Cornering on a V11 - techniques?

[Guest ratchethack]

Checked pressures ... 37 front and 39 rear ..

Does anyone have the tyre pressures for Metzler Z6s for a V11? Currently running 36 and 40, feeling rather quick, perhaps too hard and too little contact patch?

SK, at 160 lb., I b'lieve you're over-inflating the Z6's, particularly at the rear.

 

At 190 lb. with riding gear, I get ideal, stable, predictable traction and no "nervousness" wotsoever with Z6's at 34 lb. (+/- 1 lb.) front and 37 lb. (+/- 1 lb.) rear. My experience has been that these tires are a little sensitive to over-pressurization. If I were you I'd try them at 33F and 36R, which should be about right for you IMHO, and expect considerable improvement.

 

BAA TJM & YMMV

[slowkitty]

SK, at 160 lb., I b'lieve you're over-inflating the Z6's, particularly at the rear.

 

BAA TJM & YMMV

 

Roger, will try out the lower pressures. Can't wait for my Power Roads, tho.

 

btw, what is YMMV?

 

Cheers

 

Cat

[Guest ratchethack]

At NotRight and others

 

What suspension sags do you have on your bikes? I followed the various links, to and from, and all I could find were rough numbers, 20% here and 15 or 25% there. They never give any hints for shaft driven bikes e.g.

 

So what sag rear and front is proofen, at least for you? What ladden and what unladden.

 

Thanks in advance...

STOP! I do know about the difference between static and dynamic sag. Just keep it simple, it's just to give an expression of what should be the goal.

Hubert

Hubert, I've been avoiding this discussion because I find that all too often suspension setup threads wind up in a morass of confusion and subjective, incoherent speculation because so many seem to have such a poor grasp of even the basic fundamentals. There seems to be a general resistance to actually studying the principles involved. It's just not all that difficult. But your question indicates that you're well beyond the basics!

 

Your question is a very good one. IMHO it's the key that so many seem to miss.

 

I posted the following over at GizziTech awhile back, hoping to get Todd or Ed or someone to put a stake in the ground and at least give an opinion on GUIDELINES. No dice. They won't touch it, always falling back on "everyone's needs are different" and "glad you've found wot works for you".

 

As I observed when I posted this over there, I consider Todd a <1% rider, (as I think anyone who's ridden with him would agree), so "guidelines" of course would not apply to him. Probably Ed too, though I've not ridden with Ed.

 

As for mere mortals , I find the vast riding population not only needs guidelines on setting sags, but way too many often suffer terrific ride and handling problems without them.

 

So after studying it for many many years and mucking about with my suspension and upgrading it substantially over the years (with very positive "real world" results!), here's wot I came up with for "general purpose" riding for riders of all weights. For further clarification, I believe this applies to MOST riders, from those simply doing the "comfortable Sunday afternoon riding" to those doing the most aggressive "sporting" riding -- but not necessarily "road racing", and certainly not track competition:

 

Assume we are talking about a V11, where both front and rear wheel travel are 120 mm.

 

The difference between laden and unladen sag measurements (both front and rear) should ideally be 18 mm, +/- 5 mm for general purpose road work.

 

If the difference is LESS THAN 13 mm, the springs are too stiff.

 

If the diff. is GREATER THAN 23 mm, the springs are too weak.

 

FWIW, I sat on Todd's LM. I reckon he's got his sag difference set around 6-8 mm.

 

I reckon Grandma would much prefer a 30 mm difference.

 

Disclaimers and caveats abound, and of course YMMV depending on variables too numerous to mention.

 

This is intended to be a general guide, and all strenuous objections are welcome -- but by all means, please bring a logical, rational basis for your argument -- and direct experience is a big plus!

 

btw, what is YMMV?

Your

Mileage

May

Vary

[slowkitty]

The difference between laden and unladen sag measurements (both front and rear) should ideally be 18 mm, +/- 5 mm for general purpose road work.

If the difference is LESS THAN 13 mm, the springs are too stiff.

