"old" V11 sport frame

[Guest ratchethack]

spring rates are not related to shock or fork make. As long as they are linear. A 7.5 sping rear from WP or ohlins gives the same sag.

Point well made, Paul. I would also submit that in terms of linear measure, rather than percent of available travel, the stroke of the shock is critical. Without knowing what application and therefore stroke the Ohlins manual is referring to, IMHO the Ohlins numbers Dave posted have little value in this discussion.

 

There are universal principles that apply very well to all motorcycles and all suspensions. I tend to use these over any specific mfgr. recommendations, unless their products are actually the ones being used, but that's just me.

 

I was on our bathroom scale 10 minutes ago with one leg of the original silver fork. The readings are as follows:

 

kg.......30.....45.....60.....75

mm.14.....15.....15.....12

 

My younger son Kilian, always keen on helping in bike affairs, drew a line every 15kg release. The values above are the measured distances.

 

From 75kg down to 60 one can see already the progressive effect of the air gap, between 60kg and 30kg it moves quite exactly for 30mm.

 

Hubert

Hubert, this is a good attempt, my friend! I applaud the effort. But it's really impossible to measure a fork spring rate this way. It's necessary to eliminate stiction of the fork and as you've mentioned, the air spring, both of which combine to distort all the numbers beyond usefulness. I've attempted to rate springs with a scale on a bench, and this is possible, but even this is harder than it sounds.

 

By your sag numbers, I've roughly extrapolated from my own fork, which I'm almost certain is identical to yours, and my own weight, which is for practical purposes, the same as yours. Again, I think you will find that your springs are close to 1kg/mm.

[Paul Minnaert]

75kg down to 60 one can see already the progressive effect of the air gap, between 60kg and 30kg it moves quite exactly for 30mm.

 

 

that means a 10nm spring if I'm correct.

[Guest ratchethack]

Here's a thought that may help. I used to ride dirt bikes. I guess I went through about a half-dozen or so, and I currently have a great offroad moto, though it only occasionally sees trails, and more often tarmac than dirt roads. If you've been around dirt bikes for awhile, and y'er at all perceptive, you start to notice that the best riders have a regimen that they follow religiously when taking delivery of that brand-new moto.

 

They team up with a buddy, take out the rulers, and go to work adjusting preloads and measuring sags. I've seen many guys come up with a spot-on number for a "target" set of springs front and rear within just a few minutes. The correct springs, matched to load, are often the first things that go into the bike before the first tank of gas is burned - even before the rider's ideal choice of bars.

 

They aren't doing this because they're anal retentive or because they're techno-dweebs. They're doing this because it dictates the way the motorcycle handles. It defines the entire character of the ride and absolutely determines how fast you can go over uneven terrain.

 

It's one of those principles that I believe translates in a very similar form directly to both road and track.

 

This may be why I've been so focused on this for so long. For me, it's even more basic, fundamental, and important to the operation of the motorcycle than handlebars, or any other ergo's, for that matter.

 

Just a thought.

[Guest Nogbad]

Nog's STATIC UNLADEN (this is no rider but 3/4 tank of fuel) using the "stiction average" method.

 

Front 24mm Rear 21mm

 

I can't do the STATIC LADEN sag until Mrs Nog comes back from the gym given I have to sit on the beast in full leathers.

 

These figures above suggest the f**king springs are too weak or the preload too low. I suspect the former given that the front preload is non-adjustable. Never mind. My understanding is that the laden figure will condemn the springs and make it pointless pissing about with preload other than matching the front sag to the rear sag since most of the articles I read on the web suggest it is much more upsetting for a bike to be mismatched front to rear than it is if it is overall too soft or too hard.

 

Interestingly, my standard Marz forks only display a stiction difference of 6mm. This is allegedly good performance. At the rear the stiction is insignificant at 2mm

[Guest ratchethack]

Nog's STATIC UNLADEN (this is no rider but 3/4 tank of fuel) using the "stiction average" method.

 

Front 24mm Rear 21mm

 

I can't do the STATIC LADEN sag until Mrs Nog comes back from the gym given I have to sit on the beast in full leathers.

 

These figures above suggest the f**king springs are too weak or the preload too low. I suspect the former given that the front preload is non-adjustable. Never mind. My understanding is that the laden figure will condemn the springs and make it pointless pissing about with preload other than matching the front sag to the rear sag since most of the articles I read on the web suggest it is much more upsetting for a bike to be mismatched front to rear than it is if it is overall too soft or too hard.

