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Old 12th July 2009
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Default The second 7 pages of suspension from XLXR

The beginning of this paper starts at this link:
The link to the first 7 pages of suspension from XLXR
I had to break it up into 2 different threads because it was too long for one thread.

Here is an index of the different sections on both threads:

First 7 pages:
Tire pressure
Shock preload
Rider sag and preload of forks and shock
Fork stiction
Chasis pitch
Shock spring rates
How to select shocks
My impressions of different shocks

Second 7 pages:
Fork spring rates
Works Dual Rate fork springs
Lowering a bike
Ricor Intiminators vs Race Tech Emulators
Fork oil viscosity, oil height, changing fork oil
Air Forks
Loosening drive belt and aligning rear tire
Deciding how to set up your bike
Wobble thread link and summary
Steering Dampers (see post 6)
More links to suspension threads

FORK SPRING RATES

Here are some numbers I have collected over the last 2 years. I have forgotten how I got some of them. Some I measured in my garage, so they are estimates. The Works Dual Rate Spring numbers are accurate because they came directly from Works.

Stock fork spring on 06 Roadster:
20 lbs/in initial rate, 40 lbs/in mid range, 90 lbs/in final rate. I thought the stock fork springs felt way too soft. I think the reason is the spring should be in a fork with 8” of travel. With only 4 ½ travel in the Roadster forks, the springs never had enough travel to transition to the harder spring rates in the mid range and end range.

Stock Low, I think from an 06 bike:
25 / 40 / 70 lbs/in. If this number is correct, it is probably designed for lighter riders than the Roadster spring.

Stock 07 Nightster:
25 lbs/in. This is a number I found written in my notes from working on Road Chick’s Nightster. I don’t know if the final rates get stiffer, but I do know it was way too light as set up with stock preload. Even too light for 140 lb riders.

Progressive Suspension’s 11-1527 fork spring:
35/50 lbs/in. This spring is designed for the longer forks. I think it is too long for the Nightster and Low forks because they do not have enough travel to transition to the harder final rate to prevent bottoming. Unless you are a very light rider and need a softer ride.

In these first 3 cases, adding preload will stiffen the spring. But the question becomes if you can physically get enough preload in the forks to stiffen up the springs enough to prevent bottoming.

Race Tech has 4 straight rate springs:
45, 47.8, 50.6, and 53.4 lbs/ in. I tried the Race Tech emulator and 53.4 lbs/in spring. I found their recommendation to be way too stiff. I will explain in more detail when I compare the Race Tech emulator with the Ricor Intiminator.

Works Dual Rate fork springs:
This is the most flexible spring made for rubbermount XL’s. It can work in the long suspension of a Roadster and short suspension of a Nightster simply by changing the length of the crossover spacer. By test riding with different crossover spacer lengths, I learned more about how spring rate effects handling than anything else I have done.

A picture of The Works Dual Rate Fork Spring kit. Click on the Dual Rate Fork Spring Kit link on the left.

Sportytrace's thread on her 08 1200 Nightster with Ricor Intiminators and Works Dual Rate fork spring kit.

This link has pictures of how to remove and replace fork springs, comparing stock fork spring with the Works, and showing how the crossover spacer fits in the shorter spring. You can see how the coils are wound differently at either ends of the stock spring to help you understand how reversing the spring can change oil level because more or less coils are under the oil level. It also describes how she is fine tuning the forks and suspension. It also has cbnightster's description of putting Low damper tubes in the Nightster forks to gain 3/4" travel, which is huge.

Works gives you 3 crossover spacers of different lengths which fit inside the shorter spring. I test rode with different spacer lengths until I found I liked a 2 1/4" length best for my Roadster. Works say you can use different length spacers in either fork to get a triple rate spring effect. But I didn't find that necessary.

The kit is composed of two separate springs. The soft version of the kit has a short spring with an 80 lb/in spring rate and a long spring with a 60 lb/in spring rate. The springs are stacked on top of each other. The soft initial spring rate, which is also called the “total” spring rate, results when both springs are compressing at the same time.. Here is the mathematical forumula:

1/total spring rate = 1/short spring rate + 1/ long spring rate.

