Edge Traps

[Frustrated_Diver]

As new rider with just a little over 7,000 miles in 6 months on the bike, i am getting concerned about edge traps. Here in the Dallas area, the surface of choice is concrete and being a non-Texan, i can't for the life of me see the reason for it. Anyway, it tends to have lots of seams and cracks and one in particular my neighborhood makes the bike rather squirrelly when i go over it at an oblique angle.

 

So, now to my question, other than in construction areas, do these seams pose a problem? What brought it to my attention was this past Saturday, while living through a big mistake (7 plus hours in 41 degree rain but that's a horror tale for another time) i'm motoring up the Interstate and realize that every time the lanes shift, i'm going over a seam at a rather high rate of speed. Then of course, there are the hundreds of seams on the surface streets. Do any of you wise sages have any words of substantive wisdom on this issue? Anything to help me keep the Kelvar pads like new would be greatly appreciated.

[Ken H.]

Being even aware of the phenomenon is a good first step. A lot of riders aren’t. Actually I think it takes quite a parallel surface height difference to create a true edge trap. And a pretty narrow set of circumstances to be felled by one. Certainly not the 1 -2” road resurfacing height differences that are typical. The vast majority of time if approached at any angle at all the bike’s tire will either climb it or be repelled away from most surface height changes. The best plan of action of course is to always approach difference as sharply as possible.

 

All that being said, from what I’ve always understood, a true edge trap where both the front and rear tire get up against a parallel height difference greater than the height of the tire, it is not recoverable from.

[eddd]

Well from your avatar you should be ready if you get pitched off into a river or other body of water.

 

I've found the best way to handle these seams is to remain "loose". Tensing up only makes things worse. You generally aren't moving around enough in your lane to be a hazard to yourself or anyone else.

 

Mountaining biking experience has proved useful in this instance. When you are on some fast single track you hang loose and go with the flow.

[MotorinLA]

When we transitioned to the R1200RT-Ps, I noticed that these bikes seem to 'track' more than the older 1150s when riding on the freeway. This is probably related to the differences in the tire tread pattern for the different models. At first this was a little disconcerting, until i realized that there was nothing wrong with the bike, it just felt a little more wiggly on the freeway.

 

When you are new to riding a wiggly bike can be unnerving, however, it takes a lot more than most people realize to actually upset the bike to the point where it becomes a problem.

 

As mentioned earlier, try to stay loose and try to traverse cracks at as much of an angle as possible. This might entail making more aggressive turning movements when changing lanes on the freeway.

 

If you have the opportunity, take your bike to a place where you can practice going over uneven surfaces safely. Having experience in how your bike handles on various surfaces will make you more confident when you encounter similar things while riding on the streets.

 

Good luck and stay safe.

[ShovelStrokeEd]

Just ignore them and they will go away. I routinely traverse 2-3" lane height differences. A mere seam in a concrete highway is nothing whatever. Wanna get some experience? Ride the seam, traffi c permitting of course. So the bike wiggles a bit, let it, attempt no correction. When you transition back to smooth pavement, it will correct itself.

 

Even a true edge trap, 4" high curb and both wheels against it, can be steered away from just by leaning the bike. You can't go the other way, of course, but you can always steer away.

[Ken H.]

Even a true edge trap, 4" high curb and both wheels against it, can be steered away from just by leaning the bike. You can't go the other way, of course, but you can always steer away.

Not to start too big of an argument, but is that true? Given that (regardless of method) to steer lets stay right, the front wheel must always first go left, if up against a true left side edge trap, is it possible to steer/lean your way out of it? Seems to me (and other things I've read) - no.

[ShovelStrokeEd]

Since I am not still attached to the curb in front of the local donut shop, I'll have to say yes.

 

Low speed, as in paddle, and a good lean of the bike away from the curb and it will get there. It'll argue with you a bit, but you can get out. You need only gain a tiny bit of clearance and away you go.

[upflying]

I'm guessing concrete is used as a road surface because it is more durable than asphalt.

The natural stability of a motorcycle will get you through the seams and raised edges of road surfaces. Just be careful over railroad tracks and steel surface bridges. Those will wake you up.

[jaytee]

I think concrete is particularly useful in areas that see a lot of rain.

 

At first, seams really got me paranoid, but now I have to say, I ignore them. The bike will twitch, but will not lose stability. Dont worry at all, just ride nromally.

 

JT

[MotorinLA]

Ken,

 

when it comes to riding, you have to remember that Ed wasn't actually born, he was assembled at the Bayerische Motoren Werke. In their frustration of not being able to find a human being that could fully master their 2-wheeled machines, the German BMW engineers created Ed.