I agree almost entirely, y'er Nogginness. Without laden sag readings, y'er shootin' in the dark.

 

Your fork preload is adjustable via shortening or lengthening the spacers.

[Guest Nogbad]

I agree entirely, y'er Nogginness. Without laden sag readings, y'er shootin' in the dark.

 

The laden figures will be posted today sometime soon, right after the good lady gets home and can wield the measuring tape.

 

Thing is, the fuel tank is nearly full. I expect to get good figures throughout the range if the tank is empty you need to set your sags to the lower end of the range and with the tank full towards the upper. The petrol weighs about 0.74 kg/l so the difference could be as much as 13kg.

 

Your fork preload is adjustable via shortening or lengthening the spacers.

 

I know, but the factory wouldn't assume the average punter would do that. If they did, there should be a section in the book of words.

[Guest ratchethack]

. . . . the factory wouldn't assume the average punter would do that. If they did, there should be a section in the book of words.

Thank God y'er not the average punter, Nog!

[Guest ratchethack]

I guess if you ride slow enough it almost doesn't matter.

 

KB

Keith, unfortunately (or otherwise) I'm startin' to catch on that this is the rule rather than the exception. . . .

 

With the Harley crowd and garden-variety moto-appliance riders, I expect this. But has the concept of excellence in chassis setup become so foreign that it is now resoundingly rejected by vast populations of Guzzisti?

 

As Rumpole of the Old Bailey was often heard to remark,

 

Heaven forfend!

 

. . . . . . [adjust preload via spacers] the factory wouldn't assume the average punter would do that. If they did, there should be a section in the book of words.

There are no doubt certain things that are unwisely taken for granted by both factory and rider. This omission in my Guzzi manuals has never even occured to me, as I've been cutting spacers since before I had manuals to go with my motorcycles.

 

How's that for arrogance and condescention?

 

BAA, TJM & YMMV

 

Interestingly, my standard Marz forks only display a stiction difference of 6mm. This is allegedly good performance. At the rear the stiction is insignificant at 2mm

Interesting indeed. I get 1-2 mm front and rear. What fork oil are you using?

[Guest Nogbad]

Thank God y'er not the average punter, Nog!

 

Right.

 

The LADEN Sag at the front is 32mm (For the avoidance of doubt this is relative to the fully extended measure)

The LADEN Sag at the rear is 57mm similarly.

 

This wouldn't seem so bad. Perhaps all I need is a trace more preload at the front and a handful at the back given the unladen sags are too high. My reading of this is that I may be light enough for the standard springs. What say you Hacker?

 

The only fly in this ointment is that the rear laden - unladen figure is mismatched to the front suggesting mismatched spring rates........

[Guest ratchethack]

The LADEN Sag at the front is 32mm (For the avoidance of doubt this is relative to the fully extended measure)

The LADEN Sag at the rear is 57mm similarly.

 

This wouldn't seem so bad. Perhaps all I need is a trace more preload at the front and a handful at the back given the unladen sags are too high. My reading of this is that I may be light enough for the standard springs. What say you Hacker?

 

The only fly in this ointment is that the rear laden - unladen figure is mismatched to the front suggesting mismatched spring rates........

This is indeed most interesting, my Nogglemeister! IMHO, you have a very similar situation to that of Hubert, and I would not have expected this. I have to conclude that not all Guzzi production-issue 40 Marz USD forks left Mandello with the same rate springs. It seems likely to me now that the US-issue Marz fork Guzzis may have had the wimpy .6 kg/mm springs, and the European Guzzis got far stiffer ones!!! After all, stranger anomalies than this (considerably!) have been known to issue forth from Mandello!

 

IMHO, you're over-rated on the fork and even MORE under-rated on the shock than Hubert, slightly more to the extreme. Roughly, I'd summarize it this way (intentionally without regard to specific rate recommendations): Your laden to unladen sag ratios are 40% low on the fork, and nearly 80% high on the shock. This of course gives you a particularly unfortunate ride because of the degree to which it's so severely unbalanced fore-to-aft, as you've already mentioned. IMHO your rear spring is off the scale on the useless meter. You must have become accustomed to a particularly harsh and jarring ride punctuated by nothing short of something approaching spine-shattering pounding over rough surfaces.

