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Old 01-26-2010, 05:59 PM   #91
Gunslinger1
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Quote:
Originally Posted by Redbull Addict
So in order to do this, you had to buy the forks, new wheel and hub and disk brake? Did you have ABS before? Did you have to disable it?

........Emig Racing clamps, and the rest is KTM front end....forks, wheel, hub, brakes, fender...totally transformed the bike.....No ABS.
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Old 02-12-2010, 09:11 AM   #92
vince taylor
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Originally Posted by evoluzione
i hope you folks understand that we do a lot of development work that never turns into sellable products for one reason or another. in the case of the front suspension valving, there does not seem to be a lot of customer interest. also, there is the issue that we would need to do the initial modification to the cartridge (requires us to precisely machine the cartridge - if we just sold the valves and let the customer do the final machining and they mess it up, then they would need to buy new cartridges). once we do the modification, the customer will be able to change/adjust shims by themselves.

the bottom line is that if we had enough interest to machine 25 sets then it might make sense to us. i would guess that the cost would be $200-$300 a set including us doing the intial modifications to the cartridge.

Any update ? Is there a chance this might happen before I need to start looking for another set of forks ? I know you have put a lot of time in this and just want to say thanks for all your time and effort.
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Old 05-23-2010, 07:55 PM   #93
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Just bringing this back up again to see if this is still progressing or anything else new out there?

I have tried every suspension shop I can search on the web and no one makes a replacement cartridge for the X Challenge.

There is a company in the USA who could make one up but the cost would be a minimum of $1700usd. Out of my price range.

Just going to fit some Hyperpro springs and new oil to see how that goes and then maybe look at a steering damper to help with the deflection issues if they are still there.

What weight oil have people used?

My full dressed weight (bumbag & toold etc) is 110kgs. 10 weight?
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Old 05-23-2010, 09:05 PM   #94
tbarstow
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TrailTricks.com fixed my front suspension. It was spendy but completely worth it.
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Old 05-24-2010, 09:40 AM   #95
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Quote:
Originally Posted by tbarstow
TrailTricks.com fixed my front suspension. It was spendy but completely worth it.
But what did they do to it TB?
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Old 05-24-2010, 12:03 PM   #96
tbarstow
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Originally Posted by Cruz
But what did they do to it TB?

They respring and revalve the forks. The OEM valves are crimped on (or so I'm told). TrailTricks has the set up to crimp the new valves in. I don't know which valves got put in, but its an incredible difference afterwards.
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Old 06-20-2010, 05:05 PM   #97
davesmyth
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A little Suspension Algebra for the G650X Challenge

Gentlemen,

I've been reading a lot of threads that advocate softening up the suspension to improve the ride of the G650X Challenge. To a certain extent, I agree; especially if you're going long distances on hardball or improved dirt roads. Soft suspension, however, doesn't solve the constant problem of fork dive, and is particularly bad for riding in sand and loose dirt. Here's what I've come up with, so please take it or leave it as you see fit:

BMW sets the Compression and Rebound at approximately +11 clicks from "0" (all the way counterclockwise to full stop). I don't know if this is true across the board, but that seems to be the general consensus. If these settings are made for a 75kg man, then it stands to reason that you can do a little Algebra and arrive at the perfect setting for your weight. I fiddled with the suspension to get the best road setting for me using Pirelli Scorpion Rally tires, front and rear (very aggressive knobby tires, but DOT approved). I arrived at +11 for Compression, and +9 for Rebound. Rear suspension was set to 114psi and "Soft" setting using the following equation: 85kg/ 97.2psi = 100kg/ x. x = 114psi. I used 85kg because 97.2psi is what BMW recommends for a 85kg man in the G650X Challenge Owner's Manual.

+11/ +9 (from "0") is fine for a 75kg man off-road, I suppose, but I weigh 100kg with riding gear. For whatever reason, my Compression adjustment has 23 clicks, while my Rebound adjustment has 25 clicks. Doing some quick math, I realized that my optimal road settings put my Compression at 48% of max, and my Rebound at 36% of max. That is a perfect 4:3 ratio, which made it very easy for me to adjust my off-road oriented setting for my weight. I set my Compression to +15 from "0" (75/11 = 100/ x; x = 15), and my Rebound to +12 from "0" (75/9 = 100/x; x = 12). I set my Rear Suspension to "Hard", and left the same air pressure at 114psi.

