Scura suspension?

[Bruce Reader]

I had my springs replaced some time ago. 1.05kg/mm front and 1093- 11.0kg (110nm?) rear. The damping was changed as well.

 

Now the length (non loaded) of the 1091 spring was 160mm and the replacement with higher rate is 150mm.

 

What if any considerations are there with this difference ?

 

Cheers

 

Bruce

[Greg Field]

Pete:

 

The spring finally rotated on its own to where I can read it. It's last digits are 110, so I think that mens an 11.0 spring. It's really handling well, now that I got rid of the Pliot Power rear. Use a rear tire with a stiff carcass, such as a Metzeler of Dunlop. Switching to a Metzeler made an astonishing difference on my bike.

[pete roper]

Pete:

 

The spring finally rotated on its own to where I can read it. It's last digits are 110, so I think that mens an 11.0 spring. It's really handling well, now that I got rid of the Pliot Power rear. Use a rear tire with a stiff carcass, such as a Metzeler of Dunlop. Switching to a Metzeler made an astonishing difference on my bike.

 

Many thanks for that Greg. Given our seeming similarity in size, (You seem to have 'put a bit on' since we met you old rogue! ) that seems like a good starting point for the back and your front figures will be what I'll aim for too. As for the actual valving? Well, I'll fart about with that when I get the poxy thing back to Oz if it needs it, as I've oft said though as I ride like the grandfather of the oldest man in the world it will probably make bugger all difference to anything other than my enjoyment, I'll still find myself being overtaken in the corners by vicars with bicycle clips on pushbikes with a big basket on the front singing "What a friend we have in Jesus!"

 

Pete

 

PS. Wholeheartedly agree with your tyre appraisal. Guzzis are far heavier than most bikes with *sporting* pretensions nowadays and soft sidewalls, even if helped by high pressures, just don't seem to work as well as tyres with sidewalls made of granite!

[docc]

Sneaking a bit of tyre thread in are ye? Cleaver weasels. I wondered what could be pushing a Scura thread into three pages . . .

 

So, how do the Pirelli Diablo fall in that carcass rating?

[Guest drknow]

Many thanks for that Greg. Given our seeming similarity in size, (You seem to have 'put a bit on' since we met you old rogue! ) that seems like a good starting point for the back and your front figures will be what I'll aim for too. As for the actual valving? Well, I'll fart about with that when I get the poxy thing back to Oz if it needs it, as I've oft said though as I ride like the grandfather of the oldest man in the world it will probably make bugger all difference to anything other than my enjoyment, I'll still find myself being overtaken in the corners by vicars with bicycle clips on pushbikes with a big basket on the front singing "What a friend we have in Jesus!"

 

Pete

 

PS. Wholeheartedly agree with your tyre appraisal. Guzzis are far heavier than most bikes with *sporting* pretensions nowadays and soft sidewalls, even if helped by high pressures, just don't seem to work as well as tyres with sidewalls made of granite!

 

Hi Pete,

 

I ended up with 1.05 fork springs and a 115 rear spring, I'm 230lbs and 6'3". It worked great, and although the shock could stand a revalve, it was very rideable, while the forks most definitely needed the money first. Springs and a revalve of the forks first, then a shock if you're spending money.

[pete roper]

Hi Pete,

 

I ended up with 1.05 fork springs and a 115 rear spring, I'm 230lbs and 6'3". It worked great, and although the shock could stand a revalve, it was very rideable, while the forks most definitely needed the money first. Springs and a revalve of the forks first, then a shock if you're spending money.

 

Sh!t you're a fat bastard! .

 

Being honest you're probably better *built* than me. I'm 14 and 1/2 stone but I'm only five foot ten. I also have the stunning privelege of having 'Duck's Disease' I have a very long back and tiny, freakily-weird little legs. probably explains why I could ride 1970's Italian bikes without having a private chiropractor!

 

Whilst I'm not surprised it really does sound as if Guzzi got Ohlins to spring and valve the forks and shock for the Scura when Zippy the Pin-Head was in charge of the shop. (Alternatively they only paid enough for the Swedish security guard to be given the job on a long weekend in January! That's more likely!)

 

A 110 spring for the back is sounding like the go and whatever You or Greg recommend for the front taking into account my rather , err, *peculiar* physique!!!!

 

Pete

[Guest drknow]

Sh!t you're a fat bastard! .

 

Being honest you're probably better *built* than me. I'm 14 and 1/2 stone but I'm only five foot ten. I also have the stunning privelege of having 'Duck's Disease' I have a very long back and tiny, freakily-weird little legs. probably explains why I could ride 1970's Italian bikes without having a private chiropractor!

 

Whilst I'm not surprised it really does sound as if Guzzi got Ohlins to spring and valve the forks and shock for the Scura when Zippy the Pin-Head was in charge of the shop. (Alternatively they only paid enough for the Swedish security guard to be given the job on a long weekend in January! That's more likely!)

 

A 110 spring for the back is sounding like the go and whatever You or Greg recommend for the front taking into account my rather , err, *peculiar* physique!!!!

 

Pete

 

Tis true, tis true! I am a bit of a porker. I like my forks a little soft, and went too soft with the 1.05, so I'd say you shouldn't drop below 1.00 on the front. The 110 on the back sounds perfect. You're right on the stiff carcass tires, another to consider is the BT014 Bridgestone, it's a stiff carcass, comes in 160/60, true sport tire, and is a dual compound, which will eek a few more miles out for ya.

[dlaing]

I had my springs replaced some time ago. 1.05kg/mm front and 1093- 11.0kg (110nm?) rear. The damping was changed as well.

 

Now the length (non loaded) of the 1091 spring was 160mm and the replacement with higher rate is 150mm.