 

Now if you were 40% low both front and rear, this would be usable for some riders on the track. At least this would be workable because it'd be correctly balanced. But speaking for myself, I'd find this unforgivingly harsh to the point of unusable for Road Geez purposes. Now having the same kind of mismatch as Hubert, the GOOD NEWS for you here, my Nogglekommander, is that by re-springing properly, IMHO, a WHOLE NEW WORLD of handling awaits you! - and I'm talking about if possible to conceive it, greater than night & day improvement that is likely beyond your imagination, since your concept of Guzzi handling has been allowed to form around such abominably bad suspension!

 

How's that for arrogance, condescention, and self-righteous pomposity?

[luhbo]

......

Hubert, this is a good attempt, my friend! I applaud the effort. But it's really impossible to measure a fork spring rate this way. It's necessary to eliminate stiction of the fork ...

 

I bloody knew that something like that would be the answer. But you're right of course, as well as I didn't take care of that stiction I also neglected that it was just an unproofed cheap bathroom scale. Good point!

[Guest ratchethack]

I bloody knew that something like that would be the answer. But you're right of course, as well as I didn't take care of that stiction I also neglected that it was just an unproofed cheap bathroom scale. Good point!

Hubert, you may already understand this but you didn't mention it. The air spring effect is adjustable. I have no way of knowing what your air gap is, but regardless of this, it's dramatically (exponentially I think) progressive, and it's an ADDED rate ON TOP OF the spring rate, and it starts it's effect at full fork extension, ramping up nearly asymptotically (got that? ) at full compression. This is the main reason you're measurement technique (though admirable) is not very useful.

 

[Guest Nogbad]

I think I will retake the unladen / laden rear measure in case there is an offset between my measurement and the wifely one.

 

Hack, what is your opinion on the fork?

[dlaing]

Maybe - but that doesn't mean he's wrong.

 

There's been crashes/near crashes here that I heard about sounded v much like they were due to v bad suspension set up. My Scura came stock running wide & trying to chuck me off if it hit big dips mid corner, I considered it to be UNSAFE.

 

From what I see Hubert's bike is way too soft at back & the vague handling he describes is the predictable result. Don't see the argument myself?

 

I guess if you ride slow enough it almost doesn't matter.

 

KB

People do not ride slow enough.

It is usually not bad suspension on a predictable road that kills, because riders almost always stay within those limits. It is bad suspension on an unpredictable road that riders do not ride slow enough for.

Hubert's front end is almost correct. he just needs to drop the front a few millimeters....this will make a big difference.

Raising the rear end 10mm will also make a big difference.

I rode with my rear end like that for a long time before upgrading the spring.

Yes, it sucked compared to having a proper spring, and yes it was more dangerous to ride, and yes I regretted not having put the "proper" shock spring on sooner.

But this is Hubert's decision. I don't know what the roads are like in Germany, but I'll bet they are in better condition (aside from ice) than the roads Ratchet and I ride on.

It is not like he weighs 300lbs and has 50mm sag.

The improvements he gets from just taking 5mm off the front and raising the rear 10mm, will put a smile on his face, but if he gets the "proper" spring, the smile will be atleast 50% bigger.

It is his choice.

Ratchet could get a 50% bigger smile on his face, and be safer, if he had a full Ohlins setup, but I am not going to insist that he MUST DO IT!!!

It is all relative.

[Guest ratchethack]

Hack, what is your opinion on the fork?

Well, from y'er sag readings, I think it'd be more'n a little ways past my threshold of harshness for my riding weight. Didn't we figure out that you're about 10 lb less than me at 180 lb riding weight, where I'm 190 lbs. riding weight? If so, IMHO you'd be far better off, certainly lots more comfortable, and I think without much question you'd achieve a great deal more control and handling with a set of ~.8 - 8.5 kg/mm springs. And in fact, though your rear shock spring is useless to you IMHO, if you cranked up the preload until you got about 40 mm laden sag, with decent fork springs it'd still be a harsh ride at the rear alright, using a tiny fraction of available shock travel, but at least you'd have lots better chassis geometry and you'd be less likely to be constantly bottoming out against the shock cushion. BTW - I don't know how many miles you have on y'er Guzzi, but I'm curious to know - is there anything left of that cushion, or does it look like a fleet of readi-mix trucks have put a few thousand miles of bad road on it?