Report on "Progressive" fork kit

[viewdvb]

I didn't have too many complaints about the stock forks except that on some sharp bumps they transmitted such a shock through the handlebars that it jarred my grip alarmingly. The company Progressive Suspension make an inexpensive fork kit that is marketed by Touratech amongst others so I decided to fit it during the winter. The kit consists of a set of progressive rate (multirate) springs and a bottle of 15wt oil. Yes, I've seen the posts here about the undesirability of multi-rate springs. I recall a phrase along the lines of "how can you expect to set the damping up for a spring rate that isn't constant?" Only single rate springs will do apparently. What bull***t! ALL fork springing is multirate due to the trapped volume of air increasing its pressure as it is compressed by fork action. This always results in a non-linear effective spring rate, sometimes quite an extreme one. The only exception would be if the internal air in the forks were vented to outside pressure. Even racing Ohlins don't do that! I was in the habit off adding air pressure via shraeder valves as a cheap way to increase springing on some of the unadjustable forks on my early bikes. I tried leaving the valves out experimentally (thus venting the internal air pressure) and the result was disastrous fork dive just as I had anticipated.

I digress..... Did the kit improve things? Well, it is different but not much. I'm damned if I can detect the change of springs. The single biggest effect I'm sure is caused by the heavier oil. It can be set up to almost mimick a sports tourer but that's not why I bought the bike. I wanted compliant suspension. Progressive's recommended settings produced an unpleasantly harsh compression damping effect. By backing off the damping settings I arrived at a reasonable compromise and it seems to have got rid of the unwanted sharp crashes. A bit more experimenting is still on the cards. Was it worth the cost and work? Maybe when fully loaded. It isn't the transformation that some owners are looking for. For me the jury's still out. My best answer would be - try just replacing the oil with 15wt first. I suspect it will give you most of the benefits without the cost of the springs which you can always fit later if you feel the need.

 

[Wistrick]

15 wt oil, in a cartridge style fork... No wonder the damping is stiff....I would think you would be better off with a linear spring and some 5wt oil... my 2 cents

 

[avc8130]

So you are calling "b*llsh!t" on tried and true practices, pretty much declaring yourself and expert but your own knowledge lead you to a terrible solution to your suspension troubles.

Of course EVERY fork has a progressive air spring. Why would you want to ADD to that with a progressive metal spring? Now, as you adjust preload, you ARE changing the RATE of the spring.

15W in a CARTRIDGE. Laughable.

ac

 

[Mark R.]

Unfortunately, the Progressive Suspension solution did not solve your problem. I found the forks awful as delivered, very jarring, and backed off on the damping adjusters significantly. That helped. Then I bought straight rate springs from Stoltec, and put in 5wt oil (I think), and that made the forks significantly better. Enough that I am very satisfied with them, in combination with a Cogent Dynamics rear shock.

The springs were about $100, and oil and installation labor were another $100. All in all a very cost effective upgrade, and good enough that I am not looking to upgrade the forks any more.

 

[Wistrick]

Unfortunately, the Progressive Suspension solution did not solve your problem. I found the forks awful as delivered, very jarring, and backed off on the damping adjusters significantly. That helped. Then I bought straight rate springs from Stoltec, and put in 5wt oil (I think), and that made the forks significantly better. Enough that I am very satisfied with them, in combination with a Cogent Dynamics rear shock.

The springs were about $100, and oil and installation labor were another $100. All in all a very cost effective upgrade, and good enough that I am not looking to upgrade the forks any more.

this is what I am doing... Put the Penske on the back and now .90 springs up front...The next time the forks need service I will probably send them to Nick for for new shim stacks...

Dan

 

[yamadad]

I too agree that 15w oil in a cartridge style fork is not a good idea. 2.5w to 5w is the norm. In some applications you can go as high as a 7.5w, but that is not the norm. Without changing the shim stack you're better off playing the amount of oil rather than the viscosity. Also, be aware there is a good amount of variety in fork oil viscosities from one manufacturer to another. There really is not much of an industry standard, so some research will help here too. ::022::

 

[Dallara]

So you are calling "b*llsh!t" on tried and true practices, pretty much declaring yourself and expert but your own knowledge lead you to a terrible solution to your suspension troubles.

Of course EVERY fork has a progressive air spring. Why would you want to ADD to that with a progressive metal spring? Now, as you adjust preload, you ARE changing the RATE of the spring.

15W in a CARTRIDGE. Laughable.

Amen, Bruddah! Amen!

