Revisiting Rear Suspension

[jbfla]

I have read SpudRider's suspension tutorial thread several times, watched YouTube suspension videos, and read Race Tech's Suspension Bible.

There appears to be no clear answer (to me) how to alleviate the quick, sharp, up and down motions that, IMO, give a harsh ride. I cringe when I see road patches and potholes ahead.

I return from a ride with my spine and internal organs (kidneys) aching.

I was hoping that as I rode the bike more miles, the suspension would soften up.

At 2,700 miles, it hasn't.

Some of you may be aware I have been posting about this problem on ADV.

I was hoping to appeal for assistance from a wider audience.

So far, some good suggestions, but no answers.

Here is my last post. I'm at an impasse as to what to do next:

Originally Posted by pyoungbl, post: 28787595, member: 55971

Yep, you are spot on. Now, what amount of sag did you measure?

Here are the numbers, remembering they are for my riding weight and bike:

All numbers are rounded to the nearest whole number.

Rider in full riding gear = 188#
RX3: no top case, no rear rack, 5# in side cases, 2# tank bag, 1/2 tank of gas, hand guards, all other stock items.

Published travel of the RX3 rear shock = 5.6" = 142 mm (rounded).

Target sag (per RT Suspension Bible) of 1/3 of full travel = 47 mm.

Preload was measured as the number of full turns of the shock collar.

I have read that 1 full turn is equal to 1 mm, but I haven't verified this for the RX3.

preload.........................static sag (race sag)

0 turns (no preload)......56 mm
3 turns.........................54 mm
6 turns.........................47 mm
9 turns.........................44 mm

IMO, this suggests that the 6 turns would conform to 1/3 of total travel.

And is in agreement with the chart in the RT Bible.

And that the spring is NOT too stiff ?????

I haven't fully test ridden the RX3 in all combinations of preload and damping settings.

The road testing is very time consuming.

At this point, I'm puzzled; is it the spring, preload, damping or ???

The only bike to bike comparison at hand is the Indian Scout (other bikes are in NC).

The Scout, with only 3 inches of travel, and mediocre suspension at best, rides the same poorly maintained roads with far less drama than the RX3.

I'll try a few more preload/damping settings over the weekend....... and then order the Progressive shock?

I am sure there is a solution.

Any educated suggestions are welcomed.

jb

[pete]

static sag is not race sag....
static sag is the suspension compression under the bikes own weight
with out rider....

race sag or rider sag is the bike with rider on...

Static sag should be around 30/35mm

race sag , rider sag ... 33% or 1/3rd of travel....

[SpudRider]

I properly adjusted the spring preload for the Chinese shock absorber, and it was still punishing. Even if the spring is the problem, no aftermarket shock springs are available. Sadly, Chinese motorcycles are not noted for their excellent suspensions.

Therefore, I strongly recommend you purchase the aftermarket, Progressive shock absorber sold by CSC. Along with an increased suspension travel, the Progressive shock outperforms the Chinese shock on all surfaces, both paved, and unpaved.

http://www.chinariders.net/showthread.php?t=15567

[jbfla]

Originally Posted by pete

static sag is not race sag....
static sag is the suspension compression under the bikes own weight
with out rider......

Not according to the Race Tech Suspension Bible.

According to Race Tech, static sag is the difference between the shock fully extended and the bike with rider and all gear on board.

Static sag and race sag are the same (according to Race Tech).

The sag between the fully extended shock and with only the weight of the bike is called "free sag" or I have also seen it called "bike sag".

I think that is the cause of some of the suspension confusion...different terms for the same thing.

jb

[jbfla]

Originally Posted by SpudRider

.....
Therefore, I strongly recommend you purchase the aftermarket, Progressive shock absorber sold by CSC. Along with an increased suspension travel, the Progressive shock outperforms the Chinese shock on all surfaces, both paved, and unpaved. ....

Thanks, Spud. That's the conclusion I'm coming to.

The $4,000 bike is quickly becoming a $5,000+ bike...

However, some of my riding pals have ordered custom shocks (Ohlins) and had the springs matched to their riding weight.

Is the spring on the CSC Progressive shock "one size fits all rider weights"?

Doesn't seem logical.

I hope you don't mind if I borrow your picture of the two shocks.

jb

[pete]

Originally Posted by jbfla

Not according to the Race Tech Suspension Bible.

According to Race Tech, static sag is the difference between the shock fully extended and the bike with rider and all gear on board.

Static sag and race sag are the same.

The sag between the fully extended shock and with only the weight of the bike is called "free sag" or I have also seen it called "bike sag".

I think that is the cause of some of the suspension confusion...different terms for the same thing.

jb

It depends what world you live in I surpose....
we will have to agree to disagree on this one...
As yer said to meany terms for the same thing...



..

[Tranberg]

The sag from the bike's own weight is irrelevant, since it's not going very far on its own.

