Australian Streamliner Bike Build

[Jon]

Thanks Ed

Some of Woody's homework has been around tyres.

Thought this may have been of interest to some;

Goodyear D2283 (23.0 x 5.0 -15) mounted on a 4" rim, 75psi and supporting approx 300kg (660lbs).
The weight is as accurate as 1/4 of my XH Ford ute so it's a thumbsuck.

Small squares are 2mm, darker squares are 10mm (0.4").

Cheers
jon

[WOODY@DDLLC]

Jon, a SWAG is always better than a WAG! 

All that HP in that one little spot - tires are beyond amazing! 

[maj]

I would like to see that footprint at 200+ mph or even 300mph , they grow lots

[Jon]

So would I Maj, bit of work before then though.

Been asked a couple questions about my front yoke;

The lower control arm points are in so there's about 5mm gap between the rose joint and the wheelnut (lugnut) side of the wheel.
They are set back so that the virtual pivot point (where the two control arm centerlines intersect) give me the rake and trail I want.

Mounting faces of the bottom clamps;

The yoke tapers in so that the bit at the axle just fits over the tyre, two bolts up through each side.

Cheers
jon

[maj]

i realy like the simplicity of the wheel mount

I am trying these tires myself, shaving a little for a more bike oriented shape (could be a bad thing ) but wondering esp on the fast streamliners just how much the contact patch changes at speed
and if the 4" tire would actually become too small in the contact patch at very high speed, i know Assen shredded one last year at 260mph as he only had 1" clearance

[wobblywalrus]

Would a steel belted radial like a metzeler expand less at speed?

[Jon]

Thanks Maj, the whole thing is a KISS as i can think of.

By going Moninshock and having the yoke move with the wheel i have introduced bumpsteer but I dint have enough room to run a shock either side, legroom is tight now.

Was that a LSR tyre or Frontrunner Maj?
What pressure did they start off with?
They grow a bit between 50 & 75 psi, I haven't tried higher than that.


What pressure do most people run their tyres at?
I was recommended 75psi cold.
I'm not going to supporting that much weight compared to most but I'm going to run at that to reduce sidewalk flex and heat buildup.
On my ute there is a marked difference in sidewalk flex between 60 & 75 psi.


The must be racing tyres above 200 rule must limit tyre choices for sit on bikes?

cheers
jon

[Jon]

Front lower control arms mocked in to check the geometry;




Straight ahead;


Full lock, 7 degrees;

Couldn't get a pic but at full lock the centre of the contact patch moves away from the turn about 10mm.

No I'm not running with the bolts tacked on, yes I'm bracing the mount in the bottom of the yoke and yes I'm going to replace the curtain rod control arms.

Cheers
jon

[kiwi belly tank]

Steel belted tires are in fact worse at speed due to the mas of the steel. It's built into a road tire to give it protection from road hazzards. Back in 1990 Goodyear actually stated that their steel belted Wrangler would go 400 if the tread was buffed down. In the real world, the steel came out of them at about 300. Needless to say, their statement was retracted at about the same speed.
  Sid.

[maj]

d2284 at 80 psi

you making a lift with castors to turn it around ??

[Jon]

Thanks Maj; It's going to be a pain to maneuver, trailer for the return road etc.

I was planning on using double acting master and slave cylinders or pull cables on either side for steering to make sure I got no bumpsteer.
The rules state fixed, gear or linkage, what is the history behind that?
I can see single cable where on direction relies on a push motion being not so cool.

Is this something worth enquiring or am I wasting my time?

Any linkage system I make will have some bump steer when not straight ahead.
Bump steer on a bike with relatively heavy wheels spinning at a reasonable rpm is something I would prefer not to deal with.


More email tag with Woody tidying up the model for CFD;



Thanks
jon

[DaveL]

G'day Jon, fellow Aussie here, been following your build with interest. Regarding your bump steer dilemma I may be able to offer a solution. From the photos it's not completely clear to me how you intend to suspend the top of the yoke or where you intend to mount the springs/shocks. I am familiar with 'virtual' pivots or 'focusing' links. I'm assuming you'll have some sort of a top wishbone and will have the springs either mounted off the sides of the yoke or cantilevered behind the wishbone somehow. Regardless, I figure you intend to run a Steering arm off one side of the yoke attached to a Drag link connected to a Pitman arm. Standard fare for most vehicles. The problem being that the Pitman arm is reacting upon a fixed pivot point mounted on the chassis whilst the Steering arm is reacting on a pivot point that can alter subtly with suspension travel thus giving you the unwanted bump steer. An easy way to eliminate this problem would be to simply eliminate the fixed pivot point of the Pitman arm. Say you were to have a Steering shaft mounted vertically somewhere behind the front wheel, the top half of this shaft is in bearings and is rotated by a Drag link  connected to the handlebars. Now, under those bearings you have either a Uni or CV joint and then the shaft below is allowed to simply 'hang' from the joint. At the bottom of the shaft you then have a double sided Pitman arm connecting two Drag links to two Steering arms one either side of the yoke. Steering angle of the yoke is now slaved to the Steering shaft angle and the Pitman arm is non rigidly mounted, 'swinging' backwards and forwards off the Uni or CV joint in accordance with suspension movements. I would incorporate a link at the bottom of the Steering shaft to prevent lateral 'swinging' of the arm although even that wouldn't effect the yokes steering. Even without knowing your current setup I feel something similar to this should be able to be implemented. Sure simpler than hydraulics. Cheers, Dave. 

[saltwheels262]

Thanks Maj; It's going to be a pain to maneuver, trailer for the return road etc.

I was planning on using double acting master and slave cylinders or pull cables on either side for steering

cable steering is a reason that the bub 7 is  illegal for scta.

[Jon]

Thanks guys

Dave; what vehicles are you familiar with that run focus link steering? I can't find reference to many.
The top of the yoke runs to a single spherical bearing in a rocker running to a monoshock, this is to get the lean of the front wheel.
Worked up a sketch last night with a hinge action that will work but more moving parts than I wanted.

Hydraulic is pretty simple, think of a hydraulic clutch but double acting, not that unusual on agricultural and industrial equipment.


Saltwheels; One of yes, that's my question, unlike Dennis I can't afford to run my own event.

Cable can be safe if done properly IMHO, two properly rated pull cables are going to be way stronger than any person can hold onto.

I see Marlo is running Hydraulic similar to what I gad in mind and Dennis is running cable, might sit on it until after the Bonneville events are run and submit some drawings and numbers to tech.


Cheers
jon

[maj]

I hope the hydraulic is better than any i use in Agriculture, as i would not want to go faster than the 20mph mine are set up for and one even that is dodgey
Agriculture does have some very good push pull cables , but sounds like there not realy an option .