Found a problem in my front forks today!!!

[crxtasy169]

Went to do my front forks today all went well, but on break down I noticed something was wrong from the factory. The springs were installed in both forks upside down! the spring has a tight wound end and an end with the coils spread apart more, the end with the tighter coils should go up because they are heavier and that means that has more weight to move when compressing if it is on the bottom. Its called unsprung weight. The action is the same no matter which way the spring is placed, but with it placed at the top the shock doesn't have to move as much weight from bottom to top thus for making it more active and reactive. I don't know if this was the way Buell meant for to do it or if it was an accident (by the new guy),but if your doing you forks and you find the tight coils are down, when you put them back together do you and your suspension a favor and put the tight coils on top!

 

[upthemaiden]

Maybe a new guy thought the heavier part at the bottom would lower the center of gravity. I always wondered why springs were wound tighter at one end.

 

[BuellerPilot]

There wound tighter for a progressive compression compliance. The tighter winds require less weight/force to compress than the more open winds, so the tighter winds soke up little bumps, as those coils stack up the coils spaced further apart begin to compress upping the spring pressure and take the larger hits. Their "progressive" springs were one wound equally top to bottom would be "linear".

~Mike.....

 

[konarider94]

im guessing it was assembled correctly although your logic seems correct. buellerpilot also sounds like he knows what he is talking about. I highly doubt they built the forks at buell but its possible. Im thinking they are built at showa and they usually know their own product.

 

[anrkizm95]

im with kona they were assembeled right.if they were done by showa

 

[crxtasy169]

Im pretty sure they were wrong I do this for a living I'm a certified motorcycle tech.

 

[crxtasy169]

Look same principle with a set of civic race springs, note the orientation of the lettering it tells you the correct positioning of the springs.

 

[anrkizm95]

thats right i forgot you were a tech in that case ill take your word for it.sorry that being said it must have been at buell i dont think showa would have made that mistake.

 

[crxtasy169]

Maybe they were installed by this guy!!!

 

[anrkizm95]

i take that back manual states tighter wound portion of spring goes down.maybe buell reversed it for a good reason.

 

[crxtasy169]

Took it for a test ride and seems better to me. Where did you find it in the manual?

 

[anrkizm95]

page 2-74 note between step 16 and 17.

 

[anrkizm95]

if it really seem better after a long test ride in some twists let me know i may do the same to mine since i need to do my oil and seals this winter.

 

[crxtasy169]

Just took it to the construction zone over by my house for a fast run it's much smoother to me, will hit some twisty's tomorrow and give some feedback! Also going to call my instructor from Suzuki he's a good friend of mine still.

 

[crxtasy169]

It doesn't say anything about which way it goes in my manual!

 

[crxtasy169]

Just talked to my little brother he went to MMI at the same time as I he says tight wound side up too, to save unsprung weight as well. Im still saying Buells wrong or it was a mistake.

 

[mxracer409]

I feel like there is more to the unsprung mass issue. Simply placing the tighter coils at the "top" would physically make sense because the tighter wound coils contain more mass in their "section" of the spring. However, now the quick acceleration portion of the spring is actuated through the length of the loosely wound spring. That is the part that doesn't make sense to me. now, in order for the spring to absorb small chop, the entire mass of the loosely wound section has to accelerate upward into the tighter portion to absorb the small bumps. This to me seems like adding more unsprung mass.

If the spring where placed the original direction, with the tighter coils "down," when the wheel accelerates sharply up, the quick accelerating portion of the spring is the closet and would react accordingly. Allowing the "top" loosely wound section to stay stationary until needed.

From a purely physical sense I would say placing the tighter coils up would be correct. however I question the decision to place the tight coils up when the dynamics of the suspension are taken into account.
Im not a mechanical engineer (actually electrical engineer). But it doesn't seem to add up to me.

 

[crxtasy169]

True very valid assumption but wouldn't the weakest part compress first even if it is higher up top? I don't know for sure anymore with all of the second guessing going on, but I couldn't wait to take it out so I took it out on another run and burned some curve and all seemed well. If the manual says it goes down then perhaps tomorrow I will switch it back. The way I did it was the way I was taught in school!

 

[Dinuns1]

Crx , since your a motorcycle tech , im sure your familar with progressive suspension? am i correct in assuming this . well there fork springs are ''PROGRESSIVELY WOUND '' and they have a tight side and less tight side . well stated in there directions , it doesnt matter which way the springs are installed as it makes NO difference , yet they do reccomend a way which i find strange but a company that specializes in suspension says this . So i dont think they were installed wrong. Sorry ,if you think theres a difference its psych .

 

[mxracer409]

You would be correct in that the "weakest" part of the spring would compress first regardless of orientation. however I feel like with the weakest part up top at the fixed point, any mass below it must move get the spring to respond. And now since the "strongest force" portion is at the bottom it wont compress but it must physically move vertically to get the "weakest" portion to compress. Thus it seems to me that more mass is being thrown around which adds the unsprung mass total.