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bwaii
07-06-2013, 09:00 PM
I built the Tomahawk pretty close to plan - especially concentrating on fork angle. I've learned to ride it but the varmint is very squirrelly. As I understand it the high rake (70 degrees) should make it more stable - cruiser like - but for regular riding (and high speed) the thing's a beast. Why is that.

Radical Brad
07-06-2013, 09:24 PM
Do you have a side photo to post? As far as bents go, I found the Tomahawk to be moderately tempered and good a high speeds. Of course, I am comparing this to many other bents, low and tall, not an upright.

Brad

TexasTuff
07-06-2013, 09:42 PM
Between my son's recumbents and my recumbents I've ridden a wide range of styles. Every time I get a new style of recumbent to ride it has its own quirks. Sometimes it has taken as much as 100 or 200 miles to become comfortable. But in the end, they all have been good rides. Sometimes a large parking lot of Sunday without traffic takes the pressure off and you can go with the flow for awhile. It does get better.

bwaii
07-07-2013, 08:47 AM
Are low-riders naturally more "wobbly" the normal height bikes? 6 inches lateral movement on a low bike is a lot more angle than 6 inches on a high bike. I'm not cleared to attach pictures.

bwaii
07-07-2013, 08:56 AM
I'm nowhere near 100 miles, but I've got a number of trips here around town. I have 10 or 15 trips and maybe 30 miles. Not counting test rides in front of the house. I've learned some tricks, like using power to help steer and starting in low gears to accelerate quickly. Using a higher gear helps as peddling fast makes things get crazy fast. I can do a fairly small circle and figure 8 and usually start out the first try.

Ticktock
07-07-2013, 10:25 AM
Steering head angle is only a part of the story, hence Brads request for a side on photo, aimed mainly at the front end, and taken with the wheels dead straight.
The fork shape also comes into play, as it affects Trail--which is at the bottom of the mystery.
I can only say from what I have done, but the step from upright to LWB was a wobbly one at first, including wandering, false starts and sudden stops to avoiding hard landings.'
I see no reason why an even lower bike would not be the same, or harder, but usually I would expect more stability with more speed.
Practice is the key if the bike is right.
If you can measure the trail, it would help, although we can guess from the fork set up. Real numbers can be better sometimes.
Steve G
Beijing

bwaii
07-07-2013, 10:57 AM
Ah, I "figured out" the pics thing.Well, maybe I didn't. If these show up I'll try to take some more specific ones this week. Oh, hey, look! AN "insert images" button!http://www.ilhadotesouro.com/images/tomahawk.jpghttp://www.ilhadotesouro.com/images/tomahawk2.jpghttp://www.ilhadotesouro.com/images/tomahawk1.jpg

Ticktock
07-07-2013, 11:38 AM
Just a quick look at those pics, everything looks OK, and trail is around 50mm, but its a hard call at those angles--would love to know how close I got!
I would suspect that its all part of the learning curve with a bent--and its steeper the lower you get! As to trail, anything around the 50mm to 80mm should be OK for this bike 80 is probably better, but that could spark a long discussion with others!
If you fidget in that seat, you will wobble every time, for the next hundred years--the trick is not to over correct anything, and I suspect that's what happening.
Steering is so light that you could be giving it a bit too much. You are doing well (assuming its you in the pics) with the relaxed one hand riding, that I think its only a matter of time.
Texas Tuff probably has then best advice--find a car park with no cars and play with it- then (my advice) find a nice quiet road, and ride , and ride , and ride , but don't forget to go home!
I would still like to see a better side on shot, with wheels straight, but it does look ok so far.
Steve G
By the way, in the pics, what you are riding on is pretty tough ground for a beginner on a bent---if this is where you have the problem, find a better road !
You are doing well on that stuff!

