Recumbent - Trike Problems

I've owned a Sun EZ Tadpole trike for about 2 months. I've been pretty pleased with it. However there are a couple of annoyances popping up. First is the steering. The trike has ackerman type steering. At speeds over 20 mph, a slight steering input seems to be met with a over reaction from the trike. It wants to turn sharper than what I want. Pretty scary when going into an "S" curve at 25-30 mph. No problem at slow speeds. I thought about swapping the stem for a shorter one in an effort to slow down the steering and to get rid of the twitchyness. Just wondering if anyone has tried this, if it worked and if any problems were encountered.
The second problem is flat tires. I replaced the Kenda Kwest 20x1.5 tires with Maxxis 20x1.95 tires in an effort to get a little more comfortable ride. (Ultimate speed isn't a concern) When I swapped the tires, I reused the tubes which came with the trike. On the first ride, the right front tire when flat. Inspection showed the tube split near the seam on the rim side of the tube. Thinking maybe it was too small a tube for the tire, I replaced all the tubes with ones sized for the 20X.1.95 tires. A couple of weeks later, the rear tire went flat. Again the tube split near the seam on the rim side of the tube. Now I'm at a loss. This same type problem happened twice with two different tubes on two different wheels. The wheels are Alex DA-16. I run 80 psi. I'm wondering if there may be a problem with running a wider tire on a narrow rim. If anybody has any thoughts, don't be shy.

Thanks.
Garry A.

In regard to the steering, I think, I'd have a look at the alignment.

I don't know much of anything about Ackerman steering, but what I just learned, is it requires or takes advantage of "toe-out". ??

In regard to the steering, I think, I'd have a look at the alignment.

I don't know much of anything about Ackerman steering, but what I just learned, is it requires or takes advantage of "toe-out". ??

toe-in, actually. Basically, the tires are angled slightly inwards, with the tires closer near the front of the trike. The user's manual should have info about this.

I'm not sure about the tires though. It sounds like you're getting pinch flats, but again, I'm not sure...

toe-in, actually. Basically, the tires are angled slightly inwards, with the tires closer near the front of the trike. The user's manual should have info about this.

According to Google: "All racers know the difference between toe-in and toe-out (alignment). However, the many forms of toe-out can be confusing or misunderstood. Toe-out can be found in at least one of five main forms; static toe out, toe out on turns "ackerman steering", t oe out due to bump steer, steering arm toe out, and toe out due to slip angles.

The most commonly known form of toe-out is "static" toe-out. This is where the tie rods are adjusted such that the front edges of the tires to be farther apart than the rear edges of the tires when viewing the car from above.

Ackerman steering (http://www.auto-ware.com/setup/ack_rac.htm)

Ackerman steering refers to the way the steering mechanism is designed, not how you misalign the static toe-in/out. Twitchy steering on trikes has the same cause as on bikes. From what I've seen, trikes usually have steep steering angles and minimal trail. One guy in my club disliked the quick steering on his Windcheetah, so he unglued the steering knuckles and relaxed the steering angle himself. IIRC, he set it at something like 11 degrees from horizintal instead of the stock 6 or 7 degrees. This would be much harder to do with other designs, since most trikes are welded in place and cannot be adjusted short of cutting the frame.

I've got the alignment set between 1 & 2 mm toe-in. Never gave pinch flats a thought. When I originally swapped tires I made sure the tube was sitted in the tire and used tire tools to put the tire on. They held air until I took it for it's madian run on the new tires. Lasted about 1 mile B-4 it went. I put close to 60 miles on the trike B-4 the second tire went. Wouldn't pinch flats show right away?

Garry A.

If you don't get the steering improved, a "shock dampener" might work. I believe they added one to the Natalia Florence, which I posted the link to, in another thread. Also, I put one on my Jeep CJ5, to dampen the steering.

I haven't had a lot of experience with bike tires (when I was riding, they lasted for years), however on car tires with tubes (yep, they all had tubes at one time!), it was a good idea to pump them up and then deflate them, so things could straighten. Then pump them up and hit the road.

Pinch flats are sometimes called, 'snakebites' because they leave a small pinhole, usually in pairs. Like snake fang marks. A ripped tube is usually the result of the tube being pinched under the bead (between the bead and the rim) and blowing out under pressure. A tube can last anywhere from minutes to days with the tube caught this way,regardless of tire pressure. If I were you, I'd inspect the tire/bead interface *very* carefully when you install the next tube.

