gmouchawar

I, like most of your here, have more than one bike (Road, mountain, foldables and electrics).
On some of my bikes I can sit back and release my hands from the steering.
The bike will keep going as straight as an arrow provided I am at a decent speed.
On another I can't. When I can't the bike takes off left or right as soon as I let go.
What is the cause of this?
Is there anything in the adjustments that controls this? Is it related to the choice of saddle and its position? Is it a defect in the frame?
Your insight is very helpful.
Thanks,

kenhill3

From my own reckoning, I see two things that are sure to be factors in this.

1) The steeper (closer to vertical) the head tube/fork is, the more twitchy and harder to ride no-hands.

2) Front tire tread, the more aggressive the tread, the more it will want to pull to one side or the other.

bobn

I can ride "no hands" on my Columbia ballooner but can't on my Raleigh 3 speed?
Might have something to do with the wheel base?

LarDasse74

It is also possible that sometong on a difficult-to-ride-no-handed bike is bent - like the frame, fork, or saddle. I have a twitchy racing bike with darn-near perfect alignment and I can ride it no-handed for miles, but my relaxed geometry mtb has a slightly misaligned fork and it is much more difficult.

roadfix

Depends on geometry. On some bikes I can ride no-handed at 3mph while others require that I go 10mph to keep a straight line.

bkaapcke

IL sure wish my LWB recumbent would do it. That would be the ultimate in laid back rildling. But no, not to be. bk

Panthers007

Wheel-base. Frame-geometry. Width of handlebars. And if the frame is bent - good luck. All of these determine the ease with which one can no-hands on a bike.

"Look Ma! No hands!"

"Looch Ma! No teeth!"

maddmaxx 

An old head set may have indentations on the races that cause the steering to settle into one particular place.........that place may not be centered.

oldbobcat

Written by someone who has never ridden a bike with an overabundance of trail.

Too much trail will cause the front wheel too "dive" into small steering and balance corrections, turning them into over-correction. Too little trail will cause the front wheel to "float," requiring constant input from the hands to keep it pointed in the direction of travel.

Too much trail makes the steering feel heavy because the inputs too keep the bike on track need to be strong and sustained. Too little trail makes the steering feel so light and twitchy that the front wheel may seem to have lost touch with the road.

So there's a medium out there, but I haven't bothered to calculate it. I sense that optimum trail might be a function of wheel size and weight, head angle, weight distribution, and speed.

Scheherezade 

If you have a tight headset, that might make it more difficult as well.

crock

PLEASE don't bite my head off for suggesting this, but I will go out on a limb and say that geometry has nothing to do with hands off riding. Riding hands off on a bike is 100% related to correct alignment. Track bikes, road bikes, touring bikes, 20" inch wheel bikes, mountain bikes, Schwinn Stingrays...I can get get ALL of them to ride hands off if the alignment is perfect. I can't get any any bike to ride hands off when the alignment is incorrect. In my personal order of priority the alignment issues you need to deal with:

1. Both wheels in the same vertical plane, ie both straight up when going straight ahead. If this is off, then the frame or fork is bent. Unfortunately this is difficult to measure or adjust. Using drop out alignment cones is the usual method of finding something askew, but an alignment table is the only real answer-at least that I know. If anybody knows some tricks to check this then let us all know how.
2. Both wheels pointing straight ahead. This usually means that the the rear wheel is "cocked" in the rear drop outs, or that the front fork is mildly bent. You can eyeball this measurement very accurately with the help of a string or straight edge.
3. The rear wheel is offset from the track of the front wheel. All alignment experts would agree that this is the least important aligment parameter, in fact some bikes are purposely set up this way.