Radical Brad
07-07-2013, 11:52 AM
Yes, it looks like a nicely done Tomahawk to me. The only small adjustment I would make is to get rid of those BMX handlebars, and go to the "granny style" I have used in the plan. This will make require a redo of the gooseneck to place them close and up over your knees. Those BMX bars seem to interfere with the riders knees a bit.

Other than that, I also agree that it is probably just that learning curve.

Brad

bwaii
07-07-2013, 11:59 AM
These are 2 of my sons. I'm an old coger - even if I can't spell it. Thought I added a profile pic. Yes, I found out pretty quick it doesn't like sand or pot-holes. The dirt in the pics is pretty packed but wash-board. We learned here because it takes off less hide when you slide. I even wore gloves for awhile. It only dumped me once. Shoulda put the helmet on the other end ;). Most of the time I can hold it steady and even ride one-handed. But it's like riding a tiger - you never blink both eyes at once. At 20mph (30kph) I was pretty scared.

bwaii
07-07-2013, 12:04 PM
The BMX bar was temp. I narrowed a set of grannies on the final. The only real mess-up was the rear brake pins that I measured wrong. I just need to touch up the seat where I trimmed the foam and paint the kickstand.

Ticktock
07-07-2013, 12:15 PM
Give it a bit of time--20mph is not a bad effort while you are learning these things. Remeber you don't need any input to the bars when you pedal, unlike an upright, where it becomes automatic. On a bent, its just steady peddaling, and a real light hand on the bars, with no fidget in that seat. They are amazingly sensitive to you trying to move around, even if it is only when peddling.
Having said that, some wobble is unavoidable, so learn to trust the bike a bit more. That small wobble you would not notice on an upwong looks shocking when you sit down below the front wheel.
Think you are on the right track so far , unless there is a problem in the next photos, which I doubt at this stage.
Steve G,
beijing

SirJoey
07-07-2013, 01:48 PM
Are low-riders naturally more "wobbly" the normal height bikes?
In a word, yes. The lower the ride, the harder to balance. The taller the ride,
the easier to balance, which seems to surprise a lotta folks, but it's true.

Think of it like this.... try balancing a pencil upright on your fingertip. A little tricky.
Now try balancing something long, like say, a broom handle. Piece of cake, right?
Same principle. :)



**** The Truth Is Out There! ****
http://img384.imageshack.us/img384/7131/sirjoeysigmedij1.gif
(Geezer & Bent Enthusiast At Large)

bwaii
07-07-2013, 02:20 PM
Don't have time but did it anyway. 3 fresh pix.
http://www.ilhadotesouro.com/images/toma1.jpg
http://www.ilhadotesouro.com/images/toma2.jpg
http://www.ilhadotesouro.com/images/tomaFt.jpg

Radical Brad
07-07-2013, 06:38 PM
Great looking ride!
If you get a chance, please drop those in the gallery...

http://forum.atomiczombie.com/gallery/browseimages.php?c=12

Brad

Ticktock
07-08-2013, 09:21 AM
Hi,
It's a good looking bike when you get close up!
But I was wrong on the trail, based on the new pics it gets a bit lower, around 25 to 30mm, which could be the cause of your worry.
Its a bit hard to change , as you have no room to bend the forks back to increase trail--it looks too close to the frame to do this.
The only way would be to change the steering head angle back to something like what it was on the original doner bike, where I can almost guarantee the angle was less than this bikes!
Steeper head angles and less trail make for quicker steering , while lesser angle and more trail leads to slower steering, but only to a point, when wheel flop becomes a problem.
Trail on my LWB is about 70mm, and trail ,is the more important of the two items.
So I can see now why its a bit lively!
Steve G.
One way may be to cut the top of the down tube on top, and sides, allow the wheel to move forward a bit (more trail) and re weld. This will also raise the front boom a bit, but maintain existing pedal clearance.
I'm a bit cautious on this one as it means messing up a paint job, and the results are not gaurenteed, but it is the what I would do under these circumstances.
Can any one else offer a better solution--based on experience?
Steve G