Lowered Front V7 - Better!

[MGPilot]

Stopped by Moto International in Seattle. Jason lowered the front on my V7-II about 15mm.

I appreciated the gesture, but I didn't believe I'd feel the difference. 15mm seemed like a miniscule amount.

Wrong.

Bike feels a lot more planted. At times on some surfaces, the bike has felt twitchy....like it wanted to dart one way or another.  Will take more rides to confirm, but I was surprised that it felt better immediately.

[Kev m]

Bike feels a lot more planted. At times on some surfaces, the bike has felt twitchy....like it wanted to dart one way or another.  Will take more rides to confirm, but I was surprised that it felt better immediately.

That's odd, shouldn't that make it LESS planted and MORE twitchy?

[kingoffleece]

Nope.

[Kev m]

Nope.

Care to elaborate?

[Perazzimx14]

The bike geometry was changed but only by about 1/1000th of a percent. I think the bike feeling better is more the placebo effect. But "if" it feels better it "is" better

[kingoffleece]

Not really.  The above post is correct-it's not a huge change but 15mm is enough to feel in my experience.
Spend the winter with RaceTech's book on the subject.  Paul says it much better than I can.

A serious steep steering angle will make a bit twitchy (see some Buell bikes) but this 15mm change is not in that arena.

[Kev m]

I'm on the side of placebo effect in this case (for the record).

But my rudimentary understanding of the theory was that lowering the front should quicken steering NOT make it feel more steady or planted.

My question was is there a reason why such a change could in theory have the opposite effect. I.e. is there a bell curve to starting geometry changes (near such a stock setting) where it goes from one feeling to the other, then back again to the first?

[rocker59]

The bike geometry was changed but only by about 1/1000th of a percent. I think the bike feeling better is more the placebo effect. But "if" it feels better it "is" better

A 10mm to 20mm drop of the front end of a motorcycle makes a noticeable difference in feel.

On sportsbikes with already steep geometry, 10mm makes a noticeable difference.

On more relaxed bikes' geometry, it can take 15mm - 20mm to make the difference.

I have dropped my Sport 1100 (carb) 20mm to get the turn-in where I wanted it to be.

[Kev m]

A 10mm to 20mm drop of the front end of a motorcycle makes a noticeable difference in feel.

Wouldn't that depend on wheelbase?

For the record, my Sportster front end is dropped about 13mm give or take, and I do think it made a difference, but I can't say for sure.

[rocker59]

Wouldn't that depend on wheelbase?

For the record, my Sportster front end is dropped about 13mm give or take, and I do think it made a difference, but I can't say for sure.

Mainly, it's where you start out.  And, the Sportster's front end geometry is pretty conservative, so it may take more drop for you to "feel" the difference.

[Kev m]

Mainly, it's where you start out.  And, the Sportster's front end geometry is pretty conservative, so it may take more drop for you to "feel" the difference.

Well, my Sporty is probably a bad example since it started out low, then I raised the rear, then I raised the rear some more, then I raised the front, but not as much as I would have on the same model for how high the rear is raised... 

Getting back to the V7 - you've got a pretty nimble bike with a relatively quick steering (in my world). Why would dropping the front make is MORE stable (which means slower in steering to me)???

[paulbr]

I would expect it should steepen the geometry making it twitchier but would also shift the weight distribution forward which might make it feel more solid if the front was too light. But you'd think if its too minimal to notice the geo change it would also be insignificant on the weight distribution.

My Stone feels better to me if I lean a bit forward so I could imagine more forward weight would be a good thing. I wonder if the Racer with clip ons would be better with less drop than the Stone with upright bars

[Kev m]

I would expect it should steepen the geometry making it twitchier but would also shift the weight distribution forward which might make it feel more solid if the front was too light. But you'd think if its too minimal to notice the geo change it would also be insignificant on the weight distribution.

My Stone feels better to me if I lean a bit forward so I could imagine more forward weight would be a good thing. I wonder if the Racer with clip ons would be better with less drop than the Stone with upright bars

AHHHH, THANK YOU... there's something I wasn't considering! 

[rocker59]

I haven't lowered the front of my V7 Special, but I did put lower Norman Hyde M bars on.  The new handlebars lean me forward just a bit, which has made the bike feel more planted and less twitchy.

