Fork spring differences

[Kazoo]

I'm in the middle of putting in new .38 RaceTech springs to replace what I thought were .35 stock springs. Now out of the forks, I see the stockers measure about 467mm, yet the manual says that fork spring free length is 457.5mm. Could these be aftermarket springs? Am I reading the manual wrong?

Now, the new .38s measure about 472mm -- not much longer than what I've got now. Does the extra stiffness come from heavier material? Except for the extra 5mm length (which is nothing) the new springs look identical to the existing ones.

 

[owenlo]

Well it sounds to me like your not sure what springs are in your forks now but you do know what springs you want to put in. Since you already have the replacement springs, Just go ahead and put them in and forget about the old ones. You obviously bought the correct springs for your weight, RIGHT? So if this is the case install them and toss the others. THEN YOU DO KNOW YOU HAVE!!! JMO

Obie#8 :thumb:

 

[jeffw]

My racetech .38's were about 5mm longer than the stock .35's but I didn't measure either for total length so I can't help ya there. In any case the extra 5mm length will give you 25-30 mm of preload if you re-use the stock spacers, which is too much imo. Use the aluminum spacer material that came with the springs instead and try 10mm like the instructions reccommend.

 

[fatty_k]

When I measured my stock springs, they were about 30mm longer than what it says in the manuel. If they are aftermerket, they should have a number stamped on the top or bottom. I didnt see a stamp on the ones I pulled out, so I assumed they were stock.

 

[canyncarvr]

I'm looking at a stock '00 200 spring...no part numbers anywhere. They are 470mm long.

Same as my aftermarket springs (out of honda wrapping..for an XR400). No part numbers there. No numbers on the eibach springs (2 sets) I had in previously, either. ;)

The different lengths you have don't necessarily mean a thing. Just 'cuz it's longer doesn't mean it's a higher rate or a higher capacity. Actually, neither does thickness necessarily have anything to do with rate.

Unless you go to the trouble of testing them, you kinda have to trust the people what sold 'em to 'ya.

......which takes you back to what owenlo said in the first place...;)

 

[Kazoo]

No (owenlo), I don't know what springs I want to put in. My concern is that the new springs are no better than the existing ones, in which case I'll gladly take back my $100 Cdn pesos and put them into a spring that will make a difference.

Question remains, if length and thickness (canyncarver) don't necessarily have anything to do with spring rate, what does? What makes one spring heavier/softer/stiffer... than another?

 

[owenlo]

Quality of steel and tempering and manufacturing control the spring rates along with thickness and length. Just so happens that same length and thickness don't mean they are in fact the same rate spring. And if you have bought new springs and did not consider your weight when buying them then YES the first thing you SHOULD do is return them for proper springs for your weight. When you do get your new springs dont even compare them to the old ones just install per instructions and you cant go wrong. If you need help with choosing the right spring just call fredett racing and they will help you out. Here is there number>>> 708-946-0999 Good Luck.

Obie#8 ;)