Choosing Fork Springs

Got questions? We got answers....
User avatar
KDX220PHIL
Supporting Member I
Supporting Member I
Posts: 419
Joined: 08:31 am May 19 2005
Country:
Location: Nova Scotia, Canada

Choosing Fork Springs

Post by KDX220PHIL »

I am planning on replacing my factory springs and I noticed that FRP sells .38KG and a .40Kg springs. I weight approx. 160lbs and i know that the factory springs are too weak. I am not sure wich ones to choose they do recomend the .38KG Springs but isn't that just slightly higher than the factory springs. Will there be a noticeable difference. I like to jump my bike whenever i get the opportunity, not on a MX track but smaller jumps on trails (5-7ft high max.). Does anybody know what springs I should go with, and approximate rebound settings? Thanks.
User avatar
Colorado Mike
Gold Member
Gold Member
Posts: 1921
Joined: 11:42 am Feb 25 2005
Country:
Location: Colorado

Post by Colorado Mike »

I weigh about 185-190 with gear, and I put the .38 XR springs in. These made a huge difference. I like a plush ride, but my bike used to be dangerous on rough down hills and jumps. I really don't jump a lot ( I don't really consider going 2' in the air "jumping") so I like my springs. If I did more flying, I'd go with the .40's Since you're lighter you might like the .38's, but if in doubt I would say get the .40's.
Mike

Life's tough, it's even tougher if you're stupid.
'04 KDX220
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

It's all a matter of choice...but I wouldn't waste my money on a set of oem 470mm springs.

Rebound settings? It's unlikely your bike has any unless you added them after you bought it.

If you're referring to the clickers on the bottom, those are compression clickers. Not real effective with the oem valves, but set them as far out as you can and still not bottom the suspension out (all the time). If you hit bottom once in awhile, you're probably OK for the other 99.9% of the time you ride. It's the valve(s) that is (are) supposed to control oil flow anyway..not the metered orifice of the clicker assy.

Quite a few riders have tried the XR springs and like them. I sure do. Yes, I do know of one rider that did NOT like them. I also am aware of several other things he likes that I don't, so I kind'a figured that's just par for his course.

Note the thread started by Tazmanian..the XR springs are not oem length. That's a good thing.

A set of XR .38s will suit you fine.

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
User avatar
KDX220PHIL
Supporting Member I
Supporting Member I
Posts: 419
Joined: 08:31 am May 19 2005
Country:
Location: Nova Scotia, Canada

Post by KDX220PHIL »

Do you think i may require a stronger spring than the .38KG? I like the idea of having more travel, i gather this would give me less chance of bottoming out in comparison to 470 mm springs. I don't have much money after buying a brand new 05' KDX220r, So i hope to make the right decision here. Although, i think anyway i go they cant be any worse than the factory springs.
KDXSean
Gold Member
Gold Member
Posts: 107
Joined: 09:26 pm Nov 22 2004
Country: Canada
Location: Ottawa

Post by KDXSean »

I weigh 195'ish with gear. I put in .40kg XR springs. They work for me.

I'd think the .38kg XR springs would be fine for you. You'll need to make new spacers if you use XR springs and while your at it change the fork oil.

Do a search and you'll find some more info on this topic.
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

I would say (my opinion) that @ 160# the .38s will be just fine. When I put mine in I was just over 180# (no gear) and they worked fine. I'm 15# lighter now..and they're still fine.

I'm not picking at 'ya...but keep in mind that words mean things, and some of the terms you have used concern me in that I'm not sure your questions are being answered.

For example, 'I like the idea of having more travel' has nothing to do with your choice of fork spring. Well, OK...a .52 spring will travel less with the same rider/conditions than a .25 spring, but 'travel' is not a word used to describe that situation.

'Travel' has to do with the available movement of a suspension. The KDX frontend is 10.4" (or so). Spring rate (how much a spring compresses from a given input) doesn't effect the amount of travel available..it just takes more in the way of input to make a stronger spring move a like distance of a lighter rate spring.

A .38 spring will certainly lessen any bottoming situations you have now because it is a higher rate spring than the OEM springs you have in now. The length doesn't matter when it comes to load. .38 is .38 whether it's 470mm long or 530mm long (roughly speaking..there IS a difference, but don't worry about it).

