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Discussion Starter · #1 · (Edited)
I threw together an illustration of how fork legs are shortened to produce a lower ride height. This approach retains proper fork function, reduces compressed length to avoid over-travel contact with other surrounding components, and is not costly, since all that is being done is to add a small spacer above the rebound spring.

Rectangle Line Font Parallel Cylinder


This illustration applies to conventional forks. Note, as an alternative to shortening the main spring, it is also possible to shorten the main spring spacer the same length as the lowering spacer. This is particularly valuable for those retaining a stock progressive spring, who wish to maintain the progressive rate. Most will move to a single rate spring of the proper length, often adding some stiffness to reduce initial sag, to gain a little ground clearance back, or to accomodate a specific rider's weight.

USD forks are lowered in a similar manner, by placing a limiting spacer on the lower internal damping rod. However, the work required is more substantial, as the left and right fork tubes have different internal components (one acts on compression, the other rebound, etc.) so modifications require an expert for the specific fork combination to execute properly.
 

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Discussion Starter · #3 · (Edited)
I really enjoy your posts on this forum. I'm not at all trying to start an online argument.... I'm just trying to understand? Maybe "I don't know, what I don't know?" I've looked at the above diagrams, and it doesn't make sense to me??? It seems to me that if you "lower" the the length of the upper tubes (and still don't raise the fork tubes in the triples), aren't you still effectively changing the angle of the steering head, and modifying the geometry of the bike? I seems (to me) that your method of lowering the front end, would give the front suspension less travel, and still modify the OEM steering geometry? Please help me understand what I may not know??? Thank you in advance :cool: -
The method shown has been used for decades to shorten the overall length of the fork assembly. It does not change geometry, it just makes the fork shorter. There is no impact on the angle of the steering head at all, as long as the rear is also lowered at the same time. Lowering only the fork in any way, is not recommended alone, as the change in rake and trail are undesirable.

Yes, this method does reduce travel - and that is the goal and a good thing. When you lower the front of a bike, you are essentially moving the front wheel upward toward the lower triple clamp, sort of like it is hitting a bump forever. The reason to do the lowering by shortening the fork, is that the fork on the R3 has roughly 5.1" of travel when stock, and only 5.3" of space from the front fender to the lower triple clamp, and only 4.7" to the horn and bracket. If you lower the bike by 1" to 1.5", without limiting travel, you have the potential to crash the fender and tire into both the horn bracket and the lower triple clamp - as the travel will then exceed available space for the fork to compress fully (hard braking + load + bump = crash). Installing the lowering spacer as shown, reduces the front end travel under compression by the amount lowered, so there is no issue of interference under full compression. This is why this method is used.

To avoid any changes in front end geometry, lowering the front in any manner has to be done in conjunction with reducing rear ride height an equal amount - preferably with a shorter shock absorber to match the front end being shortened. The rear has the same clearance issues, but with only .25" of space available under full compression. If the shock is not limiting travel by the amount lowered, like happens with the cheap lowering block kits, there is a potential for the rear suspension to travel the full 5" of shock travel, within the remaining 3.5" to 4" of space available before the tire hits the inner fender and rear fender or fender eliminator.

Lowering the rear and front equally will maintain the rake angle of the bike as stock, which will maintain trail as well. To avoid any undesirable effects on R3 handling, both the front and rear of the bike should be lowered equally. Too much lowering of the front will result in a bike that feels less stable, and opens the door to head shake at speed or under hard braking. Too low in the rear and the bike will feel sluggish and slow in response.

Lowering a bike is a compromise with implications you cannot avoid safely. Do it right and the resulting change in handling is minimal, and risk of undesirable side effects reduced (although the lower CG, and reduced ground clearance is another topic).

Cool?
 

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Discussion Starter · #5 ·
Raising the forks in the triple will change geometry, this won't (as long as rear is lowered the same). Just like cars though, you also need to re-spring not just for your weight, but to account for the lowering.
Effectively, lowering the fork in the triple trees, or shortening the fork as shown have the same effect on ride height, and neither effect rake or trail if the rear is lowered to match. Not sure about spring rates to match lowering. I'd say that you might not want to use progressive rates, as the reduced travel makes that initial soft rate unattractive. Sag should be the same, and rate, as too stiff is bad. What makes lowering such a bad deal, is that it can create other issues, like bottoming, that can only be addressed with another bad option - over stiff preload or spring rates. After lowering several bikes, I have to say that for drag racing and show bikes, it's part of the deal. For sport bikes intended to be ridden like a sport bike... not so much.
 

