F800gs and Hyperpro review

[The Griz]

Originally Posted by tmex

San Jose BMW put my rear spring on the OEM shock for about 1/2 hour of shop labor (less than $50). I did the springs up front which I have done many times before. It is quite easy. If you do not change the oil you can leave the forks on the bike.

I had my F8 with the Hyperpro out today for the first time despite broken ankle not fully mended. Kept 30 PSI front and rear just to work the suspension harder. Did about 60 miles of mostly dirt with some very cobby tarmac connectors. I was impressed by the improvement over stock. I kept the OEM oil just in the spirit of not changing too many things at once.

It is difficult to compare suspension changes unless you can compare things fairly quickly. Your brain has a hard time recalling exactly how the old one felt versus how the new one feels. The biggest difference that I think I noticed was how well the bike glided over dirt with lots of embedded rocks. The old front would just beat you to death on that stuff. The Hyperpro seems to just glide over it even with 30 PSI. I did not do anything that would have tested bigger hits. One thing I noticed was that the bike would "judder" a bit coming to a final stop. You could only notice it on smooth pavement. I never felt that before. Could it be the Hyperpro up front? Don't know.

Thanks for the review tmex. Again, I'm excited to get the Hyperpro springs kit. So the front end was considerably better over the hard edged bumps?

One other question too. How do you orient the spring in the forks and on the rear shock when you put them on? Softer side with tighter winds to the bottom? Or Firmer side with looser winds to the bottom?

[tmex]

Originally Posted by The Griz

Thanks for the review tmex. Again, I'm excited to get the Hyperpro springs kit. So the front end was considerably better over the hard edged bumps?

One other question too. How do you orient the spring in the forks and on the rear shock when you put them on? Softer side with tighter winds to the bottom? Or Firmer side with looser winds to the bottom?

On the front I put the tighter wind side down simply for pragmatic reasons - I could access the damping rod retaining nuts more easily. On the rear the tighter wind is facing up. I can think of absolutely no physical reason why it should make any difference. The way I read the Hyperpro instructions is that they recommend putting the tighter wind up in both cases.

[Maddaddy]

I'm a bit confused by the whole "dirt bike" mentality. The fact that people are disappointed that it doesn't ride like a dirt bike straight off the show room floor baffles me.

Originally Posted by NAZDirt

It now rides like a dirt bike.

I'm not trying to bash anyone here (too hard ) But i don't seem to recall anywhere in the 800 campaign that this was classified as a dirt bike.

The suspension is a hell of a lot better than the 1200, but it's not a KTM.

I have modified my bike for it's stock short comings, but I was never surprised by any it's needed improvements.

ok I'll stop now.

[NAZDirt]

Since the bike is a dual sport by definition is should be able to handle both terrains. For the price I would hope it could do better than a street bike on the dirt. I am not suggesting you can take it to the motocross circuit but it should be able to travel on a gravel road with out shaking itself to death.

If you are happy with yours great.

For the rest of us that want to ride as it should this is a cheap fix.

Originally Posted by Maddaddy

I'm a bit confused by the whole "dirt bike" mentality. The fact that people are disappointed that it doesn't ride like a dirt bike straight off the show room floor baffles me.

Originally Posted by NAZDirt

I'm not trying to bash anyone here (too hard ) But i don't seem to recall anywhere in the 800 campaign that this was classified as a dirt bike.

The suspension is a hell of a lot better than the 1200, but it's not a KTM.

I have modified my bike for it's stock short comings, but I was never surprised by any it's needed improvements.

ok I'll stop now.

[The Griz]

I by no means have been 'disgusted' with the suspension on this bike. I actually like the stock Sachs/BMW rear shock. The front end however, is a bit too soft for me in the mid and end of the stroke, and it's initial beginning of the stroke is to hard. I just figured as long as I'm putting Hyperpro progressive springs and Hyperpro 10w oil in the forks, why not put a Hyperpro progressive spring on the rear too. And for $252.50 for the entire kit, I couldn't pass it up.

[itsatdm]

I was one that was very disappointed in the bikes suspension. Not that I wanted to ride single track or motocross, but I did expect to ride some Sierra forest service roads that any two wheel drive pickup could manage.
It is not that it couldn't, it was all the harsh feedback through the suspension that radiated both through the bike and me. The most disapointing, was that BMW chose to put some very low tech suspension on this bike, that made it very difficult or expensive to fix even to the levels I wanted to go. BMW did advertise this aspect of the bike and even got positive feedback, but for the life of me I can't understand why.
If stock is OK with you, thats all right with me, I have managed to make enough mods that is does fine for what I will use it for and I realize that it does have limitations.

[bxr140]

Originally Posted by tmex

I can think of absolutely no physical reason why it should make any difference. The way I read the Hyperpro instructions is that they recommend putting the tighter wind up in both cases.

Unsprung weight.

