Front Brakes- Yea or Nea?

[Popeye2347]

Later this week I should get started on my trike [re]build. After looking at lots of trike pictures, and a lot of reading, I have come to the conclusion my fork angle should be around 45 degrees for optimum handling. To achieve this I will be using a leading link style front end, one with the shock low and on the front of the main legs of the front end, [one with the small rocker] probably with a 'fat' front tire.

What is the consensus about front brakes? I have only noticed a couple bikes having brakes on this style front end- [of course most of the factory front ends still have brakes on them.] Laws of physics state that most of the braking power is in the front tire on a bike, I suspect a trike is the same. I plan to put lots of miles on the trike, so safety comes before styling.

So what do you guys/gals have to say on this important issue?

FWIW I found only 2 posts dealing with brakes, neither addressed this question.

TIA

Greg L.

[redneckray]

I don't use them on my trikes , but guess you need them at times, i always get the old lady to hold the front wheel when i want it to stay in one place, but she says that gets old after awhile,grinn
ll , like to see what you use on that one, alot of them around, a bear to build one , but work great,
good luck with your trike,
pics, pics
grinn
ray

[Popeye2347]

Thanks for the reply. Pics will come after we get started and have some progress [?] to show.

Confusious say, a build without pictures, is like peeing your pants in a closet.....
gives you a warm feeling but no one else know about it!

[trikes4ever]

About all it will do is put a flat spot on your tire - not enough weight to have much effect on slowing you down. Some states require a front brake, though.

[adventurer]

Lets think SAFETY. About 70% of your stopping power comes from the front brakes. Now think panic stop. I sure would not want to rely on rear brakes only in that situation.

[trikes4ever]

About 70% of your stopping power comes from the front brakes. Now think panic stop

Not on a rear engine VW trike it doesn't.

[CCrider]

I think I would rather have em and not need em, then need em and not have em.

[Budking127]

I think I would rather have em and not need em, then need em and not have em.

if thats your trike in the pic ther mabey so a raked out vw trike its a joke to have them on the front its false hope lol:Computer:

[DannyB]

I'm thinking of trying linked brakes on mine and using a bias adjuster to set the pressure to the rear with a little for the front.

Front brake is law over here

[wics51]

In Virginia, they want you to have a front brake for inspection purposes. I'm currently in the process of converting my front end from a DNA Springer to one of Trikertroy's Monster leading link front ends. I'm using the Jay Brake that was installed on my Springer, it is an easy switch. The front brake really doesn't do a lot on a rear engine VW trike, because the front end is so light.
Enjoy.

[sdewolfe]

Howdy all,

This post is a little longer than I would have liked. It still is not long enough. Brakes on a VW trike are sometimes difficult to setup and are certainly too important to not get right. I hesitated posting this because my only credentials are I can read with understanding, I have built a couple of trikes, and I've worked on cars all my life. Thin ice to be offering advice on braking. Take this with the proverbial grain of salt.

The amount of braking that can be used on the front of a VW trike is limited by traction which is determined by the weight on the front wheel and the coefficient of friction between the tire and road. The problem is more complicated than very little weight on the front of VW trike. There are dynamic forces at work. I recommend that you see the Robert Q. Riley web site for some good information about vehicle dynamics, especially trikes.

Free Development Plans, Software and Information

The two articles you are most interested in as applies to brakes and vehicle dynamics are:

Three Wheel Cars: The Factors That Determine Handling and Rollover Characteristics
Automobile Ride, Handling, and Suspension Design

As was mentioned by others, most governments require a front brake on all vehicles. Some state engineers have even thought this through and require a minimum percentage of vehicle weight on the front wheel of a motorcycle (trike). Check in your state to find out if there is such a requirement. It may save having to add weight to pass inspection.

Even though my VW trike has a complete front brake to pass inspection, I have it disconnected. I do not want to come to rely on the front brake for normal braking and then, by habit, reach for it in a panic situation. If you use the limited traction on the front of VW trike for braking, there is none left for steering. That is the short version. The dynamics involved would take up too much space for this post.

On the back end, drum brakes are prone to fade. You might encounter this problem when traveling in the mountains. The only thing to do is to wait until the brakes cool to continue your trip.

Most everyone knows that braking causes a weight shift to the front. This weight shift in conjunction with the servo action of shoes on a drum brake equipped trike can lead to lock-up of the rear wheels on a slick surface. Bad juju.

Disk brakes will eliminate servo action and reduce fade. There are several kits available with or without a parking brake. Most cost less than $400. Cheap insurance.

Another consideration is the placement of the master cylinder. If it is mounted lower than the wheel cylinders or calipers, the fluid will tend to drain back, retracting the piston in the slave cylinder. This requires excessive pedal movement to push the piston back to where it should have been to begin with. If your trike design places the master cylinder below the calipers or wheel cylinders you must use a residual pressure valve in-line between the master and slave; 10 PSI for drums and 2 PSI for disks. Residual pressure valves are available from several sources (JEGS comes to mind) for less than $25.

Anyone building a trike from scratch should understand vehicle dynamics. The previously mentioned Robert Q. Riley web site is an excellent start. Tony Foale Designs also has useful articles and some freeware downloads to help calculate CoG and more. Tony Foale's emphasis is on two wheelers but the information on front suspension can help you understand rake and trail and forces at work. His work makes for really interesting reading:

TONY FOALE DESIGNS - Home page

Here are some terms to plug into your favorite search engine. Hopefully these will lead you to some more useful information:

static dynamic friction
tire coefficient friction
vehicle moment inertia
vehicle dynamics
traction circle
brake hydraulics
drum brake servo action
brake fade
braking math
braking dynamics
brake design calculations (The first return with Google -- Engineering Inspiration - Brake System Design Calculations -- has almost all the math you need. It won't tell you why you need it though.)

I also recommend adding a few books to your library:

Chassis Engineering By Herb Adams
Engineer to Win by Carroll Smith
Tune to Win by Carroll Smith
How to Make Your Car Handle by Fred Puhn
Brake Handbook by Fred Puhn
Auto Math Handbook by John Lawlor
Motorcycle Dynamics by Vittore Cossalter
Any of the books by Tony Foale

[Gorilla]

Thank you good info

[drumdoctor]

If you check with any bike or trike builder or an experienced mechanic, they will ALL say that it is pure physics--

MOST OF THE STOPPING POWER IN ANY VEHICLE COMES FROM THE FRONT BRAKES.

If you have no front brakes and the rear brakes give out, then what?

Bottom line is SAFETY!!!

Mike ---drumdoctor@live.com

[Buggie Pilot]

We got a old school mini-spool drum on ours. As ineffficient as they are they do provide some braking...... I am in the process of building anouther one and wouldn't be without it.