Different recommended fork spring rate. - Wrist Twisters
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post #1 of 7 Old 06-19-2017, 10:02 PM Thread Starter
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Different recommended fork spring rate.

I'm having a bit of trouble picking out some fork springs. I'm rebuilding my 02' forks with 04' internals and new stuff. Wasn't going to worry about springs as was ok with stock, I never track and only push it sometimes. The roads are bad. Real bad. Gravel, corrugated, potholes, pothills and dead things. I've got a little money to spare so thought I'll chuck in some new springs to suit weight. This is where I have a little problem. I use two spring weight calculator's, sonic springs and race tech. I don't have scales at home but the ladies at the airport let me hop on their scales with my gear on. I weigh 95kg or 210lb with my kit on. Sonic springs calculator gives me two rates depending on the type of bike I select, .85 and .90. Racetech gives me a rate of .95.
I'm thinking with my riding style, bad roads and a preference for a "plusher" ride I should go with a .90? Also the rear shock is a Wilbers progressive spring 180-130. Thanks.

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post #2 of 7 Old 06-21-2017, 08:04 AM
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Quote:
Originally Posted by Islandboy View Post
I'm having a bit of trouble picking out some fork springs. I'm rebuilding my 02' forks with 04' internals and new stuff. Wasn't going to worry about springs as was ok with stock, I never track and only push it sometimes. The roads are bad. Real bad. Gravel, corrugated, potholes, pothills and dead things. I've got a little money to spare so thought I'll chuck in some new springs to suit weight. This is where I have a little problem. I use two spring weight calculator's, sonic springs and race tech. I don't have scales at home but the ladies at the airport let me hop on their scales with my gear on. I weigh 95kg or 210lb with my kit on. Sonic springs calculator gives me two rates depending on the type of bike I select, .85 and .90. Racetech gives me a rate of .95.
I'm thinking with my riding style, bad roads and a preference for a "plusher" ride I should go with a .90? Also the rear shock is a Wilbers progressive spring 180-130. Thanks.
Keeping in mind your rear spring is a 130/180 N/mm (742/1028 #/inch)I'd be trying 0.85 to 0.875 absolute max.
0.95 is simply whacko wrong for your particulars.
Ohlins has a spring that's around 0.88
Racetech needs a .90 and a .85 paired to get a 0.875, so you need a supplier who will break into 2 springs sets to make you up a blended pair.
15 mm of installed preload (that measurement determined with the ride height adjusters all the way out so all rings showing)
And use a higher oil level to give you some more spring effect for heavy braking on good pavement, said oil effect not impacting your described normal riding. Say 140 mm of oil, not 125.
Lightish on the rebound adjustment.
Stick with 10W oil, but use decent stuff.
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post #3 of 7 Old 06-21-2017, 04:38 PM Thread Starter
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Mcromo your advice is well appreciated. I've been agonizing over this for days. Not to sure if my supplier will split sets for me, I'll ask. If not I'll probably go with the .85.
Thanks mate.

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post #4 of 7 Old 06-21-2017, 05:13 PM
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I'm around 230 with gear, I went with .925. I may swap one to get to .900. You'll be fine with .85 unless you're a real aggressive rider.
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post #5 of 7 Old 06-21-2017, 05:21 PM Thread Starter
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I'm only aggressive over taking cars, always last in the pack and I'll wear my back pads out before my front.

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post #6 of 7 Old 06-21-2017, 06:12 PM
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Quote:
Originally Posted by Islandboy View Post
Mcromo your advice is well appreciated. I've been agonizing over this for days. Not to sure if my supplier will split sets for me, I'll ask. If not I'll probably go with the .85.
Thanks mate.
Keep in mind the Ohlins springs.
They have them in a rating roughly 0.88 kg/mm which translates to about 8.6 N/mm which I think are the units of measure that Ohlins lists in.

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post #7 of 7 Old 06-21-2017, 06:31 PM Thread Starter
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I can pick up a pair of racetech .85 springs for about $100 so I'm kind of leaning towards them. If I can find a pair of .88 Ohlins springs close to that price I will consider. Thanks for the help guys.

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