Rear supension setup or I'm blind with MX Bikes

Suspension Suspension Tuning Pr2 Racing Fork and Rear shock tuning

30 replies to this topic
  • Goforaride

Posted January 26, 2016 - 10:01 PM

#21

Between the subframes being lowered, and the suspension lowered, the bike sit ridiculously low. I sat on Jimmy Decotis 250f in Kamloops during the Nationals and I could flat foot. The height of the 250f are the same as the 450f...

So they do actually lower the suspension? Makes sense

  • clappedoutkx

Posted January 27, 2016 - 05:22 AM

#22

So if even pro MXers are riding drastically lowered bikes, why the heck do the bikes we buy seem to be built for pro basketballers? Or am I really that short?

  • zderekv

Posted January 27, 2016 - 05:40 AM

#23

interesting. Everything I have ever read says faster=stiffer. It seems that the pros rarely if ever do what we consider proper. We are told to have the right weight springs and have the front and back balanced. The pro does what he wants. We are given a window for sag numbers. The pro does what he wants. We are told slower/older/shorter riders need softer suspension and faster/younger/taller riders need stiffer. The pro? He does whatever he wants. Obviously someone smarter than I came up with these rules/guidelines but why does it seem that the fastest guys ignore them? It is not just in bike set up either. We are told to stand and grip with our knees. Well there are times to stand and grip but watch a pro race. They sit more than then stand and those knees are all over the place. Let's not forget elbows up! Really? Again watch the pros. I'm not saying these are not proper techniques. I'm just saying that the rules of thumb do not apply to the pros. They do what works and that is why they are the fastest in the world.


These are more like guidelines than rules. Recommended sag and suspension settings are just that - recommendations or starting points. If you are as good a rider as the pro riders, spent as much time on a bike at race speed as them, understood what altering each aspect of your suspension does to your lap times in a controlled environment and had a crew of mechanics working for you, all of the recommendations can go right out the window. However, most of us are on here looking for suspension recommendations based of what others on here are running rather than putting in the laps and figuring out what works best for each of us. Recommended setting are just to get you in the ball park.

  • Goforaride

Posted January 27, 2016 - 03:01 PM

#24

With my lowered shock, I have no free sag...

So I have 2 questions. First, with I lighter spring and more preload as in you example, wouldn't that in theory cause a more harsh ride? Why would you not have free sag on a lowered shock?

  • grayracer513

Posted January 27, 2016 - 03:40 PM

#25

The first question addresses a post of mine, not Monk's.  The answer is that it depends on the damping setup, but in general, yes.  And no.

 

With any given rider and riding style, a stiffer spring and lighter damping will normally produce a somewhat plusher ride overall than a lighter spring with heavier damping.  And to achieve the same bottoming resistance, for example, with a lighter spring, you would need to increase the damping resistance to make up for the decrease in spring resistance.  Then again, you might also set up low speed damping at a soft rate an use high speed to control bottoming.  The pros are probably not looking for a plush ride, however. 



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  • Monk

Posted January 27, 2016 - 04:13 PM

#26

So I have 2 questions. First, with I lighter spring and more preload as in you example, wouldn't that in theory cause a more harsh ride? Why would you not have free sag on a lowered shock?


1.) The Yamaha has a very slow linkage curve, combine with valving, the Yamaha shims don't have to work as hard as other manufacturers.

The shock tops out before it reaches its full length.

What's more important? To have 11.5in of travel working properly or 12in working improperly? Keep in mind, lowering suspension (in my case specifically) also effects the whole of the bike. The Yamahas in specific are very tall on the rear. Lowering it makes the whole bike operate better, your essentially changing the whole chassis by only modifying one part.

Keep I'm mind too, I'm still learning all this. But as I test and test more I'm starting to really understand that suspension is just a small part.

  • Goforaride

Posted January 27, 2016 - 09:34 PM

#27

1.) The Yamaha has a very slow linkage curve, combine with valving, the Yamaha shims don't have to work as hard as other manufacturers.

The shock tops out before it reaches its full length.

What's more important? To have 11.5in of travel working properly or 12in working improperly? Keep in mind, lowering suspension (in my case specifically) also effects the whole of the bike. The Yamahas in specific are very tall on the rear. Lowering it makes the whole bike operate better, your essentially changing the whole chassis by only modifying one part.

Keep I'm mind too, I'm still learning all this. But as I test and test more I'm starting to really understand that suspension is just a small part.

so did you just have it lowered a half inch? Would running a half inch more sag on a standard shock have the same affect?

  • Monk

Posted January 28, 2016 - 07:34 AM

#28

so did you just have it lowered a half inch? Would running a half inch more sag on a standard shock have the same affect?


No

  • Goforaride

Posted January 29, 2016 - 03:46 PM

#29

No

is it all in the valving

  • Monk

Posted January 29, 2016 - 04:06 PM

#30

is it all in the valving


Running more sag will also rake your forks out more... The YZF is tall in the rear end, it needs to be lower. With it being lower, you are changing the balance of the bike which improves everything including suspension action, turning, stability, handling etc etc.

It would be a tough argument for me to make that my bike is the best suspended YZF around because everyone is different, but I could argue it's one of the better handling and suspended bikes. Mostly through testing, unlike most on TT who just bolt on a lowering linkage and triple clamps and call it good, I put some hard time testing. And not just riding around testing, going back and forth between new and old settings (valving), different tires, brakes, fork height, oil heights and so on.

  • Goforaride

Posted January 29, 2016 - 04:14 PM

#31

Running more sag will also rake your forks out more... The YZF is tall in the rear end, it needs to be lower. With it being lower, you are changing the balance of the bike which improves everything including suspension action, turning, stability, handling etc etc.

It would be a tough argument for me to make that my bike is the best suspended YZF around because everyone is different, but I could argue it's one of the better handling and suspended bikes. Mostly through testing, unlike most on TT who just bolt on a lowering linkage and triple clamps and call it good, I put some hard time testing. And not just riding around testing, going back and forth between new and old settings (valving), different tires, brakes, fork height, oil heights and so on.

that's all good info. So how do you actually go about lowering the bike? I'm 5'6 and I ride track and woods. About 30/70 respectively. I could use an extra inch or two. I gained a little by shaving the seat but I hate how the lower seat feels. It would be awesome to be able to lower the suspension and get back to the standard seat.





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