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bikeham
12-22-2013, 09:48 PM
Hi Guys,

Down to the worst part on my streetfox, the fishmouth cut on the front boom arm for the head tubes.

I've got the frame on a bucket at one end and a sturdy box on the other with the front a slight tilt upwards. Using a round dial level, ive got the frame and front arm boom level side to side and fixed into place by screwing a 2x4 to my wood floor and clamping to the front arm boom. So all is nice a level side to side.

First wheel; i cut my fishmouth so the wheel is 90 degrees (level) as the wheel is parallel to the frame boom and i have the 75 degree tilt on the head tube. Then welded the top bead.

Now as i turn the wheel i get the following readings on my round dial level measuring across the wheel wall (parallel to the boom this reading is a perfect 90 degrees).

Turn wheel to left 22.5 degrees and wheel is 84 degrees
Turn wheel to left 45 degrees and wheel is 78 degrees
Turn wheel to right 22.5 degrees and wheel is 96 degrees
Turn wheel to right 45 degrees and wheel is 95 degrees

I have not done the other wheel yet. The wheels/tires are new and spin true.

Should the wheel be at a perfect 90 degrees throughout the turn? Is this way off and should i break the weld and start over? Im not trying to break any land speed records but i want it to be within normal tolerance for safe riding.

Thanks!

Twinkle
12-23-2013, 05:29 AM
Hi Bikeham

Due to the compound angle of the fork tubes on the cross boom , the wheels will be vertical on the straight ahead position only . Think about it the angle of the fork to wheel is FIXED but the angle around the arc of the steering tube VARIES .

Keep up the good work ( that one threw me for a few minutes )

regards emma

Ticktock
12-23-2013, 06:42 AM
Hi,
Just to reinforce what Emma said--the wheels will only be vertical in the straight ahead position. So you can relax, and enjoy the rest of the build. This change in angles is normal to all front suspensions that are set up properly. Take a look at photos of Formula One racers halfway round a bend, and you will see some real strange angles on the front inside wheels! And not upright on the outside either. What is important, once you get past this stage, is that you get the Ackerman angles as close as you can--if you upset Mr Ackerman he makes your tyres wear faster, he makes you pedal harder round anything but the slightest bend, and makes the steering feel funny. So do not annoy Mr Ackerman!
Have fun, Have great time at Xmas.
Steve G
Beijing
PS If you can turn the wheels thru 90 degrees each way, you will the extremes they get to, and the smaller changes you noticed will make more sense. Talking about the left wheel, when turned 90degrees to the right, it will be about vertical, and when turned 90 degrees to the left it will be at about 30 degrese from vertical. Thees figures are gusses, and have no real meaning, so if there is a difference4, don't worry about--you set up sounds right as it is. And I am guessing its the left side wheel you have measured!

bikeham
12-23-2013, 02:31 PM
Thanks Emma and Steve! Yes Steve you are correct, it is the left and its doing just about exactly as you describe in your PS. Whew, that had me concerned. Biggest issue ahead i see now is just figuring out where to store the trikes/bikes i build after this one!
Thanks Again,

Chuck

Twinkle
12-23-2013, 02:52 PM
I have that problem

transport i have solved , they don't sell sky hooks locally that support the weight of trikes !


:confused::taz::confused::builder2:

emma

Ticktock
12-23-2013, 11:52 PM
Trikes can be stored vertically against a wall if you make the right brackets. First one should not be tooo hard, as you had the space to build it. Its the second third and fourth that really cause the problems! Hanging from the roof will work if you have the head room, and a way to lift. Then , thinking outside the box (and house)what about on the roof???
Happy Xmas,
Steve G