34 lbs/in. = 80 lbs/in (combined with) 60 lbs/in

The short spring has a metal tube in it which is called the crossover spacer. The length of the tube will limit how far the short spring can compress as the forks go over bumps in the road. When the short spring bottoms out against the crossover spacer, only the long spring continues to compress from that point. That provides the hard final spring rate of 60 lbs/in.

Here is the bottom line. Nightsters need a crossover spacer between 4 1/4" long and 4 ¾” long to get the spring to transition very early in the fork travel. SportyTrace is still working on finding the optimum crossover spacer length for her Nightster, she will let us know what she finds. It seems adding the Ricor Intiminators have made readjustment of the forks necessary. The link to her thread is a few paragraphs below.

I like a crossover spacer about 2 ¼” long for my Roadster. That will put the transition point much lower in the fork travel. You are going to have to do some test rides to find which crossover spacer length works for you because the amount of preload/rider sag in the springs will move the transition point lower in the fork travel, and I have no idea how to calculate that correctly.

The final aspect to understand about the Works Dual Rate kit is that the two individual springs will compress different distances under a specific weight. I got myself so confused about this I had to ask Folkie for some help. The following chart does not take into account the rider sag moving the transition point lower in the fork travel, so it is more for general understanding. Here is his explanation:

Travel of the 80 lb/in spring is 75% of the travel of the 60 lb/in spring.

For any amount of total travel (at the crossover point), 3/7 of the total will be the travel of the 80 lb/in spring, and 4/7 of the total will be the travel of the 60 lb/in spring. This is because 3/7 (of something) is 75% of 4/7 of the same thing.

(Total fork travel
At crossover) = 80 lb spring travel + 60 lb spring travel

1" = 0.43" + 0.57"
2" = 0.86" + 1.14"
3" = 1.29" + 1.71"
4" = 1.71" + 2.29"
5" = 2.14" + 2.86"
6" = 2.57" + 3.43"
7" = 3.00" + 4.00"

The 80 lb spring with the cross over spacer in it is 5” long. If you want the crossover point to be at 1” total fork travel, you subtract the .43” in the chart above from 5” of spring length.

5” - .43” = 4.57” which is the length of the crossover spacer needed to get the forks to transition at 1” total fork travel. This is in the area needed for Nightsters.

For Roadsters, 5” – 1.29” = 3.71” which is the crossover spacer length close to what’s needed to get the forks to transition at 3” total fork travel.

I have a 2 1/4” crossover spacer, my 80 lb/in spring has a travel of 2¾", then the 60 lb/in spring has a travel of 2¾" × 4 ÷ 3, = 3.667". 2¾" is 75% of 3.67".

So when the heavier spring hits the transition point, total travel is 2¾" + 3.67", = 6.42". But my Roadster forks don’t have 6.42” of travel. The preload on the spring and rider sag, is probably creating the error between the actual transition point and the calculated transition point.

It seems the biggest mistakes people make when setting up their forks is not understanding the correct things to measure and change. Put a plastic tie on the forks to see how much travel you are using by test riding over the biggest bumps you hit or by doing a hard stoppie. Measure the fork rider sag to see how much you have to start with. Measure chassis pitch and how far the forks stick above the triple clamp. When you take the springs out, measure the fork oil level, and total travel of the forks. Write down all your measurements.

Just because you have the same length of spring or preload spacer sticking out of the forks before you put the caps back on, does not mean you will have the same rider sag as your buddy, (although it should be close). You must check you own rider sag.

Do not assume the fork oil height is correct. Measure it. Make sure you pump the forks enough to get all the oil out before refilling it. Make sure you pump the forks again after you refill it to bleed out all the air. Recheck how much fork travel you are using by test riding. If you are not using all available travel, you may have too much oil in it. If you suck out 1/4 to 1/2 oz oil, and you gain travel, you had too much oil in it.


