Tutorial: Adjusting the Shock Spring Preload for the RX3

[SpudRider]

Originally Posted by pete

Road bikes set for
10mm static & 20% rider
so if you set somewhere in the middle
of road & dirt you could be about right...

Be a Soft road set up or a hard dirt set up...

Thanks for the additional input, Pete. I was going to research that information, but I haven't had the time to do so.

[SpudRider]

Originally Posted by AZRider

I used a shock spanner wrench and jacked the bike up to lift the rear wheel as Spud suggested. It was a bit fiddly, but I was able to make 3 full turns in a few minutes without removing anything.

Good for you, George. Have you had time to do a test ride? If so, what were the results.?

[SpudRider]

Pete's method is certainly the correct way to configure the shock spring preload, and I should have mentioned that at the beginning. However, I was anxious to improve the sometimes punishing ride of the stock configuration, and I know RJ in Walla Walla was also looking for some relief. I strongly suspect the stock shock spring is too weak for many occidental riders, and we will need to find a stronger, aftermarket shock spring.

I should be able to confirm my suspicions when my friend is available to help me perform the correct method. Until then, I will keep my current configuration, since the ride is much better on both pavement and dirt with the increased spring preload I have configured.

[pete]

Originally Posted by SpudRider

I suspect either the limited suspension travel (5.6 inches) is not adequate for dual purpose riding,

if thats all it's got you will need to use harder settings or you will
bottoming out on ruts/pot holes etc
8" - 200mm would be far better for a ADV bike..





.

[AZRider]

Originally Posted by SpudRider

Good for you, George. Have you had time to do a test ride? If so, what were the results.?

Unlike your results Spud, I found the suspension had been set too firm so I loosened it by 3 turns. The shock now soaks up the bumps rather than jar my coccyx, but I didn't find any noticeable difference in handling. The rear wheel follows the contours of the road much better, although I still need to play with the rebound for additional fine tuning.

Once I have the rear set up, I'll turn to the front and review your comments on fork oil viscosity. I don't want to make too many changes at one time so that I can isolate the effects of each one.

[SpudRider]

Originally Posted by AZRider

Unlike your results Spud, I found the suspension had been set too firm so I loosened it by 3 turns. The shock now soaks up the bumps rather than jar my coccyx, but I didn't find any noticeable difference in handling. The rear wheel follows the contours of the road much better, although I still need to play with the rebound for additional fine tuning.

Once I have the rear set up, I'll turn to the front and review your comments on fork oil viscosity. I don't want to make too many changes at one time so that I can isolate the effects of each one.

You are wise to make one change at at time. If you loosened the shock spring preload by three turns, you now have virtually no spring preload. Is that correct? If I may ask, how much do you weight?

[SpudRider]

Originally Posted by pete

if thats all it's got you will need to use harder settings or you will
bottoming out on ruts/pot holes etc
8" - 200mm would be far better for a ADV bike...

Undoubtedly, 8 inches of shock travel would be much better. I'm hoping a shock absorber with more travel designed for another motorcycle might fit the RX3. I will take some measurements when I have time. In the meanwhile, I would like to install a stronger shock spring.

[SpudRider]

I got my friend Andy to help me make some measurements. Here is the current configuration of the shock spring preload for my Zongshen RX3.

R1, the first measurement, was made with the rear wheel lifted, and the suspension totally extended.



R1 = 23"

R2, the second measurement, was made while I stood on the foot pegs, with full riding gear.



R2 = 21-1/4"

Race Sag = R1 minus R2 = 23" minus 21-1/4" = 1-3/4" = 1.75 inches

Total suspension travel = 5.6 inches

Race Sag should be roughly 33 percent of total suspension travel. (1.75 inches Race Sag) divided by (5.6 inches total travel) = 31 percent

R3, the third measurement, is the bike supporting its own weight.



R3 = 22-3/8"

Free Sag = R1 - R3 = 23" minus 22-3/8" = 5/8" = 16 mm

I obtained these numbers with the spring preload tightened to 6 turns beyond minimum preload. The shock travel is still a little too soft for me, so I need a heavier shock spring. This situation is also corroborated by the size of the Free Sag.

The current settings give me an acceptable ride, but I will certainly be looking for a stiffer shock spring. I am also interested in an aftermarket shock absorber with more travel, or a shock absorber designed for another bike with more travel.

[oldqwerty]

Be careful what you ask for. 8 inches of suspension travel adds ~1.6 inches of ground clearance and seat height, contributing to the top heavy feeling of other adventure boats. Think KLR, Versys, Strom, and about any BMW GS other than the original 650 single. All of these bikes borrow from racer suspension technology to try to create what is essentially a dirt road tourer. Such faddish engineering does not provide good results. Back in the olden days us old farts raced everything with 5-6 inches of suspension travel. We went a LOT faster than any Cyclone will ever go (140mph was a competitive speed) on 5-6 inches of well controlled suspension travel.

