Quicker steering

[Presson]

Just contemplating lowering the triple clamps by 3mm to make the effect of the steering input quicker. Any views?

 

I like the stability of the bike but would like a bit extra responsiveness to adjust the line mid corner to avoid potholes and gravel. 

I jacked up the back of the GSXR by 5mm and got a massive improvement for 'flickability' without comprising straight line stability, but doing the same on the VFR is a bit more involved due to shock mount location.

 

Alternatively I suppose I could go and do strength training...

[Mohawk]

Mine are down 7mm & the rear is raised 2" & its still rock solid stable. But turns much faster than before 👍 So no need to worry.

[Presson]

You must be almost on your nose! 😁

Thanks for the reassurance though. I'll work the triples down slowly.

[SEBSPEED]

What tires have you mounted?

What is the pressure in them?

When were your forks last serviced?

When were your head bearings last serviced?

What type of head bearing is installed?

What condition is your rear shock in?

What amount of experience do you have?

Do you keep a tight or loose grip on the handlebars?

How worn is your chain?

What sprocket combination is installed?

 

All those things need to be considered before you mess around with changing the geometry. 

 

Not that you can't or shouldn't change it... it's just a bit pointless and/or creating new problems if you haven't addressed that list first. 

 

[Presson]

Thanks Sebspeed; a comprehensive list of questions but I'm not chasing a problem, just wondering about slightly increasing sensitivity to input.

 

Since you ask tyres a Michelin Road 6 with only 2k miles on and pressure as standard (36/42), forks serviced 500 miles back, head bearings are stock as the bike has only 12k miles on it and same for the shock. Been riding for 40 years. If there's a problem it's the state of roads in UK with potholes and loose gravel appearing right on line when pressing on through corners.

[raYzerman]

I'd bump that front tire pressure up to at least 38......

[SEBSPEED]

21 hours ago, Presson said:

Thanks Sebspeed; a comprehensive list of questions but I'm not chasing a problem, just wondering about slightly increasing sensitivity to input.

 

Since you ask tyres a Michelin Road 6 with only 2k miles on and pressure as standard (36/42), forks serviced 500 miles back, head bearings are stock as the bike has only 12k miles on it and same for the shock. Been riding for 40 years. If there's a problem it's the state of roads in UK with potholes and loose gravel appearing right on line when pressing on through corners.

 

Since we don't know each other, it's safer to ask.

 

At 12kmi, your standard head bearings are in need of service and possible replacement. Were they inspected when the forks were serviced?

 

Have you set the suspension up properly for your weight and riding style?

 

The short answer is yes, lowering the front end of your bike will steepen the rake angle and shrink the trail value which will make the bike steer quicker. 3mm is not a significant change.

 

Conversely, if your rear shock is collapsed, overworked, or otherwise insufficient for the task(as most oem are), the rear of your bike will be sitting lower than intended. This will cause the opposite of the effect you're looking for. Compensating for this by lowering the front is a band aid fix and can cause other issues like ground clearance and wallowing of the chassis. 

 

I'm not trying to talk you out of modifying or improving your bike... I've got more money and time and extra parts in my VFR than anyone really should... I'm trying to help you make it the best it can be... 

[Presson]

Thanks Sebspeed, all understood and no offence taken. 

 

The head bearings were checked when the forks were serviced and found to be in good shape. I also had the suspension professionally set up last Summer ( well checked actually as I'd already got it almost bang on). 

 

I'm going to experiment with a little more pressure in the front tyre as raYzerman suggested to see what difference that makes. Depending on that, I'll then consider dropping the triples slightly and see what difference that makes. As I said earlier I'm only looking for a marginal change. Cheers!

[bmart]

Which VFR is this? No years in your profile info. 

 

Try not to fix one problem with creating another. If you have a suspension or geometry issue, PSI won't fix it even if it makes it "feel" better under normal circumstances. 

[Presson]

Thanks Bmart. It's an 8Gen but there is no problem with bike. It's more about personal preference.

 

I'm grateful to everyone piling in with advice about geometry and suspension. I think this thread has run its course for my needs.

[bmart]

More advice, semi-solicited, I guess!

 

I'd start with the right spring rates, sag, and damping adjustment. Modifying geometry before that won't likely give you a good result under any stressed conditions. And having a bike set up properly for you is so much more enjoyable, and safe, to ride. 

 

I would add setting up controls, as most of them point to the sky creating all kinds of bad body position. 

 

Get good body position, still critical for normal on road duties. 

 

Then geometry. 

 

Then ergos. 

 

It sounds like a lot of work, but it really isn't, and the outcome is so much better!

 

Good luck. Let us know how it goes. 

[Presson]

8Gen VFR steering update:

 

Took raYzerman' advice and increased front tyre pressure to 38psi. Noticeable but marginal improvement in steering sensitivity.

 

Dropped the triple clamps down by a modest 5mm. Instant improvement in speed of turn in, no stability issues at high speed (80mph), my sense is of improved front end feel and particularly the slightly harsh initial compression damping seems much smoother (8 Gens have stiffer suspension damping than earlier gens).

 

Body positioning, control position, ergos and basic suspension settings are always sorted first on my bikes before anything else is done.

[gropula]

I agree with previous posts. Get sag right first. If needed change the spring rates to better suit your weight. 

 

Lastly, jack up the rear to get better response. Dropping the front has the same effect but reduces ground clearance, although overall effect of dropping the front might be slightly more effective because the center of gravity ends up lower than if the rear is jacked up.

 

Putting a shim in-between the top of the shock and subframe is a simple and dirt cheap way to get the rear higher.

 

I really like the YSS shock I got on my 6th gen. The stiffer spring is better suited to my weight as I don't need as much preload to get right sag, while maxing out the preload enables the same sag while loaded to the max with passenger and luggage. The length adjustment at +5mm jacks up the rear a lot through leverage. Front end feel vastly improved, as is the initial turn in and changing of direction.

[BusyLittleShop]

Basics of Rake...
Rake is defined as the angle of the steering head with respect to a line drawn perpendicular to the
ground (left). A smaller angle, or less rake, is sometimes referred to as being steeper. Less rake =
quicker steering and less straight line stability whereas more rake = heavier steering and more straight
line stability...

 

Basics of Trail...
Trail gives a motorcycle stability because of the self-centering effect caused by the front wheel being
behind (or trailing) the steering axis. Too little trail, and this self-centering effect is decreased to the
point of instability. Too much trail, and the effect is so great that steering becomes heavy.

 

Stock VFR

Rake 25.5º

Trail 95mm

 

Shimming the rear shock 6mm will change rake and trail towards these numbers...

 

Mod VFR

Rake 24.5º

Trail 92mm

 

Count the number of chain links to insure you have 110... if you have `108 your cassette will cost you ride height because it is not at the 6 O clock position...

 

Wrong... lost ride height...

Right... correct ride height...

[Harvsnova]

Hi. Literally just joined ten minutes ago. If you have Facebook and join the VFR UK owner's group, there's a guy on there who's just put something in to jack up the rear end by 20mm. I don't know what he used, but he seemed very happy with the results. Hang on, it wasn't you was it?😄