Jump to content
Sign in to follow this  

.45 or .47 fork springs q?

Recommended Posts

Hey guys, so I'm about to get some stiffer fork springs and I'm using the race tech calculator and need some feedback on what rate to chose.

 

 I'm about 165/170 pounds,Enduro/Trail riding/A-Class.  

 

The bike is a 1999 XR4 with 6 shims removed from the "center bolt" and 4 inches of oil height with stock springs and a fork brace.  It doesn't take much to bottom it out HARD right now.  The forks are incredibly too soft and I have the clickers all the way in.

 

If I select 30-44 as the age classification, Race Tech recommends a .47, if I switch to 45 and older, it recommends .45.

 

I'm leaning towards the .47 and looking for feedback from anyone whose been in my shoes.

 

I'm 44 now and will be 45 in a week, hope this makes sense.

 

 

Thanks

 

 

 

 

Share this post


Link to post
Share on other sites

Forget the calulator unless you are racing SX. It is WAY OFF for offroad riding and most MX.  I weigh 185lbs and the stock springs are more than enough. I only removed 3 or 4 shims. I believe 6 shims out is way too much. I use Maxima RFF 5wt at 110mm.  Be sure to set rear sag to 105mm. That is a bit more than normal but the bike handles better that way.

Share this post


Link to post
Share on other sites

Thanks Dwight.

 

I'll start by putting 2 or 3 shims back in.  I took out the shims and put the brace on all in the same job so I'm not sure what made them so soft, probably a combo.

 

I will say, after the work, she is plusher and handles better but she bottoms out big time it I hit pretty much anything with bad intentions.

Share this post


Link to post
Share on other sites

For your wight 6 shim remove. .43 springs 2 1/2 wt oil. This is for trail riding. Take ractech bible throw away,try not to use ractech springs in Xr4.They dont fit right,ill fitting.

Share this post


Link to post
Share on other sites

The .47s offer a 15% increase in stiffness over what I believe is in there now.  As I mentioned the forks bottom incredibly easily so I went with the .47s and will report back once installed.

 

The fork brace removes allot of flex and therefore transfers more of the weight directly down to the front axle, this is the reason I shied away from the .45s.

 

I got Eibach springs and expect to have to DIY  spacers.

 

 

We'll see......

Share this post


Link to post
Share on other sites

I'm 230lbs and .47's are perfect for me for dual sport riding.  Agree on the .43's which is about stock isn't it?

Share this post


Link to post
Share on other sites

I weigh the same as you and I had .46 springs for a while in mine. I found that you will not have enough rebound damping (stock set up) with springs that stiff. Your front end won't settle in for turns and the bike will handle like a dump truck. That was my experience anyway. I went back to just 1 rate above stock (sold my stock springs then wished I hadn't) and set the oil height about 5mm higher instead. That will decrease the air volume and help with bottoming more than springs will while still leaving the initial couple inches of travel nice and plush.

 

I would suggest only .41 or .42 springs at the most. The 96-97 XR's had .38 springs stock and the 98 and newer had .40 stock and lighter comp. damping.

 

Just my 2 cents! Good luck!  :thumbsup:

  • Like 1

Share this post


Link to post
Share on other sites

Thanks guys, looks like I may have swerved and over corrected  :facepalm:  but it's OK, it will eventually work out. Like Momma always said, education ain't cheap :confused:  I continue to learn that lesson.  :doh:

 

So if these end up being way too stiff I can use one  and come in at a .44 rate overall, provided what's in there is .41. At .44 it's a 7% increase in spring rate as opposed to 15% with the .47's.  

 

I can say this, what is in there right now will not work and it's not even close!   I have a high fork oil level with a thicker oil and the clickers all the way in.  Since they aren't marked  I  can't be positive on the rate but my suspicion is, stock rate.  

 

I've been happy with the Race-Tech calculator when I've used it for my other bikes, what it recommended for my XR250 was perfect, wish I could find that data but it's long gone.  

