CC - important springs Q
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canyncarvr
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- Oct 14, 1999
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cc to ci, multiply by .061
ci to cc, mulitpy by 16.38
Didn't check my math (that's not a good sign! ;) ), but roughly 17cc in volume reduction will get you 12.5mm in level reduction.
So, while oil level is checked with the spring out and the fork collapsed (and held straight up), you can remove a given volume and know the corresponding level equivalent by using a syringe and measuring an amount taken from each fork.
If you know you are starting from an 85mm level and you remove 17cc of fluid, you will have an 97.5mm oil level.
You can't 'remove 25mm' of anything if you're referring to volume. That would be like getting 3' of water. 3' of what? A straw? A 6' diameter pipe?
So, using your syringe (probably with a piece of suitable tubing firmly attached, unscrew the fork caps (bike on a stand!), use a bike strap to cinch the wheel up thus pushing the fork springs out of the upper tube (much easier if the bars are off. That only takes a couple of minutes..mark 'em before you take them off so you don't have to mess with orientation when you put them back on).
Insert your tubing and extract 20cc from each fork and give 'em a try.
There was a post recently that had a linear measurement/volume equivalency. A couple of searches and I didn't find it.
Do your own math and gripe at me if I'm off a bunch. I did not allow for rod volume displacement in the listed equivalent. I figured inner fork diameter to be 1.625" or roughly 40mm. Guessed at that from measuring a spring and figuring there to be some space to either side.
Keep track of the numbers so you know next time you do a fork oil change what level you want to use.
Good luck.
BTW..you still running 19mm preload? You changed it?
ci to cc, mulitpy by 16.38
Didn't check my math (that's not a good sign! ;) ), but roughly 17cc in volume reduction will get you 12.5mm in level reduction.
So, while oil level is checked with the spring out and the fork collapsed (and held straight up), you can remove a given volume and know the corresponding level equivalent by using a syringe and measuring an amount taken from each fork.
If you know you are starting from an 85mm level and you remove 17cc of fluid, you will have an 97.5mm oil level.
You can't 'remove 25mm' of anything if you're referring to volume. That would be like getting 3' of water. 3' of what? A straw? A 6' diameter pipe?
So, using your syringe (probably with a piece of suitable tubing firmly attached, unscrew the fork caps (bike on a stand!), use a bike strap to cinch the wheel up thus pushing the fork springs out of the upper tube (much easier if the bars are off. That only takes a couple of minutes..mark 'em before you take them off so you don't have to mess with orientation when you put them back on).
Insert your tubing and extract 20cc from each fork and give 'em a try.
There was a post recently that had a linear measurement/volume equivalency. A couple of searches and I didn't find it.
Do your own math and gripe at me if I'm off a bunch. I did not allow for rod volume displacement in the listed equivalent. I figured inner fork diameter to be 1.625" or roughly 40mm. Guessed at that from measuring a spring and figuring there to be some space to either side.
Keep track of the numbers so you know next time you do a fork oil change what level you want to use.
Good luck.
BTW..you still running 19mm preload? You changed it?
- Aug 11, 2002
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No, I am still running the stock spacer.... I'm going to replace it to make the preload about 9mm. I hear some 8's and some 10's so I'll go with 9mm. I don't know the actual preload... The way I did it makes since to me... preload means how many mm the spring is compressed (by the spacer) right? if that is true then my method must be right.... I dunno, it just seemed to easy to be right.
I'm going to probably test that (preload) without changing the oil height. This way I know what adjustment does what and go from that. I won't have much time to get it done before sunday though. I don't want to get started and not be done in time or be hurried and forget something. I could probably do it after school tomorrow but then I wouldn't have time to get used to the feel. I'm going riding instead to get used to it as it is now.
I'm going to probably test that (preload) without changing the oil height. This way I know what adjustment does what and go from that. I won't have much time to get it done before sunday though. I don't want to get started and not be done in time or be hurried and forget something. I could probably do it after school tomorrow but then I wouldn't have time to get used to the feel. I'm going riding instead to get used to it as it is now.
Hondaxrguy
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- May 17, 2001
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Removing your forks, adjusting your oil level correctly, and reinstalling the forks should only take about 20mins if you've done it before. Well worth the time IMO. I'd think it'd take longer keeping the forks on the bike, and you still don't know exactly what your oil level is at.
Jeremy
Jeremy
canyncarvr
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- Oct 14, 1999
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Too much preload for sure (19mm)!
If you have actual honda springs, they are hotwound and won't have the collapsing tbls that coldwound springs often have. So, a 'skinny' preload setting isn't a problem.
What's important is where in the fork stroke the bike is operating. Reduce your preload...a lot, take out some oil and from there play with your clickers (turn out, likely) a bit. All of that will have the effect of lowering the 'operating' range of your forks.
Bet you'll like the change.
