xr400 spacer and preload

[Woodbyrd]

I finally made the dicision to try the xr springs. I got the .40's because I weight 195 in just shorts. I measured the springs and they came upto 535mm each. Now when I put the spring in fork and I attach the fork cap there is about .5mm to 1mm space left at the top. I am assuming (hopefully not making an A** of myself) this lenght would be the spacer and any extra I added would be the preload.

Now my question is, can I use washers along with the one factory washer (the ones with the lip) to make up my preload and spacer becuase the distance is so small? If I can is there any type of metal that reacts poorly with suspension fluid to stay away from?

Thanks
Woodbyrd

 

[moridin]

If you go with 8mm of preload for 9 to 10 total (what is 1mm between friends), you are looking at about 1/2".

For that kind of sze, the schedule 40 PVC should work really well.

I think my length was 7/8" as I had 9mm to make up and went with 9mm of preload.

I just cut mine on a power chop saw - cut was perfect.

 

[Woodbyrd]

Moridin,

I only have a hand saw. I do not think I will get to good a cut from that. Let me see if I can find a friend who has a table saw I can barrow for 2 minutes.

Did you find the 8-10 mm preload and spacer better for the riding you do? I was thinking of starting small, somewhere around 3-5 and then working up to find the perfect ride. I would still like to have it kindof soft because I rarely leave the ground and there is a lot of rocks and roots where I ride.

 

[moridin]

I find the 8-10 works really well. I spend 90% on single track littered with rocks and roots - it is such a difference from stock it is hard to explain. They are by o means harsh and you have a much more positive feel over stock. I think the 3/4" ish spacer cut square will work really well with you. You can experiment with oil levels to fine tune a bit.

I think the washer concept will cause problems.

Sean

 

[Woodbyrd]

Sorry my computer decided to loose a HD.

Moridin,
Did you have the stock valving in? I am looking for the same plush ride the old springs gave but better. I decided to go with the 2 stock washers put back to back, this gives me about 3.20mm preload. I am going to try this while I work on getting a spacer cut. I will only get a short chance to try this Sunday I will let you know what I think about it.

 

[motorider200]

I put xr springs in my bike and cut the spacers out of PVC. I cut it with a jig saw and then sanded it down two the correct length. It doesnt have to be a neat cut if you sand it down so you can use about anything to cut it. I dont remember the exact length i think they were around 8mm and i used the stock washers.

 

[Braahp]

I have a cool little Excel preload/suspension calculator that someone passed on to me. I can't attach it here so email me RippinR@citlink.net if anyone wants it. You can plug in all different spring rates and preload amounts and it will show you force, travel, etc.

 

[Woodbyrd]

Braahp,
I already have that sheet, Thanks for sending it to me. I am still looking at a way to improve it.

It turned out that I have used both washers to make my preload and put it back together. You know what, just the springs and that little preload makes a world of difference!!! I did not get any real riding in, just stumps in the back yard but it was a real difference. I look forward to taking it out to the woods for a real shake down so I can see the true difference.

 

[canyncarvr]

I left out one washer to get down to the preload I wanted (about 3mm). I'd rather have used it, but would rather do without the 1.5mm it would have added.

Actually, a bit more than that because the spacer (pvc) I did use would've had to be longer to accomodate the 'lip' on two centering washers.

Your assumption is correct.........IF you also take the washer/spacers into account. You didn't mention them........

 

[Woodbyrd]

Canyncarvr,

If I left out the washer/spacers (the ones with the lips) I had no space between the spring top and the fork cap. This is where I thought I will not really need a spacer I can just use washers. I measured the both washer/spacers and they measured 3.20 mm, this would take me to my preload I wanted. I had to deal with the lip on the washers so I placed them back to back, one lip inside the spring and one lip inside the fork cap. Seemed to fit real nice with no slop in the washers or spring. Plus my springs measured out to be 3mm longer than yours did, 535mm.

 

[canyncarvr]

I never tried the fit of the washers with the lip IN the cap. That's not the measurement I needed.

As long as the lip fits inside something......right? You're not putting the force of the spring on the lip but the flat of the spacer?

 

[Woodbyrd]

Correct, I am having the force applied to the flat space of the washer and not the lip. I plan on a good shake down this weekend. But just from my short ride and eyeballing it, it looks perfect.

It seems to be going better than I expected.