preload is increased unless so much preload is added that the soft end becomes coil-bound. That's a possibility though largely theoretical as it would be extremely difficult to to compress the spring that much and still engage the fork cap.

As we have pointed out repeatedly, preload only affects ride height, the position of the at-rest laden bike in relation to available suspension travel.

Progressively wound springs can go into the fork tubes either way so I don't want to confuse that issue. Honda SM says tightly wound (softer) end down but other guides suggest the other way around. It doesn't matter to the spring and how it works.

 

[Bmacleod]

Adding preload doesn't move the spring rate up the Y axis of the spring's plotted rate.

I don't disagree with that, in a linear rate spring. One cannot argue that adding preload doesn't compress the spring, that's how it raises the ride height to the proper sag number. My concern or perhaps I should say question is with a progressive rate spring does that not first remove all the soft portion of the spring leaving the firmer portion the more you compress it. I don't think one could argue that for two different springs, if your sag or ride height is exactly the same you will be at the same tension or pressure on either spring, but my thought is the progressive will be halfway through its scale and starting to firm up quickly.
I should be sure and state that I am speaking of adding excessive preload to a progressive spring.
I agree that whichever way the spring is put in makes no difference.

 

[dduelin]

What is confusing sometimes about adding preload is the concept we may have of a spring in a tube. If the tube was a fixed length then adding a 1" spacer on top of the spring would compress the spring by 1" and move the spring rate up the Y axis. But our forks are not a fixed tube rather is of variable length between fully compressed and fully extended. After the 1" spacer is added, think about it like this- the tube is not fixed in length - the tube, or stanchion, slides up and down in the lower leg. So the bottom of the spring rests on the lower spring seat located in the lower leg and the fork cap sits 1" higher because the spacer lifts the cap and the stanchion it is screwed into by 1". The spring remains the same length - only the tube containing the spring extended 1".

If that is understandable, go on to see that the top clamp is now 1" higher, the handlebars are 1" higher, all of the parts of the bike supported by the fork is 1" higher until you measure height of parts closer to the shock and further from the fork. (if the shock is not lengthened the rear of the bike did not raise a corresponding 1") The cap is 1" further away from the ground as is the top clamp so the ride height of the front of the bike was raised 1" just with the spacer. The spring is the same length as before.

 

[dwalby]

One cannot argue that adding preload doesn't compress the spring, that's how it raises the ride height to the proper sag number. My concern or perhaps I should say question is with a progressive rate spring does that not first remove all the soft portion of the spring leaving the firmer portion the more you compress it.

What Dave and I are saying is that the spring compression inside the fork is exactly the same regardless of what length spacer you use, and if I understand you correctly, you disagree with that.

Whatever portion of the 'soft' part is compressed for spacer length X, will be exactly the same with spacer length Y. The only difference is how far the fork slider had to travel to reach that degree of compression, and that's what determines the ride height.

The spring compresses until its force equals the force of the weight of the bike+rider. Since that doesn't change, the spring compression doesn't change either, how could it? What does change is where the endpoints of the spring are located inside the fork tube, and that affects ride height, but nothing else.

edit: to think of it another way, if the spring needs to compress by 100mm to offset the weight of bike+rider, the spring doesn't know if it was compressed by 100mm from one end and 0mm from the other, or 50mm from each end, it compresses the same 100mm distance either way. Adding 50mm of preload on one end just reduces the required travel on the other end by 50mm, which is what changes the ride height.

 

[Bmacleod]

Adding preload doesn't move the spring rate up the Y axis of the spring's plotted rate. It still starts out at the soft rate even if preload is increased unless so much preload is added that the soft end becomes coil-bound. That's a possibility though largely theoretical as it would be extremely difficult to to compress the spring that much and still engage the fork cap.

