Stock front forks

[robfriedenberger]

Kept stock weight, didn't want to change damping speed.


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[robfriedenberger]

Just added some more to each side, it nice and firm now! It's up to 450cc on each leg , is that to much ?


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[jsyzdek]

I'm reading the thread and come to conclusion I need to check my fork, too. With gear and backpack I weigh about 210 lbs. And when I brake hard I totally hit the limits. No fun. Bike's from 2006 and judging how it was mistreated by the previous owner - the fork oil has probably never been replaced, or even checked.

I was considering getting the sonic springs. Do you think I should go for the 0.85 or 0.9?
When I order the springs do I need to order anything else? I heard something about PVC tube that you need to cut to size... Is that right? Or springs come with everything I need?

[BockinBboy]

I have .85 sonics... I bought them when I weighed 190lbs(maybe another 10-15 with gear)... Then lost  30 lbs in ten weeks, and another 10 since, and I was riding often during that time. What I noticed was that at 190 the .85s were great for everyday easy riding. But they were still lacking if I was pushing through the twisties. Now at my current weight of 150 the .85s are on the verge of  being too stiff for everyday easy riding, but excellent for riding more spirited - which I now do more often than not anyway. Now depending what kind of riding you do, you may want them softer or stiffer, but from my personal experience I'd suggest .9s only knowing your weight... But the best person to chat it out with would Rich Desmond who is a member here on the forum and owner of sonic springs.

- Bboy

[robfriedenberger]

Were finally getting a break in the rain so today Ill be taking it out to push it. I weigh 200 with out gear and maybe another 10-15 with so it should be interesting to see how it dose!


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[burning1]

I'm pretty sure stock is 15 or 20. 10 is way too light.

100mm should be okay with the stock springs. Eyeball it to make sure that you aren't going to hydrolock when the forks bottom out.

[BockinBboy]

Stock is indeed 10W  ... I had also replaced with 10W when I swapped for sonic springs.  I have since replaced with 15W, and I have been satisfied by the change.  Before, just the springs were a huge upgrade so I it was hard to notice or realize the 10W was too thin.  I suppose it may depend on the conditions in which you ride and the damping you actually need for that, but 15W was more suitable for my conditions... and I think most folks would find 10W is too thin also if they experienced the difference.

- Bboy

[gsJack]

Just added some more to each side, it nice and firm now! It's up to 450cc on each leg , is that to much ?


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[robfriedenberger]

Thanks for the info, I was just wondering if any one had any Info when hydrolocking becomes possible, I haven't bottomed them out yet but I did take a ride with my wife and I was impress how it handled under breaking. I was lazy after I realized it wasn't much better after u changed the fluid to stock levels, so instead of ripping every thing apart I jut topped it off while on the bike. So idk what the level is at right now. I don't think I'll bottom them out under normal conditions now, even under heavy breaking (almost and endo) they don't bottom out!


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[jsyzdek]

the best person to chat it out with would Rich Desmond who is a member here on the forum and owner of sonic springs.
- Bboy

I heard about Rich before, how do I find him here?

and do I need PVC piping?

Another quesion concerns this:

It states the oil level without the spring and with the fork compressed. Now, sonic springs are longer and have larger volume of metal. And from the pictures I've seen - you don't need the big spacer that comes in originally. Is there a correction factor for these changes? or do I just take my original springs out, spacers out, suck the old oil out, pour new oil in up to 99mm from top, drop in the new springs, spacers(?) and put the caps in?

I really wanna do it, just want to be sure I'm not missing anything. I wanna do this the easy way, like described here (except using sonic springs):
http://pantablo500.tripod.com/id2.html

[BockinBboy]

Sonic Springs come with PVC which you cut to size (1'' diameter schedule 80 I think, and cut them level with top of fork tubes).  They also come with some washers to help zero in on your sag.  I wish I wrote down what I put into each fork, because I did do it the 'lazy' way too when I replaced my springs... I had drudged up a number in mm from the top, posted on the forum from someone who had done it the 'correct' way first, and later measured what it was when they were not compressed.  I marked a tube to that length in mm and siphoned it to the correct level using that mark... Now, I still have the tube, but the mark must have worn off because its not there now!  I want to say it was like 115mm or something, but I really cant be for certain on that, because now I'm thinkin' maybe it was 120, 130, etc... So hopefully someone can fill in that void for us - its really bugging me!

- Bboy

[gsJack]

I have the Progressive front springs and they specify a 140 mm (5.5 in) oil level to accommodate the heavier springs.  Don't know for the Sonics but it's probably closer to the Progressives than to the stock springs.   Will add to above info.

I took the Progressives out of my 97 GS and put them in my 02 the easy way.  Just hung the front end and sucked out some oil to drop them in, no need to pull fork tubes.

[andymach23]

I have just fitted Hagon progressive springs to my 98 GS and it has transformed it. I'm a lighter rider and was bottoming out the suspension regularly. The bike is so much better now.

The stock springs are truly poor. 

[RichDesmond]

Just added some more to each side, it nice and firm now! It's up to 450cc on each leg , is that to much ?


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Way too much. The stock level is on the high side to begin with. Also, you really should set the level rather than use a volume measurement.

[RichDesmond]

I'm reading the thread and come to conclusion I need to check my fork, too. With gear and backpack I weigh about 210 lbs. And when I brake hard I totally hit the limits. No fun. Bike's from 2006 and judging how it was mistreated by the previous owner - the fork oil has probably never been replaced, or even checked.

I was considering getting the sonic springs. Do you think I should go for the 0.85 or 0.9?
When I order the springs do I need to order anything else? I heard something about PVC tube that you need to cut to size... Is that right? Or springs come with everything I need?

0.85s for normal commuting/touring, 0.90s if you're riding more aggressively. 15w fork oil. The springs come with the spacer material, washers and instructions.

[jsyzdek]

I'm playing with my band tonight, gotta take the 4 wheels...

I should have a little more time next week. I'll place the order then and get going with this. I ride sort of aggressively, but I'm still learning. My guess is that it will only get more aggressive as the time goes by...

Any fork oil you recommend, apart from being 15W? does going cheap really affect anything? or you just pay premium for the name but there's no significant difference in performance/durability?

[burning1]

Just added some more to each side, it nice and firm now! It's up to 450cc on each leg , is that to much ?


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Oil level is measured by height from the top of the fork tube with the springs out and the fork fully compressed. Measuring the volume of oil is wildly inaccurate. Getting the fork oil level correct is critical for performance; the air gap is part of your suspension system; it stiffens the forks up as you near bottoming out. Even a couple of MM height change makes a big difference.

With the stock springs, 99 is a good starting point. You can go as high as 90mm.
With after-market springs, 120mm is a good starting point. You may be able to go as high as 100mm, but that's dangerously close to hydrolock.

[burning1]

Thanks for pointing this out. Stock is indeed 10w; I ran 15 weight on my race bike, BUT... That weight is with emulators, which can blow off to let more oil through the forks. Stock forks don't have a blow-off valve, and 15 weight can be dangerously stiff. I had issues on the track with terrible rebound performance when the forks were cold with 15 weight; the tire would easily slide due to overly stiff rebound.

[robfriedenberger]

Well I took it all back apart again, removed the spacer spring and washer, the oil level was at 30mm compressed, so I drained it back down to 100mm, my buddy suggested that I pump them slowly for 10 minutes to allow any air pockets to come out, it seams like it's back to normal again, I see a spring upgrade, or fork swap in my near future.

Also cornering was slightly scary with the front end that ridged


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[burning1]

That doesn't surprise me. You were probably down a couple inches of travel. Glad your seals are okay.