sonic spring info

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Thinking about going to 1.2 sonic springs.
Will be keeping oem rear for now.
230lbs
What spacer length
What oil depth
What weight oil worked for you?
Remember I am still using the soft oem spring.
Thanks
 

T_C

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Larry,
I emailed Sonic earlier this year, I upped from stock to 1.2 springs also, gave my weight of 230# and said I do more touring then carving.

From them:
Sure, I've attached the instruction sheet. Only thing I'd change is oil
weight, go to a 7-8w fork oil for the type of riding you do.
If you don't have the spacer material with the springs it's just 1"
schedule 40 PVC. A 10' stick is just a few dollars.



Oh... looks like the instruction sheet is a word document, let me see if I can get it posted somewhow.
T
 

T_C

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Okay.. parsed out the relevant data.
ST1300 Notes:

10w oil set at a level of 125mm, and spacers cut to 130mm are a good starting point. On reassembly, there is a stock washer that goes between the spring and stock spacer. In our setup you move that washer to the top, between the spacer and fork cap, and then use the washer we provide between the new spring and new spacer. 4 washers come in the package, but you only need to use 2 of them.
 
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Igofar
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After talking to the nice gentleman at sonic springs today, I've decided to order a set of the 1.2 springs, cut the spacers to 125mm, use 7.5 wt. oil per his recommendation at 125mm down the tube, and see if that helps my sagging front end. I tried the nylon tie check tonight...It sags over an inch just sitting on it, and moved the tie 4 inches just coming to a gentle stop in the driveway.
I'm also thinking about ordering a complete rebuild kit for each fork leg and replace all the bushings and seals etc.
For some reason, I'm getting a clanking sound when I push down on the forks, that can be both heard and felt through the grips, and its not the steering head bearings.
Will update this thread after my install when the parts arrive.
Igofar
 

dduelin

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Good deal. Glad to help.

Just my opinion.......lots of folks apparently like the Sonic spring but if you put 115 lb rider weight or 315 lb rider weight the Sonic calculator recommends the same 1.2 kg/mm spring. That dog won't hunt.

Race Tech's calculator gives a wide range of spring rates based on different rider weights which makes more sense to me but use what works for you.
 
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Good deal. Glad to help.

Just my opinion.......lots of folks apparently like the Sonic spring but if you put 115 lb rider weight or 315 lb rider weight the Sonic calculator recommends the same 1.2 kg/mm spring. That dog won't hunt.

Race Tech's calculator gives a wide range of spring rates based on different rider weights which makes more sense to me but use what works for you.
Funny I just ordered a pair of .95's for the Strom yesterday, and I played with the calculator some, changing the bikes and my weight five or six times to see the result, it worked fine for me.
One thing I did notice is that all the fields must be filled in to get a response. :capwin:
 

dduelin

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Funny I just ordered a pair of .95's for the Strom yesterday, and I played with the calculator some, changing the bikes and my weight five or six times to see the result, it worked fine for me.
One thing I did notice is that all the fields must be filled in to get a response. :capwin:
Try it with the ST1300 and see if that changes the recommendation.
 

okckeith

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I put in a set back in Jan. I needed to replace my fork seals. I hope you like yours as much as I like mine. I wish I would have done it many years ago.
 
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Igofar
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I put in a set back in Jan. I needed to replace my fork seals. I hope you like yours as much as I like mine. I wish I would have done it many years ago.
I can't wait for them to arrive! What setting did you settle on for your rear preload adjuster after you changed the front fork springs?
Just curious
 
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I believe they max out at 1.2 for Sonic Springs. Therefore the bike and even a light rider equal their heaviest spring depending on the style of riding you tell it you'll be doing.
I don't believe it is the calculator being broken or not working, it is saying what it is programmed to do. A 130 lbs rider and 735 lb bike, spot touring, set for relaxed cruising get a 1.0. More rider weight equals 1.1, then the jump to 1.2. Then 1.2 is it there is no 1.3.