Again, it's not the spring that is handling the oil flow. You may well have the correct spring rate for your weight/riding style and such and still have a number of handing problems if the rest of the suspension (valving for one) isn't any good.

You will be a much better rider with a good suspension than with more power. Riders usually go about it backwards..want all sorts of blingage junk to be cool when the starting point of bike improvement should be the suspension.

Sure. You may require a stronger spring than the .38s. I Doubt it.

Check the RaceTech site and they'll likely want to sell you some .40/.42s. They're always on the high side of things.

BTW, there's a difference between springs from Honda for an XR and springs from an aftermarket mfg. for an XR.

No warranties expressed or implied. Professional driver on a closed course. Do not attempt in your bathtub. Death or personal injury may result.
Last edited by canyncarvr on 01:03 pm May 20 2005, edited 1 time in total.

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
User avatar
KDX220PHIL
Supporting Member I
Supporting Member I
Posts: 419
Joined: 08:31 am May 19 2005
Country:
Location: Nova Scotia, Canada

Post by KDX220PHIL »

Doesnt a 520mm Spring have more travel then a 470mm spring, that is what i was refering to. I thought it meant the length of the spring, and by replacing the factory spacer with a shorter one i thought ths would give me more travel before bottoming. Travel being the top of the spring stroke all the way to the bottom. If this is corrrect would it not give me roughly 50mm more travel? and 50mm less chance of bottoming? correct me if I am wrong, I am kind of new to this.
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

re: Doesnt a 520mm Spring have more travel then a 470mm spring,

No.

re: I am kind of new to this

No problem. Everybody is new to everything at some point in time.

Note: I said, 'there IS a difference, but don't worry about it.' Categorically speaking...from my understanding of what you are asking..the answer is still, 'No.'

The internal workings of the fork determine how much travel you have. 'Travel' is not defined as the distance you can compress a fork before the spring hits coil bind.

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Post by KDXGarage »

Are you jumping 5 to 7 feet high and landing on a flat surface or are you jumping a tabletop, double or what? If this is a single jump landing on flat ground, then I would definitely suggest .40 rate springs.

The amount of travel is not determined by spring length. Getting a longer fork spring will NOT give you more travel. The fork is designed for a certain amount of travel and changing the fork spring length will not affect that.
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
User avatar
KDX220PHIL
Supporting Member I
Supporting Member I
Posts: 419
Joined: 08:31 am May 19 2005
Country:
Location: Nova Scotia, Canada

Post by KDX220PHIL »

Yes, more often than not I am landing on flat ground, and it is pretty rough with the oem suspension. What kind of negative effect would the higher rating spring (.40) have on trail riding? And if I were to buy the .40KG (not that i have decided), would I still be looking for a Honda XR Spring?
User avatar
dave04kdx
Supporting Member II
Supporting Member II
Posts: 256
Joined: 01:01 pm Nov 09 2004
Country:
Location: Casa Grande, Arizona

Post by dave04kdx »

I got the .42KG's for my forks. After the first ride I boxed them up and sent them back for .40KG's. I weigh 205 with gear. The .42kg's beat me to death in the desert terrain that I ride in. The .40KG's work excellent for me.

F.R.P will trade springs within a reasonable amount of time if you dont like the ones you have.
At age 4 success is . . not peeing in your pants.
At age 12 success is . . having friends.
At age 16 success is having a drivers license.
At age 35 success is having money.
At age 50 success is . . having money.
At age 70 success is . . . having a drivers license.
At age 75 success is . having friends.
At age 80 success is . not peeing in your pants.
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Post by KDXGarage »

OUCH! I bet you do have some hard landings. I am glad you already know to get some stiffer springs.

Stiffer springs will make it less plush over gravel, rocks, roots, ruts, small logs, etc. The stock springs will give more on such hits, but as you already know, they give too much on the jump landings.

For now, and possibly even after you get the stiffer springs, you may want to check your fork oil level and go with more oil. Raising the oil level (within the adjustable range) will help to reduce bottoming.

The Honda OEM springs are available in .38 and .40 rates.

On the longer springs, the stock spring spacer is removed and a smaller one is used.