The end of the spring with the coils that are spaced closer (not technically any "softer" than the other end, but that's a tangential discussion...) are the first to touch each other as the spring compresses. As that happens, those coils essentially become a solid mass. If that mass is on the bottom, its always moving with the suspension. If that mass is on the top, as the suspension compresses the total unsprung weight actually decreases.

Is spring orientation really an issue on the F800GS? Considering the rest of the suspension, I doubt it.

[tmex]

Originally Posted by bxr140

Unsprung weight.

The end of the spring with the coils that are spaced closer (not technically any "softer" than the other end, but that's a tangential discussion...) are the first to touch each other as the spring compresses. As that happens, those coils essentially become a solid mass. If that mass is on the bottom, its always moving with the suspension. If that mass is on the top, as the suspension compresses the total unsprung weight actually decreases.

Is spring orientation really an issue on the F800GS? Considering the rest of the suspension, I doubt it.

The springs are not part of the "unsprung weight". The wheels, calipers, and lower fork tubes are. The springs are essentially part of the sprung weight.

[bxr140]

Originally Posted by tmex

The springs are not part of the "unsprung weight".

Unsprung weight, by definition, is the stuff that moves as part of the suspension. In suspension theory, springs are considered semi-unsprung, since their mass doesn't count 'one-for-one' with the mass of the fully suspended components. Its similar to the semi-unsprung effect of a rear swingarm or a control arm in a car's suspension...but again, that's another discussion.

In the specific 'progressive' circumstance described above, the fully compressed coils of the spring become dead weight. You'd have a similar situation if you cut the spring and put a slug of metal in its place. If that dead weight is below the spring, it is most certainly "unsprung".

[tmex]

Originally Posted by bxr140

Unsprung weight, by definition, is the stuff that moves as part of the suspension. In suspension theory, springs are considered semi-unsprung, since their mass doesn't count 'one-for-one' with the mass of the fully suspended components. Its similar to the semi-unsprung effect of a rear swingarm or a control arm in a car's suspension...but again, that's another discussion.

In the specific 'progressive' circumstance described above, the fully compressed coils of the spring become dead weight. You'd have a similar situation if you cut the spring and put a slug of metal in its place. If that dead weight is below the spring, it is most certainly "unsprung".

I see your point.

[NAZDirt]

Wow, well said by both sides. That was the best discussion with oppposing views I have heard yet without crying and name calling.

For the naysayers on which side goes up.... I was told orientation doesn't really matter since the valving is the same over the entire travel and it is not dynamic like many high end shocks used in the racing industry.

[bxr140]

Originally Posted by NAZDirt

I was told orientation doesn't really matter since the valving is the same over the entire travel and it is not dynamic like many high end shocks used in the racing industry.

Unfortunately...

The previous 'progressive spring orientation' issue aside, which way the spring is oriented has no bearing on which end of the spring compresses first. In a nutshell the "softer" end will always compress first, regardless if its on the top of on the bottom. For a straight rate spring, the compression is basically even across the length of the spring.

Furthermore, the valving of the GS's suspension is indeed 'dynamic'. Its not as sophisticated as many higher end shocks, but the way it works is more or less the same.

[NAZDirt]

I agree the softer part will compress first. During this segement of shock travel the dampening is going to be softer/slower than when say hitting the ground hard from whoops. The shocks are only dynamic in that the pressure of the fluid flow will change through out the cycle and "affect" dampening. If we had high end shocks we would be lucky enough to have bypasses and multiple valve rates as the high end shocks get.

Originally Posted by bxr140

Unfortunately...

The previous 'progressive spring orientation' issue aside, which way the spring is oriented has no bearing on which end of the spring compresses first. In a nutshell the "softer" end will always compress first, regardless if its on the top of on the bottom. For a straight rate spring, the compression is basically even across the length of the spring.

Furthermore, the valving of the GS's suspension is indeed 'dynamic'. Its not as sophisticated as many higher end shocks, but the way it works is more or less the same.

[bxr140]

Originally Posted by NAZDirt

I agree the softer part will compress first. During this segement of shock travel the dampening is going to be softer/slower than when say hitting the ground hard from whoops.

But that's not really exactly true. When describing damping characteristics, "soft" leads to higher speeds, and "hard" leads to slower speeds, not the other way around. Also, the damping characteristics of the suspension are speed dependent, not position dependent. So other than the effect of the progressive spring on the F-M-D system (which basically make the suspension travel faster and feel "softer" at the beginning of the travel), its largely irrelevant where in the travel the suspension might be when determining the actual damping.

Originally Posted by NAZDirt

If we had high end shocks we would be lucky enough to have bypasses and multiple valve rates as the high end shocks get.

I'm not sure I'm pickin' up what your puttin' down. We do have "multiple valve rates".

[The Griz]

I'm chompin' at the bit to get these springs!!

They're not shipping until Wed due to my special black rear spring request.