 

What if any considerations are there with this difference ?

 

Cheers

 

Bruce

The only consideration I can think of is how to wipe the grin off you face that you will get. ...and make sure the sag is set up well.

The firmness of the spring will mean it will need less preload, so you should have enough adjuster range to get the sag right, despite the spring being 10mm shorter. So don't worry!

[S251]

Dear Mr Roper,

 

I took the time to set the ride height and all the static measures in line with the OHLINS manual and S251 was a mess on the road in nearly all conditions.

 

NextI took the spring, and dampening to near max and S251 was stable in turns tight and wide but really unstable in a straight line, not dangerous but pitching left to right with near zero input.

 

Over the last few weeks I have reduced spring and dampening to near the lowest settings and the straight line stability has improved. ( This may be why MPH reccomend taking the forks through the yokes a bit?)

 

Stablity in turns tight and wide is good. Reaction to quick throttle movements is not so good. (too soft all round)

 

Questions come to mind.

Are the spring rates wrong? (It could be so) Need to keep the bike stiffer without extending the fork due to tigtening the springs.

 

Is the fork length right for the frame geometry? (Dont know seems to corner beyond my capacity to ride.)

 

Works OK on the track and street. Just likes to pitch about a little.

 

I have kept a record of the measures but the details are too many to list here.

 

Regards

S251

[Baldini]

....Are the spring rates wrong?.....

 

If you can't obtain decent suspension sag measurements, or can only do that by maxing preload then your spring rates are wrong for your/bike's weight.

 

V11 is heavy & frame is fairly flexible. If you ride them hard they will move about a fair bit, but if they are set up good on correct springs, they seem to settle OK. If you ride like that; make sure you have suitable tyres, don't panic & always carry clean underpants. They are best suited to smooth riding.

 

KB

[Paul Minnaert]

look here where italian bikes are made for, the difference between me and an italian. Place your own picture next to it :-)

[pete roper]

look here where italian bikes are made for, the difference between me and an italian. Place your own picture next to it :-)

 

 

Bad shoes, nasty shirt and we won't mention the shorts.......

 

 

 

Pete

[Guzzirider]

A very happy couple!

[Paul Minnaert]

A very happy couple!

The key to our luck is that we both have the silver book: "Moto Guzzi - Quando le moto hanno l'anima" written by Goffredo Puccetti, 571 pages guzzi.

[dlaing]

If you can't obtain decent suspension sag measurements, or can only do that by maxing preload then your spring rates are wrong for your/bike's weight.

 

V11 is heavy & frame is fairly flexible. If you ride them hard they will move about a fair bit, but if they are set up good on correct springs, they seem to settle OK. If you ride like that; make sure you have suitable tyres, don't panic & always carry clean underpants. They are best suited to smooth riding.

 

KB

 

Here is my highly controversial off the fairway, from planet Remulac, result of demon possession, yet nearly definitive guide to sag settings:

 

Step 1 Drop the triple clamps down the forks 5-10mm from stock. WARNING make sure fender and tire won't collide with anything when bottoming out.

 

Step 2 Measure sag with bike unladen and laden

Get a competent assistant to measure.

For laden sit in riding position with full gear on, and loaded with typical load (stuff like the clean underpants that Baldini mentioned).

Fuel tank about 2/3 full.

Be sure to take into account stiction by taking high and low readings at the respective stiction points and averaging out. RaceTech has a good article on how to do it.

http://www.race-tech.com/articles/SuspensionAndSprings.htm

 

Step 3 set sag to the following:

If you can't get close by adjusting preload, you will need different springs.

What is close enough is up to you.

I believe the most critical number for determining if your spring rate is ideal, is the difference between unladen and laden sag.

Some people on this forum target to 18mm unladen and 36mm laden for both the front and rear with a difference of 18mm.

If you are within 5mm of those numbers, or better yet within 5mm of my numbers below, you should be in good shape.

 

I target the following:

REAR Sachs

10mm unladen

30mm laden

(difference of 20mm)

FRONT

20mm unladen

35mm laden

(difference of 15mm)

 

MODIFIERS (all are rough guesses or opinions...what is your's? )

*Racing, subtract 1 to 5 mm from laden sag.

*Touring, add 1 to 5 mm to laden sag.

*Frequent two up, subtract 1 to 6 mm from rear laden sag, and subtract about half of that from front sag. Note: this is assuming sag is measured without passenger.

*Ohlins, add 5mm to rear laden sag.

*Progressive springs, add 2mm to laden sag and subtract 1mm from unladen sag.

*Short legs, add laden and unladen sag at a ratio of maybe 4mm additional laden for every 5mm additional unladen. (because shock needs to be firmer as travel decreases)

*Rider weight greater than 80kg, add 1mm rear laden sag for each additional 20kg, and 1mm front laden sag for each additional 40kg

*Rider weight less than 80kg, subtract 1mm rear laden sag for every 20kg less than 80kg and subtract 1mm front laden sag for every 40kg.

*Personal preference, (no sag nazis here) add or subtract whatever you want to laden and or unladen sag numbers. This forum has 200#riders who have found 550# shock springs to be too stiff, and yet there are some like Dr.Know who might weigh 250# in full leathers, that that use 115N/mm or 657# spring. So everybody sure has there own taste in what works. Often trial and error is the best way to go, but the above info should help you get close so you won't have to try and error too many times.

My numbers above are the result of a homogenization of opinions by experts and amateurs and some of my own limited experience and as you can tell they are rounded to the nearest 5mm. The 18/36mm numbers are a result of the 15/30 percent rule, also nice round numbers.

Next year, after my fourth shock spring and third fork springs, I might modify them based on what works better for me

SAA, YMMV.