The OP decides he knows more that literally every credible suspension engineer in the world - both on two- and four-wheels - and wonders why the outcome was less than satisfactory. "Laughable" is indeed the right word. ::025::

And as has been mentioned, there is *WILD* variation in actual oil viscosities vs. labeled oil viscosities when it comes to fork oils. Here's just a small illustration regarding that:

Note how Yamaha, Kayaba, and Showa suspension oils are very close in specification.

Pretty much best to stick with Yamaha calls 5-weight and experimenting to get the proper level, and get a straight-rate spring. Could have saved some money doing that in the first place.

Dallara



~

 

[mcrider007]

My best answer would be - try just replacing the oil with 15wt first. I suspect it will give you most of the benefits without the cost of the springs which you can always fit later if you feel the need.

You shouldn't be giving spring and damping advice until you learn how they actually work and interact with each other.

 

[avc8130]

You shouldn't be giving spring and damping advice until you learn how they actually work and interact with each other.

Agreed. That advice is so wrong it is scary.

If anything, the "best answer" would be "try just replacing the springs with proper rates and fresh 5W at the proper height". This is a pretty darn good solution for someone looking to spend <$100.

ac

 

[Mzee]

Is there a specific oil recommended by Yamaha?

 

[avc8130]

Is there a specific oil recommended by Yamaha?

There is. Of course it is their "house brand". Yamalube 01.

ac

 

[Dallara]

Is there a specific oil recommended by Yamaha?

There is. Of course it is their "house brand". Yamalube 01.

ac

Also known as Yamalube 5wt...

Which, oddly enough, is exactly what Nick Stolten at Stoltec Moto put in my forks when he rebuilt and revalved them.

Dallara



~

 

[viewdvb]

So you are calling "b*llsh!t" on tried and true practices, pretty much declaring yourself and expert but your own knowledge lead you to a terrible solution to your suspension troubles.

Of course EVERY fork has a progressive air spring. Why would you want to ADD to that with a progressive metal spring? Now, as you adjust preload, you ARE changing the RATE of the spring.

15W in a CARTRIDGE. Laughable.

ac

Thanks to all for taking the trouble to comment. You may all be right and I may decide that the stock setup or something different would be better but the cost of experimenting was negligible. Suspension engineers tend to agree that the final arbiter of suspension changes is the seat of the pants test. If that were not so, MotoGp racers would not spend so long playing with different setups eventually ending up with substantial variations even for the same bike at the same circuit. At present, I prefer the current setup to stock. Interesting that one major suspension manufacturer didn't think 15wt laughable nor did Touratech who market a range of aftermarket products that normally work well. As for the springs, I note that Yamaha, who have some of the most extensive research facilities in the world not to mention their link with Ohlins, chose not to fit linear springs. What would they know? They only designed the bike. Which raises the matter of qualifications. Obviously Yamaha R&D is packed full of highly qualified technicians and engineers. I don't doubt Progressive Suspension has a few. I have only a Bsc in Mechanical Engineering and 20 years successfully racing bikes that I designed and built. I don't have any special qualifications in suspension engineering. As many of you are so authoritative, we deserve to hear YOUR qualifications so we can evaluate your comments. How about it? In the absence of a PhD in suspension technology, I stick by my advice that you might like to try a cheap option like 15wt oil (or any other grade you think might work) which is easily reversible if you don't like it.

 

[snakebitten]

Re: Report on &quot;Progressive&quot; fork kit

I love this bike.
I love this board.
And I'm crazy about this subject.
But some threads just feel a bit wound tight. Lol
This one sure does.

 

[avc8130]

Thanks to all for taking the trouble to comment. You may all be right and I may decide that the stock setup or something different would be better but the cost of experimenting was negligible. Suspension engineers tend to agree that the final arbiter of suspension changes is the seat of the pants test. If that were not so, MotoGp racers would not spend so long playing with different setups eventually ending up with substantial variations even for the same bike at the same circuit. At present, I prefer the current setup to stock. Interesting that one major suspension manufacturer didn't think 15wt laughable nor did Touratech who market a range of aftermarket products that normally work well. As for the springs, I note that Yamaha, who have some of the most extensive research facilities in the world not to mention their link with Ohlins, chose not to fit linear springs. What would they know? They only designed the bike. Which raises the matter of qualifications. Obviously Yamaha R&D is packed full of highly qualified technicians and engineers. I don't doubt Progressive Suspension has a few. I have only a Bsc in Mechanical Engineering and 20 years successfully racing bikes that I designed and built. I don't have any special qualifications in suspension engineering. As many of you are so authoritative, we deserve to hear YOUR qualifications so we can evaluate your comments. How about it? In the absence of a PhD in suspension technology, I stick by my advice that you might like to try a cheap option like 15wt oil (or any other grade you think might work) which is easily reversible if you don't like it.