I understand what you guys are saying. That makes perfect sense. Thank you.
What Dave says here is basically what I am trying to stress.
The point I was trying to make is that if somebody is too heavy for the factory springs, their weight will overpower the soft part of the progressive springs and get into the firmer part which could be more then a higher rate linear spring. Dave, I don't think it would be as hard as you think to coil bind the soft end of a progressive spring, but that's just a guess. Remember, you may still be able to get the cap on but there's another inch + of bike and Rider weight to compress the spring to the SAG number. Even if the soft part of a progressive spring is not coil bound at that point, it won't have to travel far before it happens and then the spring could get stiff quickly. When @Kevcules mentioned his suspension getting stiff after one inch that is what come to my mind and started me on this train of thought.
To the OP, I meant to mention earlier, I agree with dwalby and if it were me I would be switching to a lighter weight oil to see what kind of difference that makes. Also, oil level is very important, be sure it's not too high

 

[bigbikerrick]

This has been a fascinating discussion, and even though I have been a "shadetree" suspension tuner since the early 70's with dirt bikes, etc. I still learned a few things, from the excellent explanations. Thanks guys for taking the time to write all that up.
FWIW, I just finished rebuilding the forks on my 05, and it was very easy with the articles read here. I was able to purchase a pair of the 1.2 kg/mm Sonic springs from a member here at a great price,and put those in, with the spacer recommended by Sonic, the Sonic springs were much longer than the oem, so the spacer was shorter, by the same amount. I added a total of 4 washers 2 above and 2 below the springs, for added preload, and used 10 wt fork oil, about 65 mm from the top.
I rode it for a few days, then popped the forks off again, and replaced the 10wt fork oil with ATF. same quantity. I like it much better now, the damping is just right it seems, as well as the spring rate, since the weight of the sidecar is transferred to the fork, especially when hard braking.
I am wondering though, if I may have done something wrong, because even though "my front end is really stiff" ......I am still not a "Hit with the ladies!" ;>)

Rick Duarte

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[Kevcules]

lol.....I got a good chuckle out of some of your responses. This is a great group of riders each contributing their knowledge and experience, without throwing punches at each other. I like it!

Now, I read all the responses at different times today. My head is spinning now, on the X axis!

I feel the same as some of you, where I feel that my spring is coil bound and not wanting to compress very much anymore. Like there's no travel left. OR, the soft compression portion has been compressed already, leaving the stiffer coils left. Either way, when I try to stop in my garage or at a traffic light quickly, trying to compress the front shocks, I get maybe an inch of very firm compression.

I agree that trying a lighter oil to increase damping(flow) will help. I'm already using Belray stated 7wt. Maybe I could try 5wt?
I'm using the same set up as Dave's suggestion a while ago. We're the same weight and I used the same preload spacer as he suggested (16 mm more than stock I believe) and a lighter oil. Definite improvement but no where near good enough. I wonder why you had success and I'm not? That makes me believe that I may have a defect in my shock tubes. I replaced the bushings already with no change. I double and triple checked the alignment and it's ok.

Since the 1300 has a progressive, seemingly dual rate compression spring, what's the advantage of going with a straight rate spring? Are they all in fact longer than stock? I was hoping for a lighter compression ability throughout the springs range and that's where I think I want to be. I'm just hoping to hear from someone who has tried the straight rate springs and get their review.

I'd like to try the .90 kg/mm RaceTech springs using the same 7 wt oil, then even going to a 5 wt. But maybe I have a mechanical issue that I haven't found yet. What do you guys think?

thanks.......Kevin

 

[dwalby]

5wt is stock on the 1100, not sure about the 1300, but they are sometimes similar so it wouldn't surprise me if the 1300 came with 5wt from the factory. In that case you're currently using a heavier oil than stock.

Bmacleod had an excellent suggestion to double check the oil level. If its too high the compressed air becomes another spring in the system, and could explain your symptoms.

I think I recall reading that the 1300 springs are much shorter than the 1100 springs, so I won't try to advise you at all regarding springs, hopefully the 1300 riders can offer experience and advice regarding that.