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Discussion Starter · #7 ·
Exactly, you have to counter with stiffer spring rates, and progressive springs are a bad idea when lowering. On cars, it's a different story, but on bikes the risk of bottoming becomes a hazard, and over stiff springs negatively affect riding in different ways. I'm short, and I get it, it sucks at first that you can't touch the ground with ease. Like everything though, it just takes practice and getting used to. Better to learn how to ride with correct geometry and spring rates than to learn bad habits.
Funny, but over the years, I find I don't generally put both feet down, even though I can. Much more convenient at intersections to keep the rear brake applied with the right foot (keeps the brake light on as well as holds the bike in place) and support the bike with the left leg. Holding the front brake with fingers at lights is tiring in traffic with frequent stops. Using the rear brake leaves the throttle hand free to control the gas, easing off the rear brake while putting the left foot up rolling off. Learned this on the Falco, which had a tall, wide seat, and watching a 5'-7" friend on his BMW R1250 GS (35.8 seat height) he rides literally everywhere - rain, snow, paved, gravel and dirt - a true enthusiast. He's never had two feet down on that monster. When I asked about that, he just laughed "The factory only provides one kick stand to park the thing, I manage with one leg down, whichever is up hill. Left leg down, right foot on rear brake. Right leg down, right hand front brake, simple enough. Don't even think about it anymore."
 

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Discussion Starter · #12 ·
The clearance to the rear body with the rear suspension at full compression is just under 0.37". Clearance with front fork to compression springs, between horn mount is -.40", to lower triple clamp is roughly 0.8". This means that any attempt to lower either end without shortening fork or rear shock travel will result in contact at full compression. At the very least, anyone lowering the forks in the triple clamps should relocate the horn, as it is already inside front suspension full compression travel range. Anyone lowering the rear with lowering blocks on a stock rear shock should also add a snubber to limit rear shock travel at full compression.

For novice, street only riders, lowering compromises to handling will not be noticed, until they learn to push the bike near its limits. A properly lowered bike, with shortened fork and matching rear shock, with tuned spring rates and damping profiles will produce a reasonably acceptable ride, up to the limits of ground clearance, which can be mitigated with relocation of rear sets to raise foot pegs. However, as skills improve and the rider pushes harder, the effects of lowering on rear suspension dynamics and CoG will become more apparent. For new riders, this will be a few seasons down the road. For experienced riders, it will be felt right away.

Note: The R3 is a big seller in Asian countries where riders are under 5'-5" for Men, and under 5'-2" for women, who generally ride them without modifying ride height - so any adjustment should be made conservatively, and as little as necessary - and always to both ends at the same time.
 

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Discussion Starter · #15 ·
A sincere thank you to both @GoFaster & @KevinW 2017R3 for "entertaining" my questioning attitude...... I value both of your opinions as, you are appear (to me), to be @ both ends of the "spectrum", and a good balance between track & street. I ride both, and always want to learn how to improve my riding experience :cool:-
Thanks. I've stopped applying racing mods and setups on street ridden gear. Street bikes are far better when riding on softer settings with less tight damping, to comply with the range of conditions from harsh edges to undulations. Racing demands faster recovery, max. Lean angles and edge grip, on predictable surfaces (since you repeat the same lap and can change lines to suit conditions.) A few extra horsepower on the street is irrelevant as well. On the suspension side, having enough travel to absorb conditions that would throw you off the saddle on a race bike is more critical than ultimate maxed out knee dragging, which is not advisable on public pavement. I've screwed up more good bikes and cars with race derived hardware. Hopefully I can help others see that there is a difference between street and race, that is too often lost in the compulsion of owners to mess with their toys.
 

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Discussion Starter · #17 ·
All of my comments can be taken out of context and taken to the extreme to prove I am somehow advocating a bad approach. I do not, nor have I ever suggested using mushy springs, lowering one end without the other, or suggest that lowering is a good idea in general. I offered post one to show how a fork is lowered (shortened) properly, to address the issue of interference that occurs when forks are slid up in the triple clamp. That's it. The follow up clarified the need to address front and rear together, to avoid undesirable geometry changes.

I do see an odd conflict of those suggesting that lowering the front and not the back is bad, while suggesting that installing a longer rear shock to jack up the back, without increasing fork length, is good. The effect on steering geometry is the same. As far as the more complex jacking effect on the swingarm - seems secondary to the front end geometry, especially under hard braking. But, that goes back to the approach of applying race tricks to street bikes, which I disagree with, as noted. Actually, for street use, Yamaha got the R3 more right than wrong, so I see no need to bugger it up with big changes, other than tuning for rider weight, which I have done to address an overly soft front end under braking due to my weight, and upgrading the Gen 1 bike to the Gen 2 rear shock, to compliment the change to radial tires (in my case to Battleax S22's).

My point from the off is that improper lowering to suit rider height is potentially dangerous, to which there are proper solutions - but remaining compromises that need to be understood before hacking at the bike.

Time to put this one to bed now. Signing off for fresher fun elsewhere. Cheers.
 
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