If the diff. is GREATER THAN 23 mm, the springs are too weak.

 

Yes, will try this weekend. I've learnt to be patient with setting up suspension, one click, record, ride around .... one click, record, ride around.

 

Cheers

 

Cat

[Greg Field]

After you get some rest, please elaborate.

 

Al I really mean is that you must brace your body so that you are not bearing any of your weight with your arms and hands. Gripping the tank tightly with your thighs makes this all so much easier, especially on a bumpy road. With all the load carried by your back, aided by the wind on your chest, the bike will steer more easily and feel lighter. Owrks for me, anyway.

[Guest ratchethack]

Wot Greg said!

 

I've always found that gripping the tank firmly gives superior control & feedback. Without this, the bike seems relatively vague and disconnected. I've had R-100 knee pads on my tank since day 1 and have practically worn them out from gripping the tank. I'd probably fall off without 'em. I also find that not propping my weight on the bars, but instead, supporting the upper body with a combo of back muscles and wind blast -- while up forward as far as possible, arms bent -- makes the bike far more neutral and light handling in the twisty stuff, as Greg noted.

[Skeeve]

Not tried Metzelers on the Guzzi, but used to club race a GSXR600 & 750 on them for a while, never liked them, though they grip very well, I found that they tended to let go without warning. Differant bike, differant tyre spec I know, but they gave me some scary moments...

 

MeZ1s or Z4s? Those were designed before Pirelli took over Metzler. The Z6 "sport touring" tires are essentially the Pirelli Dragon Stradas by another name. Excellent wear & traction; I really like'em [much moreso than the Z4s I used to run, which were incredibly unnerving given any level of humidity above "really dry" and paint lines on the street... :!:

[Baldini]

...Owrks for me....

 

 

OWRKS FOR ME TOO

 

KB

[Guest ratchethack]

Not sure about this, but I b'lieve I prefer cornering on a V11 without OWKRS.

 

-- No. None for me, thanks just the same.

[dlaing]

 

Assume we are talking about a V11, where both front and rear wheel travel are 120 mm.

 

The difference between laden and unladen sag measurements (both front and rear) should ideally be 18 mm, +/- 5 mm for general purpose road work.

 

If the difference is LESS THAN 13 mm, the springs are too stiff.

 

If the diff. is GREATER THAN 23 mm, the springs are too weak.

 

FWIW, I sat on Todd's LM. I reckon he's got his sag difference set around 6-8 mm.

 

I reckon Grandma would much prefer a 30 mm difference.

 

Disclaimers and caveats abound, and of course YMMV depending on variables to numerous to mention.

 

This is intended to be a general guide, and all strenuous objections are welcome -- but by all means, please bring a logical, rational basis for your argument -- and direct experience is a big plus!

Your

Mileage

May

Vary

From my experience, the 18mm target sounds like a good target for the rear with a Sachs shock.

I think lighter rider may need less and heavier riders more because of the ratio of the bike to rider weight, but it is not a big difference.

I think the front springs should provide less sag difference than the rear spring because of the need for the front suspension to handle bottoming.

Ohlins suggests

Without rider:

Rear: Road and Track 5-10 mm

Front: Road and Track 25-30 mm

With rider:

Rear: Road and Track 30-40 mm

Front: Road and Track 35-48 mm

Notice they recommend more difference in the rear, but then again the rear wheel travel is about 140mm. Other experts generally recommend firmer springs and less sag than Ohlins does, and I agree with them, up to a point.

I think if you take the tighter Ohlins numbers you would be doing very well:

Without rider:

Rear: Road and Track 10 mm

Front: Road and Track 25-30 mm

With rider:

Rear: Road and Track 30 mm

Front: Road and Track 35 mm

For a difference of about

Rear: 20 mm

Front: 5-10 mm

 

What you set your sag to should also take into consideration geometry.

I find that a high rear and a low front make the bike handle better.

Some of that can be adjusted by moving the triple clamps down the forks, but more sag in the forks than at the rear is a good thing.