LOWERING A BIKE

People like the Tamarack lowering blocks

Link to Progressive web site with picture of lowering springs and damper rods

Page 28 of Progressive catalog has color pictures of Drop In Lowering Springs in cut away forks

A link discussing Progressive's Drop In Fork Spring kit

Some people need to lower the bike to be able to get their feet on the ground. Others want to lower their bike to attain a certain look. Either way, lowering the bike causes 2 problems. First problem is the reduced cornering clearance. The second is limiting total travel. With limited travel, it becomes very important to set up all other aspects of suspension tuning correctly because there is little room for error.

Lowered bikes can be dangerous, especially if the rider pushes the limits of cornering or speeds. I read one report where a guy’s kick stand caught on a manhole cover and threw him off the bike.

Last year, I was following a $30,000 custom bike with lowered suspension. The guy was getting throw off the seat just going over normal size bumps. He hit a big bump while in a curve, almost lost control and almost ran off the road. This was at only 45 mph.

In order to get lowered suspensions to work, you must use stiffer shock springs. Stiffer springs provide a stiffer ride. Carrying a lot of weight, such as 2 up riding, generally means using a shock spring that is so stiff, solo comfort is severely compromised. Or, if you get a spring soft enough for a solo rider, it will probably bottom out too much when 2 up.

However, IF the spring has long transition zone, IF the initial and final spring rates match rider weight, and IF the rider goes slow enough and IF he avoids major bumpy roads, it is possible to get a reasonable ride. I guess I should add another IF. IF the rider has no clue what good suspension really is, anything is better than stock.

Sportytrace is a 140 lb rider who needed to keep her Nightster low so she could keep her feet on the ground. We accomplished this by using the 13.5” 1200 S shocks which have a light 54/78 lb/in spring. The spring matched her weight, but in order to get her feet to the ground, we had to use 1” lowering blocks. This proved a very good combination for her.

Sportytrace’s Nightster set up with Intiminators and lowered 1200S shocks.

Combining the 12 ¾” Road King air shocks with the 1” lower block is another good combination to carry a lot of weight while keeping the bike low. Be careful to not exceed the factory weight limitations of the bike itself.

There have been questions about how using lowering blocks affect the spring rate. The answer is it all depends on too many factors to predict accurately. I experimented with 1” lowering blocks. Some shocks smoothed out a little bit, others didn’t.

When you lower a bike, you must verify you have enough tire clearance. If you jack the bike up and take off both shocks, and then lower it very carefully, you can see how low it can go. Measure the shortest distance between the shock mounting bolts. The shocks bottom out and that limits how low the rear of the bike can go. If you take off one shock and lower the bike to bottom out the shock, you can verify you have enough clearance left over.

Early years of Rubbermounts had electrical wiring under the rear fender that the tire can rub on.

Nightsters have a reflector under the fender that will hit the belt guard. Early shocks from Progressive had too much travel and broke off the reflector. The newer shocks have less travel. So be careful if you buy older shocks for a Nighster.

If you lower the front end by lowering the triple clamps, it is possible the lower fork tubes will hit the lower triple clamp when the forks compress fully. The first 07 FI bikes had front fenders that hit the voltage regulator. Something you want to avoid.

Lowering, or raising, a bike may make it necessary for a kick stand of a different length.

There are 3 lowering kits for forks that I am aware of. Harley offers their own kit with a new spring and damper tube. This kit is not very common. I suppose because it is too expensive, especially if you have to pay the dealer to do the work.

Progressive offers 2 different lowering kits. The original 10-1560 kit uses the standard 11-1527 main spring, but includes extra 1’ springs called lowering springs. Harley calls them rebound springs. Others call them top out springs. These springs ride on the damper tube in between the upper and lower fork tube. Stock forks have only one rebound spring which softens the hit when the forks fully extend and the fork tubes hit against each other. Adding 1 or 2 extra lowering/rebound/top out springs pulls the upper fork tube farther down into the lower fork tube. The big disadvantage is you have to take the damper rod out to add the extra springs.

Progressive’s new kit is 10-200 “Drop In” kit. In this kit, the main fork spring is replaced with 2 different springs. You do not need to remove the damper tube to do this, just pull out the original spring and drop in the new springs. The long spring is the main spring which supports the bike’s weight and compresses and extends in response to road bumps. The other spring is very short and weak. It is so weak, just the weight of the bike will cause it to compress 2” until the coils hit each other. This is called coil binding. When the coils hit each other, the weak spring stops compressing and becomes a solid rod, leaving the other spring to do all the work. You can see pictures on Progressive’s web site.

