Proper springs! Who can I trust?!

[jesusmannen]

Im a 40 years old b-rider. Havent been riding for a couples of years. Earlier I could use stock suspension springs. Now I lost some weight and feel like Im not that fast anymore.

Do You guys out there suggest me to respring the bike? I weigh about 155 lbs in my underwears.

Racetech suggest 0,42 springs for my weight!?

Stock is 0,47 and the bike is a crf 250 2013

Rear sag is 30mm/95mm with stock spring.

Forks feels a bit harsh

[j368]

Have you tried to soften up the compression yet? Where are the comp & rebound clickers set at now?

[mlatour]

I found the Race Tech calculator to suggest slightly too soft front springs rates in my application.

 

From your CRF's stock .47 to .42's is a big step, you may only weigh 155lbs but that's still a heavy bike for .42's

 

Pretty sure the Race Tech calculator takes into consideration your are also using all of their suggested components and settings :

meaning their RT Gold Valves / stacks / oil level etc.

Edited November 18, 2015 by mlatour

[mossman77]

The 2004-2009 manual says 0.45 kg/mm and 5.3 kg/mm for the stock spring rates.  Did they stiffen things up for the 2012?

[susco64]

Im a 40 years old b-rider. Havent been riding for a couples of years. Earlier I could use stock suspension springs. Now I lost some weight and feel like Im not that fast anymore.

Do You guys out there suggest me to respring the bike? I weigh about 155 lbs in my underwears.

Racetech suggest 0,42 springs for my weight!?

Stock is 0,47 and the bike is a crf 250 2013

Rear sag is 30mm/95mm with stock spring.

Forks feels a bit harsh

Racetech calculator will get you close. You will benefit from lighter springs.

Things to remember:

Honda lists their rates in N/mm, most other spring manufacturers use kg. Do the conversion.

Industry standard production tolerances are +/- 5%, in other words a spring marked 5.0 could range from 4.75 to 5.25.

Your sag is adjustable with pre-load rings on shock. Do the free sag/ static sag math to determine if your spring is correct.

[mossman77]

+/-5% seems high. If the tolerance is that much, then why do they sell shock springs in 0.1kg increments and fork springs in 0.01kg increments?

[jesusmannen]

Have you tried to soften up the compression yet? Where are the comp & rebound clickers set at now?

Suspension clickers is set to standard, from the manual.

The problem is the breaking bumps in the end of straights... So it feels like the first 4-5 inch of travel needs to soften up a bit.

Im thinking about buying 0,43 springs and remove 5 face shims on base stack.

What do You guys think of that as a start?

[jesusmannen]

Racetech calculator will get you close. You will benefit from lighter springs.

Things to remember:

Honda lists their rates in N/mm, most other spring manufacturers use kg. Do the conversion.

Industry standard production tolerances are +/- 5%, in other words a spring marked 5.0 could range from 4.75 to 5.25.

Your sag is adjustable with pre-load rings on shock. Do the free sag/ static sag math to determine if your spring is correct.

Sag measurements is 30mm static and 95mm race sag

Edited November 19, 2015 by jesusmannen

[susco64]

Sag measurements is 30mm static and 95mm race sag

How much pre-load is on spring? Ideally you want 6-12mm. If you have 0 pre-load and only 95mm race sag, then you do need a lighter spring.

Race sag should be set between 95-105, depending on track terrain, rider style, and fork set-up.

Play around with fork compression and rebound to try to make it more plush.

[mossman77]

From what I've heard/read, your race sag should be between 100mm and 110mm, and free sag between 30mm and 40mm.  In that case, you're pretty much spot on, which makes sense since the bike is setup for a 160 lb rider.  If you wanted to, you could back off a bit on the preload so that you have around 100 mm of race sag and 35 mm of free sag.  I'd recommend a fluid change on the forks and experiment with fluid levels and clicker settings before you start replacing springs and removing shims.

Edited November 19, 2015 by mossman77

[jesusmannen]

How much pre-load is on spring? Ideally you want 6-12mm. If you have 0 pre-load and only 95mm race sag, then you do need a lighter spring.

Race sag should be set between 95-105, depending on track terrain, rider style, and fork set-up.

Play around with fork compression and rebound to try to make it more plush.

Should I measure preload from the big locking nut or the top of the spring? From lock nut I have about 1/2 inch, 12-13 mm

[jesusmannen]

Then I could go with 35/105mm without any problems, as I can see

[mossman77]

You don't need to measure preload. Just set your sag to 100mm or 105mm then if your free sag ends up under 40mm you're e good.

[susco64]

Pre-load is measured from the springs free length to the compressed length. Pre-load is fairly critical especially when lighter that stock springs are being used. Try to get a 4.1kg spring to have 40mm of free sag with 100mm of race sag on a CRF250 with a 100lb rider. Won't happen, bike weight is too much for that light of spring. Pre- load becomes only gauge of correct spring rate.

[mossman77]

I agree. My point was that the OP doesn't need to be concerned with measuring his preload. He simply needs to set his race sag, then measure where his free sag ends up. If he ends up between 30mm and 40mm then he's good to go.

[jesusmannen]

I agree. My point was that the OP doesn't need to be concerned with measuring his preload. He simply needs to set his race sag, then measure where his free sag ends up. If he ends up between 30mm and 40mm then he's good to go.

Then I am good to go then! Thanks guys!!

Edited November 20, 2015 by jesusmannen