MotoMojo: Changing Motorcycle Seat Height

Jun 17, 2015 View Comments by

MotoMojo: Changing Motorcycle Seat HeightHow to Make Your Bike a Better Fit –

The “one size fits all” philosophy may work pretty well for baseball hats but not for motorcycle seat heights. Folks who have an inseam that is a little shorter or longer than the center of the statistical bell curve are often left with bikes that are 
perfectly good in other ways, but the seat is either too high or too low for comfort and safety.

If a rider can’t reach the ground with both feet when stopped, it’s disconcerting and can lead to a spill. And if a rider is too tall for the seat height, it can lead to a cramped feeling, knees bent too much for comfort, and a poor riding posture.
Just imagine if automobile seats were fixed in one position! Fortunately, there are a number of things one can do to remedy this situation from modifying the seat to changing the suspension’s ride height.

Progressive lower shocks on HarleySeats
Several brands, particularly BMW, have introduced models which have adjustable seat heights. Using this feature is the easiest and most expedient way to alter seat height; hopefully more manufacturers will adopt this useful design. Many brands and models also have seats of varying heights available either at the time of purchase or as a factory designed accessory, offered at franchised dealers. This is a great deal if one can get it at the time of a purchase at no extra charge. When purchased after the fact, they are often quite pricey, but some are sold used on eBay and other websites, including brand-specific clubs.

Another source for seats with different heights is the aftermarket. There are a number of companies that supply lower seats and even a few offering taller ones. Modifying existing seats is usually the least expensive way to change saddle height. Often, the covering can be removed and the foam and padding cut down to lower the seat height. Then, the covering can be pulled down and reattached (usually with staples).

Reducing seat height by trimming down the padding can make it feel like sitting on a bare frame, and brings the footpegs closer, which may force a rider to bend his or her knees more than he or she would like. Gel padding and premium seat foams can help offset some of the loss in padding. Discuss this with a seat expert before having the work done.

Progressive lower shocks 444-series_10Raising seat height is an alternative as well, and I had it done on my Yamaha FZ1 at the same time the seat was recovered. The original saddle had the front portion of the seat “scooped out” at the factory to accommodate shorter riders. I had my upholsterer cut and trim the foam to smoothly fill in the lower area. The result was a much more comfortable seat that can be ridden on for hours and doesn’t push me forward. Adding foam to seats, which are cut down in a similar fashion, can be done quite simply on many motorcycles to accommodate taller riders. Some manufacturers also offer a taller “comfort” seat as an accessory.

Changing Suspension Height
Raising or lowering the suspension ride height will effectively alter the seat height as well. Lowering a motorcycle also affects ride quality and handling, and therefore, safety. So, only do this if it’s absolutely necessary and consult an expert (at a local dealership or motorcycle repair shop) before making any changes. Lowering a bike may reduce suspension travel and cornering clearance, which could result in a harsher ride. One may have to corner more slowly to avoid dragging parts. Some hard parts can lever the rear tire off the ground when leaning over at steep angles.

Both front and rear ride heights must be changed in equal amounts to maintain steering geometry for safe handling. Some brands offer models in standard and low versions. Swapping suspension parts with the “low” version to a standard bike can lower the bike using factory engineered parts. Some folks reduce spring preload to lower their bikes, but unless the rider is light in weight (with proper spring sag settings to match his or her weight), this detracts from ride and handling. Using shorter springs with a higher spring rate (stiffer) for lowering a bike are preferable to just releasing preload on stock springs.

fork-spring-kit_2Slipping fork tubes up through the triple clamps and reclamping them is a popular way for lowering front ends. On some motorcycles there’s very little fork travel before the front fender and tire hit the lower triple clamp when hitting bumps or during hard braking. The fender could jam against the tire and skid the front tire leading to a crash. On sportbikes, about 1.5 inches is generally considered the maximum for lowering suspension. Always have an expert check it for interference at full front spring compression.

Shorter rear shocks are available for many models and are a popular and effective way to lower rear suspensions. Lowering links in the rear suspension are popular because they are cheaper, but lengthening the links to drop the suspension also alters the shock linkage’s progressive spring rate. Changing the length of some linkages by only 10mm may raise the progression rate 20 percent. This may result in a stiff ride. Therefore, work with a suspension expert before making linkage changes.

There are fewer ways to raise a bike to accommodate tall riders. Some motorcycles, such as KTM Adventure models, come in two different versions; one has a taller suspension than the other. The suspension parts, which are unique to the taller model, can be used to modify a lower model if that is what one has. Other ways to raise a bike are to use slightly longer shocks and longer, stiffer springs. Often, tall riders are heavier than average rider weight, and boosting suspension components work well with the added weight. It’s important to vary front and rear heights equally and make only the smallest changes necessary.

Final Thoughts
If the motorcycle height is changed significantly, sidestand length will also have to be modified or replaced. Keep this in mind before making changes and arrange for it to be done at the same time. Some can be cut down, others may have a section removed and welded back together (by a certified welder), and some might need to be replaced. Centerstands typically are not adjustable and may also need to be modified, which would require cutting and welding.

Each type of change is a compromise, which involves trade-offs. So, take time to learn the pros and cons of each method before making changes and consult a professional suspension expert.

 

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