I've been having fun reading about Rake and Trail and wondering if it's possible to predict how a bike will ride by looking at the numbers. I know there are many factors but I'm looking at these to see which bikes I might like the feel of. Of course, nothing beats riding them. Among other factors wheel type and size would also effect the ride. I love shopping on Craigslist and the dealers and was thinking I could eliminate unnecessary test rides with math! For example, SuperLow and Street Bob have these numbers:
I've been having fun reading about Rake and Trail and wondering if it's possible to predict how a bike will ride by looking at the numbers. I know there are many factors but I'm looking at these to see which bikes I might like the feel of. Of course, nothing beats riding them. Among other factors wheel type and size would also effect the ride. I love shopping on Craigslist and the dealers and was thinking I could eliminate unnecessary test rides with math! For example, SuperLow and Street Bob have these numbers:
Looking at the numbers I would think the SuperLow is an easier ride than the Street Bob. What do you think?
Here is a very interesting statement that begs to be understood. But it is not obvious why the writer says it the way he does. I suspect once we understand this statement we will understand all we need to know about rake and trail.
Here is the statement ....
The rake (caster) is set to a rather large angle of 30 degrees. This is necessary for a motorcycle that leans into a turn. A two wheel motorcycle transitions from caster to camber (steer to counter steer) during speed changes where a trike or quad typically only uses caster to control turning and feedback.
Note how he describes it "A two wheel motorcycle transitions from caster to camber(steer to countersteer)"
Caster is the kind of wheel that is on a grocery store shopping cart. It can flop back and forth. According to the statement, caster(rake) is necessary for a bike to naturally flop (steer) into the turn after the bike is leaned.
Coming up with a formal definition of handling is tough, in part because as opposed to the race track where such things can be quantified by telemetry or a stop watch, on the street handling is largely subjective. So rather than a formal definition let’s just say that handling might be described as how much effort it takes to get the bike to do what we want it to, when we want to do it, and how stable the bike is while it’s doing it.
Caster is what keeps your steering straight.The casters on a shopping cart are a different USE of the same word.To align the front of a car,you adjust caster,camber, and tow-in..
Orange= a fruit. Orange=a color.
OP,you really won't feel a noticeable difference in 2 degrees of rake,but the lesser rake will usually feel a tiny bit lighter when turning at low speed.
Caster is what keeps your steering straight.The casters on a shopping cart are a different USE of the same word.To align the front of a car,you adjust caster,camber, and tow-in..
Orange= a fruit. Orange=a color.
OP,you really won't feel a noticeable difference in 2 degrees of rake,but the lesser rake will usually feel a tiny bit lighter when turning at low speed.
The caster on a shopping cart is very similar, The contact patch of the wheel is offset from where the steering head intersects the ground. However, the "trail" of the shopping cart is negative whereas for a motorcycle it is positive.
According to this, Rake is the reason we can take our hands off the bars and the bike will still go straight...
In any event, some bright engineer discovered that inclining the fork rearward a few degrees induced stability and voila, we have Rake. Once Rake was introduced, the wheel no longer tried to change directions at the slightest provocation. The extreme riders of the day soon realized you could even ride the newfangled designs with your hands off the bars, a stunt that no doubt greatly impressed the young lovelies of that bygone era.
I went from a Blackline to a Breakout and the rake on the Breakout is more by a few degrees. And for me, even after a year, it's still "spooky" going around some sharp turns in town. That and the bike is about 100lbs heavier. It's funny to me because on my panhead, I had a long front end with no rake and never had any trouble at all. I even passed my "in and out of the cones" riding part of the test on it.
Looking at the numbers I would think the SuperLow is an easier ride than the Street Bob. What do you think?
You can't judge how a bike feels by looking at numbers.
First of all, the Superlow is 100 lbs. lighter than the Street Bob, which will help at lower speeds. Other than that, none of these bikes are set up with such crazy specs that they pose a problem.
Even if you're a new rider, you'll get used to the handling and weight of whatever bike you choose. It's just a matter of practice.
You should test ride the models you're interested in and decide from there. Don't let the science get in the way.
I went from a Blackline to a Breakout and the rake on the Breakout is more by a few degrees. And for me, even after a year, it's still "spooky" going around some sharp turns in town. That and the bike is about 100lbs heavier. It's funny to me because on my panhead, I had a long front end with no rake and never had any trouble at all. I even passed my "in and out of the cones" riding part of the test on it.
A small rake would be more maneuverable I would think.
A small rake would be more maneuverable I would think.
There is a trade-off between stability and maneuverability, they are opposites.
Trail is more important than Rake.
Because the center of the tires contact patch is behind the steering axis a self-centering force, an imaginary lever so to speak is created. (Figure 2) It’s this lever that enhances a motorcycle's stability, and helps restore it when it’s disturbed. In basic terms, it works like this: When you’re riding in a straight-line, the wheel is held in the straight-ahead position by a combination of Rake and the Trail “lever.”
And gets even better....
If something turns the front wheel, be it an obstacle or the riders input, the lever instantly tries to turn the wheel back to the straight ahead position, but that’s not all it does. The length of the Trail lever determines how much effort it takes the rider to make the bike turn, and how much effort it takes to hold in the bike in a turn and it’s also largely responsible for the way our bike “feels” as we’re steering it, this is because the Trail acts directly against the front wheel, and that input is transmitted via the fork and handlebars directly to the rider.
A bike with a lot of trail, like a chopper, will not corner easily. A chopper must have been designed for the highway.
Last edited by ChickinOnaChain; 11-17-2016 at 04:09 PM.
11-17-2016, 10:04 AM
Rake & Trail
