Rear touring trunk aerodynamics

[Open Fire]

anybody notice a "drag" or "pushing" left or right after installing the factory Yamaha rear touring trunk? (or any trunk for that matter).

I finally installed mine today and took her for a spin and noticed quite a bit of difference from without it. It wasnt windy at all, just normal conditions

Just as bit of info, I noticed the height of the trunk as measured above ground is higher as compared to my RT1150, probably 10".

Just wondering.....

 

[2006FJR]

anybody notice a "drag" or "pushing" left or right after installing the factory Yamaha rear touring trunk? (or any trunk for that matter).

I finally installed mine today and took her for a spin and noticed quite a bit of difference from without it. It wasnt windy at all, just normal conditions

Just as bit of info, I noticed the height of the trunk as measured above ground is higher as compared to my RT1150, probably 10".

Just wondering.....

I was able to do about 145 with mine on a few weeks ago. The bike handled fine.

 

[vandy]

I ride with a trunk most of the time due to two up riding but when I take it off I don't really notice a difference.

 

[RICLET]

I ride solo and do find the topbox seems to catch the wind and just push me arround a little, take the box off and the issue disappears

 

[angus]

I never use the trunk when riding solo on a windy day it seam to move me all over the place.

 

[canucklehead-biker]

Never noticed much difference due to the top case (I have Givi Maxia 52litre, not the stock Yamaha).

Maybe your mount isn't quite square?

Griff

 

[JRO]

I've taken to leaving my Yamaha box at home, when I don't need the space, or am alone. It makes the front end light, at high speed, and it does catch wind and tosses me around a bit, when it's windy.

Haven't noticed it pulling to one side or the other, however.

 

[wfooshee]

I don't notice my E52 pulling me around, but it has a definite effect on fuel mileage!

 

[Open Fire]

canuckle - pretty sure I got it on right, there are only three bolts. it is definately secure to the platform. it wasnt giggling because it was loose, more of a airplane tail effect.

2006FJR- I havent had a chance yet to get up over 80mph, but it definately was catching.

this may sound funny, but in the afternoon sun, in certain places in my peripheral vision I could see the shadow of the box which I am not used to and it weirded me out.

somebody chasing me :crazy:

I probably will just take it off until needed.

I gotta give Yamaha props, it is a really sexy looking top box. best i've seen from the factory. :thumbsupsmiley:

thanks for the input guys

.

 

[Knifemaker]

This has been gone over in other posts, and simply seems to be something some, not all experiance. As I don't want to search for the other posts on this I'll give you the quick answer.

The space between the riders back and the front of the topcase can create a turbulant pocket of air. This seems to depend on the size and height of the rider.. (short thin riders have less problems) the windscreen you use and it's position up and down. This unstable air can make the bike feel a bit "wiggly" especialy at speed.

I ride with mine on all the time, but have a wider shield and keep it raised more than lowered, and I also ride alot with a passneger, which eleminates the problem.(and I am a short thin guy)

I do notice a very pronouced back pressure if riding solo..if I was just wearing a t shirt the air will actualy try and lift it off of me. (I have to keep my jacket sides cinched down tight)

Many have found that simply lashing a bag to the passenger seat helps fill that void and solves the issue.

Some say it is not as bad if they take the sidecases off, some say it does not make a diffrence.

You also have to realize that side winds will effect the bike more simply because there is a larger surface area for them to push on. If you do not really need the case on the bike take it off, and if you go on a trip and need the storage, remember to bungee up a pack behind you to fill in the space.

KM

 

[sonicspeed]

riding solo with my top case on gives me a quite of bit of wobble at highway speeds so i leave mine off unless 2-up

 

[HaulinAshe]

You might also check your body position symmetry. With the Yami top box on, and no passenger in place, even a tiny shift of your body to one side of center has a noticeable effect at higher speeds.

Most human bodies are very assymetrical!

 

[sonicspeed]

Most human bodies are very assymetrical!

are you saying my body looks like an ass?????

:lol:

 

[David C]

I don't notice a difference with my Givi E-52, but I only use it when I'm two up.

David

 

[Violione]

I have the Givi E52; unloaded it will cause the bike to "catch" a cross wind but loaded it has little affect. Now remember the Givi is a completely different shape than the Yami box. (Givi is egg shaped the Yami is well boxy) The Yami box is damn good looking but it is not as aerodynamic as the Givi (I am not knocking the Yami at all). The Yami is very flat/blunt in the front and on the sides. What JeffAshe & Knifemaker are saying makes a lot of since as far as human body symmetry and the type of wind screen you have in front of you and the space between you and the box. Right up until 3 weeks ago I was running the stock screen and I could feel the boxes effect on the bike when I pass 18 Wheeler's; when their bow wave would hit the box after the front of the bike went through first. Now I am running the V-Stream and I don't feel the box hitting the bow wave because it is riding in the slip stream of the V-Stream shield. Its all about aerodynamics and there are many variables; shields, riders, helmets, the outrigger heat deflectors are in or out, weight in the box vs. effect on the front wheel & steering, etc... I guess you will learn the different "feels" of the bike as you farkel along.

One word of advice that has been said by many riders out there; before you take a long trip fully loaded, you should load up a few days before the trip and ride around and get accustom to how the bike feels and behaves when loaded to the gills. You don't want any surprises while your 100 miles from home.

V.

 

[HaulinAshe]

2006FJR- I havent had a chance yet to get up over 80mph, but it definately was catching.

So your new bike is still in the dealer's parking lot???

Why don't you take it out for a ride???

 

[Duff]

Obviously, you are not pushing the air far enough out. This would indicate that there is not enough "girth" in front of it. In short, you are not fat enough to push the air around the trunk.

Eat more!

Problem solved.

 

[Open Fire]

So your new bike is still in the dealer's parking lot???Why don't you take it out for a ride???

I meant over 80 with the new box on....

without it, already have over 1k miles and saw 130 already... (didnt just say that) cause that would be illegal <_<

Duff, at 230lbs I am not eat'n any more to gid rid o my turbulence!

I do like the idea of a bag between me and the trunk. that didnt sound quite right... :huh:

 

[twowheelnut]

Infamous top box wobble. Been discussed since the Early Days. I finally got to experience this effect this weekend, but with the pillion seat full of camping gear the effect disappears.