I took my trusty bike off-road and rode in the training area near my house. The sand out there is terrible, and with soft suspension, your nose dives and it is miserable going. With my harder settings, I was able to glide effortlessly through the sand. I accidentally hit a 3ft deep, 10ft long, and 4ft wide hole coming over a blind hill that I couldn't avoid. My suspension soaked it up like it was nothing! I also drove through a creek that had water crashing completely over the bike. The bike was totally submerged and made it through like it was the most normal thing in the world. I would estimate that the water was 3.5-4ft deep. My balls and ass definitely got wet!

On improved and gravel roads, the front wheel felt like it floated a bit, but I never felt like I was not in control. I was also moving down the road at 55-60mph (90-100kph). On the road, these suspension settings allowed for a smooth, firm ride with no headshakes until around 70mph (110kph). For the type of riding that I do 90% of the time, that is about ideal. If I want to ride longer distances and spend more time on hardball and improved dirt roads, I can adjust my settings easily back to my +11 C/ +9 D, change the Rear to the "Soft" setting and be good-to-go.

Suspension is a very personal thing, so you have to find what works best for your style of riding. I hope that these numbers provide you with a good start point for your own suspension adjustments. If you have any questions about how I arrived at my numbers, feel free to send me a PM.

Regards,
Dave

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Old 06-22-2010, 11:07 AM   #98
sideway5
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Quote:
Originally Posted by davesmyth
Gentlemen,

I've been reading a lot of threads that advocate softening up the suspension to improve the ride of the G650X Challenge. To a certain extent, I agree; especially if you're going long distances on hardball or improved dirt roads. Soft suspension, however, doesn't solve the constant problem of fork dive, and is particularly bad for riding in sand and loose dirt. Here's what I've come up with, so please take it or leave it as you see fit:

BMW sets the Compression and Rebound at approximately +11 clicks from "0" (all the way counterclockwise to full stop). I don't know if this is true across the board, but that seems to be the general consensus. If these settings are made for a 75kg man, then it stands to reason that you can do a little Algebra and arrive at the perfect setting for your weight. I fiddled with the suspension to get the best road setting for me using Pirelli Scorpion Rally tires, front and rear (very aggressive knobby tires, but DOT approved). I arrived at +11 for Compression, and +9 for Rebound. Rear suspension was set to 114psi and "Soft" setting using the following equation: 85kg/ 97.2psi = 100kg/ x. x = 114psi. I used 85kg because 97.2psi is what BMW recommends for a 85kg man in the G650X Challenge Owner's Manual.

+11/ +9 (from "0") is fine for a 75kg man off-road, I suppose, but I weigh 100kg with riding gear. For whatever reason, my Compression adjustment has 23 clicks, while my Rebound adjustment has 25 clicks. Doing some quick math, I realized that my optimal road settings put my Compression at 48% of max, and my Rebound at 36% of max. That is a perfect 4:3 ratio, which made it very easy for me to adjust my off-road oriented setting for my weight. I set my Compression to +15 from "0" (75/11 = 100/ x; x = 15), and my Rebound to +12 from "0" (75/9 = 100/x; x = 12). I set my Rear Suspension to "Hard", and left the same air pressure at 114psi.

I took my trusty bike off-road and rode in the training area near my house. The sand out there is terrible, and with soft suspension, your nose dives and it is miserable going. With my harder settings, I was able to glide effortlessly through the sand. I accidentally hit a 3ft deep, 10ft long, and 4ft wide hole coming over a blind hill that I couldn't avoid. My suspension soaked it up like it was nothing! I also drove through a creek that had water crashing completely over the bike. The bike was totally submerged and made it through like it was the most normal thing in the world. I would estimate that the water was 3.5-4ft deep. My balls and ass definitely got wet!

On improved and gravel roads, the front wheel felt like it floated a bit, but I never felt like I was not in control. I was also moving down the road at 55-60mph (90-100kph). On the road, these suspension settings allowed for a smooth, firm ride with no headshakes until around 70mph (110kph). For the type of riding that I do 90% of the time, that is about ideal. If I want to ride longer distances and spend more time on hardball and improved dirt roads, I can adjust my settings easily back to my +11 C/ +9 D, change the Rear to the "Soft" setting and be good-to-go.

Suspension is a very personal thing, so you have to find what works best for your style of riding. I hope that these numbers provide you with a good start point for your own suspension adjustments. If you have any questions about how I arrived at my numbers, feel free to send me a PM.

Regards,
Dave
The reasoning behind the setting for the rear shock I can totally dig, but you misinterpret the front settings imho. The compression and rebound settings has nothing to do with rider weight per se. What these settings do is simply limit the speed of which the fork is allowed to compress or retract and their setting is ultimately determined by your riding style and to the terrain you ride. They provide a dampening effect to the spring which is the actual component that according to BMW is chosen to suit a 75kg rider. So in essence, if you weigh significantly more or less than 75kg you really should consider replacing the spring with a proper one for your weight. That being said, your setting for the fork may be excellent, but your "math" to get there was somewhat strange.