I have no experience with either lowering kit. Neither offers the adjustability of the Works Dual Rate spring kit.

RICOR INTIMINATORS vs RACE TECH EMULATORS

Both are valve bodies which you install between the damper rod and fork spring. Both control oil flow and compression damping, but in dramatically different ways with dramatically different effects on the ride and handling of the bike.

To give you better idea how forks provide damping, there is a picture of stock damper rods from a Nightster and a Low a few paragraphs below, post 289 of the Intiminator thread. The large holes to the right are the compression damping holes. As the forks compress, oil is forced through the compression holes. The holes resist the oil flow and that provides compression damping. Drill the holes larger, more oil flows and less resistance is created, and the forks can compress faster in response to road bumps.

The rebound damping holes are on the opposite end of the damper rod. Rebound damping is created only when the forks extend and forces oil through those holes.

The Emulators have a valve stack which control only compression damping. A valve stack is like a bunch of washers stacked on top of each other. When the forks compress, the oil pushes on the washers, bending them open and the oil flows through. A threaded rod with a spring and nut goes through the center of the washers. If you tighten the nut, the spring puts more pressure on the washers, reducing how much the washers can bend, increasing compression damping, and making the forks feel stiffer.

This is basically the same way cartridge forks work. However, good forks have one shim stack for compression damping, and another for rebound damping. Similar to damper rods having compression holes at one end, and rebound holes at the other end.

Race Tech’s recommendation for me was to use their 53.4 lb/in (95 kg/mm) straight rate spring, drill out the compression damping holes in the damper tube and use 20w fork oil. Trying to force 20w fork oil through the rebound holes created way too much rebound damping.

I started to reduce the Emulator spring tension to reduce compression damping. I eventually got to the point where I took the Emulator out completely. Then I reduced fork oil viscosity from 20 to 10 to 5w. 5w provided too little damping. 10w was good. 10 w oil with the compression damping holes drilled out, but the stock rebound holes, provided the best balance. Or so I thought until the Ricor Intiminators came out.

The Ricor Intiminator actually has 2 separate oil circuits. The first is controlled by a metal collar that floats on a spring. When the wheel is not moving up or down, the collar blocks off some oil ports. When the wheel moves up in response to a bump in the road, the collar’s position remains stationary but the ports move up with the wheel. When the ports are uncovered, massive amounts of oil can flow through. This effectively blows off (high speed) compression damping which allows the forks to compress very quickly and absorb bumps in the road.

The second circuit is a shim stack. It provides damping to keep the chassis from falling down as the wheel moves up.

Another big difference is the Race Tech 20w fork oil recommendation drastically increases rebound damping, but the Ricor 5w fork oil recommendation reduces rebound damping.

This is why I constantly say the stock forks are over damped. Changing to 15w fork oil in stock forks over damps already over damped forks.

The main Intiminator thread

Post 53 has an animation of how the Intiminator works. However, for our bikes, the oil ports are above the moving yellow collar. If you look at the tube in the very center of the animation, near the bottom where the collar reverses direction, you can see the ports open and close as the collar moves up and down

My test rides are on posts 136, 173, 185, 295.

Post 289 has pictures of fork damper rods.
Post 298 CBNightster explains how to change damper rods. He used a Low damper rod in his Nightster to get some extra travel.
Post 337 is a picture of my fork cap installation clamp.

Trying to compare Intiminators to Emulators is like trying to compare a Corvette to a Chevette.

FORK OIL VISCOSITY, OIL HEIGHT, CHANGING OIL

Fork oil viscosity controls how fast the forks can move up and down in response to road bumps. Fork shaft speed is the term used to describe how fast the forks can compress and rebound. The stock fork oil viscosity is 10w. 5w reduces damping so the shaft speed increases in response to road bumps. 20w increases damping which slows the shaft speed.

Going too far in either direction can be dangerous because the wheel may loose its ability to stay in contact with the ground. It is entirely possible you could ride many miles without a problem and then hit the wrong set of bumps at the wrong time.