Dave, was it the springs or the valving? :grin: I have heard others complain about the stock valving after going with aftermarket valves and valving. I am just wondering.
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
Wallydog
Member
Posts: 3
Joined: 06:53 pm May 16 2005
Country:

Post by Wallydog »

I put .38 XR 400 springs in my previous KDX. It was a huge difference for all round use. I weigh about 170 lbs. I have a pair of .38 springs for sale in the FS section. You could try them as it is a fairly easy install and good to put fresh oil in the forks also. I went with Mobil 1 ATF with great results. Sell them if you don't like them. Lots of riders like the XR springs.
User avatar
dave04kdx
Supporting Member II
Supporting Member II
Posts: 256
Joined: 01:01 pm Nov 09 2004
Country:
Location: Casa Grande, Arizona

Post by dave04kdx »

Jason

It very well may be the valving on the forks. The forks perform better with the .40kg springs. Revalving the forks and shock is on my list of mods. :supz:
At age 4 success is . . not peeing in your pants.
At age 12 success is . . having friends.
At age 16 success is having a drivers license.
At age 35 success is having money.
At age 50 success is . . having money.
At age 70 success is . . . having a drivers license.
At age 75 success is . having friends.
At age 80 success is . not peeing in your pants.
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Post by KDXGarage »

Thanks for the report, Dave.
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
User avatar
KDX220PHIL
Supporting Member I
Supporting Member I
Posts: 419
Joined: 08:31 am May 19 2005
Country:
Location: Nova Scotia, Canada

Post by KDX220PHIL »

Alright, I have made my decision and I am going with the .38KG XR400 Springs, should I be looking for a specific year? Also does anybody know how much difference it makes to install Race tech's Gold Valves, what is involved and can it be done in the average garage or would i have them installed by a pro.
User avatar
KDX220PHIL
Supporting Member I
Supporting Member I
Posts: 419
Joined: 08:31 am May 19 2005
Country:
Location: Nova Scotia, Canada

Post by KDX220PHIL »

Sorry, Is Race Tech a company that does the installation or provides the kit?
karbon_dunn

Post by karbon_dunn »

They do both, provide the kit and do the installation if so warranted by you. In my opinion get what you want for your setup and do it yourself...I know Jason is laughing at that coming from me. I had Jason do my suspension a couple weeks ago with new gold valving and he went through and inspected everything and let me know what I needed to replace and even went the distance to get all the parts together. I just sent him the $$$. I wouldn't know for sure but I know I saved several hundred dollars by having Jason do it instead of sending them up to Race Tech.
User avatar
KDX220PHIL
Supporting Member I
Supporting Member I
Posts: 419
Joined: 08:31 am May 19 2005
Country:
Location: Nova Scotia, Canada

Post by KDX220PHIL »

Would I require special instructions for this procedure, or would it be covered in the manual? I hope it is just an assembly procedure and not a permanent modification. I dread the idea of cutting holes in my 05' KDX220. HAHA :shock:
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Post by KDXGarage »

Someone in a previous thread mentioned the part number and / or the years in which the Honda XR400's came with .38 springs.

Race Tech (http://www.racetech.com) is a company that makes various suspension products. They make the Gold Valve kit. It is a replacement for the stock parts that control the compression damping. Like karbon_dunn said, they also do suspension service.

No laughing from me, karbon_dunn. I was glad to work on your forks (shock, too!). Thanks for mentioning it. :prayer:

The kit comes with instructions, but there are some finer points that are left out which would make it easier / better. Disassembly of the base valve assemblies is not covered in the OEM service manual. There is more to it than just unbolt, bolt back up.

You can always go with just changing the fork springs now, then changing out the base valving later on if you want. Another company that makes a base valve replacement kit is Racing Suspension Products.

http://www.racingsuspensionproducts.com ... vekit.html

You might want to check into their product.

When you get around to making the cartridge holding tool, you should take the base valves and damper rod out to clean them, as well as to better clean the fork internals. It will show in the OEM manual how to do that. Little bits of metal can float around in the oil, especially when new, so it is a good idea to give it a proper cleaning and fresh oil.

There are a lot of variables that can be adjusted to get your suspension set up for your specific weight and riding style. Be sure to read up on everything. I am sure you can get it better tuned to your needs.
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
Post Reply