Lowering seat height
Here you will find our point of view about lowering the seat height of a motorcycle.
Lowering my seat height?, How?
This is one of the most common questions when purchasing your first motorcycle.
There are many ways to do it, but one of them (and the most common) is the LESS recommended.
We split it in bits and pieces in this post!
I don’t reach the ground with my feet!
For some people, especially at the very beginning of riding a bike, can be a huge problem.
Motorcycles are heavy, and it’s difficult to keep the balance with your toes barely reaching the ground. , But, at the end, it’s just a matter of habit and get used to the bike weight.
I have seen very short people moving a Maxi-trail on a park lot with a whole more ability than a tall person.
For those who do not trust to end up getting used to the weight and inertia of their motorcycle, there are several options on the market to lower the seat height of the motorcycle, although I personally discourage them outright. I explain you the reasons. Then you decide…
There are more and more in the market, especially now with the rise of the Trail, Trail-Adventure and Maxi-trail.
Longer linkages lowers the back of the motorcycle, making it easier to reach the ground with both feet.
For some people the story ends here.
But let me explain something: by doing this you change the whole geometry of the bike (which someone in the factory has bothered to optimize) and the lever ratio or progressivity of the rear shock absorber, which can even make it “regressive” from some point of the shock trave (just the opposite of progressive!).
What are geometries?
It is the motorcycle chassis dimensions that gives to the bike the ability to turn, being stable at high speed and some ease of driving.
By lowering the rear end of a motorcycle and being fast explaining it, causes the motorcycle to be slower in the entry of corners and also has a serious tendency to go wide while being leaned.
In addition, it can create a criminal predisposition for “shimmies” (violent oscillation of the handlebars in a fraction of a second).
On the other hand, many try to compensate that loss of rear height by lowering the front end also to keep the front-to-back geometry balance, , but problems grow: ground clearance is lost so it is very easy to hit with manifolds on a bump, curb, sinkhole or any irregularity of the terrain, clear predisposition of the front wheel hitting the coolant radiator during a hard braking and impossible to use the side stand (it should be shortened as well).
As for the operation of the rear suspension, as mentioned before, the lever arm is changed and can cause unwanted effects.
At the end, with a longer linkage, the lever arm is increased so applying the same force, the shock absorber is compressed… MORE!
Therefore, it will feel softer, making the bike to lose even greater height clearance during riding.
For all the above, I never recommend to use this option. It’s dangerous and can make very difficult to learn to drive.
Keep in mind that changing the rear height by only 0,078inches affects the handling of the bike in a great way. Varying it 1,20 inches … destroys any kind of handling and stability. Don’t do that, please. Keep yourself safe.
Shortening suspension travel to lower the seat height
This is one of the most used options to transform a MX to Supermoto.
And… well, this also lowers your bike.
An off-road motorcycle has something like 11,8 to 12 inches of wheel travel. If you shorten this travel in 1 inch and use the bike with flatten jumps, it’s not a real drama.
Also, those bikes have a good ground clearance, so you still be playing on the safe zone.
But, if a road rear shock is shortened 20mm when it has 40mm of travel… You are going to have problems. Serious ones.
You could easily bottom out the shock (something that both manufacturers and you want to avoid). If you never experienced bottoming out a shock, imagine that someone hits your back with a hammer.
So avoid bottoming out your suspensions.
Internally you don’t cut anything to shorten a shock. It’s as easy as installing bushings with the proper length, so the shock/fork doesn’t extend all its length.
On the other side, a shortened suspension preloads the main spring the same exact distance you have shortened it, so you also should modify your spring rate to get your dynamic sag again.
Resuming: don’t shorten your suspensions for street use.
Changing the seat
This is the more expensive option, if your bike has it as an option on the manufacturer’s accessories catalogue, but it’s the best option because you change your position regarding the frame, not the frame attitude itself. In other words, you’re lowering your seat height, not your bike height.
If this option is not available for your model, you can always modify your seat’s internal foam or change it for a slimmer gel foam. This last one is much more confortable and slimmer, so you can reach the ground easily!
Changing your seat’s foam has an obvious limit, but you can reduce seat height by 1- 1.2 inches, which can be a madness if you do you by using longer linkages, for example.
I know that what you didn’t want to read, but I feel morally obliged to explain it to you and avoid a crash.
Lowering seat height can create steering and stability alterations, so if you ask me again, I’ll reply exactly the same: modify your seat!