F800GS - RXV Shiver'ed Fork Conversion

On the first page...

So in principle you need to reduce the travel by making a spacer that can be seen in the picture from -W-

Then the next step is to adjust the preload, which can be bit more tricky...

So how does one adjust preload without preload adjusters?

That is an art?

Hi.I know about the spacer but if You see on the picture ,the spring plate is quite to high than the original part.My question is o I need too cut the tube to relocate the spring plate?Thanks.

I did cut the tube and then used the original spring plate. But even by doing that, i struggled a bit with the preload adjustment (minimum was 13mm). Difficult to explain :/

Another option is to use shorter springs...?

Shorten the spring is also an option but I don't want to spend too much money.I've got Hyper Pro progressive springs and I want to use this.Many thanks.

Progressive springs are a tuner's nightmare. They have to valve not only for the usual, but differences in a changing spring weight. I used my Hyperpro springs with a Bitubo insert and they were very harsh on and off road.

Ducksbane on the other hand, used them with his Xbike cartridges on his F800gs and likes them.

Both of these cartridges are different than what you are contemplating, just do not be surprised if they are problematic.

I did not want progressive springs and went to Öhlins... And even got those modified now (shorten)

I think the reason that the progressive springs work for me is that I am using XChallenge cartridges which are much better than stock 800GS ones, but aren't nearly as good as a "proper" Marzocchi Shiver cartridge. About the only successful mod to the XC forks was progressive Hyperpro springs, so I guess this carries on to their new life in the 800.

As few people have ever done this mod and owned both bikes I feel it's safe to say that they definately work better in the 800 than they ever did in the XC!

When I did my Shiver swap 2 yrs ago I had the HyperPro progressive springs. I played with valving, preload and fork oil wt and I was never happy with the performance and was dumping the Shivers in favor of Ohlins cartridges. Then I swapped to single rate Race Tech springs and the difference was night and day. The bike feels planted but not harsh, no brake dive, it floats over washboard and soaks up the big hits. I'm extremely happy with the conversion.

I managed to get a set of RXV Shivers into Australia to do this conversion.
I've stripped these apart and stripped the F8 forks too.

Here's what I've found so far -
The springs from my F8 are 0.5kg/mm and the springs from the RXV are also 0.5s. :huh
Both are the same free length of 474mm.
The RXV spring seat is 21mm higher than the F8 but the spring sits 4.5mm further into the top cap of the RXV, so already there will be a preload height / static sag gain of 15.5mm.
The F8 used a spring preload spacer of 30mm.
The F8 & RXV cartridge bottom out at exactly the same length measure from the top cap but, as mentioned by a couple of the guys previously (and an exceptional write up too), the RXV tops out 40mm higher.


Top is the RXV shiver 45 fork, spring, stripped cartridge & complete cartridge. Then the F8 cartridge, spring and fork.

My plan is to use a 30mm top out spacer and gain the extra 10mm of travel - I'm 6'2" so touching the ground isn't an issue. I'll probably reuse the 0.5 springs and the stock 30mm preload spacer at this stage and see how it goes.
Hopefully the machining can be done this week and I can get it all back together next weekend.

Once again, brilliant write up. I wouldn't have attempted this without the info posted by everyone here.
I'll post more as I go along.

Hi All. After a few weeks of waiting for the same parts I've finish My conversion.Yesterday I rode about 100km.on and off road (gravel ,sand in forrest).Everything works very good. Now I must make more kilometers with screwdriver in the pocket for same settings.Thank for You All and special thanks for -W- and Gangplank for His job. Thanks.

Are the Xchallenge cartridges a direct drop in for the F800GS legs? How much adjustment do you gain?

Yes ... there is no machining, they really do just drop straight in ... but ... you do need a spacer to restrict the travel. I have an extra 15mm. I probably wouldn't go beyond an extra 20mm ... 250mm unless you are going to raise the rear as well.

The other but is that you have to have some springs. I used my Hypepro progressives, but perhaps straight wound springs would be better. I woudn't use the standard springs as they are too soft in my opinion. If you use springs that are designed for the 800GS and you have more travel you will need a preload spacer to take up the extra travel. I rushed this a bit and the only thing I don't like about my conversion is that when you have the 800 airborne there is a slight clck as they top out when the forks fully extend. If I have them apart I will have proper preload spacers machined.

I will have to say something controversial ... the worst problem with the 800GS forks isn't that they are not adjustable ! :eek1

The worst problem with the 800GS forks is that the cartridges are complete crap and don't have a hydraulic bottoming circuit. Therefore they just bottom (frequently) with a big "clack". They are also not rebuildable.

The XChallenge fork cartridges are also not rebuildable and are also crap ! However they are a much better looking effort than the 800's. They also have a bottoming circuit and are sort of adjustable. Each fork top has an adjustment, one for compression and one for rebound. The compresssion works quite well, but the rebound could be better.

So the last question is ... are they any better? The answer ... Yep, heaps. Much nicer bike to ride, doesn't bottom much if at all, has less fork dive on the road and rides much better. It's not as good as the modified XChallenge with its modded Husqvarna cartridges and its 300mm of travel, but its not bad at all. One of the first things I did was ride it down a road that has a lot of water bars and use to frustrate me completely on the 800 (quite liked it on the stock XC !) and it was a whole different experience ... no bottoming (just that clicking when topping out) and it was fun.

I would think this mod is a good one for the average rider who can't get along with the standard forks ... if you are an off road riding God, you probably need to spend more money for something better. I've never got near Mount Olympus so I'm pretty happy!

I wonder if thicker oil viscosity give you better rebound control?

Could do I suppose, I think 10 weight is probably about right in this application ... a lot of people put 5 weight in their standard XChallenges and thought it was an improvement. I'm actually going to try a couple of clicks more rebound next time I ride it, so I'll see what happens.

The major issue with the rebound is (surprise!) that the cartridge with the rebound adjustment could have been better!

PM' you with some questions

Got the machining done last week and it was a perfect job.
Put it all back together over the weekend with no problems


Sag measurements are approximately (I had my wife measure while I held the bike) -
40mm (no rider) & 60mm (with me but no gear).
Now all I need is some time to give it a test ride and see how much tuning it needs.
Assuming it performs as well as others here have had, this has been a cheap upgrade.

Now, any suggestions for the rear ?

I listed my F800GS for sale... forks may be available in a swap + cash. PM me if anyone is interested....

Another one bites the dust...

690 or 990? ;-)

Lol... No thanks. More like an SV650 trackbike & smaller dualsport maybe.
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