I have a 100 mile suspension test route that I use for suspension testing. It includes everything I ever encounter. High speed, low speed, mountain roads, multi lane highways, big and little bumps, and even a few dirt roads thrown in. After I took out the Emulators and reduced to 5w fork oil, I found one, and only one, set of bumps that caused the front wheel to hop and loose contact with the road surface. I switched back to 10w and the problem was gone.

Doxbike tried Harley Screaming Eagle heavy duty fork oil. 20w. It slowed the fork shaft speed so much I could see light under his tires on concrete highways. He had the Progressive fork spring and stock damper rod holes. He tried 5w and also felt it was too under damped. He went back to 10w and the problem was gone.

The only exception is to use 5w when you use the Ricor Intiminators.

Never assume oil height in your stock forks is what it is supposed to be. I have seen several Harley and non-Harley bikes with improper fork oil heights from the factory. It is always a good idea to take the springs out and measure fork oil height first whenever you start making changes to the forks. This will verify your starting point.

Oil height can be changed by changing springs, or just by turning the springs upside down. Springs with progressive rates have one end with the coils very close to each other. Putting those coils under a set oil quantity can increase the oil height when compared to a spring with fewer coils under the oil level. I like to have the loosely wound coils down to allow for more oil for a given oil height.

Oil height controls bottoming of the forks. (Spring rate, preload, oil viscosity, and rider weight also have some effect on total fork travel.) There is an air chamber above the oil. As the forks compress, the air chamber compresses increasing air pressure, and that creates more resistance to any more fork compression. If you add way too much oil, the forks will lock up and not move at all because the liquid oil cannot compress.

When you change the fork oil, you must pump the forks up and down to get out all the oil. Letting them just drain will end up with too much oil if you just add what the factory recommends. If you put a plastic bag around the bottom of the fork, it will catch the oil instead of squirting it 3 feet across the floor when you pump the forks.

Be careful removing the small drain screws. They will strip very easily. It is a good idea to replace them with allen head bolts.

The manual gives recommendations for oil quantity and how far down the oil level should be from the top of the forks. They state the oil level must be measured with the forks off the bike and held vertical, spring out and fully compressed.

I never do it this way because I do not want to take the forks off the bike every time I change oil. And, I do not like to compress the forks when the bike is on the jack because that might knock the bike over.

Tilt a glass full of water and see how the distance from the oil level is different to the top of the glass on the low and high side.

When I add or change oil, I pour in an extra ½ oz. It is very important to pump the forks to get all the air out before you measure oil height. Then I use a turkey baster with a hard copper tube to put down the forks and suck out any extra. I put a plastic tie on my copper tube to set the level I want. The first time I do this, I add the factory recommended amount of oil, pump the forks, measure the distance with springs out and forks fully extended. That establishes my base level which I compare all future adjustments to. I always measure down the back side of the fork tube.

Generally, you can add up to 2 oz’s extra oil for the long forks, 1 extra oz for the short forks. It is very important to establish total fork travel and use a plastic tie on the forks to ensure you can use all available travel. Too much oil can hydro lock the forks and cause seals to blow out or maybe worse.


AIR FORKS

Adding air valves to the forks has a similiar effect as adding oil to reduce bottoming. It is just another option. If you already have the tools, it is cheap and easy. Having to buy the tools makes it more expensive.

The fork caps are so thick, you can back drill the cap from underneath to reduce how many threads you have to cut.

No one knows who much air pressure can cause damage. I doubt if anybody would ever need more than 5 psi. One big advantage of air forks is they are very easy to adjust for different riding conditions. Another advantage is it makes it easier to add or remove oil with a small tube.

Air for mod tutorial

LOOSENING THE DRIVE BELT and ALIGNING REAR TIRE

As delivered by my dealer, the drive belt was so tight on my Roadster it would jerk the engine backwards as I rode over bumps in the road. The belt is tightest when the rear axle is in line with a line formed by the swing arm bolts and the center of the front pulley. This is because the axle is rotating on a different radius and center than the drive belt.

