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alevand
human power expert

USA
3425 Posts

Posted - 11/15/2018 :  17:29:24  Show Profile  Visit alevand's Homepage  Reply with Quote
I bough a cheap trike off Craigslist in Yellow Springs, Oh. Its a XPR arrow trike. 42 lbs, cr-mo steel frame, 20 front 26 rear. I made a set of shortened crank arms for it, 145 mm. I cut the main tube and welded it back to lower the BB from 18 to 15 inches. I also lowered the seat 1 inch made the seat back straighter. I thought it had a mseh sear, but its 1 inch nylon strapping, very stiff with gaps. It needs a proper mesh. I dont like how far the seat laid back.

It had cross over steering:

I have a question, can disk brakes be reversed? can I put the wheels on the oposite side?



C:
Tony Levand

Edited by - alevand on 12/23/2018 08:38:32

warren
human power expert

USA
6423 Posts

Posted - 11/16/2018 :  07:51:37  Show Profile  Visit warren's Homepage  Reply with Quote
I'm pretty sure they don't make left and right disk brakes for bikes, so I think that's ok. Be sure to turn the rotors around so the rotor spokes are going the right way. Some rotors have arrows indicating the wheel direction.
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Jerry
human power supergeek

USA
1422 Posts

Posted - 11/22/2018 :  19:07:45  Show Profile  Reply with Quote
On my disc brakes the right cable goes under the brake and pulls downward. The brake cable on left goes over the top of brake and pulls backwards. They are the same brakes as far as I can tell.

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Edited by - Jerry on 11/22/2018 19:59:18
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alevand
human power expert

USA
3425 Posts

Posted - 12/06/2018 :  08:58:13  Show Profile  Visit alevand's Homepage  Reply with Quote
I am going to change the USS to ASS. Without the cross linkages under the seat, the bottom can be lowered another 2 inches. This will put the bottom of the seat mesh at 7.5 inches, on par with more exceptional trikes like the 700. The seat back will be raised 2 inches, as it is it is too leaned back. It gives me upper back aches and even after two weeks of riding my neck is tired, and I dislike using the head rest. I can gain 1/2 mph with my arms in front, behind my legs as opposed to on the sides of the seat. I will put the tie rod in front of the steering axis, under the boom, but will relocate the pivots outboard to retain Ackerman. Another rod will attached from one pivot to the center steering arm above the boom. I wont be able to jump out of the seat anymore. I can get left/right hand threaded rod ends and nuts from mc master carr.
.

I haven't decided which is better, a 16 inch wide fairing with front wheels exposed or a 32 inch wide fairing covering the wheels. Track is 31 inches with 1/2 inch of camber. I could narrow the track, to maybe 27 inches but I would have to do a cut and try again to get the geometry right.

C:
Tony Levand

Edited by - alevand on 12/06/2018 09:09:10
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Jerry
human power supergeek

USA
1422 Posts

Posted - 12/07/2018 :  16:00:25  Show Profile  Reply with Quote
Depends on what you want. For racing and speed, the 16" will be the faster of the two. If you want to tour, the 32" wide you can carry more stuff. You don't carry much of a load on a tour, so 16"-18" would do you. I would make some wings out of foam for the cruciform and fairings to go around the wheels.
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alevand
human power expert

USA
3425 Posts

Posted - 12/08/2018 :  08:50:29  Show Profile  Visit alevand's Homepage  Reply with Quote
The narrower fairing would be easier to build, would attach to the seat frame, be lighter and would retain the full steering motion without wheel openings..I can glue fabric to the rims as wheel disks, though my last experience with movable fairings is they are not good at speed on windy days and two lane highways where one would want to hug the white line.

... The trike rider asked the upright rider; "Have you hugged your shoulder today?"