[jbfla]

Originally Posted by pete

It depends what world you live in I suppose....
we will have to agree to disagree on this one...
As yer said to meany terms for the same thing.....

Pete, yes, I have found many terms used differently.

I was going by the RT suspension book's term.

Just today, I was watching another suspension video that used "static" sag as you have, "the suspension compression under the bikes own weight with out rider...."

Race Tech calls that "free" sag.

Regardless of what it is called, my sag numbers were calculated by measuring the fully unloaded shock number and subtracting the fully loaded number (bike, rider and gear).

It would be a lot easier if everyone would use the same word for the same thing.

Thanks for your response.

jb

[Jay In Milpitas]

I know that the shock pics were taken during warmer weather.

Having said that, am I the only one wondering why Spud's pants are under the shocks?

JB, I agree with you about springs being matched to rider & machine. As far as the cost, I know that GS owners are known to put an aftermarket shock on their $20k+ bikes. Then again, I've known HD owners that put complete new engines in their bikes around the second scheduled service.

Heck, I think ALeong has already bought a couple thousand dollars of goodies and hasn't even received his bike yet.

[fishman10]

http://www.ebay.com/itm/2008-KAWASAK...VWx9gE&vxp=mtr i might have to gamble an see if this works,,,sure looks very similiar,,,,i just cant afford $400- $500 for the csc one right now.

[Dualsport Chic]

Watching this thread very closely as this is the exact same reason I gave up a brand new, totallly farkled Triumph Tiger 800 in 2012. I have a bad spine with two surgeries behind me and that thing was the cause to the second surgery. I even put a custom Ohlins shock on it for $1K and it still performed horribly. All the road feedback ran right up through the frame of the bike into my body and caused my already weak spine to collapse at the L4/L5 disc (known weak spot).

I totally get what your talking about and have $1K deposit down on an RX3 but this would indeed be a deal breaker if there is no viable solution for it. I cannot risk a third surgery as from what I am told from my surgeon, the next one would end my riding days.

Wishing you luck with finding a solve for this issue as I know all too well how devastating back issues can be.

[SpudRider]

Originally Posted by jbfla

Thanks, Spud. That's the conclusion I'm coming to.

The $4,000 bike is quickly becoming a $5,000+ bike...

However, some of my riding pals have ordered custom shocks (Ohlins) and had the springs matched to their riding weight.

Is the spring on the CSC Progressive shock "one size fits all rider weights"?

Doesn't seem logical.

I hope you don't mind if I borrow your picture of the two shocks.

jb

CSC is selling the Progessive shock with two different springs. I have the heavier spring on my shock absorber. Talk with Ryan, and he will recommend the correct spring for your riding weight, et cetera.

Of course, you are welcome to borrow my photos.

[SpudRider]

Originally Posted by Jay In Milpitas

I know that the shock pics were taken during warmer weather.

Having said that, am I the only one wondering why Spud's pants are under the shocks?...

I was fully clothed, but the Swedish Bikini Team suddenly appeared, and begged me to dance with them in my underclothing.

[SpudRider]

Originally Posted by Dualsport Chic

Watching this thread very closely as this is the exact same reason I gave up a brand new, totallly farkled Triumph Tiger 800 in 2012. I have a bad spine with two surgeries behind me and that thing was the cause to the second surgery. I even put a custom Ohlins shock on it for $1K and it still performed horribly. All the road feedback ran right up through the frame of the bike into my body and caused my already weak spine to collapse at the L4/L5 disc (known weak spot).

I totally get what your talking about and have $1K deposit down on an RX3 but this would indeed be a deal breaker if there is no viable solution for it. I cannot risk a third surgery as from what I am told from my surgeon, the next one would end my riding days.

Wishing you luck with finding a solve for this issue as I know all too how devastating back issues can be.

Let me preface my remarks by saying the RX3 is an excellent value, and I like the bike a lot. In addition, we are very glad you joined us here at China Riders.

However, I would be remiss if I didn't tell you my opinions regarding the stock shock absorber. Perhaps I got a bad shock, but the Chinese shock absorber can be punishing at times, even while riding on pavement. Given the condition of your back, I think the aftermarket, Progressive shock absorber is must buy for you. Even then, the RX3 won't have plush ride, but the Progressive shock will definitely improve the suspension.

[SpudRider]

Originally Posted by fishman10

http://www.ebay.com/itm/2008-KAWASAK...VWx9gE&vxp=mtr i might have to gamble an see if this works,,,sure looks very similiar,,,,i just cant afford $400- $500 for the csc one right now.

Fish, I think you would lose the gamble by purchasing that shock. Getting another shock to fit the RX3 involves a lot of variables.

Tight clearance between shock and frame
Tight clearance between shock and air box
Proper suspension travel
Correct width of shock at upper mount
Correct width of shock at lower mount
Correct spring weight

Et Cetera

CSC did a very good job developing the Progressive shock absorber. It is a job not easily duplicated.