My sequence for installing a tire/tube goes like this:
1. Install one side of the tire on the rim. Align tire logo with valve hole in rim (for future reference.)
2. Install tube. Inflate tube just enough to give it shape.
3. Install second side of tire
4. Inspect carefully. There is usually a line on the tire, along the bead, that can be used as a gauge to see if the tire is on straight. If the tube is pinched, it will most likely be at the spot where you got the last bit of the bead over the rim, or at the valve. Pushing in on the valve stem will help pull the tube back inside the tire if you think the tube is pinched at the stem. Elsewhere, pushing in on the bead will let the tube pop back where it belongs.
5. If everything looks OK, inflate to ~10 psi and recheck tire for proper seating.
6. Only if everything still looks OK do you inflate to full pressure.

Thanks for the all the tips. This weekend I'll re-check the alignment and replace all tubes and take a little more care in doing so.

Garry A.

Thanks for the all the tips. This weekend I'll re-check the alignment and replace all tubes and take a little more care in doing so.

Garry A.
I believe I know why your tubes flat in the location described in your original post. Had it happen to me several times until I figured it out. When you run large tires on a trike, particularly ones with a stiff sidewall, the tube can squirm against the rim tape. If your wheels have cloth rim tape, the tape saws holes in the tube. It will continue to happen unless you replace the rim tape with rubber rim strips. This probem has NOTHING to do with how carefully you install the tubes. The rim strips solve the problem permanently.

Accurate alignment is always a good thing!

Chip
The Recumbent Trike Shop
Denver, CO
303-618-5711

I own a Sun Tadpole CX and have also experienced the twitchy handling when exceeding 20 mph. I've only put about 100 miles on the trike so far so maybe I'll eventually get used the steering's quick response. If not, a solution is needed.

I've also had the flat tire problem and found that the clearance holes that are drilled in the rim for inserting the spoke nipples, were not properly deburred. Some of the burrs were large enough to cut through the rubber rim protector and into the tube. I have since deburred all the holes in the three rims.

Owen2,

This past weekend I was at the LBS where I purchased the trike and talked to a mechanic about the flats. He made mention about maybe the spoke nipples having something to do with the flats. I'm due
to take the trike back in for it's free check. I'll make mention checking the nipple holes. Thanks for the tip.

Garry A

I don't remember what rim strips were on the rims when I took off the low pressure Kenda's. and replaced them with Comets. If you have not replaced the rimstrips with cloth or plastic ones do so. Also, the I asume that the tires you are running are the Hookworms. I do not recommend their use with a DA-16. Try some Comp Pools. You are really sluging down an already speed challenged trike with the Hookworms, they gotta be the slowest tire I have ever used. As for the steering I have not noticed the problem. I really slam it into the turns at 20mph and like to lift a wheel when I do it, but then I'm a bit nuts. I have a large bruise on the inside of my thigh from a MTB crash on Sunday. I still try to be 11 years old. Although, I'm actually 5 11 year olds.

More info. on tire problems & twitchy handling at 20+ mph.

FLAT PROBLEM
My Sun EZ-Tadpole CX has had another flat and I have finally determined the cause. The CX has tubular rims (the SX Model does not). My CX had a rubber rim strip to cover the spoke nipple clearance holes, which will not work for long with 100 psi tires. Rim tape (16mm) must be used. The LBS where we bought our two CX's is going to reimburse me for the tape and two tubes that failed.

TWITCHY HANDLING AT 20 + MPH
I found that the seat back to bottom hinge bolt was very loose. Tightened it and the high speed handling improved considerably.

This past week I've removed the tires, de-burred the nipple clearance holes. (They weren't bad. Some had rough edges though.) The existing rubber rim strips looked ok. Didn't find any obvious cuts / tears.
Replaced the rubber rim strips with rim tape anyway. Lowered the air pressure to 60 psi from 80. Took it out for a 20 mile ride today. No problems yet (knock on wood!) If this doesn't work, then it's either rims from the SX model or can the Hookworms for the stock type tires.

Thanks for all the tips. If I get this cured, then on to the steering.

Garry A.