How does one stabilize the front end of a tricycle?

[MikeFairbanks]

I realize the nature of tricycles are that they follow different physics than bikes, but I'm wondering if there is a simple way to keep the front end a bit more stable at moderate speeds. It shakes a bit, and I'm wondering if any of you have suggestions that might help. Thanks

 

[Mundo]

You could try something like this....

 

[MikeFairbanks]

Wow, that looks really interesting. Hmm. I think I'll look into that. I could engineer something like that on my own fairly easily. The trike is fully controllable, but once I get beyond about 15mph I have to hold firmly. ONe hand really isn't sufficient like it would be on a bike.

It's not like I care to ride one-handed, but the thing is with a tricycle is that the front wheel, if not monitored closely, can make its own decisions. That's not a good thing.

For what it's worth, the shaking is not from an unbalanced wheel or anything like that. I think it's just physics.

I also wonder if a different set of handlebars would work, or perhaps steel suspension forks in the front.

 

[fechter]

I think you want more trail in the steering. The tire contact patch needs to be behind the steering axis slightly. Changing the fork might help if you can find one that does this. The fork needs less offset than the one you have. You could crash it into a wall and bend the fork back slightly. Another approach is to give more rake to the steering head, but that would be difficult.

 

[chilledoutuk]

perhaps forks with suspension would make it more stable.

Little confused by fechter's suggestion of trail when most motor bikes have the opposite with the wheel angled forwards.

 

[Chalo]

I realize the nature of tricycles are that they follow different physics than bikes, but I'm wondering if there is a simple way to keep the front end a bit more stable at moderate speeds. It shakes a bit, and I'm wondering if any of you have suggestions that might help.

Trikes have different steering dynamics than bikes. But for reasons of cost, availability, and poor understanding of the principles, they often get set up with bicycle forks and bicycle head angles. As a result, they exhibit bad wheel flop and variable, unpredictable effects on dynamic steering forces.

Ideally, a trike should have a fairly slack head angle and a fork with enough offset to just about eradicate the natural steering trail resulting from the head angle and wheel diameter. Steering trail is the lever a bike uses to steer itself back underneath you when you lean the bike, but on a trike it is a lever with which centripetal force tries to steer you to the outside of your turn, or downhill when you are riding across a slope (like the crown of a road).

Since the head angle on your trike is already set, I'd recommend trying a triple-clamp style chopper bicycle fork, because those have a lot more offset than mountain bike forks like the one in the picture. Also, you can experiment with the effective head angle by raising or lowering the legs in the triple clamps until you have what works best for you and your trike. The other factor you can play around with is the front wheel diameter.

 

[Chalo]

I think you want more trail in the steering.

He could get an easy 3 inches more trail by just turning his fork around, but I think that would make the trike handle worse and not better. Trail stabilizes a two-wheeler, but destabilizes a three-wheeler.

 

[ddk]

Mike,
just adding a "bent springer fork" solved almost all my trike issues. Esp. the "riding down the crown" tendencies delta trikes generally exhibit.
This trike was stable to 30mph but felt like opposites day above 30 (stable,but you have to apply pressure to the steering slightly opposite of what you would normally do)
-that might have been a caused by the angle of the handlebars

View attachment 1


however, I introduced additional "bend" to the head angle and lengthened the trike chassis 9" to make it perfect.

cost was ~$50 for the bent springer fork from chubbyscruisers.com and a locally manufactured head to replace the inadequate spring holder that comes with the fork (~$10)

 

[dogman dan]

I'm far from expert at frame geometry. The shimmy sounds like high speed wobble to me. Do you see much flex from side to side in that frame? If so, maybe the frame makes the fork issues amplify some?

I simply stopped riding the schwinns above 15 mph. They didn't shimmy, they tracked fine at 30 mph. They just were hard to jink around to dodge any road debris above 15 mph.

 

[MadRhino]

It is steel Mike, you can do whatever you want with it at reasonable cost.
Nevertheless, delta trikes never have a perfect handling.
They come much closer to proper handling when they are tilting, but we are talking a lot of mod work, or big bucks.


If I would ride a delta trike, it would be a drifting trike. I believe it wouldn't be such a big welding job to mod yours close to this geometry.

 

[Sancho's Horse]

What ddk, and chalo, and madrhino said. I made some appreciable improvements in the handling of my trike. Mine was the Worksman Adaptable model. I altered the head angle, which did the most to change handling. I did this in a way which required a lot of work...a lot. Yours would not require so much work though.

Mine now has the controller directly below the seat, a completely modified seat post attachment, 16" longer wheelbase (front to back), 12" or so wider track, but actually my favorite improvement is that my cranks are far enough forward that I can still move from sitting to standing on the pedals when I need to, but with my seat so much lower I can put my feet directly on the ground behind the crank space comfortably at stops, and although I haven't had a tip yet...it just feels like if there was a tipping situation, I could make a bit of contact with the ground with my foot and eat the energy...instead of pavement...or at least have pretty safe dismount...Evel Knievel speaking.

It does feel a bit like riding a motorcycle...although not there yet on motor/battery...just speaking of the riding position. I don't think my geometry is optimized for biking, but with a motor it seems like it will be an excellent compromise.

 

[ddk]

derp- I forgot to ask:

Have you checked your headset bearings for play?
-just askin' cause I destroyed several sets whilst experimenting on my trikes during higher speed tests, especially before I "got it right"

 

[2moto]

The issue is definitely trail. The easiest test, as already suggested by others, is to simply turn the fork around. It won't be a final solution, but will give you a quick indication if you're on the right track, so to speak. If the shake goes away, then it confirms the problem to be a lack of trail. The next thing I would then try is a straight fork, i.e. the axle is in line with the steering tube. Otherwise, you'll be looking at welding work to either change the fork or the head tube angle to give more trail.

A bigger wheel will also give you more trail, but that would require a new fork as well. You might as well get a zero offset fork and stick with the current wheel size. BMX bike often have zero offset forks, so might be a good source.

Here is a pic that explains what trail is:

 

[MikeFairbanks]

Thanks, guys. Lots of good advice, and that drift e-trike above looks really killer.

I met Curt today (e-biker on Endless Sphere) a few miles up the road, and he gave me a steel suspension fork that just might be perfect for what I have in mind.

I'm excited and will install it Monday. I'll let you guys know how it goes. It should make a big difference, not only in terms of stability, but also will smooth out the bumps a lot.

I'm excited.

I just sold (to Curt) my e-bike that I seldom ride, and will now focus on the tricycle, especially with stabilization, lowering the center of gravity, and loading it up with a lot of "fuel" to extend range.

 

[Sancho's Horse]

I destroyed a set of headset bearings by just not knowing any better and using tools to tighten. I think the rule is hand tighten and loosen a bit. I just used the worksman forks...actually ordered a new set which wasn't bent. ddk...I hope I got it right because I hit my spending wall a long time ago.

The trike is a challenge...and bike rules do not quite apply...well most do, but steering wise its a bit of a different game. I wish I could post all my pics, but I am waiting on a few things. I just want it to be finished...esque. Tired of posting bits, but pretty much articulated many of the things I used for stability.

I feel a bit like I made a really old style car...I mean when there were real bits of wood and curtains...and just personal details...10's, 20's, 30's maybe specialty car makers from the 40's. I don't know...I can't wait to take it out for the evening walks. Time to oil up the old handlebar mustachio and promenade with the fine ladies and gentlemen. Hey...Lets shut down part of the street during the fine cool times of the evening and have some fun. Seriously.