If you have actual honda springs, they are hotwound and won't have the collapsing tbls that coldwound springs often have. So, a 'skinny' preload setting isn't a problem.
What's important is where in the fork stroke the bike is operating. Reduce your preload...a lot, take out some oil and from there play with your clickers (turn out, likely) a bit. All of that will have the effect of lowering the 'operating' range of your forks.
Bet you'll like the change.
I'm not so sure that we don't have cold-wound and hot-wound confused. Unless the same principles used in manufacturing cold rolled and hot rolled steel aren't applied here, cold wound springs are more expensive to produce b/c all the metal modifications are done at room temperature, whereas hot-wound springs are done under heat (obviously). Metal loses a certain amount of resillience and strength after being subjected to heat, so it seems to me that cold-wound springs would be better.
I wonder if hot-wound means that they anneal the spring after it's coiled? If this is the case, it makes sense that hot-wound springs would be better (and more expensive). Annealing (or baking) takes a lot of the residual stresses out of the metal, assuming it's cooled back down slowly. It would allow smoother motion and larger deflections. If cold-wound means it hasn't been baked, it would still have a fair bit of internal stress within the spring material. Is that right? I know it's off topic, but I thought it was kind of interesting. Anyone know what the diff is between hot and cold wound springs? How did this come up anyway? ;)
canyncarvr
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- Oct 14, 1999
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The information I listed came from jeremy wilkey of mx-tech.
My knowledge of the spring making process is zip.point. I had an eibach spring failure (collapse) that led to the conversation I had with mr. wilkey regarding aftermarket spring quality (cold) vs: oem (hot).
He said coldwound (most if not all aftermarket) springs be bad...oem springs (hotwound) be good.
I've looked briefly at the mx-tech site for some such note. Didn't find it.
A google search turn up:
from: http://216.239.57.100/search?q=cach...2010.doc+spring+hot+cold+wound&hl=en&ie=UTF-8
I'd suppose from that simple statement that mr. wilkey has determined that the properties he is looking for in a bike fork spring are better supplied by a hotwound spring.
roland: Check the listed link and you'll read exactly what you said (relieving stress, baking, residual stresses and such).
My knowledge of the spring making process is zip.point. I had an eibach spring failure (collapse) that led to the conversation I had with mr. wilkey regarding aftermarket spring quality (cold) vs: oem (hot).
He said coldwound (most if not all aftermarket) springs be bad...oem springs (hotwound) be good.
I've looked briefly at the mx-tech site for some such note. Didn't find it.
A google search turn up:
from: http://216.239.57.100/search?q=cach...2010.doc+spring+hot+cold+wound&hl=en&ie=UTF-8
I'd suppose from that simple statement that mr. wilkey has determined that the properties he is looking for in a bike fork spring are better supplied by a hotwound spring.
roland: Check the listed link and you'll read exactly what you said (relieving stress, baking, residual stresses and such).
Last edited:
Jim Crenca
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- Mar 18, 2001
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But to keep it all in perspective...
When Jeremy did my forks, he said that only a pro would be able to tell the difference between Honda springs and good aftermarket units. He WOULD order the Honda springs but said it just wasn't worth it. I wish I could get excited about riding fast again; my shoulder still hurts from a fall last November, the weather stinks, and I'm afraid of another good smash up at age 45.
Fork springs don't matter as much if you're just trail riding... :whiner:
When Jeremy did my forks, he said that only a pro would be able to tell the difference between Honda springs and good aftermarket units. He WOULD order the Honda springs but said it just wasn't worth it. I wish I could get excited about riding fast again; my shoulder still hurts from a fall last November, the weather stinks, and I'm afraid of another good smash up at age 45.
Fork springs don't matter as much if you're just trail riding... :whiner:
canyncarvr
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I've looked for some expert input on the issue. Didn't find exactly what I was looking for. Posted the question on the suspension forum. MarcusG was nice enough to look well enough to find what I'd missed. His post:
This is what jer posted
(I'm taking some liberty with the quote part..MarcusG didn't use ""..)
Note mr. wilkey saying, '...can be reset after...'
This tends toward the idea of applying heat after the extrusion process (as collegeman ;) roland said), not extruding hot metal. Hence maybe the confusion in the first place over the term 'hotwound'.
I stick by the idea originally expressed..that 'hotwound' is preferable to 'coldwound'.
This is what jer posted
(I'm taking some liberty with the quote part..MarcusG didn't use ""..)
Note mr. wilkey saying, '...can be reset after...'
This tends toward the idea of applying heat after the extrusion process (as collegeman ;) roland said), not extruding hot metal. Hence maybe the confusion in the first place over the term 'hotwound'.
I stick by the idea originally expressed..that 'hotwound' is preferable to 'coldwound'.
Jim Crenca
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- Mar 18, 2001
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Sounds like more of an issue of longevity and consistency over time as opposed to absolute performance.