The ability to get a bike in perfect aligment is a HUGE factor in getting a bike to ride well. In fact the bike can just about ride itself. This single factor is why I am biased for steel frames. Steel frames are relatively easy to align. The ability to ride hands off is a great indicator of alignment.

nerobro

Nope, it's entirely, fully, all, the amount of trail the bike has. More trail = more stable. And Im' talking the technical trail, not what fork mfgs call it. :-) Head tube angle has an effect to, by altering the amount of trail as the bike leans, and the steering angle changes. Steeper head tube angles make trail numbers larger.

gmouchawar

Thanks so far for a healthy discussion. Things that make sense to me so far are the tire thread, the geometry of the frame/fork and the alignment.
I will consider the alignment issue. How can it be checked?
If it was off, wouldn't the bike wonder in the same direction every time.
Mine it is 50-50. Sometimes left others right!

cyclezealot

Guess, I must be an unbalanced kind of rider. Never...

AnthonyG

Here's another vote for it mainly being an alignment issue. Issues such as trail, wheelbase and headset adjustment have some influence but having a bike go off line immediately after taking your hands off the bars is clearly an alignment issue.

Wheel alignment is fairly straight forward to check on a bike. Turn the bike over on its bars and saddle, take a long straight edge and place it against the tire of the rear wheel and run it past the front wheel. Correct alignment will have the straight edge touching four contact points along the tire (2 per wheel) dead evenly. You will see misalignment as a gap between the edge and the tire when both tires are pointed in the same direction.

My custom racing bike has a VERY small trail and is quite twitchy but I can easily ride it straight with no hands. I have some cheaper bikes with relaxed geometry and long trail that are difficult to ride no hands because of poor alignment.

Anthony

Road Fan

I'm almost as strong as Crock about this. There are technical reasons why trail MIGHT affect no-handing especially at low speeds, but I'm 100 % certain (have been thrown off by this) that I can't ride a frame with a fork that's out of line in the right way. I've also not been able to control one that had a brinelled headset. But my bikes' trails range from 45 mm to 65 mm, all good no-handers. Same for a '57 Schwinn Traveler I worked on, and it was near 70 mm.

I can understand the "quick response and overcorrection" argument, but I think that sensitivity can be mitigated by careful riding, at least I haven't found it to be a problem. Maybe the fork/handlebar has a moment of inertia is too high?

I think there's so much benefit to having a bike that steers smoothly and goes straight well, that I'd recommend that if a bike does not no-hand easily enough, have the alignment (frame, fork, wheels) checked and make sure the headset is right. THEN see if trail is an issue.

Road Fan

What do you mean by "technical trail?" Based on a wide range of texts, websites, and threads here on BF and elsewhere, trail is the distance along the ground from the point where the steering axis intersects the ground, and the center of the tire contact point.

The equation is (Radius*cos(HeadTubeAngle)-Rake)/sin(HeadTubeAngle).

This ignores subtleties such as pneumatic trail.

Note that trail is not the same as rake. Rake is the same as fork offset.

Texts and articles involving motorcycles often use different terminology, so that can be a source of confusion.

What's the "fork manufacturer's convention?" Based on the formula, trail cannot be deternined just based on the fork; it involves the head tube angle and the wheel radius, which are properties of the bicycle on which the fork will be used. It would be silly for a fork manufacturer to advertise a "fork that gives XX trail," and actually I've never seen one do that.

roadfix

But frame/fork geometry also determines how SLOW you can ride no-handed without wobbling side to side.

oldbobcat

It's rather amazing how little definitive information exists on bike steering geometry, but this page on motorcycle forks explains the theory pretty succinctly: https://www.american-v.co.uk/technica...etry/body.html

VeloBase.com has a nifty trail calculator on this page: https://velobase.com/Resource_Tools/ForkCalc.aspx. I like it because wheel size is one of the independent variables.