 

As such, he can do things that normal riders would classify as 'impossible', i.e. pulling away from the 4-inch edge trap, staying stopped for seconds on end without placing any of his body parts on the ground, etc., etc.

[ShovelStrokeEd]

My Swiss, Irish and Italian ancestors would take exception to that. Not to mention that I ride a Honda (gasp).

 

BTW, I can only stop with my feet up when I'm not thinking about it, once I realize I have stopped and should probably put a foot down, I NEED TO.

 

I do still own a couple of Beemers and plan on using my 78 R100S as my primary commuter bike. If I ever get a week or so straight in my garage, I might resurrect my '94 RS. Thing only has 17K miles on it and has been patiently waiting for me to fix it since '95 when it quit on me after doing a 4 corners tour. Gotta work out a different front master cylinder and switch gear though, I replaced 2 in that time and it needs another.

[MotorinLA]

BTW, I can only stop with my feet up when I'm not thinking about it, once I realize I have stopped and should probably put a foot down, I NEED TO.

 

Now you're just trying to be modest.

[Wooster]

Frustrated Diver,

 

Dirt riders use a suspension loading method to confidently move from one deep rut to another, namely stand up, push down on the foot pegs and spring up while crossing the ruts. The bike, moving up from the compressed supension seems almost to fly over the rut. On a 600 lb street bike it works just as well. Practice pushing down while standing and you get a feel for the bike's rise and fall; then simply time the edge crossing when bike is on the rise.

 

Wooster

[ShovelStrokeEd]

Yup, or downshift and gas it. Same idea, just unload the front wheel and it will glide over the bump/seam/transition. The rear will follow, albeit with a twitch if the thing is on the taller side.

[zbassman]

I've made it a point of riding over seams again and again so they don't fret me as much.

 

Worse then seams to me are those darn tar snakes. I ride a lot of two-lane blacktop outside of Austin and on hot summer days, say over 100 degrees, those tar snakes start to get pretty slippery. Nothing like going through a turn leaned over at a good angle and ride over a tar snake and feel that back wheel start to slide a bit to get your heart rate up!

[Ken H.]

Since I am not still attached to the curb in front of the local donut shop, I'll have to say yes.

 

Low speed, as in paddle, and a good lean of the bike away from the curb and it will get there. It'll argue with you a bit, but you can get out. You need only gain a tiny bit of clearance and away you go.

Sure, agreed in that scenario. I guess I was thinking more about while underway?

[motoguy128]

Only bad things happen from riding parallel to and abrupt change in pavement height.

 

The best practice is to be good at scanning the road for these hazards. My thousands on miles on bicycles has made me good at this since just a 1" wide crack or 1" concrete lip can drop you to the pavement quickly. You simply don't ride parallel to these.

 

It's the same common sense that tells you not to turn or brake on icy or muddy surfaces without knobbies or studs.

[ShovelStrokeEd]

Well, I've never put myself up against a 4" curb at speed and I imagine it would be difficult to extricate oneself from that. I've crossed plenty of 1-3" high stuff on the highway. Actually, the higher stuff had some transition to it for the most part, repaving with a soft edge. I'm pretty aggressive with lane changes anyway as I tend to use them for swerving practice and really, it has never been an issue. At worst, the bars will give a bit of a wiggle. If you are in the habit of changing lanes with glacial slowness (collective you here, not Ken) you ask for trouble with these things. A quick flick over to cross the obstacle and back to resume position in the new lane makes the entire thing a non-issue.

[knight88]

Great more stuff to think about while riding, how about just trying to avoid going into them as much as possible? I never thought about having to transition to motocross on the freeway but I guess you got to expect the unexpected.

[sgendler]

Didn't Dick Frantz go out and find a big "edge trap" and put his bike into it just to prove that it really wasn't that big a deal a while back? I know I've dealt with many a spot where road crews were repaving the highway one lane at a time, often leaving an edge trap that is at least 3" high. I've never had any trouble with 'em. Of course, I don't intentionally parallel 'em so that my wheels can get 'trapped' fit that is what would actually happen, but bumping up and down across them is no trouble at all.

[motorman587]

Wait until you go over a metal bridge. Remember to look down you can see the water. Seriously, relax and just let her wiggle.

[Scriber]

As new rider with just a little over 7,000 miles in 6 months on the bike, i am getting concerned about edge traps. Here in the Dallas area, the surface of choice is concrete and being a non-Texan, i can't for the life of me see the reason for it.

 

Well, since no one has mentioned it, I will. The reason for all the concrete is that Texas has a ready supply of all of the materials to make it. There is limestone everywhere, and lime is a major component of cement. Eons ago Texas was under a vast shallow sea, and sediments of lime were laid down on the floor of that sea. Central Texas has lots of cement plants scattered around, all of which make good use of this ready source of lime.