For adventuring I'd rather have a well controlled 5.5 inches of travel with the corresponding lower center of gravity since I generally ride at slow-down-and-smell-the-roadkill speeds these days. After all, that's what an adventure bike is for.

If you prefer dualsport riding, pretty much a play racer with lights, the Cyclone is the wrong bike for you. Get yourself something with a chassis designed for less weight and longer travel. There are a plethora of such bikes available form a variety of manufacturers. I'll happily putt along on my TW or Cyclone with 5-6 inches of suspension travel and let the play racers with their 9-11 inches of suspension travel pass. I'll generally catch up to them when they crash.

My opinion is trying to turn the Cyclone into a dualsport bike will ruin the unique character of the bike.

[SpudRider]

My Zongsen ZS200GY-2 has 6.5 inches of fork travel. The XT225 shock absorber I installed on it has 7.5 inches of travel. I have ridden this bike over 69,000 miles, and traveled on it for many multi-day trips to Nevada, Utah, Wyoming, and Montana. Of course, I have also ridden it extensively throughout East and Central Idaho.

I don't race my Zongshen Sierra. I enjoy riding it at a slow pace, just as you do with your TW200. The suspension in my Zongshen ZS200GY-2 is much superior to the stock suspension of the RX3, at all speeds. Perhaps after you receive your RX3, and start riding it, you might get a different impression of the bike's suspension. However, I certainly do plan to experiment with a stiffer spring on the stock shock absorber before I start looking for alternative shocks.

Indeed, if you are a lighter rider, the stock shock absorber might work perfectly for you.

[Weldangrind]

Spud, did you go through this process with your 200? I don't recall seeing a thread about it.

[SpudRider]

Originally Posted by Weldangrind

Spud, did you go through this process with your 200? I don't recall seeing a thread about it.

After I performed my XT225 swingarm conversion, I noticed the XT225 shock absorber was too soft. Doing some research on the XTT225 forum, I discovered this was a common complaint for many larger riders. The solution was to order a stiffer shock spring from Cogent Dynamics.

http://www.xt225.com/forums/ubbthrea...t&Number=61341

I ordered the Cogent Dynamics spring, and installed it on my shock absorber. After installing the stiffer shock spring, I adjusted the shock preload as described in this thread. However, I did not post a thread on this topic.

You rode my Zongshen Sierra with that shock absorber over 500 miles to the Bonneville Salt Flats two years ago; what do you think?

[oldqwerty]

Originally Posted by SpudRider

My Zongsen ZS200GY-2 has 6.5 inches of fork travel. The XT225 shock absorber I installed on it has 7.5 inches of travel. I have ridden this bike over 69,000 miles, and traveled on it for many multi-day trips to Nevada, Utah, Wyoming, and Montana. Of course, I have also ridden it extensively throughout East and Central Idaho.

I don't race my Zongshen Sierra. I enjoy riding it at a slow pace, just as you do with your TW200. The suspension in my Zongshen ZS200GY-2 is much superior to the stock suspension of the RX3, at all speeds. Perhaps after you receive your RX3, and start riding it, you might get a different impression of the bike's suspension. However, I certainly do plan to experiment with a stiffer spring on the stock shock absorber before I start looking for alternative shocks.

Indeed, if you are a lighter rider, the stock shock absorber might work perfectly for you.

I'm not a light rider, and I'm not saying the ride can't be improved. Every bike I've ever owned has needed some help in the suspension department, doesn't matter if it was new, old, big, little, fast, or slow. That's just part of the personalization process every rider could do to maximize satisfaction with any bike. All I'm saying is 5.5 inches is enough travel for the bike's intended use and that 5.5 inches needs to be well controlled. Of course, your definition of "adventure" may be quite different from mine, and that's okay, too.

Nor do I always ride slow. Plenty of other riders have commented on even Tdub's ability to keep up with bigger bikes.

The shock will have to be really bad for me to spend the money to replace it. I'll get it the best I can without spending a ton of money and ride within its limits, which shouldn't be a problem because my Cyclone rides will demand significantly less of the bike than yours. We are not blessed with the plethora of beautiful back roads you enjoy. Our back roads are paved, and what isn't paved is pretty much in a fenced park where you ride in circles or reserved for horses and hikers. Yes, it sucks.

I didn't buy an inexpensive bike to spend more than it cost to turn it into a Strom or BMW. That's what I did with Tdub2 and CSC comes out with the Cyclone for 1/3 the price and pretty much the same mission objective. If I'd have known, I would have made Tdub2 into a really gnarly offroader with the stock TW34 tire on the front and some ATV meat on the back. I'm going to build one of those next.

Zong on!

[oldqwerty]

Found this link on another site.

[SpudRider]

Originally Posted by oldqwerty

Found this link on another site.

Question: Who needs suspension, anyway?
Answer: Not those guys!