[kirkemon]

Yes, it does not take much.
On some bikes I've gone to a slightly taller rear tire and achieved similar effect.

[kevdog3019]

I would expect it should steepen the geometry making it twitchier but would also shift the weight distribution forward which might make it feel more solid if the front was too light. But you'd think if its too minimal to notice the geo change it would also be insignificant on the weight distribution.

My Stone feels better to me if I lean a bit forward so I could imagine more forward weight would be a good thing. I wonder if the Racer with clip ons would be better with less drop than the Stone with upright bars

Yes... lots at play.  Another thing is airflow on that front end at speed.  My Super Lario's sump is level with the ground with a very low front end.  It is fantastic in every respect for me.  Never felt twitchy or turn-in too easy and at speed it is REALLY planted.  I raised my stock Lario and don't like it as well.  It needs to go back down to where the PO had it.

[sib]

I feel relieved that the only bikes I've ridden in the last 35 years are a '13 Stone and a '16 Stone.  Since I have nothing to compare their rides to, they feel just fine to me.  Ignorance can indeed be bliss.

[Rough Edge racing]

 When you lower the front or raise the back it lessens the trail.....I believe the trail is what affects the handling ...The rake and fork tube offset are the factors contributing to the trail...
  Kev's Sporty has probably about 31 degrees rake but quite a bit of offset ,2-1/2 inches, so the steering isn't as slow as rake alone would indicate.

[Guido Valvole]

When I had a Yammie SRX-6 I lowered the front about 20mm. My other bike was a Ducati Darmah, 61-inch wheelbase, 31-degree steering head angle. Ducati hadn't discovered same-day steering response. The SRX felt like its little brother. Dropping the front made it turn in right now, not next week, no effect on stability.

My Monza feels light in front so I sit at the front of the seat, as far forward as possible. On the V50, with V7 Caf� seat and clubman bars, I'm even further forward and lower and it's better. I'd like to lower the Monza front but since there's a lip on the top triple clamp to stop the fork tubes from going any higher, disassembly and machine work will be needed. Not that much of a priority. But my feeling is that weight distribution of the smallblocks is too far back, old-days chassis geometry.
cr

[normzone]

Can we please clarify the terminology ?

When we say " lowered the front ", I'm assuming that what is being referred to is dropping the fork clamps around the fork tubes by a little, effectively lowering the front of the frame/engine, while of course the front forks are remaining where they were and not going anyplace.

By doing so the geometry comprised of the triangle of the wheelbase (tire contact patch to patch) and the pivot point (arbitrary location in the joint between the fork and the frame) is modified.

I would think the dimensional effect would be to (digs out the angle measurement reference cheatsheet from the back of my calculator)

negligibly lengthen the wheelbase
shorten the " a " side of the triangle

I guess I should have gone searching for education on line before trying to figure it out live here...

The PO dropped mine by about half an inch, and I think it feels twitchy. But I've not been a rider for years, so I've not much to compare it to.

[rocker59]

Can we please clarify the terminology ?

When we say " lowered the front ", I'm assuming that what is being referred to is dropping the fork clamps around the fork tubes by a little, effectively lowering the front of the frame/engine, while of course the front forks are remaining where they were and not going anyplace.

By doing so the geometry comprised of the triangle of the wheelbase (tire contact patch to patch) and the pivot point (arbitrary location in the joint between the fork and the frame) is modified.

I would think the dimensional effect would be to (digs out the angle measurement reference cheatsheet from the back of my calculator)

negligibly lengthen the wheelbase
shorten the " a " side of the triangle

I guess I should have gone searching for education on line before trying to figure it out live here...

The PO dropped mine by about half an inch, and I think it feels twitchy. But I've not been a rider for years, so I've not much to compare it to.

Norm,

We're talking very incremental changes here, but dropping the clamps on the fork tubes to lower the front end will steepen the rake and shorten the wheelbase.

Again, we're talking very small changes, since we're talking lowering 10mm to 20mm, or 0.4- to 0.8-inch.

[normzone]

Yes, of course, that's exactly what I meant to say.

When I used the word " lengthen ", I intend it to mean " make distances shorter ".

