Front Forks

[Marc B]

The bike has the Marazocchi with no preload adjustment.

Currently there is way to much movement on the bike, I have the compression dampning one click away from full. and the rebound around 3/4

 

Is there a recommended sring for these forks or is it a matter of shimming.

 

Thanks

Marc

[gthyni]

Is there a recommended sring for these forks or is it a matter of shimming.

 

You could preload the spring by lengthening the preload tube inside the fork leg,

or better get are harder spring. I think the firm Lindemann has come up in

the discussion as an exelent american source for suspension fixes.

[beauchemin]

When you say "there is too much movement", I assume that you mean that the forks feel under-damped?

 

It sounds like you need a heavier fork oil so that you can get your compression and rebound adjustments closer to the middle of their respective ranges.

[Guest ratchethack]

Marc, there seems to be some strong consensus around the idea that the stock Marz fork springs are about the right rate for a 125-150 lb. rider. For all others they will be some shade of inadequate, depending on how you ride. Much discussion and helpful spring comparo data with graphs are to be found in the infamous "Marz Fork Spring" thread:

 

http://www.v11lemans.com/forums/index.php?...hl=fork+springs

 

After admittedly getting a little wacky on springs in that thread , I finally ordered new Wilbers progressives which came in last week, but can't comment, as I haven't put 'em in yet.

 

Good luck!

[al_roethlisberger]

Marc, there seems to be some strong consensus around the idea that the stock Marz fork springs are about the right rate for a 125-150 lb. rider.  For all others they will be hopelessly inadequate.  Much discussion and helpful spring comparo data with graphs are to be found in the infamous "Marz Fork Spring" thread:

 

http://www.v11lemans.com/forums/index.php?...hl=fork+springs

 

After admittedly getting a little wacky on springs in that thread , I finally ordered new Wilbers progressives which came in last week, but can't comment, as I haven't put 'em in yet.

 

Good luck!

56785[/snapback]

 

 

 

...wow, the "ideal" rider seems to be losing more and more weight every time this subject comes up

 

The last I heard, ~170lbs was the ideal Italian jockey

 

 

Anyway, regardless... yes, that is the consensus, that if you are over... let's just say 150ish... the stock forks are going to start to let you know that you might have to do some more serious adjustment/modification to get sag and damping in the right range.

 

But you definitely can set them up satisfactorily, and don't have to toss them.

 

I do have Ohlins, but they aren't necessary to enjoy the bike.

 

Get some correct springs for your weight, and have the forks dialed-in by someone who knows what they are doing, and you should be happy.

 

al

[Janusz]

My weight is 225 lbs and riding style very aggresive. After replacing fork springs with heavier ones (I think 1.05?) quite a while ago from LE I think the old faithful Goose is as good as only possible in her suspension department.

 

Which, come to think of it, is excellent really for what it is.

 

The OME Sachs does not need any improvements IMO and it looks and works the same as when new (lucky me, I guess).

 

Sure, one could install the most exotic forks and shock possible but would that improve anything? The whole suspension will only work as good as the weakest element of the whole setup. Short of reengineering frame, swingarm and drivetrain it will never come even close in handling control to say my new R1.

 

I love my V11 as it was meant to be and consider it very well balanced as long as everything works properly.

[dlaing]

And others of us are of the opinion that the OEM Sachs is sprung for someone well under 200 pounds.

I would be surprised if Janusz did not favor a five hundred pound spring if he tried one.

My 475# spring was under $80 shipped. If I were to order it again, I would get a 500 pound/inch spring, and even that may be too light for my 210 +++ pounds that bottom out the suspension.

An easy test to is push the bottoming bumper forward and go for a ride over a moderately bumpy road.

If it pushes the bumper back down to the end, you can be pretty sure it is bottoming on bumpier roads.

If your roads do not cause you to bottom, you are probably fine.(or over-spung)

The Sachs is not a bad shock. Heck, it has both compression and rebound damping.

Since I resprung it, it is much more in harmony with the Ohlins forks.

[dlaing]

The bike has the Marazocchi with no preload adjustment.

Currently there is way to much movement on the bike, I have the compression dampning one click away from full. and the rebound around 3/4

 

Is there a recommended sring for these forks or is it a matter of shimming.

 

Thanks

Marc

56767[/snapback]

 

Shimming the springs is pretty easily done.

Most people will be better off with stiffer springs.

To find out, you need to know your sag numbers.

The two numbers are how much the weight of the bike sags the springs from fully extended, and how much your combined bike's weight and your weight (with gear) compress the spring.

Their are many FAQs or HOW TOs on sag setup on the internet and possibly on this forum/

[antonio carroccio]

Marc, you live in Seattle, right?

 

 

 

..........Get your ass to Enzo!!!

He will fix it in the right way..

[txrider]

Here's Racetech's recommended procedure on setting sag-

 

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

[Janusz]

And others of us are of the opinion that the OEM Sachs is sprung for someone well under 200 pounds.

I would be surprised if Janusz did not favor a five hundred pound spring if he tried one.

My 475# spring was under $80 shipped. If I were to order it again, I would get a 500 pound/inch spring, and even that may be too light for my 210 +++ pounds that bottom out the suspension.

An easy test to is push the bottoming bumper forward and go for a ride over a moderately bumpy road.

If it pushes the bumper back down to the end, you can be pretty sure it is bottoming on bumpier roads.

