There are a few adjustment to your bike setup that should be done prior to making adjustments to your suspension. If your current components have more than 15,000 hard miles on them, you can bet it’s time for a rebuild. Since compressing air makes it act as a spring, raising the oil level leaves less room for air, resulting in a rising rate throughout the fork’s travel. First, verify that oil height is correct. Come join the discussion about performance, modifications, troubleshooting, maintenance, and builds for all Indian models. Is it the front or rear causing it? Rake–the steering neck angle (not the fork angle) relative to vertical, which varies with changes in ride height. Springs are position sensitive, caring only how much they have been compressed, not how quickly (as with damping). Furthermore, since the bottles of Harley branded oil have no weight associated with them, and only have names like SE Heavy and E, I have no idea what I'm really using. The types of riding determine you expected setup.  As a street rider typically expects a more compliant and plush suspension that needed to soak up the rougher roads and to be more comfortable while riding.  This more relaxed stable setup will actually help over the long haul of street riding because of less rider fatigue with a stable.  Track riding has different goals of pushing the bike so it provides the optimum effectives for the track.  The track does not translate directly into a good street bike and vice versa. Furthermore, if you can achieve the damping curve that is needed, it does not matter what brand name is on the component. Step 5: Adjust the preload.  To adjust sag use the preload adjusters, if available, or vary the length of the preload spaces inside the fork. If you cannot get them to align, it is likely the frame isn’t straight, or the bike might even have been designed with the rear wheel offset from the front. Over-pressurizing a tire will reduce casing flexing and prevent the tire from getting up to the optimum operating temperature and performance again suffers. This is often best done with two people, one working on each end of the bike. Then take a 30-40 minute ride on your favorite twisty piece of road to get your tire temperature up, then measure the tire pressure immediately after stopping. Plus, the oil must form a layer on parts to prevent formation of corrosion. When the pace picks up, however, the feeling of control is lost. I ride two up and I'm a full figured man!!! Decrease compression until sliding stops and traction is regained. A good linkage (rear sag) has less than 3mm (0.12″) difference, and a bad one has more than 10mm (0.39″). Wiggle the lower run of the chain as close as possible to the middle. If corrosion starts, it won’t stop, spreading and depositing flakes of contaminant in the oil that act like sandpaper and scour metal parts until they’re worn out. When you let go, the suspension should rebound quickly to its original position–but not beyond. During every riding session the suspension stroke should be carefully checked. Measuring front-end sag is very similar to the rear. Contrary to the fork’s controls, rear rebound damping is changed from the bottom of the shock. Rebound Damping (1)  is the adjuster knob on the shaft . How does it affect the wear and grip of a tire? One of the major keys to a successful suspension setup is the condition of the components. Working with the front and rear individually, soften the damping adjuster, and try your bike again over the same road. Symptoms: The bike will not turn in entering a turn. You want the chain at maximum extension – or with the front sprocket, swingarm and rear sprocket all in line with each other. Get free shipping, 4% cashback and 10% off select brands with a Gold Club membership, plus free everyday tech support on aftermarket Harley-Davidson Fork Oil & motorcycle parts.. When dropping the front end of a bike by adjusting fork height, it’s a good idea to keep an eye on clearance between the front tire and radiator, and also–on a conventional fork–to ensure the sliders don’t bottom out on the lower triple clamp. Thanks Keep running chains too tight and you can do a lot of expensive damage. So, setting must be set harder. Step 2: Downward Compression suspension with Rider on the bike and measure. chickenhawk tire warmers also have a low temp setting where you can almost have the warmers on the low setting all day. What you want to end up with is what we’ve shown in the main diagram – where the distances “A” (the gap between the string and the edge of the tire) and “B” (ditto) on the trailing edge of the front wheel are equal to each other; And the distances “A” and “B” on the trailing edge of the back wheel are equal to each other. No matter what shock or fork you have, they all require proper adjustment to work to their maximum potential. Lets Get Busy with how to adjust Suspension Setup, Rebound Damping (1) – the screw adjustment at the top is rebound damping (not to be confused with the larger spring preload adjuster). If the fork or shock over-extends past its free sag, and then compresses again, more rebound damping is required. Also, keep notes for different types of riding street, touring, tracks–as your setup will change depending where you are and the conditions. A well adjusted and lubricated chain transmits the power smoothly (you can actually see the difference on a dyno), lengthens the service life, smooths out your gear changes and makes the bike feel better to ride.         