13.5” shocks on a Roadster move the swing arm through this point. Bikes with shorter shocks do not move though this point, however, the belt still gets tighter as it approaches full shock travel of the shorter shocks.

An over tightened belt will give the bike a very strange flexy frame feeling when you hit a big enough bump. Really scary in corners.

If you take the shocks off, move the rear tire up and down so the axle moves through the line formed by the swing arm pivot bolts and center of front pulley. You will feel the swing arm bind up if the belt is too tight. ½ turn on the adjuster will go from binding to not binding.

You must also align the rear tire. I use a piece of aluminum 1” angle. I put a small bolt on one end and ground down the tip of the bolt to fit in the dimple in the center of the swing arm pivot bolts. I locked the bolt in place on the aluminum angle with nuts and adjusted the length to clear the foot pegs. I used a plastic tie on the opposite end to set and compare the distance on both sides. 1/64” accuracy is probably good enough.

DECIDING HOW TO SET UP YOUR BIKE

If you want to get the opinions of other riders about particular suspension set ups or components, be sure to ask the right questions. Start of with rider weight, length of shocks, spring rates, preload settings, chassis pitch, how aggressive a rider is he, what type of bike he has and what kind of riding he does. Slower riders don’t need fork braces and better tires. If the guy’s weight is a lot different then yours, his opinion will not help you much.

Getting RK air shocks and adding oil and preload to the forks is by far the cheapest suspension mods. Adding air valves to the forks is next.

Spending the money for Intiminators is a good place to start, especially if you think your shocks are a bit too stiff. With the Intiminators, you might be able to reduce shock preload enough to make the shocks you have comfortable.

If you really want to ride aggressively, you will have to add better tires, I like the Avon Venom X’s, fork brace, Intiminators with drilled out compression damping holes, Works Dual Rate springs and high end shocks. So far Ohlins are the only shock I have not heard any complaints about. However, Ricor is still working on their inertia shocks.

If anyone sees glaring errors, let me know in the next week so I can fix them.

More links to make you really crazy.

The famous Wobble thread

Common causes of wobble are bad tires, loose spokes, loose nuts or bolts on suspension components, warped wheels, misaligned rear wheel. over tightened drive belt, loose steering head bearings, rider has too tight a grip on the bars, windshields, no fork brace, front too low or rear too high creating too much forward chassis pitch, improper tire air pressure.

Did I miss any?

If you have the wire spoked wheels, you can tap the spokes with a small wrench. If they make a ring sound, they are tight, if they make a thud sound, they are loose. Tightening spokes improperly can warp the rim, if you don't know what you're doing, take it to somebody who does.

Rubbermount pivot shaft / wobble investigation with lots of pictures

Harley data base of springs and shocks by Whittlebeast

Fork info on an 883R with 144 lb rider by Colinb

An excellent series of suspension articles which I didn't write.

And the original It ain't the rubbermount and it don't have to ride stiff and handle lousy!!! for those who just can't get enough.
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Last edited by XLXR; 23rd July 2009 at 07:09..
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Old 12th July 2009
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XLXR, you deserve a medal, definately some rep. I've printed out the 14 pages. should make for a very interesting read. Thank you!
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Old 12th July 2009
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Wait a minute, I am still fine tuning.
.
.
.
There, now I'm done.

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Thanks for the write up. Glad to see someone is thinking about this stuff.
BTW, have you tried, or know someone who has tried Ikon shocks? I have always been told they are the best you can buy.
http://www.ikonsuspensionusa.com/servlet/StoreFront
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These should be combined and STUCK !!!

You have done some great work Bro, If I were you I would have put all this down and SOLD A BOOK !..Publishers would jump on this kind of info....Or even a Personal website linked to XLF for all this info.


Matt
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Old 19th July 2009
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Steering stabilizers are another option that has good and bad aspects. They can improve a bike's stability. However, they can also hide a problem that may come back and bit you. I was able to eliminate all the wobble problems with my 2006 Roadster without adding a steering stabilizer, so in my opinion, all possible causes of wobble or instability should be fixed before considering adding a steering stabilizer.