C:
Tony Levand

Edited by - alevand on 12/08/2018 09:00:37
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Jerry
human power supergeek

USA
1422 Posts

Posted - 12/09/2018 :  10:01:33  Show Profile  Reply with Quote
The trike with a narrow fairing and nothing on the wheels would still be faster than just the trike. Wheel discs on the trike will be a lot different than a 2 wheel bike. It seems that the wheel on the opposite side helps stabilize the front during crosswinds. Since my fairing is so large, it does try to raise the wheel on the side the wind is coming from. I lean into the wind and keep pedaling. The only time I had a real problem trying to stay on my side of the white line was in wind gusts above 30 mph. Of course I weigh 200 pounds and tend to carry an extra 20-30 pounds when riding. My water jug alone weighs over 6 pounds! 1/2 gallon of ice water, jug, 5 layers of camping pad, and tape. And yes, I still carry my full size floor pump!
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alevand
human power expert

USA
3425 Posts

Posted - 12/10/2018 :  15:28:09  Show Profile  Visit alevand's Homepage  Reply with Quote
I have a question on setting up the steering geometry. How does one account for steering axis inclination and caster angle. Its not in a simple plane like the diagrams show. Im thinking that I would take a the distance from the pivot normal to the steering axis as my arm length and use the plane that intersects this point as the triangle to the rear axis, though maybe I should project the arm onto the horizontal plane.

C:
Tony Levand

Edited by - alevand on 12/10/2018 15:31:19
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alevand
human power expert

USA
3425 Posts

Posted - 12/11/2018 :  15:44:15  Show Profile  Visit alevand's Homepage  Reply with Quote
Does anybody know if they account for tire slip angle when they design these trikes? My Ackerman is way off, the two front axles cross two feet in front of the rear axle at full lock, the inside turns far too much. I'm tring to find a spot that has a constant distance as I steer the wheels, I thought I could use the existing steering as a guide.

C:
Tony Levand
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Jerry
human power supergeek

USA
1422 Posts

Posted - 12/11/2018 :  21:27:24  Show Profile  Reply with Quote
http://www.ihpva.org/Projects/tstrike/building/frontend.htm

Scroll down to Ackerman compensation from Hiroshi Sakurai. I don't know if it helps.
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alevand
human power expert

USA
3425 Posts

Posted - 12/12/2018 :  07:39:43  Show Profile  Visit alevand's Homepage  Reply with Quote
I made the new tie rod attachments yesterday, will weld them on today.

https://ismasupers.com/downloads/tech-talk/tech-04understandingsteering-4.pdf br /

Well, the trike doesn't have rack and pinion steering, I think this is what he's looking at, the tie rod arms are shorter, thus play an effect in the Ackerman compensation.

I'll just ignore slip angles for now and assume the xtc steering is just badly designed, it does scrub the inside tire at low speed and full steering, like making a 3 point turn, but is fine otherwise. I guess I'll find out if I need additional Ackerman. I can change back and forth before finalizing it by leaving one of the cross rods attached and using the USS and new tie rod. Will report back the results on cornering...



... Well now in my experience the design of the XTR is no good for low speeds. Much much better turning now, I can make a circle in the driveway and don't have to fight the trike wanting to straighten and tires scrubbing. One pivot was welded 3/8 inch off from the other side, much closer now. I'll have to test it at higher Gs, see how fast I can go in a circle between the two.

.. Well defiantly much more slipping of the front tires with the original steering. Im thinking now that its not negligence but intentional, its Lawyer steering, Can't tip it over before the front tires skid out.

I cant seem to get the disk brakes to not rub and not flex the disk, maybe calipers need to be disassembled and lubed.

C:
Tony Levand

Edited by - alevand on 12/12/2018 12:01:09
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Jerry
human power supergeek

USA
1422 Posts

Posted - 12/13/2018 :  11:52:34  Show Profile  Reply with Quote
Good work Tony.
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alevand
human power expert

USA
3425 Posts

Posted - 12/16/2018 :  12:27:51  Show Profile  Visit alevand's Homepage  Reply with Quote
I have a scheme for ASS, it will put the remote steer tube about 5 inches in front of the cross member and steer in the same direction as the wheels. I am going for a ride today so I will work on it some other time.