Using this calculator, I found the trail for my four road bikes, whose head angles vary from 73.5-74 degrees and fork rake ranges from 43-45mm. The range of trail using a 700c x 23 wheel is 48.8-54.0 mm. All of these bikes are straight and have properly dished wheels. The wheels are roughly "training weight", not super light but not boat anchors. Riding no-hands at about 20 mph, the bike with 50.9 mm of trail is the most stable. It's a '60s vintage general-purpose track bike that I fit with a Kinesis aluminum road fork with 43 mm of rake. The oldest stock bike has the shortest trail and the newest has the longest. My calculations are based on a mix nominal (manufacturers') and measured specifications. While not being definitive, I believe they are accurate enough to illustrate trends.

Interestingly, I came across the site of one builder, Kirk, who prefers to build with a trail of 5.9-6.0 cm: https://www.kirkframeworks.com/Fitting.htm. The galleries of his builds show that his fork rakes tend to be on the short side, and he might be using a larger wheel diameter in his calculations.

The bike with the longest trail that I ever rode was a friend's experiment in custom framebuilding. Through a miscalculation of chain- and seatstay lengths, the head angle ended up at around 72.5 degrees. (We were aiming for 73-parallel.) Using a rake that was common for British criterium designs of the time, around 40 mm, we ended up with a trail of over 63 mm. At normal riding speeds, with normal racing-training wheels of the time--36-spoke Super Champion Arc-En-Ceil rims, Campy Record hubs, double-butted spokes, and 280 g tubulars, if you need to know--the bike handled like a 30-foot bus in a crosswind--an experience I also have first-hand knowledge of. No-hands was out of the question, as was out-of-the saddle climbing and sprinting. The bike would respond to small shifts in weight by diving over, requiring massive amounts of steering and weight shift to bring it back up. Later, using the fork from a touring bike that he'd built (longer rake), the bike handled quite nicely.

What does this have to do with riding no-hands? No-hands requires the front wheel to track, that is follow the direction of travel, favoring long trail. It still must be able to be steered with only weight shifting, favoring short trail. Head angle affects the overall nimbleness of the bike but the rake must be coordinated to get the trail in a reasonable range.

Tracking is also affected by the momentum of the spinning front wheel--tracking tendency increases with mass and velocity. If you don't believe this try a no-hands trackstand. Thus the current use of lighter wheels might partially explain why the somewhat shorter 43 mm fork is now fairly standard for medium and large (73-74.5 degree head angle) road bikes.

And, by the way, the effect of handlebar width on no-hands riding will be limited to the momentum of the mildly pitching handlebar--more to do with the length of the stem and mass of the STI levers.

oldbobcat

The VeloBase calculator can show how even this bike can be stable: https://www.flickr.com/photos/nielsam...n/photostream/

Retro Grouch 

Try checking the rear wheel dish. Improperly dished rear wheels are common as dirt.

I'm thinking that a rear wheel that's not in line with the frame will force you to lean a bit to one side to balance. When you do that the angle of your headset will make the wheel turn to that side. The combination of the two factors will have you going back and forth and will make the bike hard to ride no handed.

krome

As Retro stated, dish can be a factor.

On my normal ride, I can no-hands quite well and have no trouble steering and such. The other week, I noticed my front wheel bearings were making noise, so I decided to swap out front wheels until I could address the bearings (I've got a small stockpile of salvage parts). I put the front wheel on, and I noticed that I had to adjust the brakes significantly. turns out the wheel was improperly dished. I don't have a dishing tool, nor did I have the time to fool with it, as it is my main ride, and my backups are all in need of work so I rode it anyway. I could only no hands it if I leaned way to the left which was very uncomfortable and not as secure as I was used to.

I re-dished the wheel by sticking it in an unused fork and systematically loosening one side of spokes and then tightening the other side. It isn't perfect, but it improved matters enough that I can live with it until I borrow a proper dish tool from my friend.

You must have proper dish on the front and back wheels for no-hands riding to work well.

LarDasse74

What he means is that he doesn't know his arse from a hole in the ground.

roadfix

Then let's assume everything is aligned and adjusted perfectly. You will still come across bikes that are almost impossible to ride no-hands.

Road Fan

I'd like to see that bike. Unless it's something really odd like a motor-pace geometry.