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Old 01-05-2013, 06:00 PM   #1
VargasD OP
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Yet another 800GS front suspension thread. This one is for noobs

I'll start out by saying I'm not a hardcore off-roader. I use my bike for my week-end job commute and for some leisure 300 km-400 km rides along twisty roads and gravel paths around towns in Costa Rica.

I think my 2009 F800GS is well-suited for the kind of riding I do. It's not too heavy, it's height is about right, and it has a nice engine. But then I rode 1.600 km on a G650GS Sertao covering a bicycle race this past December. I immediately noticed that the front suspension was firmer and did not dive as hard as my F800GS (on a cheaper bike!!!). I confess I kind of liked that front suspension better... but just the suspension.

I started reading about complaints on the F800's forks. "Too soft, too crappy" is what I mostly ran into.

So here's the thing. I'd like a firmer front suspension... just a tad firmer, but I don't believe I need a super-pro front fork setup.

Different oil, progressive springs, or just live with it. Does it make sense to put in springs just on the front? Will a different oil give me a little bit of firmness that I'm looking for?

I'd like to hear from more experienced F800GS owners their take on this.

Pura vida!
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Old 01-05-2013, 06:04 PM   #2
zig06
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Compression or springs ...

Have you tried increasing the compression damping? Or do you feel that it was stiffer because of the spring rate?
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Old 01-05-2013, 06:37 PM   #3
VargasD OP
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You lost me there. I'm just getting familiar with the suspension terminology. But as I understand it, the front suspension on the F800GS is non-adjustable. Can adjusting the rear make the front better in any way?
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Old 01-05-2013, 07:40 PM   #4
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Quote:
Originally Posted by zig06 View Post
Have you tried increasing the compression damping? Or do you feel that it was stiffer because of the spring rate?
How are you going to do this on forks that are not adjustable?

I wish I could give some advice, but I haven't done anything on my 2013. Mostly because there is nothing out for it. Supposedly Ohlins is releasing a fork cartridge kit for the 2013 for a reasonable price. For you I would probably say the Hyerpro spring update would be ideal.
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Old 01-05-2013, 08:08 PM   #5
runnin4melife
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Vargas,

Sadly you have to meet this head on. I just searched and found this decent write-up for suspensions. Learn the jargon, the mechanics and go from there.

http://www.sportrider.com/suspension...pension_guide/

If you do not want to go with an adjustable fork, then springs and different viscosity oil might be the best option for you. This is a quick fix that many people like. After you read up on suspension, then come back to the forum and search it (I usually search via google, what ever I want + advrider typed in the search box).
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Old 01-05-2013, 08:09 PM   #6
itsatdm
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More preload can be done by putting a longer spacer under the spring. The stock front spring is .46kg. It is soft for most riding, I would just replace it.

Something I sort of know about, as I have had a Hyperpro variable rate 52-74kg, Bitubo .60kg and a .55 Ohlins in my forks.

The Hyperpro is a pretty good bang for the buck. I do think that the bike weight compresses the spring enought to collapse the lower weight coils together and you end up riding in the heavy portion of the spring.

My current Ohlins spring works well with a pressurised cartridge tube, I suspect it might be still a little light for the stock cartridge, for my riding.

I loaned out my Bitubo spring to a friend and he wanted it for his bike. I would try that one, depending on what you weigh. That spring is longer than the others and may not need a spacer with the stock cartridge.

10 wt oil seemed to work best for me along with a greater than stock air gap. Keep in mind there is no standard for oil viscosity. Hyperpro and Bitubo supply rebadged oil that seems similar.

I never thought about the shock until I resprung the front. It is not all that bad but you will notice it in comparison to the front. You also might get a bit of hobby horse effect. I did, so I resprung the rear also. Still have my Hyperpro rear and I think works pretty good.
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Old 01-06-2013, 05:08 AM   #7
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For a very informative read on dualsport suspension I recomend buying Neduro's Ebook.
He wrote it with someone from SuperPlush Suspensions.

