suspension

[inxs]

- primary suspension parameters are stiffness, damping, sprung and unsprung mass, and tire characteristics
- suspension setup is pretty vital, some factors affecting it are

tyres and tyre pressure​

wheel bearings​

steering head and swingarm bearings​

fork brace​

spokes​

wheel alignment​

balanced oil ammount and spring preload​

weight distribution​

bent frame​

uneven fork lengths​

handlebar mounts​

axle nut and holder tightening missequenced​

- basics from the suspension shop and super streetbike
- trail

- rake

- 3 way spring preloader

- emulators

- race tech and here

- lowering forks

- just to get started.......

 

[inxs]

- suspension 101 and 201 ...wrrdualsport

- aerodynamics ...tony foale

- unsprung weight

- interesting if youre into tech

- rake and trail ...from streetchopper

- leaf spring ...from kiwi

- weight transfer ...all things motorcycle

- traction ...swingarm angle, chain pull, antisquat

- antidive

- effective braking ...from motorcycle cruiser ... and the lazy motorbike

- braking ...boomer biker

- dampening ...penske shocks...interesting overview on dampening from p17

- set up ...bikechatter

- a racers view ...sigma performance

 

[gentlemanjim]

Another masterful tech report from the XS Master INXS

 

[Trebor13]

thanXS .

 

[Travis]

I've had that streetchopper link bookmarked for a while now.. It talks about false trail vs. true trail.

A lot of builders will measure trail from the tire contact point to the point where the steering axis intersects the ground. We call this false trail. To determine vehicle dynamics, you need to measure the leverage that the tire has over the steering axis. The correct measurement is the perpendicular distance from the steering axis to the tire contact point. To clarify things, we often call this measurement true trail.

So what is the right true trail?

Not enough trail will make your bike wobble and too much trail can make it steer like a tank. Too much trail can even make the bike unstable in the weave mode. How do we make sure our trail is going to work for our bike? While there are a number of variables involved, we have seen that as a general rule if the true trail is between 1-1/2 to 5 inches, your bike should be good. Bikes with less trail steer quicker and are more agile, and often more fun to ride. Bikes with longer trail tend to take more muscle to make them change direction. It is really a matter of personal preference.

Now saying that it is a matter of rider preference may make many of you unsettled. I hear people everyday telling me that exactly 4.1 inches is right. This is especially comical because typically they are measuring false trail anyway. In addition, there are errors in determining true trail due to tire deflection, pneumatic trail, and other factors.

 

[inxs]

- read this thread emulators

- more race tech

- fork oil

 

[chizler62]

I have the math to calculate mechanical trail if anyone is interested.
1-1/2" to 5" IMO is out to lunch. These numbers are stumbled on by custom builders that let production parts limit their designs. EX. OEM for legs.
You also need to include rear wheel trail using tire radius, axle to crown and Head tube angle.
Mechanical trail or true trail as it's call here, can and should be narrowed to within 1".Remember that tire profile makes a difference and will change mechanical trail.
Ground trial or false trail is only use as a tool to find Mechanical trail.

In reality you're limited to changing Head tube angle and tire circumference. Changing fork offset is impossible unless going with a custom fork.

Just keep in mind. Mechanical trail or true trail is realistically a lever combined with the tire contact patch that produces a self righting effect on your motorcycle. LONGER the LEVER, more Mechanical trail, the less influence the ground conditions have on your motorcycle. That simple.

using 1-1/2" to 5" as an acceptable RANGE is copout for the builder who's determining design by mismatching parts. The same "springer" front end sold to you for your XS650 is the same one sold to a Harley owner? Different HTA, Wheel size, wheel base, handle bar offset and bar length.....all factors in how the bike "handles".

Just my opinions. Rick

 

[jd750ace]

I'm all in on straight rate race tech springs and emulators for damping rod forks. My Road Star and SV650 both have them, and an upgraded rear shock, and they ride like they are on rails. Excellent product.

 

[abyssmaltailgate]

I have the math to calculate mechanical trail if anyone is interested...

Using 1-1/2" to 5" as an acceptable RANGE is copout for the builder who's determining design by mismatching parts. The same "springer" front end sold to you for your XS650 is the same one sold to a Harley owner? Different HTA, Wheel size, wheel base, handle bar offset and bar length.....all factors in how the bike "handles".

I have two questions for you, Rick: 1) What does HTA stand for? My internet searches have not been fruitful, and 2) I'm interested in the math to calculate mechanical trail if you'd like to private message me or just post it to this thread. Thanks!

 

[TwoManyXS1Bs]

HTA = Head Tube Angle

Here's a good reference site for your build:

http://chopperhandbook.com/rake.htm

 

[wherearewe]

Thanks INXS!!

 

[arcticXS]

Maybe the ultimate in "period looking" forks and triples. Ceriani 35mm and 38 mm in various configurations. And really nice 35 and 38 mm triples. And drum brakes to die for, if so inclined:
http://caferacersuspension.com/ceriani-type-gp-35mm-front-forks.html

 

[arcticXS]

Obviously a bit OT, posting about stupid expensive stuff....A friend actually ordered a 35 mm fork with triples, and a front wheel with a "Robinson" 230 mm 4LS drum for his BSA A65 project.. 3000 Euros or 3500 Dollars just for the front end. But since he has already spent more than twice that on the engine, it does not sound too crazy. 900 cc 270 Nourish crank, ported head, etc.....