 

Thanks again my friends.   :thumbsup:

Edited by BLL

Share this post


Link to post
Share on other sites

I weigh the same as you and I had .46 springs for a while in mine. I found that you will not have enough rebound damping (stock set up) with springs that stiff. Your front end won't settle in for turns and the bike will handle like a dump truck. That was my experience anyway. I went back to just 1 rate above stock (sold my stock springs then wished I hadn't) and set the oil height about 5mm higher instead. That will decrease the air volume and help with bottoming more than springs will while still leaving the initial couple inches of travel nice and plush.

 

I would suggest only .41 or .42 springs at the most. The 96-97 XR's had .38 springs stock and the 98 and newer had .40 stock and lighter comp. damping.

 

Just my 2 cents! Good luck!  :thumbsup:

Thats what we found out .46 springs perfect word Dump Truck handling.That good old beat you to death feeling..Over rock ,roots,square edge.

Share this post


Link to post
Share on other sites

michigan400 and Baja Trail Rider, I'm curious if you ran fork braces and removed 6 shims from the "center bolt?"

Edited by BLL
  • Like 1

Share this post


Link to post
Share on other sites

I bought 46kg fork springs for my 2000 XR250R. They are currently being installed with the Race Tech Gold Valves. I found after fitting a Superbrace to my bike I had a few hard hits and found the limit of the front forks travel - not sure if this was due to fatigue in that they are now 15 years old and had never been adjusted/rebuild that I know or what. Will report on how the new setup goes.

Share this post


Link to post
Share on other sites

I just swapped out springs and raised oil height a touch (just a few mm's) and set rear sag to 105mm and ran the forks flush with top of triple clamp. Setting the sag kind of high at 105 will also take just a little weight off of the front end and help some. 

 

No fork brace but the ole XR with 43mm forks is just about as stable in the soft sand as my KTM is with 48mm legs so it wasn't high on my list.

Share this post


Link to post
Share on other sites

michigan400 and Baja Trail Rider, I'm curious if you ran fork braces and removed 6 shims from the "center bolt?"

Yes 6 shims removed.One of our 400s has fork brace.Ours are set up long distance trail riding (Over 100mile 4/6 days riding) Not racing.I did race a few friends on there 500KTMs over the woops.Managed to stay up with then,but will never do that again.Xr4 not good woop bike.With the stiff spring you want,you will need good valving.Maybe gold valves.The 6 shims remove on our bikes work perfect,I wish our USD fork bikes would work like that. 

Share this post


Link to post
Share on other sites

Ok, I got the 47s in but we're getting rained out so I won't be able to get her out for a while.  It feels fine, not too stiff but I've got to believe I'll need to get a handle on the rebound so the mini saga continues, the forks are back apart.  That being said I am excited to be back on an XR, it's been about 10 years since my last one and I  regretted selling her as soon as she left my garage.  She was a 1996 XR280 with a tag, gold valves, sprung for me and a fork brace.  She was a good girl.

Edited by BLL

Share this post


Link to post
Share on other sites

Quick update:  Took her out yesterday, trails started out slick and muddy but got faster as the day went on.  I slapped the .47 springs in and didn't like the way the bike felt just right there on the ground.   There was no rebound adjustment to speak of and the rebound was off the charts fast.  So I pulled them back apart, figured out the needle/rebound deal, added two shims to the piston on the damper rod, also added two shims to the "center bolt."  Oil height is 4 inches with ATF and rear sag at 105.

 

The bike handles freaking great, tracks straight, dives into corners, plows without hint of diversion, it's AWESOME, for what it is, for what I was hoping for.  

 

Now I'll move to the rear end, where I only plan on lubing the linkage (replacing if needed), servicing the shock and putting a bumper back in, for some reason I either can't see the shock bumper in this bike, or it doesn't have one.

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×