I tried Race Tech as well. They seem to have a greater selection for my bike, a 2003, but all smaller than I need and their heaviest seems to be 1.0. Even when I overload their weight to generate a 1.2 requirement the heaviest available is a 1.0.

I do believe other manufacturers make more selections and have a greater variety available, at a greater cost.

Just my observations for the "calculators".
 

dduelin

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I can't wait for them to arrive! What setting did you settle on for your rear preload adjuster after you changed the front fork springs?
Just curious
There is no hard and fast rule for setting rear preload. Some people may prefer the quicker turn in that lots of preload may give providing the shock spring is good for their weight. Using sag numbers can give some objective targets for preload. The rear spring on the ST is fit really for only the lightest of solo riders. Heavier riders need lots of preload to hit decent sag numbers and this tops out the spring when the bike unloads the suspension. FWIW I once made a chart that correlated my rider sag with turns of preload and lines on the Showa adjuster. After time though I just know I like about 7 clicks when unladen and chillin, about 10-12 if unladen and riding in a sporting manner, adding more clicks if packed for a trip - adjusted for chillin or hauling the mail on tight roads. I weigh about 150-155 in street clothes and 20 more in gear. A heavier rider would need more clicks to equal the same sag.
 
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okckeith

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I can't wait for them to arrive! What setting did you settle on for your rear preload adjuster after you changed the front fork springs?
Just curious
I never touched it. I'm probably 3/4 hard. It is a little stiff. But it is smooth as can be when I'm loaded. I just keep it that way.
 
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Thinking about going to 1.2 sonic springs.
Will be keeping oem rear for now.
230lbs
What spacer length
What oil depth
What weight oil worked for you?
Remember I am still using the soft oem spring.
Thanks
I went with:
1.2 Sonic Springs
140mm spacers
125mm oil
7.5w BMW fork oil

I'm also 330lbs (was more when I did the build), so your preload needs may vary. I can always crack open my forks and take preload out if needed. So far, it's fantastic, and like everyone else, I wish I did this when I first got the bike.

On top of this, I've also swapped in a Progressive rear shock, and highly recommend that as well.
 
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Highrider

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I can't wait for them to arrive! What setting did you settle on for your rear preload adjuster after you changed the front fork springs?
Just curious
Made the change about 6 years ago, also went with 1.2 Sonic Springs, 140mm spacers, 125mm oil level, 7.5w fork oil (50% 5W / 50% 10W), stock rear spring at full preload. I'm also at 220 lbs.
Amazing improvement, the ride will seem a bit stiff at first, compared to what your coming from. You won't realize the full potential of the change until you make your first panic stop!!.
Last year I put a Racetech rear shock on, I should have done that sooner.

 
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Made the change about 6 years ago, also went with 1.2 Sonic Springs, 140mm spacers, 125mm oil level, 7.5w fork oil (50% 5W / 50% 10W), stock rear spring at full preload. I'm also at 220 lbs.
Amazing improvement, the ride will seem a bit stiff at first, compared to what your coming from. You won't realize the full potential of the change until you make your first panic stop!!.
Last year I put a Racetech rear shock on, I should have done that sooner.

I have the racetech .95, with this setup I did a full blown hammer to the metal panic stop. So much the abs kicked and I swear I did a stoppie. My helmet hit the windshield and broke my sunglasses inside my full faced arai helmet. But the bike stopped clean and straight on a down hill slope with no avenue for escape. I do not think I could have done this with the stock springs.
 

dduelin

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I have the racetech .95, with this setup I did a full blown hammer to the metal panic stop. So much the abs kicked and I swear I did a stoppie. My helmet hit the windshield and broke my sunglasses inside my full faced arai helmet. But the bike stopped clean and straight on a down hill slope with no avenue for escape. I do not think I could have done this with the stock springs.
Quite possible with stock springs with the correct preload.
 
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