1. Touratech makes "accessories". They sell everything from bags to skids to shocks. BMW makes a nice car, that doesn't mean I would buy their hamburgers. I'll choose to stick with someone that SPECIALIZES in nothing but shocks when I need to plunk down $800+ on a SHOCK.
2. Yamaha has to design the bike for the masses. They may not have chosen "straight rate" springs, but they sure didn't choose "progressive" either! They chose a 2 rate spring.

I don't need to disseminate my qualifications. You don't need to trust my advice. It really doesn't matter to me. My bike rides AWESOME, as does countless other Teneres I have setup for others. Your bike rides like crap, so I should hope others would do a tad more research before putting suspension oil SIGNIFICANTLY thicker than Yamaha suggests into their bikes. By your own statement, why would you change JUST the oil? With Yamaha's immense resources surely they would have stumbled on that during the design phase themselves.

Good luck sorting your bike.

ac

 

[sportsguy]

Yeah, not groovin' on the angst here...

I don't see the problem.

1 - a guy tries something
2 - a guy shares his thought son what he tried
3 - those thoughts are "advice" based on HIS experience

Don't like it? Don't agree with it? Don't do it...

I get no one likes to see factually inaccurate data around, but, ah...this place, called the Interwebs, it's chalk full of the shite! At least here we have people doing something then reporting their findings.

And my questions are rhetorical - I don't want responses, I won't read responses, I won't think about responses to responses, I won't even turn on a light in my living room, leading me to my computer if I think anyone's responded to my points in this thread... (well, maybe I'll check int he morning to see what's beiong tossed at me... )

Now, what I do like about this thread is...

It showcases the passion people have for some topics.
It showcases a sharing of knowledge that it tough to suss out on the ol' Interweb of Junk
It shows people, on a fundamental level, feel inclined to protect others through education and info sharing.

::020::

 

[snakebitten]

Re: Report on &quot;Progressive&quot; fork kit

Oil & Tire threads are for sissies.
Suspension threads are not for the feint of heart.

 

[Dallara]

~


Hey, I'll play! ::012::

I'll be happy to match CV's with the OP, but before we do I wanna' know what we win... Pretty sure I got him beat, especially in that race background area, etc. Just wondering if it's worth all the typing. ::025::

As avc8130 so eloquently pointed out, Yamaha did *NOT* choose "progressive" springs for the Super Tenere. they chose a dual-rate spring, and for obvious reasons. Let me know if you want me to explain it to you.

When you're talking about those suspension engineers making changes to race bikes... Next time you're at a race watch carefully what they're doing when they make a spring rate change. You'll see 'em swapping out straight-rate springs. And it's not hard to imagine different riders, even on the same brand race bike, ending up with different spring rates, damping settings, etc. After all, they all don't weigh the same, nor do they have identical riding styles or race backgrounds...

One thing they do have in common - straight-rate springs - if they're riding bikes that use wound coil springs (some of today's MX and off-road race bikes are using air forks - again).

Further, again as avc8130 pointed out, Touratech is far, far from being any sort of suspension company. Mostly they sell overpriced, overstyled, overhyped bling that performs better down at the Starbucks than it does out where the world gets rough. About the only place they outperform anyone in the motorcycling world is in the weight of their catalog... ::025::

And "Progressive" - the suspension company (and in their case I use the term "suspension" loosely) - is not exactly at the leading edge of suspension development. Ever notice how they usually only make *ONE* fork spring for any model of motorcycle? Doesn't that make you wonder, even just a bit, about their motives? It doesn't take a rocket scientist to figure out that *ONE* spring will not be optimal for all weights and style of riders, yet that's usually all they make... Why is that? In other words, calling Progressive a quality suspension company is like calling McDonald's a gourmet restaurant.

Last, but certainly not least... In the original post the OP said "I didn't have too many complaints about the stock forks except that on some sharp bumps they transmitted such a shock through the handlebars that it jarred my grip alarmingly." Hmmmmmm... Let's see. You have what is obviously *NOT* a springing issue, but instead a problem high-speed compression damping rate being excessively harsh, and your answer is to put *HEAVIER* weight oil in there? Yeah... OK... ::025::

So, before we go on, what do I win when we compare CV's? ::003::

Dallara



~

 

[Mikeybikey57]

Ooooooooooooh I do love it when people get arsey with each other about who knows more about the thrunge sprocket retaining gromit on their bike. And I thought that the guys on the Classic British Bike sites were nit-picky. Fish slapping at dawn anyone? ) Monty Python, The Fish Slapping Dance

 

[scott123007]

More fuel for the fire for the know it all's...http://www.dirt-bike-secrets.com/progressive-springs.html