Cause:   The trouble is probably due to a combination of sag and ride height settings that leaves his bike riding high up front. Valving is a combination of check valves, holes, ports, shims, springs, etc. Packing–a phenomenon caused by excessive rebound damping. (At least an upper limit.) Damping force is determined by the speed of the fluid movement, not the distance of suspension travel. . And most importantly, squared-off or worn out tires will mask almost any suspension change you make. If it takes more than approximately one second for the suspension to return to position, less rebound damping is needed. Fork Oil Level–the level of oil within the fork as measured when fully compressed without the spring installed. Where it stops, measure the distance between the wiper and the bottom of the triple clamp again. Front end dive while on the brakes becomes excessive. Once the rebound is set properly, the compression damping can be fine-tuned according to the setup section. However, the fork action and overall bike handling is fine everywhere else.         Cause: These characteristics could be the result of a squared-off rear tire (too much straight-line riding) or notchy or too-tight steering head bearings;         Solution: if the bike has a steering damper mounted, it may be adjusted too tight. Adjustment advice: Compression damping should be adjusted together with front fork oil level. Please note that these numbers tend to be too high for maximum traction but in turn increase the life of the tire. Try increasing the fork spring preload first, and progressing in small increments until the handling begins to be negatively affected (remember to watch the rebound damping when increasing the spring preload). chickenhawk tire warmers also have a low temp setting where you can almost have the warmers on the low setting all day. It’s important that you do not bounce! The ride is overly harsh, especially at the point when bumps and ripples are contacted by the front wheel. Sag–the amount the front or rear of the bike compresses between fully topped out and fully loaded with a rider (and all of his riding gear) on board in the riding position. If the same troubles occur after trying this bike with the steering damper backed off, checking his tire and adjusting his steering head bearings, the problem is most likely in his bike’s chassis attitude. Triple Clamp Offset–the distance from the center of the fork tubes to the steering stem center. This will also give you the added benefit of a smooth ride for daily use; you can always dial in a tad more rebound when you get to your favorite road where the surface is more of a known quantity. – Oversteering!         Solution:   The quickest solutions here are to increase the front fork spring preload and/or raise the front ride height by dropping the fork tubes in the triple clamps, or decrease the rear ride height by shortening the shock (if possible). If the preload adjuster becomes maxed out during testing and dial-in, a set of heavier rate springs or a larger preload spacer (inside the fork) may be necessary. How to set your sag. However, if suspension bottoms at the place were the maximum grip is essential the tire cannot create the best traction, because it also has to perform as spring. The following sections of this article go into the dynamics of what happens when changes are made to the suspension. Free Sag–the amount the bike settles under its own weight. With excessive rear end squat, when accelerating out of corners, the bike will tend to steer wide. Problem: The bike’s steering feels super heavy at low speeds, and once he gets his bike turning by using lots of muscle, it practically falls into corners. It should maintain the pre-determined sag, which will allow the steering geometry to remain constant. Everest seem like a day hike. Once again, L2 and L3 are different due to stiction or drag in the seals and bushings, which is particularly high for telescopic front ends. You have two riders, ‘super fast john’, and ‘average joe’ go out on the recommended 31psi pressure and ‘averages joe’s’ tires come in with the correct hot pressure (lets say 34-35 psi for example using Pirelli’s recommended hot pressure) you can bet that because that ‘superfast John’ will be working the tire harder, spinning it more and his tire might come in reading 37psi. The ride is characterized by excessive fork dive under braking and hydraulic lock when encountering square-edged bumps. – Feels harsh over the bumps. Alternately, if your bike has a lot of free sag (you can lift the rear a bunch before it tops out), you need a softer spring. Simple. The suspension’s reluctance to maintain tire traction through these sections erodes rider confidence. As speed increases and steering inputs become more aggressive, a lack of control begins to appear. Rear end will pack in, forcing the bike wide in corners, due to rear squat. If the rebound damping is cranked up to the maximum and the bike still feels soft and wallowy, you may need to rebuild the suspension components. It can also be used as a standard tape measure. Wrap the string around the front of the front wheel, as high as possible without snagging fairings and associated under-bike hardware when you run each end of the twine under the machine. Looking at Belay 10, 15, or 20W for my Roadmaster but not sure what is best option. Once you obtain this pressure increase for a given rider, bike, tire, road and road temperature combination, check the tire pressure again while cold and record it for future reference. The closest oil we have to these specs is the Ipone Fork Fluid 3W, you will easily have enough oil to do both fork legs with a litre bottle. Shock preload can be altered with a spanner wrench or with the time honored hammer and punch. A race stand is often a good option. Rough pavement makes the fork feel as if it’s locking up with stiction and harshness. Therefore, I thought I would share with everyone some Harley-Davidson fork oil specifications – in particular, information regarding the proper fork oil weight to use and capacities for major models. Suspension Fluid–used inside a shock absorber to create damping when forced through orifices or valving. Outside temperatures affect your tire pressure far more profoundly, however. Most of us don’t have the equipment needed to measure tire temperature directly so we measure it indirectly by checking tire pressure since tire pressure increases with tire temperature. Damping cares about vertical wheel velocity, not bike speed. After hitting bumps at speed, the front tire tends to chatter or bounce. Once again, make small changes between test sessions over the same road to feel and compare the different settings. 