C:
Tony Levand
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alevand
human power expert

USA
3425 Posts

Posted - 12/20/2018 :  07:47:27  Show Profile  Visit alevand's Homepage  Reply with Quote
Im thinking of u-joint steering. I have a 3/8 socket universal, but there is some play in it, the steel is too hard to squeeze it, Id have to heat it. Its strong enough, 100 ft lb rating. I was thinking of a ball end hex key. I can buy a 13mm key and a 1/2 in socket or a 3/8 key and 6 point socket, 10 mm key is .018 too big for a 3/8 socket. It would need something to hold them together, like a slotted washer welded to the socket or with a spring. The hex ball end has 25 degrees of motion.


... hex key idea is out, I'll try the 3/8 universal.

C:
Tony Levand

Edited by - alevand on 12/20/2018 08:30:36
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alevand
human power expert

USA
3425 Posts

Posted - 12/21/2018 :  21:15:27  Show Profile  Visit alevand's Homepage  Reply with Quote
I worked on the steering today, maybe tomorrow I can try out the ASS. The steering arm was close to my heal, I shortened it and put the link on the other side.

I made the link an inch too short, I thought the arm should be normal to the link, apparently it wants to be straight ahead for symmetrical steering locks.

C:
Tony Levand

Edited by - alevand on 12/22/2018 07:20:41
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alevand
human power expert

USA
3425 Posts

Posted - 12/22/2018 :  15:49:39  Show Profile  Visit alevand's Homepage  Reply with Quote
I have the steer tube welded in, I welded it in before lowering the seat. The seats now at 6.5 inches, 2 1/2 inches lower and the tube now is a little high. I'll put the handle bars under the top bearing and cut the tube off above the bearing. Seat needs to be welded back up, restrung and brakes and shifters put on, The one bar end shifter is on really tight and I stripped an allen key trying ti get it loose. I thought the seat frame was cr-mo but its not, its hi tensile carbon steel, rusty inside.

When I lowered the seat I found the splice, used to remove the back, was made from solid steel round, zinc plated to look like aluminum. I replaced them with 5/8 x .028 x 3 long tubing.


C:
Tony Levand

Edited by - alevand on 12/23/2018 17:19:22
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alevand
human power expert

USA
3425 Posts

Posted - 12/23/2018 :  17:21:04  Show Profile  Visit alevand's Homepage  Reply with Quote
Bar end shifters don't fit inside the aluminum tube. Brake cables are a little too short. I replaced the two smaller idlers with one larger one. Chain drive is smoother. I can do circles in the driveway! Rear rack has to go. The 1 3/4 boom is actually quite flexy when pushing on the bars. I may ride it to Elburn for Xmas.








C:
Tony Levand

Edited by - alevand on 12/26/2018 10:20:22
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alevand
human power expert

USA
3425 Posts

Posted - 12/25/2018 :  20:23:00  Show Profile  Visit alevand's Homepage  Reply with Quote
Rode 40 miles to Elburn fo xmas dinner. Still some snow left...


No warning that the trial was closed, easy walk around. I walked on th e hose carrying the trike to stay out of the mud. Of course the made a crossing for the golf course. Im not use to the front wheel sticking out into the road so far.



C:
Tony Levand

Edited by - alevand on 12/25/2018 20:44:51
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alevand
human power expert

USA
3425 Posts

Posted - 12/26/2018 :  10:20:32  Show Profile  Visit alevand's Homepage  Reply with Quote
I used the bathroom scale and weighed each wheel then lifted the left front wheel a foot and redid the weights, I should be able to calculate the CG.

Trike weighs 38 lbs, 4 lbs less than when I bought it. Me and trike weigh 178 lbs. flat weight are 62,62, 52 lbs. That puts the CG 11 inches behind the axle. When I lifted the left wheel the right wheel 13 inches weight went to 103 lbs.

Tipping trike alone 21.5 inches balances on two wheels at 21.5 inches.