It's a regional affectation.

How can the resulting effects be quantified, other than by reference to dimensions and seat of the pants reports ?

[rocker59]

How can the resulting effects be quantified, other than by reference to dimensions and seat of the pants reports ?

Suspension set up is art and magic.  Seat of the pants and lap times are about the only two ways I know of.

Since we're not talking about a bike that will be on the track, what feels better IS better.   

[Kev m]

When you lower the front or raise the back it lessens the trail.....I believe the trail is what affects the handling ...The rake and fork tube offset are the factors contributing to the trail...
  Kev's Sporty has probably about 31 degrees rake but quite a bit of offset ,2-1/2 inches, so the steering isn't as slow as rake alone would indicate.

FWIW

OEM specs of the 1200 Low when I started:

Rake (steering head) 29.6°
Fork Angle 29.6°
Trail 4.7 in. (119.4 mm)

OEM specs of the R model (I'll explain why I'm adding this):

Rake (steering head) 29.6°
Fork Angle 29.6°
Trail 4.6 in. (116.8 mm)


When I started it was a Low - with something like 11.5" shocks (while the 1200R came with 13.25" shocks).

I believe it currently wears 13.5" Progressives and a 1200R front end (which was taller by an inch or two than the 1200L front end, I'm betting almost 2 exactly from the difference in specs). But the forks are protruding up through the trees about 1/2".

So in the end I've raised the rear slightly higher than a stock 1200R and dropped the front slightly lower than a 1200R.

[canuguzzi]

I'm on the side of placebo effect in this case (for the record).

But my rudimentary understanding of the theory was that lowering the front should quicken steering NOT make it feel more steady or planted.

My question was is there a reason why such a change could in theory have the opposite effect. I.e. is there a bell curve to starting geometry changes (near such a stock setting) where it goes from one feeling to the other, then back again to the first?

You are correct.

What the OP is likely feeling is the miniscule weight transfer forward and thinking that the front end feels more "planted". This is a common thing when riders drop the bike in the triples and think it feels more stable. Often, this is because they ride at a slower speed first off and then immediately think how great it is. Since they've also changed their riding position slightly, putting more weight on the bars, that too creates an illusion of increased stability

After a while, as speeds go up the realization of the trade off sets in.

Lower the handlebars by the same 15mm and it would feel much the same but the higher speed stability would remain the same.

[canuguzzi]

Lowering the front end means raising the tubes in the triple clamp. Raising the front end means lowering the tubes in the clamp.

This is very easy to see if you put a bike on its center stand and weight the rear of the bike so that the front tire is off the ground. The front wheel and entire suspension raises or lowers as you move it up and down in the triple clamps.

Saying that the front end is being lowered by loosening the triple clamp and allowing the tubes to sit higher is backwards.

[oldbike54]

 Alright , using some high school geometry , and a bit of algebra , here is , in nice round numbers , the real effect of raising the forks 1/2 inch , or 13 MMs .

 Assuming a wheelbase of 61 inches, a rake of 30 degrees , an overall unadjusted fork length of 36 inches , raising the forks 13 MMs creates a fork rake of 29.3 degrees . A 1.4 percent decrease . Now , the overall 36 inch length may be off , didn't measure .
Go ahead and poke holes .


  Dusty

[rocker59]

V7 has a 57 inch wheelbase and 27 degree steering head, if I'm not mistaken.

Length is 30.5 inches, top of tube to axle center.  I just measures mine

[oldbike54]

V7 has a 57 inch wheelbase and 27 degree steering head, if I'm not mistaken.

Length is 30.5 inches, top of tube to axle center.  I just measures mine

 Using those figures , we come up with an effective fork angle of 26.6 degrees . A 1.5 percent difference .

  Dusty

[normzone]

Alright , using some high school geometry , and a bit of algebra , here is , in nice round numbers , the real effect of raising the forks 1/2 inch , or 13 MMs .

 Assuming a wheelbase of 61 inches, a rake of 30 degrees , an overall unadjusted fork length of 36 inches , raising the forks 13 MMs creates a fork rake of 29.3 degrees . A 1.4 percent decrease . Now , the overall 36 inch length may be off , didn't measure .

Ah, now it's getting interesting...