Skid plates and frame flex


22 replies to this topic
  • wes513v

Posted June 27, 2015 - 12:14 PM

#1

So I've been pondering my need to protect my motor from errant rocks and such but wondered, with the flex characteristics of a frame being so affected by even the smallest change( Husky owners remove one bolt out of their subframe, Kawi owners for several years would run a later models motor mounts and modify the headstays, etc.) how detrimental to the handling of my bike will bolting up either an aluminum or carbon fiber skid plate be? It seems that a thick aluminum plate rigidly bolted to the bottom of the frame introduces a large amount of rigidity that engineers have worked hard to eliminate. Thoughts?



  • GHILL28

Posted June 27, 2015 - 02:53 PM

#2

Yup.  Putting more flexible motor mounts on to these bikes makes a noticeable difference.  Almost all aluminum frames have a lot to gain with more flex in them, not less.

 

I didn't notice any ill-effects from my Cycra full wrap plate.  But it does feel kind of cheap.

 

I run a Hyde basic skid plate on my 2T.  Aside from the initial fitment being a complete bitch, it does work well and doesn't make things louder.



  • rr558

Posted July 05, 2015 - 05:36 AM

#3

I have the plastic Cycra just for that reason . With an aluminum skid plate on a KTM it vibrates like an old cr500 .

  • torkd14

Posted July 06, 2015 - 04:46 AM

#4

The only thing I notice with a ricochet aluminum skid plate is a ton of engine noise echoing off of it. Didn't notice anything different in the way it rides though.

  • woods-rider

Posted July 06, 2015 - 05:34 AM

#5

I don't believe anyone who tells me they can feel the difference in handling after putting on a "stiff" skid plate... Unless they are a national pro or something.

  • wes513v

Posted July 07, 2015 - 09:13 AM

#6

I don't believe anyone who tells me they can feel the difference in handling after putting on a "stiff" skid plate... Unless they are a national pro or something.


Believe, dont believe. Your choice, but I can definitely say that when I changed my motor mounts and modified my head stays on my KX it improved in several areas including turning, so I have no doubt that it has an effect.

  • woods-rider

Posted July 07, 2015 - 09:41 AM

#7

Believe, dont believe. Your choice, but I can definitely say that when I changed my motor mounts and modified my head stays on my KX it improved in several areas including turning, so I have no doubt that it has an effect.


But you also knew that they were changed and knew what they were supposed to do.

I would love to have the resources to do blind testing with parts and a group of riders. Let them all ride the bike completely stock and get their impressions. Take the bike somewhere they can't see or hear for a while, change only one or no parts at all and have them ride it on the same terrain and get their impressions again. Do this about 100 times and see what parts the average rider can feel and see how much of it they make up in their head.

  • EarthCruzn

Posted July 07, 2015 - 09:57 AM

#8

I installed a "works connection" thick aluminum plate on mine. (these shown are for a Honda............they make skid plates that are bike specific)

It is designed for the flex in the frame, hard to explain how it mounts..... bolts on to the frame in the front and at the rear has bolts that hold slots brackets that slide over and under the frame/swingarm point connection that will allow the "flex"

 

Great product. Has holes for maintenance.

10-077.jpghttp://www.worksconn...uct=400&video=1

 

They also make this one as well.

10-070.jpg


Edited by EarthCruzn, July 07, 2015 - 10:17 AM.


  • Wiz636

Posted July 07, 2015 - 11:58 AM

#9

Based on the distance between the mounting points and their relative angle to each other I very much doubt that an aluminum skidplate can have more than a negligible affect on the frame flex characteristics...especially considering the size/weight/strength of the engine mounts. 

 

However, if it is a concern there is an excellent alternative to aluminum skidplates. The SXS slide plate is made of UHMW and is light, strong, and flexible. I put 1600 miles in Baja on mine as well as several off road races...a few of which have EX sections and I couldn't be more impressed.

 

http://www.sxslideplate.com/



  • Zackdocks

Posted July 07, 2015 - 12:28 PM

#10

I didn't notice with the skidplate, but I definitely noticed a lack of flex from my protapers after installing handguards! I hate how rigid the bars are now. 



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  • EarthCruzn

Posted July 07, 2015 - 01:00 PM

#11

I didn't notice with the skidplate, but I definitely noticed a lack of flex from my protapers after installing handguards! I hate how rigid the bars are now. 

They make handguards for "flex" bars now.

They mount different than the conventional type.



  • Zackdocks

Posted July 07, 2015 - 01:16 PM

#12

I don't have $450 worth of hate for my loss of flex lol



  • EarthCruzn

Posted July 07, 2015 - 01:32 PM

#13

What............  These are $179.00, come in 3 versions

 

pro5.jpg

Edited by EarthCruzn, July 07, 2015 - 01:40 PM.


  • jcm3

Posted July 07, 2015 - 06:56 PM

#14

I have the plastic Cycra just for that reason . With an aluminum skid plate on a KTM it vibrates like an old cr500 .

 

I have the Cycra one on mine also, but didn't ride it without it so I don't know how it felt before.



  • mxman47

Posted July 08, 2015 - 01:32 AM

#15

I don't have $450 worth of hate for my loss of flex lol


Here you go. These are pretty slick.
http://reflexracing.com/

  • Krannie McKranface

Posted July 08, 2015 - 08:45 PM

#16

I don't believe anyone who tells me they can feel the difference in handling after putting on a "stiff" skid plate... Unless they are a national pro or something.

 

Just lowering the torque number of all the engine mounting bolts makes an immediate change on rut stability.



  • woods-rider

Posted July 09, 2015 - 04:01 AM

#17

Just lowering the torque number of all the engine mounting bolts makes an immediate change on rut stability.


Again, I don't believe that you can actually feel the difference. Ever heard of the placebo effect?

  • Krannie McKranface

Posted July 09, 2015 - 05:53 AM

#18

Again, I don't believe that you can actually feel the difference. Ever heard of the placebo effect?

 

Yes. 

 

Have you heard of  longitudintal vs. axial / rotational flex?


Edited by KRANNIE, July 09, 2015 - 06:07 AM.


  • grayracer513

Posted July 09, 2015 - 06:53 AM

#19

 

Have you heard of  longitudintal vs. axial / rotational flex?

 

Don't set yourself up.

 

Just lowering the torque number of all the engine mounting bolts makes an immediate change on rut stability.

 

Reminds me of the time you told me you could make a graph with one axis.

 

Cow-Patty-907116.jpg

 

Whether a skid plate stiffens the frame in any measurable/detectable way depends not only on its own construction, but also on how and to where it mounts onto the frame.  They rarely bolt onto things that are "that" stiff, or use bolts that have a whole lot of clamping force.  If you stick the tail end of one in a vise and grab the top front, most skid plates will turn out to be pretty flexible, anyway. 



  • Krannie McKranface

Posted July 09, 2015 - 07:24 AM

#20

Don't set yourself up.

 

 

Reminds me of the time you told me you could make a graph with one axis.

 

Cow-Patty-907116.jpg

 

Whether a skid plate stiffens the frame in any measurable/detectable way depends not only on its own construction, but also on how and to where it mounts onto the frame.  They rarely bolt onto things that are "that" stiff, or use bolts that have a whole lot of clamping force.  If you stick the tail end of one in a vise and grab the top front, most skid plates will turn out to be pretty flexible, anyway. 

 

 

My god, stop it.


Edited by KRANNIE, July 09, 2015 - 07:45 AM.






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