CG of just the trike is 13 inches above the ground. Cg of trike and rider is about 21 inches +-

Distance from CG to to tipping axis is 11 inches (22 inches effective track width) trike should tip with a 1/2 G turn.

So far it seem I haven't come close to tipping it.

When i rode to Elburn yesterday, the shifter was rubbing my thigh and out a hole in my jeans. I moved the shifter up today.

The last modification is going to be a new low Q BB and boom, then I can start with the coroplast fairing. Presently it doesn't shift to the granny gear because the derailleur support tube is too far to the right.


C:
Tony Levand

Edited by - alevand on 12/26/2018 11:49:11
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alevand
human power expert

USA
3425 Posts

Posted - 12/27/2018 :  19:27:36  Show Profile  Visit alevand's Homepage  Reply with Quote
I made a wheel disk. The boom is a weird size, 1.665 dia, so I decided not to make a narrow BB. I cut and moved the derailleur support tube to the left ny .25 inches so now it goes onto the granny gear.

I was so windy and rainy today, that I don't know if its any faster, is seems like it.



C:
Tony Levand

Edited by - alevand on 12/27/2018 19:28:15
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warren
human power expert

USA
6423 Posts

Posted - 12/28/2018 :  10:36:00  Show Profile  Visit warren's Homepage  Reply with Quote
Looks great. I like the OSS. I may have to modify my trike in a similar manner.
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Jerry
human power supergeek

USA
1422 Posts

Posted - 12/28/2018 :  16:35:02  Show Profile  Reply with Quote
Looking good Tony. Get that fairing on it and it will be way faster! And warmer.
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alevand
human power expert

USA
3425 Posts

Posted - 12/28/2018 :  18:33:41  Show Profile  Visit alevand's Homepage  Reply with Quote

Today I made a wheel cover for the left front. I had to take the wheel and rotor off to made the inner disk. It rubbed on the tie rod. I ended up making pin holes and gluing it to the spokes. Next time I'll make the inner one first and sew it to the spokes to made clearance to the tie rod. I also made the inner fender walls for the rear wheel to keep water out of the baggage compartment. I think I need to raise the return chain up above the frame so I can attach coroplast to the frame without spacers.


C:
Tony Levand

Edited by - alevand on 12/28/2018 18:51:18
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alevand
human power expert

USA
3425 Posts

Posted - 12/29/2018 :  10:18:43  Show Profile  Visit alevand's Homepage  Reply with Quote
Hi Warren, One thing is I cant just plop down into the seat anymore, some acrobatics are needed. There is enough leverage in the steering. When I did the CG test I raised one front wheel 14 inches and climbed into the seat. I was able to keep the wheels straight with out too much effort, it has 3 inches of trail and 120 lbs on the front tires, so probably had 50 lbs lateral force and 15 to 20 lbs restraining the handlebars. Your setup with the trailing steering arms would probably be easier. The center arm is 3 inches and the following arms are 4 inches, just because I needed heal clearance, but works fine. It has +/- 90 degrees steering.

Letting the coroplast relax..


I need to trim off this flange splice, makes riding uncomfortable,


C:
Tony Levand

Edited by - alevand on 12/29/2018 14:40:44
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alevand
human power expert

USA
3425 Posts

Posted - 12/31/2018 :  16:27:17  Show Profile  Visit alevand's Homepage  Reply with Quote
I got a new 195 lb gas cylinder this morning. After filing and cutting to try to make the MTB brake levers further inboard without touching my knees, I use some top bar levers, reversed. They don't have enough pull, but have lots of leverage. I can rest my wrists on them too.


C:
Tony Levand
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alevand
human power expert

USA
3425 Posts

Posted - 01/04/2019 :  13:31:58  Show Profile  Visit alevand's Homepage  Reply with Quote
I made linger seat braces that brought the seat back up, so I don get neck and upper back aches. I had to poke a small hole through the front wheel covers... to adjust the disk brakes. I need to start the fairing...



C:
Tony Levand

Edited by - alevand on 01/04/2019 13:32:10
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