If your roads do not cause you to bottom, you are probably fine.(or over-spung)

The Sachs is not a bad shock. Heck, it has both compression and rebound damping.

Since I resprung it, it is much more in harmony with the Ohlins forks.

57020[/snapback]

 

Here I was, totally satisfied that my suspension was sorted and what you did? You forced me to think and try more; I don't like you

 

Excellent remarks, I have no other choice but try. Did you have your sag properly set before you decided that you still needed a heavier spring? I had to turn the collar 3 x360* before my sag was acceptable and assumed that the spring was OK.

 

Do you happen to know off hand what is the stock spring weight, which you would recommend for my 225 lbs and where I can get it?

And is it all you need there, just to replace the spring? Is it easy to do?

 

Thanks again.

[dlaing]

I wish I could say I got a decent sag reading on the OEM Sachs spring.

I never did.

To keep it from bottoming, I gave the OEM spring so much preload that I had zero bike only sag. This left me with over an inch of rider sag, but I cannot say how much exactly.

Perhaps some other person could chime in their OEM Sachs sag numbers and weight.

Regardless, you should start by getting an accurate measurement of free(bike only) and static (bike and rider)sag.

In my opinion, if you set the bike only sag to 5-10mm, your static sag should be about 1/4 to 1/3 of total travel, or about 30-40mm. I even think 40mm static sag is likely to bottom out too easily. I am sure everyone has their own opions on this.

I am set to 5mm/30mm with the 475# spring, and it still bottoms more easily than I would like, but is fine for touring, and an improvement over stock.

I think the ideal target for sport riding would be 10mm/30mm which would require (if my math is correct) a 20% firmer spring or roughly a 575# spring.

For the mix of riding that I do, a 500-525# spring might be about right.

I sit pretty far back, so my 210#+++ may have the same sag as a 250# rider who sits up by the tank.

I would guess you would need a 550# spring, which is what Lex got.

Mike Stewart is a bit lighter at about 200# and he found the 550# too firm, so he went for a 500# which is probably about right for him.

As for the spring to buy, I went to http://www.hrpworld.com and got the Hypercoil 2.25 inch by six inch spring. My 475# spring is marked 468/475, so I suspect it may actually be a 468# spring

It is shorter than stock, so it slips in without the need of special tools to compress it.

The inner diameter is greater than stock, so it may not center as well on the perchs.

Mine seems to be staying centered...I am not sure why

Ideally new perches should be made or some sort of spacers added.

I am not sure what LE does when they fit hypercoils to our Sachs....Anybody know?

Also, I gave my extra stock Sachs spring to Ratchethack so that he might measure the spring rate.

I wonder if he got anywhere with that???? Ratchet???

FWIW I stood on the spring and very crudely measured deflection, giving me an estimate that the spring was MAYBE 350#/inch. But heck, I could have been off by 100#!

One thing that still perplexes me is that the 475/468# hypercoil deflects about 12 or 13mm on the shock when my weight is applied in riding position. Theoretically, half the spring rate directly over the rear axle should deflect it half an inch on the shock(one inch wheel travel) So my sag measurement may still be wrong #$%#@$@!

 

The biggest problem was getting the stock spring off.

I used two ratcheting tie downs to compress the spring. It took over an hour of figuring out that I need to loop the strap a couple times to get the block and tackle effect going.

The guy on our forum who recommended straps attached pictures of the blood on the shock from his hands. So be careful!!!

If I were to do it again, I would get my fattest friend to sit on the bike while I tightened the straps, and then remove the shock, and then the spring.

A strap around the wheel and saddle could replace a fat friend.

Aside from overcoming the force of the spring, you will have to balance the force with the straps to keep the spring straight.

I probably also made the mistake of setting the pre-load to minimum instead of maximum, before using the straps.

Oh yah, and getting the shock off is pretty easy. Support bike, Remove fuel tank and airbox, and the rest is easy. I had my rear wheel and starter off at the time, but I don't think it was necessary.

But before you take my advice, measure the static and free sags. If you have not added so much pre-load that there is no bike only weight, and your weight alone causes a change of more than 30mm, I would say you MUST up the spring rate. Hate me now, thank me(and others on the list) later.

Also, try pushing the bottoming bumper up and then go for a ride and see if you are bottoming without knowing it.

I have been wrong before, but I think at your weight, it is a sure bet that you need more spring

[Guest ratchethack]

I gave my extra stock Sachs spring to Ratchethack so that he might measure the spring rate.

I wonder if he got anywhere with that???? Ratchet???

Well, I tried 2 different bathroom scales rigged up with various Rube Goldberg-style configurations of blocks, clamps and beams on my workbench, applying principles from the Roadrunner and Coyote School of Advanced Newtonian Physics. But in the end I was frustrated by an inability to get repeatable readings for other than just one point of travel . I haven't given up, however. Soon's I get a "round tuit" I'll see if I can hunt down a suspension shop to see if I can get an accurate set of measurements. Will advise.

[dlaing]

Well, I tried 2 different bathroom scales rigged up with various Rube Goldberg-style configurations of blocks, clamps and beams on my workbench, applying principles from the Roadrunner and Coyote School of Advanced Newtonian Physics.   But in the end I was frustrated by an inability to get repeatable readings for other than just one point of travel <_ . i haven given up however. soon get a tuit see if can hunt down suspension shop to an accurate set of measurements. will advise.>

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[Marc B]

Thanks for all the info & links, lots to research and read

 

Marc