Happy riding!
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Old 06-22-2010, 12:32 PM   #99
davesmyth
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Front Suspension Math

Sideway5,

I'm going to disagree with you on the statement that the springs themselves are designed for a 75kg rider. If the springs were designed for a 75kg rider, then there would be no reason to adjust for Compression and Rebound. As justification, I would ask you to refer to the manual where it provides rear suspensioin ratings for both 75kg and 85kg riders. Additionally, BMW states that your Front Suspension Settings (Hard or Soft) need to marry up with the Rear Suspension Settings (Hard or Soft). If you are over 50% on the "+" side of the Compression or Rebound, I'd advise to set your Rear Suspension to "Hard"; if you are over 50% on the "-" side, I'd advise you to set your suspension to "Soft".

Mass has everything to do with suspension settings and how those settings respond to the Force applied to the suspension. Force = Mass (measured in Kg) x Acceleration (Meters/ Seconds Squared).

Once again, suspension settings depend on your size, fitness and style of riding. Why don't you try my formula and see how it rides? If it doesn't work for you, throw it out. If you don't try the formula and test-ride it yourself, you can't speak with authority as to whether or not it works.

How do you adjust your suspension?

Regards,

Dave

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Old 06-23-2010, 05:45 AM   #100
sideway5
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Quote:
Originally Posted by davesmyth
Sideway5,

I'm going to disagree with you on the statement that the springs themselves are designed for a 75kg rider. If the springs were designed for a 75kg rider, then there would be no reason to adjust for Compression and Rebound.
With all respect, that statement is just...completely wrong. A spring with no damping would wobble like crazy. You would have absolutely no traction at all.


Quote:
Originally Posted by davesmyth
As justification, I would ask you to refer to the manual where it provides rear suspensioin ratings for both 75kg and 85kg riders.
I'm guessing now as I don't have the manual in front of me, but those figures refer to air pressure in the bladder right? The pressure in the bladder is also known as PRELOAD. A higher preload (higher pressure) ,somewhat simplified, does the same as a spring with higher spring rate would do to the forks. It has absolutely nothing to do with comp or rebound dampening.

Quote:
Originally Posted by davesmyth
Additionally, BMW states that your Front Suspension Settings (Hard or Soft) need to marry up with the Rear Suspension Settings (Hard or Soft). If you are over 50% on the "+" side of the Compression or Rebound, I'd advise to set your Rear Suspension to "Hard"; if you are over 50% on the "-" side, I'd advise you to set your suspension to "Soft".
No argument there.

Quote:
Originally Posted by davesmyth
Mass has everything to do with suspension settings and how those settings respond to the Force applied to the suspension. Force = Mass (measured in Kg) x Acceleration (Meters/ Seconds Squared).
Also correct but if you have the wrong spring rate for your weight your fork will not perform in optimal conditions. If you weigh significantly more than the spring is rated for your forks will operate in a constant too compressed state. The spring compresses in a linear fashion so to compress the first say 5cm is going to require half the energy compared to the following 5 cm. This means if you are riding around with your fork constantly 5cm compressed your fork isn't going to be as supple as if you fork was extended to where the optimal ride height is. You need to understand that NO amount of compression or rebound dampening can correct this. The second and equally important thing to understand is that if your fork sags too much it will affect the geometry of the bike making it either nervous or too stable(hard to turn).

Here is a good guide on setting up your suspension the correct way. Please note the last section on setting up the fork where it says "-Your static sag should be within the limits given in your owners manual. If it is not, you need to change the
spring, set the race sag, and measure again."

http://www.harrymoto.com/MX/RaceSag/...r_race_sag.htm

Quote:
Originally Posted by davesmyth
Once again, suspension settings depend on your size, fitness and style of riding. Why don't you try my formula and see how it rides? If it doesn't work for you, throw it out. If you don't try the formula and test-ride it yourself, you can't speak with authority as to whether or not it works.

How do you adjust your suspension?
I can speak with authority on that formula as it is in part based on bad assumptions.

I am fortunate to weigh approx 75 kg so my setup is very close to neutral. I have a few clicks negative on rebound and compression as I like it on the soft side.

No hard feelings, just trying to help out.
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Old 06-23-2010, 06:01 AM   #101
davesmyth
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No hard feelings

No hard feelings at all. I enjoy the dialogue because I am getting ready to run my first Hare Scramble this weekend and I recognize that I will be adjusting for different courses throughout my race career, however long that lasts.