My front is 26mm/36mm with a difference of 10mm. I think I need a stiffer spring up front, so I guess for my front the 18mm±5 does not meet my needs, and I need a little less than 10mm difference.

But my rear is 6mm/31mm for a difference of 25mm. I think I need a stiffer, but more importantly a more progressive rear spring. Probably 8mm/28mm would be about ideal for me. But my Penske rear suspension is probably about 136mm of travel as opposed to the 120mm Sachs. If I was using the Sachs, 18mm rear would be just about perfect.

[slowkitty]

SK, at 160 lb., I b'lieve you're over-inflating the Z6's, particularly at the rear.

 

At 190 lb. with riding gear, I get ideal, stable, predictable traction and no "nervousness" wotsoever with Z6's at 34 lb. (+/- 1 lb.) front and 37 lb. (+/- 1 lb.) rear. My experience has been that these tires are a little sensitive to over-pressurization. If I were you I'd try them at 33F and 36R, which should be about right for you IMHO, and expect considerable improvement.

 

 

Okie .. It's me again .... reset the pressures.

 

Rear is fine, front is a bit skittish and sensitive, nearly lost it when it dipped in a left turn at about 60 km/h. So what do I tweak now? Tempted to tweak rebound, just one click?

 

Cheers

 

Cat

[dlaing]

Did you lower the triple clamps down the forks yet?

You will want to make sure you have atleast 130mm of travel clearance above the fender from the fully extended. To make measuring easy, take 130 and subtract bike only sag, and make sure you have that much room between the fender and what it will hit if you lower the front too much.

Increasing preload in the rear might also help.

But knowing your sag is really step number one. (After ensuring that nothing is busted or out of alignment and that the shaft is aligned correctly as Pete recommended checking)

[Guest ratchethack]

Things that make me go, "Hm":

 

Interesting feedback, Dave. Let's consider:

I think lighter rider may need less and heavier riders more because of the ratio of the bike to rider weight, but it is not a big difference.

Hm. So you're saying a 150 lb. rider would need less sag difference, or a greater spring rate relative to the combined vehicle and rider weight of a 250 lb. rider? I can't disagree more. The difference in laden and unladen sags is related to spring rate and overall laden weight alone -- regardless of the ratio of rider weight to overall weight.

I think the front springs should provide less sag difference than the rear spring because of the need for the front suspension to handle bottoming.

Hm. I don't recall in recent memory (or ever, for that matter) any air-spring assisted fork bottoming, unless it's suffered a blown seal. Do you? I believe that with a rising rate air spring assisted fork, this is for all practical purposes nearly impossible enough to forget about under normal circumstances, barring something like a crash. My zip-tied forks (for indication of extent of compression travel) on many motorcycles I've owned tell me it's never happened to me, despite some fairly substantial whomping loads on the fork. Is there some reason you believe that "the need to handle bottoming" would be more of a concern for a fork than for the rear shock -- and that this should be a reason to target unbalanced front/rear sag differences?

What you set your sag to should also take into consideration geometry.

I find that a high rear and a low front make the bike handle better.

Hm. What makes a high rear "high" and a low front "low"? Relative to what? What kind of geometry are you referring to here that would make the handling "better"? Relative to what? How long is a string?

Some of that can be adjusted by moving the triple clamps down the forks, but more sag in the forks than at the rear is a good thing.

Hm. A "good thing" based on Ohlins specs, a flying guess, a stab in the dark, or what? Generally, I disagree with this as a blanket statement, but that's just me.

 

NOTE: The sag difference is wot we've been talking about here. It might be important to understand that you can increase or decrease both laden and unladen sags while keeping the difference between them the same.

My front is 26mm/36mm with a difference of 10mm. I think I need a stiffer spring up front, so I guess for my front the 18mm±5 does not meet my needs, and I need a little less than 10mm difference.

