Do I need new springs

Ive been trying to set up my sag in the front aiming for 25-30mm. But I have my preload adjusted the whole way in and I can only get 40mm. This makes me think Ill need new springs for my weight, I have the stock springs in now stock forks that were just freshened up. Is it the springs?

 

Yep. How much do you weigh and what bike?

 

135 w/ gear and its an 01 F4i

 

I can't believe that at 135 you need heavier than stock springs? Are you sure your measuring sag correctly?

 

Yeah at 135 (pounds) if anything you'd need lighter springs... describe how you're measuring sag. Have you tried going the other way on the preload adjusters, just to make sure you're going the right way? (I know, sounds retarded, but wouldn't be the first mistake of that sort I've made.)

 

Front lifted off ground measuring from bottom tripple to dust seal. The forks are conventional. 5.03''


Front on ground w/ rider, Compressed and settle. 3.48''
Front on ground w/ rider, Extended and settle. 3.50''


5.03'' - 3.49''= 1.54'' = 39.1 mm

And I believe that I add preload to bring the number down? I had it set midway and I was getting 45mm. I was thinking I would need softer springs? Reacetech says on their website that the ideal weight for my stock springs is 165.

 

Looks legit to me. Weird that you'd have so much sag being that light though. I'd wait for someone with more experience than me to chime in but yeah, my inclination would also be toward stiffer springs.

edit: Just saw you were thinking about lighter springs.. that's what'd make sense based on your weight but based on the sag I'd be thinking stiffer. Unless I'm totally turned around, possible.

 

Yes your right. If I went softer it would compress even more and I would get a greater sag. Stiffer would prevent compression and reduce sag I was a little mixed up. Could the stock springs get worn out over 9 years and 20k miles? I dont know much about mechanical wear and whatnot. PENSKE said everything looked fine when they refreshed my forks.

 

The stock spring rates in the F4is are stupid light. Like .7 light.

 

Wait, you said front lifted off ground and measured.

Are measuring it with the front extended or are you allowing it to settle and then measuring without rider?

 

Using a tripple stand with the front wheel off the ground. Is that wrong?

 

Okay there is your problem

You want to lift the front up (extend the forks) and then let it settle back down. Now measure. Then sit on the bike, once again, extend the forks and let them settle, now measure again.

Subtract b from a = sag.

 

That measurement is only going to give you the difference between static sag and rider sag.

 

Right.

 

Everything ive read says take a measurment with fully exteneded forks wheel off the ground.
Then do rider measurement ( wheel on ground ) taking 2 measurments with the rider, compress and settle then extend and settle to account for friction/stickyness.

I havent taken any measurments with no rider( wheel on ground ) to get a static sag Ill do that later today and recheck my process.

 

http://www.onthethrottle.com/content/view/73/73/

 

True story

 

At 9:27 in the video he says the topped out travel when the wheel is lifted off the ground is 4.something. So he was going by the manuals topped out measurment. I am actually doing the topped out measurment by lifting the bike. Not trying to be an ass here just want to make sure I am understanding.

 

Could also be that the measurement from extended dust seals to triple is not the true travel length of the forks. There may be an extra 1" of travel your adding that doesn't exist. The manual may actually be correct with the measurement that onthehrottle is using in the video. I know that one time I actually removed and measured a fully assembled fork tube and then compressed it and found that the manual was right on the mark. I think it was a 929 but can't remember for sure.

 

I've got the same bike as OP and manual says 120mm of travel for the forks. I measured that distance from fork seal with fully extended forks and marked it on the fork tube, then used mark on tube for point of reference.