Quote:
Thanks for the write up. Glad to see someone is thinking about this stuff.
BTW, have you tried, or know someone who has tried Ikon shocks? I have always been told they are the best you can buy.
http://www.ikonsuspensionusa.com/servlet/StoreFront
I don't know anything about Ikon suspension. It has been mentioned once or twice.

There is no "best you can buy". There may be the best for your application and budget.

Quote:
You have done some great work Bro, If I were you I would have put all this down and SOLD A BOOK !..Publishers would jump on this kind of info....Or even a Personal website linked to XLF for all this info.
I'm done with it. There is plenty of information all ready out there. There is very little specifically about Rubbermounts.
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Old 20th July 2009
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Quote:
i just purchased a set off a lowered electra glide with 600 miles on them
The part number for these shock are 54661-02A
eye to eye measurement is 12".
i also purchased the 1" lowering blocks.

54656-97A/54565-97B/54965-97C are 13" eye to eye
i do beleive the difference in part number is for 1 or 2 shocks
54565-09 is 13" eye to eye same as above but for 09 models not sure what they have done different maybe valving?
when i was looking for mine i had to read up and check specs on shocks this is what i found hope this helps.
Thanks to Colonelangus for supplying this information.
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Old 20th July 2009
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I don't know if this is the thread to make comments, but I couldn't find a link for discussion.

Some things I wanted to comment on, which you might or might not agree with:

1. Solidmounts are lighter than rubbermounts. It might be worthwhile to note relative suspension and rider weight might be slightly off for Solidmounts. This might play a role in the 1200S suspension, as it might allow a slightly heavier rider on a solidmount versus rubbermount. Additionally, I believe you can replace the springs on the S shocks... unfortunately I don't know what brand makes comparable sizes... and the whole "how long will 12 year old gas filled shocks last" thing...

2. Chassis pitch: I can see how rear swingarm geometry would effect suspension travel/performance with chasis pitch, but I think trail, and to a lesser extent weight shift play the major role in handling. I tend to think of trail as the final measurement for putting a number to stability versus responsiveness in the steering, wobble issues aside. Raising or lowering one end versus another changes trail... sometimes considerably... along with tire pressure.

3. Race Tech: I have to say that the Intiminators are worth every penny to upgrade from Emulators, but I have to say that with the Emulators, my suspension performance was much more predictable than stock, I didn't have bottoming out issues, and wheel hop in potholed streets I frequent was reduced.

I had the Race Tech recommended spring rate too. The ride was stiff with the Emulators with that setup, but I didn't have a chance to try it with lower wt fork oil. I have the same springs in with the Intiminators and it seems perfect for street. I don't go offroad, so I know that the springs might not be good for your 1 foot holes, but downtown Milwaukee is full of patched and unpatched potholes, sometimes measuring 2-3 inches deep. Additionally, with my setup, I'd tend to think a lot of the weight is shifted to the rear of the bike, and added to my steep rake it might really exacerbate oversprung forks, but I wouldn't want my springs any softer than they are now.
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Last edited by Weo; 20th July 2009 at 10:17..
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Old 20th July 2009
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All good points.

Calculating or measuring rake and trail is not necessary unless you are making significant changes from stock chassis parts. I'm not saying they are not important, just that stock bikes have limits built into them.

Chassis pitch due to front and rear ride height changes is just easier to understand and measure. Measuring and setting the frame rails level to the floor with the rider on the bike is just a safe starting point for Roadsters. The most important thing to understand is if you get into a stability problem, at least raise the triple clamps to reduce forward chassis pitch, assuming there are no other related problems.
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Old 22nd July 2009
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http://www.napaonline.com/MasterPage...ion=Tank+Valve

This is a link to NAPA's air valve that will fit in RK air shocks and can also be used for air forks. Part # 90-294 is short, 90-290 is longer. NAPA calls them tank valves. There is another company that has chrome ones, but I don't know the name or link to it.

Harley makes a crossover kit that connects both shocks with one schrader valve fitting. Harley also offers a special pump and guage gizmo. I never used it. I used the crossover pipe, a bicycle pump and a push button pressure guage to set the pressure.

My Road King shock air line install with pictures and part numbers.

Last edited by XLXR; 22nd July 2009 at 16:25..
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