Hm. To each his own. But if you go to stiffer fork springs with an already relatively "tight" 10 mm sag difference on your Ohlins fork, I would predict a Todd Eagan-esque "rock hard" ride that would (at least in my case) tend to knock my back teeth loose on many of the favorite roads I ride, and force me to take pain killers with me. I ain't interested in that, and I suspect that somewhere around 99% of riders (given the choice -- especially after sampling) would agree. But o' course, I can only speak for myself. . .

But my rear is 6mm/31mm for a difference of 25mm. I think I need a stiffer, but more importantly a more progressive rear spring. Probably 8mm/28mm would be about ideal for me. But my Penske rear suspension is probably about 136mm of travel as opposed to the 120mm Sachs. If I was using the Sachs, 18mm rear would be just about perfect.

Hm. I consider progressive vs. straight rate entirely transparent relative to rates, and therefore sag differences. But that's just me.

 

Hm (Part VII). I would tend to agree that with a 25 mm difference, it would seem that not only are you a little soft in the rear by rate, but that this would not work well with such a relatively stiffly sprung fork with just a 10 mm difference. IMHO the most balanced suspension has sag differences front and rear fairly closely matched. And yet you want to go even stiffer on the fork springs?

 

So the manufacturer of the component would make a difference relative to the sag difference guideline? Based on what? Travel? IMHO a difference in travel from 120 mm to 136 mm is so trivial relative to the dimensions we're talking about that your 2 mm difference is hardly significant.

 

Just another thought that seems to fit here:

 

Now it seems to me that you and many others no doubt, believe that Ohlins suspension components represent "the pinnacle" of suspension development for motorcycles. I would not deny that they are very good components. But neither would I ever tend to believe that Ohlins or any other manufacturer owns the "benchmark" for some kind of a fictious conditio sine qua non in suspension. IMHO, despite all the groupthink and hype that tends to surround and drive the popularity of such items, such perfection does not, cannot, and never will exist. As I've mentioned before, when you're dealing with a motorcycle that's in the neighborhood of 150 lbs. overweight compared to many of its displacement, considerably underpowered relative to many of half its displacement, with a walloping 40 lb. rear wheel hub assembly with a transmission in it, unfavorable fore-aft balance, a relatively flexible spine frame, etc. . . when it comes to the design of the current crop of "high zoot" suspension components, such considerations become a "great equalizer" among suspension components on the Guzzi, making subtle differences in their design (if not the overall basic function) of suspension components that much less of an important differentiator.

 

BAA, TJM & YMMV

[Guest ratchethack]

Okie .. It's me again .... reset the pressures.

 

Rear is fine, front is a bit skittish and sensitive, nearly lost it when it dipped in a left turn at about 60 km/h. So what do I tweak now? Tempted to tweak rebound, just one click?

 

Cheers

 

Cat

Cat, I find it pretty hard to respond to this. I'd like to offer assistance if possible, but need so much more info to respond. . .

 

Front end "skittish and sensitive"? "nearly lost it"? This is a little difficult to interpret, my friend. Are you getting your weight as far up forward as possible?

 

With so little info, I would hesitate to advise you off into the weeds!

 

In case you haven't made use of the following, some thoughtful study may help. I would suggest getting the basics right first -- spring rates and sags, and once these are nailed down properly, move on to rebound and compression damping:

 

http://www.strappe.com/suspension.html

 

http://www.racetech.com/articles/SuspensionAndSprings.htm

 

http://www.peterverdonedesigns.com/oilheight.htm

 

Hope this helps.

[Dan M]

Al I really mean is that you must brace your body so that you are not bearing any of your weight with your arms and hands. Gripping the tank tightly with your thighs makes this all so much easier, especially on a bumpy road. With all the load carried by your back, aided by the wind on your chest, the bike will steer more easily and feel lighter. Owrks for me, anyway.

 

Greg makes probably the most important point here on riding technique for this bike. Getting your weight off of your arms, yet still forward on the bike makes worlds of difference.

 

Tires are truly personal choice. Someone above edited a quote to elude that Metzelers break away quickly. I've had great results with Metzeler Z6s and Pirelli Stradas, very predictable, quite the opposite with the factory Bridgestones.