PDA

View Full Version : Stupid Question



Phantom
01-14-2015, 09:35 PM
:017:

Many GL1800 Trikes have the rake modified with an additional 4 - 6 degree forward angle to make the trike easier to steer.

What would happen if we added 4 degree rake on the standard Goldwing/F6B ????

I'm not complaining about how my bike rides, just curious of the outcome :popcorn:

Ridlikhel
01-14-2015, 11:03 PM
I like it the way it is. Long neck and a stocky body doesn't sound right to me.

Deer Slayer
01-15-2015, 08:56 AM
Wait for it. Scotrod will tell us. :yikes::poke::cheers:

Hornblower
01-15-2015, 09:04 AM
Logical thinking tells me steering would be slower with increased straight-line stability at higher speeds. Rake design is always a compromise and personally, I like what Honda has chosen for us.

shooter
01-15-2015, 09:52 AM
That's exactly right Ken. In other words it would corner like a turd and steer like a Mack truck.

Old Ryder
01-15-2015, 10:03 AM
Almost traded for a 2002 Deuce a few years ago---until I rode it. It was raked just a few degrees--hard to notice until the guy told me. When you got over about 10 MPH it was fine and rode like any other bike. But at walking speed it was almost impossible to steer. The term was the bars "got heavy". When you went to turn them, they wanted to keep on turning. I was about 270 lbs at the time and it caugut me off gaurd and gave me quite a scare. Needless to say, I passed on the deal. If all raked bikes are that hard to ride, then I know why we don't see more of them.

Retired Army
01-15-2015, 10:05 AM
Don't know if this helps or not.

Steering

Although there are many kits on the market that change Trike steering geometry, the affect of these kits on Trike handling characteristics is often not fully understood. Rake is the angle measured between the steering axis and vertical. The steering axis is the line about which the steering system turns. Although the angle of the fork tubes from vertical is often the same as the rake angle, they are not always the same. Trail is the distance measured from where the steering axis meets the ground to where a vertical line drawn though the front axle meets the ground. It can be thought of as the distance that the front wheel “trails” the steering axis.

The effects that rake and trail have on steering performance can best be explained using a shopping cart front wheel as an example. The front wheel of a shopping cart is a castor that has a vertical steering axis that is in front of the wheel. The vertical steering axis results in zero rake, and having the pivot in front of the wheel results in a significant amount of trail.

This results in the front wheel tracking directly behind the pivot regardless of the direction the cart is pushed. If the vertical pivot axis were directly above the wheel axle, the wheel would not track directly behind the pivot. In this case both the trail and the rake would be zero resulting in a wheel that has as much possibility of turning sideways as it does going straight. This is a very unstable condition for both a shopping cart and a motorcycle. Motorcycles and Trikes both use a certain amount of rake and trail to ensure proper handling and steering response. In general, more rake provides greater straight-line stability, less rake makes the bike more responsive. This is why the forks on a sport-orientated motorcycle are more vertical than those on a cruiser or touring motorcycle. In short, smaller rake values result in quicker steering, while larger rake values result in slower steering.

Limoles
01-15-2015, 10:25 AM
It's not a stupid question , but the answer could be helpful .

Motorcycle rake
Rake can be described as an angle at which the headstock of the motorcycle is inclined when compared against a vertical line drawn perpendicular to the ground. The rake angle effects steering ability, the smaller the rake angle then the easier the bike is to corner but will be less stable in a straight line.
Motorcycle trail
The distance on the ground between a straight line drawn through the center of the front wheel spindle and a line drawn through the center of the headstock axis. The greater the trail distance, then the greated the straight line stability but the harder it is to make the bike corner.
Motorcycle offset
The distance between a line drawn through the centre of the steering stem/ headstock axis and the centre line of the front fork tubes. Typically the offset inversely affects trail, if offset increases then the trail will decrease.
The diagram below illustrates each of the measurements and how they are calculated:

The relationship between rake, trail and offset
• If you increase the rake, the trail increases
• If you increase the trail, the rake increases
• If you increase the offset for both yokes then the trail decreases
• If you increase the offset for only the top yoke/ triple tree then the trail will increase
• If you increase the offset for the bottom yoke/ triple tree independantly then the trail will decrease

BBB
01-15-2015, 10:45 AM
If you just add the "raked triple tree" without modifying the actual rake of the FRAME NECK ANGLE, it actually REDUCES the trail (in the extreme case, it would make the bike unstable at high speed)
That's why raked out choppers have the raked triple trees so that the trail numbers (increased by the added neck angle, reduced by the raked tree) can be within the reasonable amount for the bike to be actually rideable.
I built a chopper with a kit by chopper kit usa (it's a kit designed and made in Germany... German engineering! Lol) which had an adaptors that you can mount to the frame which changes the steering neck angle without cutting into the frame. It came with the raked tree which brings back the trail number to be somewhere closed to the geometry of the stock set up.
It added 18 degrees of rake (neck angle PLUS the raked tree) (my suzuki intruder was at 33 degrees on stock form) which resulted in over 50 degrees angle of the front forks. Despite the radical look of the front end, it was actually very easy and nice to ride without any issue.
It's all about the geometry of the front end (the trail).
So if you get the "raked front LOOK" by adding the raked trees, it actually reduces the trail and makes the steering LIGHTER, but doing so without careful design/ caliculation could result in "not enough" trail which translates to a very dangerous situation of high speed wobble.

Old Ryder
01-15-2015, 11:19 AM
Boy am I getting a headache reading all of this. You guys are smart! :icon_cool: All I know how to do is twist the throttle.

Limoles
01-15-2015, 11:42 AM
Car and motorcycle companies spend a lot of time and money to engineer their products , following rules of physics for adaptation of performance and our safety .

choptop
01-15-2015, 07:07 PM
My god, a F6b Darksided and raked, get da women and kids off the streets !!!!!!!!!!!!!!!!! lol

grendl
01-18-2015, 07:20 PM
My god, a F6b Darksided and raked, get da women and kids off the streets !!!!!!!!!!!!!!!!! lol

hmmm... Leave the women ...:icon_cool:

choptop
01-18-2015, 08:54 PM
hmmm... Leave the women ...:icon_cool:

OK :icon_wink: How are you doing ? Met you in the parking lot at Wing Ding, Madison.