I have it and read it before I decided to blow the bucks from working too much last year.

After reading it I started to understand what the more experience people were trying to say, and what the company's are trying to claim about there products.

I just can't tell why there is such a huge price difference between a Bitubo, a Traxxion, and an Ohlins.

Good luck an take the time to read through much of what's here in ADVrider, there is alot of knowledge and you get to learn from others mistakes
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Old 01-06-2013, 09:07 AM   #8
VargasD OP
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Thanks guys. Did a couple of things yesterday on the subject. 1, I read a bunch of info and saw some videos on suspension basics just to understand the basic terms. 2, Checked out my bike's owner's manual and they actually give you basic settings on the rear suspesion. Realized I had those messed up, changed them and took the F8 for a quick ride... no magic changes, but it's a good start to have the bike the way BMW intended it to be and improve from there.
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Old 01-06-2013, 11:26 AM   #9
toowheels
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Quote:
Originally Posted by VargasD View Post
Thanks guys. Did a couple of things yesterday on the subject. 1, I read a bunch of info and saw some videos on suspension basics just to understand the basic terms. 2, Checked out my bike's owner's manual and they actually give you basic settings on the rear suspesion. Realized I had those messed up, changed them and took the F8 for a quick ride... no magic changes, but it's a good start to have the bike the way BMW intended it to be and improve from there.
Good that you did some reading to get the basic knowledge! Knowing that will obviously give you a better understanding of set-up and options for changes.

That being said I would recommend the Hyperpro progressive springs. The problems with stock are the springs are too soft for most (depending on weight and riding style/terrain) and poor valving (primarily compression damping) which leads to spiking, sitting too deep in the travel and bottoming too easily. Those both also lead to the "excessive" brake dive.

Hyprepros progressive springs keeps a soft initial stroke and then ramps up keeping the fork higher in the mid-stroke and then offers more progressive action to prevent bottoming.

They work! I noticed an immediate difference throughout the range. Better small bump performance, better mid-stroke performance (less spiking and blowing through the travel), less brake dive, and very good bottom out resistance.

They come with oil too which too which you'll definitely want to do if you've not changed the oil on your forks. The oil is a slightly different weight (that's a whole other story since unlike engine oil fork oil weight is not standardized) and works well too.

Here's page 8 of the major thread that talks about the Hyperpro options:
http://www.advrider.com/forums/showt...=527133&page=8

lazy install method on page 10 of that thread:
http://www.advrider.com/forums/showt...527133&page=10

Lot's of "experience" from itsatdm on there . One of the first to try a myriad of suspension options for us!
Thanks!

It's easy to do and a relatively inexpensive way to make a big difference to the ride on both road and gravel/dirt IMHO! Hyprepros (or the like) I think will work well for you.

Pre-load on the back end of the bike is also very important to the handling so make sure you change it depending on what you're carrying! If it's too soft the bike doesn't want to turn as well for one.

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Old 01-06-2013, 11:06 PM   #10
Snowy
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Increasing the spring rate will increase the effect of compression damping.




So if you are searching for a particular setup, you may not want to increase spring rate AND use thicker oil straight up. Do one, ride it a few times, then do the other. You may end up draining the oil out and going back to the standard grade. It depends on where/how you ride, and exactly what sort of springs you got for your weight.

To make sure you understand WHAT changed in setup, you should only make one change at a time and then give it a good evaluation. Preferably over the same ground at the same speeds.
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Old 01-07-2013, 09:23 AM   #11
itsatdm
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Lets not put too much thought into this, this is basic suspension. Both front and rear are sealed units. There is no compression adjustment for either end, no preload or rebound for the front. In other words, there is not much you can do.

The OP did not say how much he weighed or what he carries on the bike. IMO anything over a 185lb would benefit with respring, more so, if doing any type of bumpy terrain.

Hyperpro springs give a pretty detailed instructions. You can buy a "kit" that includes front and rear springs along with the oil.