I never said you would have a fork with no damping adjustment, I just said that there would be no need to have adjustment if the springs were specific to one rider weight/ mass. There are a ton of motorcycles on the road with no compression or rebound adjustment on the front forks. A good, and pricey example, is my BMW K1200R Sport. It has the duolever front end with no adjustment.

I've looked at the aftermarket progressively wound springs, and they don't make one that is stiff enough, by their own formula, for my weight. That's why I have never spent the $100-200 to replace them. There is an advantage to a progressively wound spring, but not enough, in my opinion, to justify the expense and time to replace.

I ride a mountain bike with no suspension, front or rear, so I am much more cognizant of how I ride and the quality of the tires I ride on. That may be why I am more comfortable with stiffer settings on my G650X.

Do you race, or do you just ride recreationally?

Dave
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Old 06-23-2010, 06:23 AM   #102
Cruz
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Dave, I have raced mountain bikes for years (steel and Ti hardtails) and I weigh about 110kg with my gear on. I tried all adjustments on my forks that were possible but the fork still handled like you and sideway said.

I have fitted progressively wound springs for my weight to the forks and used new 10 weight fork oil. The fork works a lot better than it used and exhibits the same feeling and handling that you mention with your adjustments, though it is still no where near perfect.

I am going to play with the rebound and compression adjustments next to see how that goes and then maybe go to a lighter 7.5 weight oil to make things a bit softer if the adjustments don't give what i am after.

The compression adjuster seems to only influence the last couple of inches of travel to stop bottoming the fork out, while the rebound side actually feels like it looks after both the initial compression and the rebound. Have a play with your cartridges when pumping oil through them (during a fork service etc) and you will feel the effect I describe.
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Old 06-23-2010, 06:42 AM   #103
sideway5
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Quote:
Originally Posted by davesmyth
No hard feelings at all. I enjoy the dialogue because I am getting ready to run my first Hare Scramble this weekend and I recognize that I will be adjusting for different courses throughout my race career, however long that lasts.

I never said you would have a fork with no damping adjustment, I just said that there would be no need to have adjustment if the springs were specific to one rider weight/ mass.
I stand corrected. Misread that section totally sry.

Quote:
Originally Posted by davesmyth
There are a ton of motorcycles on the road with no compression or rebound adjustment on the front forks. A good, and pricey example, is my BMW K1200R Sport. It has the duolever front end with no adjustment.
True but that is due to the fact you seldom take the K1200R off the tarmac right? Have you ever seen a dirtbike without adjustment? That goes to show that the comp/rebound adjustment is there to adapt the bike to the terrain and not the weight of the rider. See the logic in that?

Quote:
Originally Posted by davesmyth
I've looked at the aftermarket progressively wound springs, and they don't make one that is stiff enough, by their own formula, for my weight. That's why I have never spent the $100-200 to replace them. There is an advantage to a progressively wound spring, but not enough, in my opinion, to justify the expense and time to replace.
A linear spring would do just fine as long as it is the right rate for your weight. Replacement time would be about ten minutes. Unscrew top nut, pull out old spring, drop in the new one, check oil level, adjust if needed and screw the top nut back on. Presto.


In the end it's a matter of priority and personal taste I guess. However, the correct geometry and ride height impact the rideability of the bike more than anything else I can think of and that includes tires and engine.

Quote:
Originally Posted by davesmyth
I ride a mountain bike with no suspension, front or rear, so I am much more cognizant of how I ride and the quality of the tires I ride on. That may be why I am more comfortable with stiffer settings on my G650X.

Do you race, or do you just ride recreationally?

Dave
I ride recreationally only. I try to avoid the trees and go as fast as I can in between. An equal amount of and .


Brgds / Sideway5

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Old 09-04-2010, 06:27 PM   #104
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I have finally given up on these forks and have on the way as set of KTM 48mm Forks and EMIG racing triple clamps.

I might finally get some feeling and confidence in to the front end of this bike. A ride last weekend finally convinced me it was a constant battle with the front end and it was average terrain.
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Old 09-17-2010, 08:07 PM   #105
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Oil Weight!

I've had an Ohlins in the rear since last winter, and threw in some Hyperpro progressives in the front for the heck of it with 15w. I'm back to the stock springs but what has been really great is the addition of 5W oil! With 10 and 15 the forks seemed harsh and to "freeze" up, now the forks finally feel like they are working. Heavier springs might be good for riders heavier than me or loading their bikes up with gear and extra fuel...

5w--do it!
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