2003-2020 © Copyright - Superbike-Coach Corp, New date for Track Academy from last December, Superbike-Coach Announces Its 2021 Schedule. Increase “gradually” until control and traction are optimized. Get and assistant to balance the bike from the rear, then push down on the front end and let it extend very slowly. Symptoms: Front-end dives severely, sometimes bottoming out over heavy bumps or during aggressive breaking. – Understeer! Rebound Damping – Work the ring nut (1) to set shock absorber rebound damping. The different level of oil effects the spring ratio from the middle of the stroke and has a very strong effect at the end of the stroke. May 30, 2015 | Comments; If you thought that your bike only needed engine oil and brake oils, think again. The primary advantage of cartridge forks is they are less progressive than damping rod forks. While the most scientific means of determining if a particular pressure is the use of a pyrometer to assess whether the rubber has reached the manufacturer’s recommended temperature, charting the pressure increase of a tire after track sessions will give a good impression of how hard a tire is working. Solution: Decrease compression “gradually” until control is regained. Front and rear sag should be checked and set correctly, followed by another ride to check for any changes in handling. Maxima Fork Oil (20w) 20: 65.60: 12.90: 201: 202: 0.80: 5.09 Red Line (Heavy) 66.80: 16.00: 256: 256: 0.76: 4.18 Shell Advance Fork 15: 15: 67.00: 10.37: 120: 143: 0.85: 6.46 Silkolene Fork Oil (20wt) 20: 67.70: 8.75: 101: 101: 0.87: 7.74 Castrol Fork Oil (20wt) 20: 68.00: 11.20: 150: 159: 0.84: 6.07 Repsol Moto Horquillas Fork Oil (15W30) 68.00: 11.20: 150: 159: 0.84: 6.07 Agip Fork (15wt) 15: 69.00: 11.50: … High-Speed Damping–damping to control fast vertical movements of suspension components caused by road characteristics such as square-edged bumps. Front end alignment. Valving–the mechanical hardware that creates damping. The oil level should be 437 mm (17-1/4 inches) below the flat face of the fork top nut to the oil level. For example, trail drops off dramatically when the bike reaches full dive under braking, giving a rider more leverage to initiate steering inputs. A tight chain will place a lot of unnecessary strain on itself, the sprockets and even gearbox bearings. Symptom: Bumps and ripples are felt directly in the triple clamps and through the chassis. Decrease rebound to keep rear end from packing. (Gee, I wonder why they’re harsh?). Decrease compression until harshness is gone. I want to go about 5W heavier fork oil, if Indians fork oil is 10W I want to go 15W.        Cause: The rough ride is most likely due to a generally too-stiff setup–with too much compression and rebound damping. Similarly, compression and rebound damping should be somewhat stiffer. In part, this is due to the fact that the manufacturer has put the damping curve in an area outside of your ideal range. Take a close look at the various problem scenarios we’ve listed and see if one of them sounds similar to a dilemma you’ve been struggling with. For longest tire life it is my recommendation that you strive to keep them at the higher limit of those recommendations (regardless of what your motorcycle owner’s manual might say to the contrary.) Looking at Belay 10, 15, or 20W for my Roadmaster but not sure what is best option. Where it stops, measure the distance between the axle and the mark on chassis again. There are trade offs that can be given for each adjustment that you make to your bike. Typically, damping rod forks have very little low-speed damping and a great deal of high-speed damping. – The rear “jumps” on the bumps instead of following the surface. Anyhow, I've already filled one fork with 'B'. I am still in the process of rebuilding the front forks on Cal (my 1972 Harley-Davidson FLH Shovelhead), and I thought I would put together a quick FAQ about motorcycle fork oil – nothing ground shattering here, but certainly a list of reasonable questions that people sometimes ask.1. If out of balance, there will be vibration in either wheel Steering head bearings and torque specifications, If too loose, head will shake at high speeds. Your order may be eligible for Ship to Home, and shipping is free on all online orders of $35.00+. – The front can feel unstable. Preload Spacer–material used to adjust a fork’s preload internally. Step 4: Do the number crunch: The spring sag is in the middle of these two measurements. First, push down on the rear end about 25mm (1″) and let it extend very slowly. To accomplish this as economically as possible, manufacturers install valving with very small venturis. The ride is plush at cruising speeds, but as the pace increases, the chassis begins to wallow and weave through bumpy corners. Both streetbikes and race bikes require 0 to 5mm of free sag on the rear. Harshness hurts rear tire traction over bumps, especially during deceleration. Recommended for use with our fork suspension products. The bike might try to be working the opposite of the preceding paragraph solution, or check out the understeer/no front traction problem scenario for more suggestions. 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