The forks are cartridge type, meaning on compression, the oil is forced around washers held in a stack of them. Enough compression force bends the edges allowing more oil to pass. Changing viscosity forces the oil to bend the washer rather than go around the edges. It just won't flow fast enough other wise. It slows the compression of the spring.

It is hard to explain the sophistication of the valves when crimped into the tube. They are pretty budget/basic.

Springs store energy when compressed. Once the force compressing them is released, they spring back. That rebound has to be controlled also. Again it is the viscosity of the oil that determines that, usually by being forced through a hole near the top of the cartridge tube.

Air gap is the volume of air left in the fork when compressed. Oil won't compress, but air does. More air will soften a ride, sometimes to the point of allowing the forks to bottom out, more oil will aid or prevent that.

The year I spent trying to turn the stock forks into something I could live with resulted in numerous oil viscosity's, air gap and preload adjustments(changing spacer height, even used spacer springs)

For my weight, terrain and riding style, I should have just followed the instructions. It was educational.

As for doing both springs? I recommend it. You will have different rated springs front vs back. They will compress and rebound at different rates.

I call it hobby horse effect, you feel it as two separate events as the bike travels over a bump.

When tuning suspension, it is easier to match valving with straight rated springs. Tuners hopefully match valving and most good suspension has controls to fine tune it. Variable rate springs complicate the tuners job, in trying to match valving need with whatever spring weight as it compresses. You don't have the ability to fine tune. I think I could do better experimenting with a straight rated spring.

For the average rider, the Hyperpro is pretty much plug and play and will cover a wide range of riders.
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Old 01-07-2013, 12:05 PM   #12
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perfect !

itsatdm, toowheels, snowy.

thank-you,

for my purposes, thats just the information i was looking for.


itsatdm, in a different thread you talked of shortening the springs by 3/8" or so, but i think now you are suggesting "follow the instructions" and ride.

i can do that!

thanks.

bb.
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Old 01-07-2013, 02:06 PM   #13
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My final solution did just that. I shortened the spacers to 7/8" long. I do not remember how much shorter than stock. I ran the fork tubes in the stock location. You lose a little suspension travel that way.

Beside the weight balance issue, I found that while I had proper sag according to the "Internet Guru's" more than half of it was the bike weight alone.

You compress these springs over an inch just to get the cap on, couple that with the weight of the bike, caused me to believe the closely wound coils were being compressed together, turning them into spacers themselves and by the time my weight was added, I was actually riding a heavier portion of the spring.

I thought cutting the spacer would alleviate some of that and soften the initial stroke. Provide a little more room, so to speak. Whether that had any merit depends on what the spring did with me on the bike. I really did not detect any great suspension improvement but still think weighting the front did improve front end tracking.


That is one of the reasons that I now think I could have done better with a straight wound spring. But I would have had to do all the oil weight, height, air gap, spacer size BS all over again.

Beware though, spring replacement is just bait. Before you know it you will find the bike handles better and you can go faster than before.

Then you discover the real problem, your valving can't cope with your new found skills. It sucks.
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Old 01-09-2013, 03:34 PM   #14
toowheels
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Yes I agree Snowy! You should always do changes in increments.

I didn't do the oil when I did the Hyperpro springs for that reason and also since I'm light I didn't want to change the compression damping (and rebound which I generally prefer fast). I suggested it for the OP since his oil will be due for a change since it's a 2009.
Although the theoretical weight difference between 7.5wt (stock) and the Hyperpro 10wt. is possibly "virtually undetectable" especially since it's not standardized, riders say they have felt a difference in feel for the better. If only fork oil weight was standardized that would make it all much easier. Then there's air cap as itsatdm mentioned.

Go by the "book" for starters...

I also forgot I wasn't going to post suspension info without my weight etc!
I'm about 170lbs. (77kg). with gear. So at the lower end of the spectrum. I ride fast and fairly aggressively on dirt (only one dent in the front rim though!) so that will affect the set up too and then there's rider preference. I'm happy with the improvements the springs made.

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