XR 4 vs FRP .39's and spring questions in general

Well in my xr600 the aftermarket springs are about 50-70mm shorter and thus you have to use the supplied PVC pipe to make spacers. It was enough that I would bottom on the spacer before the forks would reach full travel.

Check the link on Ebay for those springs that I found. $35 plus shipping is cheaper than either one you mentioned.

Fatty_K, it can be hard, I went through this myself. None of the springs have markings, so I guess the ONLY way to be sure of what you have is to either a) get your spring rate measured or b) buy a new set.

When I did all this I initially measured my spring length and they were indeed a little longer than spec. maybe 10mm or so. I decided that the chances of them being aftermarket springs were low, so I went ahead and purchased new ones. At least then you know what you've got.

I purchased Eibach springs to suit an XR400, for approx $75 US. They measured up at 512mm compared to the 470mm of my stock springs. I believe the OEM handa springs are longer again (canyncarvr reports around 530mm from memory) and are hotwound, whereas my Eibachs are coldwound.

As to the debate about hotwound Vs coldwound, well I know nothing about either process so I'll leave that one to the experts. Suffice to say that I personally don't believe cold wound springs are any more likely to collapse than any other process. I certainly haven't had any problems so far.

So I suppose it all comes down to money, and personal preference. I guess that the longer OEM spring would be more likely to ride higher, but I could be wrong. Either way, I'm sure you won't be unhappy with the result.

Hope this helps a bit.

Cheers,

Dazza uses XR400 springs. Likes 'em quite a lot.

The coldwound=hi fail, hotwound=won't isn't my idea. Got that from jeremy (mxtech). I HAVE had a failure (collapse) of a coldwound spring. Certainly it isn't true that ALL of them do that. Just a higher %. If YOUR springs fail, that's 100% failure rate for YOU.

It's not the length of the spring of course that determines where the forks 'ride'. It's a combination of spring rate and preload. Use exaggeration to make the point. Take a five foot long spring that looks like something out of a ball point pen. You're going to be real low in the stroke with that spring!

BTW...the reference to no preload. You don't want that. Also, don't mix up the preload spacer length with the preload. Don't know there's anything but clarity on that point..but, well..call it a hunch is why I brought it up.

re: .40 rate for the XR springs. That didn't come from my own self neither. From a local tuner. I know .42s I had were AWFUL...and the XR springs are great. There's more to that than a .01 kg/mm rate diff I'm sure.

That said...anything close to the right rate will be an improvement over the weenie stockers.

Hello folks,

I revived this old thread because right now I'm debating on this very issue myself. ... Still in a quandry as which way to go. I was wondering if fatty_k purchased the frp springs and if so do you like them?

... And if you like them, what rate did you get and are you using the stock spacer as such? How much do you weigh with full gear? Thanks.

canyncarvr
I did use em and yes they "my opinion" the best spring to suit the std KDX fork.I found a second hand set put em in 8mm preload and never had a problem.
can not compare them to my new white powers as it is an unfair comparison.
You will not have a problem with the Honda springs.
At least you will get a tube full of spring.

A few months ago I decided to revamp my front forks with Gold Valves and new springs. I thougt it would be cut and dried. What a nightmare of suggestions I got. I searched threads and must have called 10 different people and got 10 completely different ideas on what spring rate I should use. Race Tech and their online calculator as well as speaking with them on phone was useless. They suggested a .46kg spring. Yeah right...maybe if I was a bigtime motocrosser. Fredette made the most sense with his belief that anything stiffer than .39kg will beat you to death on the trails. Still getting different opinions I bought FRP .39kg springs and XR400 springs which I was always told were .40kg. The installation is so easy I ened up switching back between the FRP and XR400 springs to compare numerous times. With oem preload and 10mm preload. What woked best for me was the FRP 22lb springs with oem pre-load. The XR400 springs felt very simlar but I just didn't like the ride with only 10mm preload. Maybe the FRP springs worked best because of the GV stack specs Fredette setup for me. 10mm preload just felt like nothing to me....others use way less but I don't get it. I weigh 220lbs and the 39kg springs work wonders in the trails but bottom pretty easily on MX track. But hey, I rarely ride MX. The XR springs can be bought for about $60 Us dollars from Service Honda. Not sure what that is in Canadian. Its amazing how preload correlates with spring rate and travel stroke. I've got a handy dandy fork spring/preload spreadsheet calculator if anyone is interested just email RippinR@citlink.net and I'll send it to you. You gotta just find what works best for you......one thing for sure its no cut and dried simple answer that all agree on as to which springs you should use.

picky-picky-picky....

In the general scheme of things...make sure the term 'preload' does NOT refer to the length of the spacer. Yeah..they COULD be the same, but probably not.

And the XR springs are only good if they are HONDA springs...not springs FOR a honda from, say...racetech or anyone else. Braahp is very clear on that point..and their is a big difference.

Neither of which may apply to any of these posts...but I've seen the erroneous perceptions before.

re: "10mm preload just felt like nothing to me.."

Different strokes and all that. Absolutely spring choice should be arrived at by a rider's own 'feel' for the situation..NOT what someone else told him (sheesh...or HER!). That said...the above quote is exactly what I was looking for!

An aftermarket set of .40s in my bike and I could feel every pebble I went over. With the XRs (same preload)..I didn't feel any of that sorta stuff...and I don't wanna either! I relate that to the longer spring. Part of the 'slower' impact transfer characteristic of a longer spring.

..which is GREAT.....sez me! ;)

Likely a lot of riders can't/won't buy several sets of springs to 'try out'. My situation worked out that way largely due to mx-tech's (jeremy's) interest in working with me... getting me what I wanted. Braahp's due to (I'm guessing) him being interested in figuring it out for himself. THAT'S the way to go about it!!

Seems most dealers will take back a set of springs if you don't like 'em.

fatty:
If they say '.40' on 'em, either that's what they are...or someone is wrong about something. THAT covers it pretty well, huh?

re: "beat to death on small...." stuff.

Less preload will help that. Is 15mm your preload or the length of your spacer? Shouldn't need more'n 5mm actual preload. Changing from a 10w fork oil to something lighter will help. MX-tech recommends Mobil1-ATF which is generally considered to be around 7w. AND..(you're gonna love this), what will REALLY help is a revalve.

..well...and XR springs......;)