Steel grate deck bridge

[dwvoss]

While it didn't work out to go to the rally in WV this week, I did get my wife to go for a weekend outing, we had a great ride south along the Mississippi River until we got to Sabula, IA, where we encountered -- the bridge.

My first clue that crossing this bridge was going to be a little different should have been the 25 mph speed limit that is posted on it. I was probably going a little faster than that when I transitioned from the concrete approach to the steel deck. As soon as the bike was on the steel deck, the bike felt unstable, as the tires seemed to be getting pulled into an unseen groove in the deck. It reminded me a lot of driving on ice, so I think my instinctive reaction was to handle it the same way as I would handle a slippery road in a car - stay off the brake, slow down by letting off the gas, and don't make any sudden adjustments in direction.

As I got near the end of the bridge, I remembered that at the end of the bridge is a "T" intersection and that all traffic coming off the bridge must stop and then turn left or right. The steel deck slopes down toward the stop sign with only 1-2 car lengths of concrete. This meant that unless I applied my brakes, which my instincts were telling me not to do, gravity would be accelerating me toward the stop sign.

I let the bike accelerate down the slope, and braked hard as soon as my wheels were on concrete. Got stopped for the stop sign, and then continued into Savannah, IL.

I'm not sure if I handled this correctly or not, so would be interested in hearing the experiences of others with steel grate decked bridges. The funny thing is, this is not the first steel grate bridge I've crossed. Last fall I crossed at Lansing, IA, and don't remember it being the same type of experience.

Anyone else with tips on riding on bridges with steel grated decks?

Thanks!

 

[Jethro]

Best to just keep a light grip on the bars and let the bike wander a little bit. No sudden movements and braking should be primarily done with the rear wheel. These kind of bridges only really scare me when they are wet.

 

[KGB]

You did well.

Braking downhill on a steel bridge, I would apply more or only the rear brake. This way even if it locks up , the bike can still steer.

One other point, my GS has bias ply tires, the Triumph radials, the GS "wanders" , the Triumph doesn't.
The tire has a lot to do with this also

 

[Bert Patterson]

Have to agree with Geoff (not really uncommon actually). Keep a light grip on the bars and let the tires wander a bit. I just went over the Lansing IA one last weekend. The Pirellis seem better on it than Metzelers did, but it's still creepy.

 

[Steve]

... my GS has bias ply tires, the Triumph radials, the GS "wanders" , the Triumph doesn't.
The tire has a lot to do with this also

I don't know how much the radials help there. I know they make a big difference in cars, but I have not yet ridden a radial-equipped bike.

I DO know that tread pattern can make a big difference, too. If you have grooves that basically go around the circumference of the tire, they will tend to track cracks, grooves and bridge grates. I have Dunlop E3s on my Wing. Last summer I had the pleasure of driving across the Mackinac Bridge, which has over a mile of steel grate. I was pulling a trailer, too. I have crossed many steel grates before, with my Kawasakis on older-style tires, so was somewhat prepared for an interesting ride. Imagine my surprise when the ride was so stable that I grabbed my camera and started taking pictures. Yes, that required taking one hand off the bars and diverting a bit of attention from the road, but the ride was that stable. \\/

Here is a picture of the E3 tread:

 

[mark]

I grew up in Seattle and commuted my Honda CB750 bike over long grated bridges for a long time, wet, dry whatever, some at freeway speed. I must say that I got used to it after a while and it wasn't a big deal. Your tires wander around a bit, and you have less traction, but its really not that dangerous I think.

Putting a little more weight on your footpegs helps a bit.

 

[Sandy]

Like the others say just let the bike do its thing. It's just the tires hunting from one groove to next. Ribbed front tires are the worst. When you get used to it the queezy feeling will go away. Unless of course you're prone to vertigo and you accidently look down while on the bridge deck. LOL.

 

[dwvoss]

Like the others say just let the bike do its thing. It's just the tires hunting from one groove to next. Ribbed front tires are the worst. When you get used to it the queezy feeling will go away. Unless of course you're prone to vertigo and you accidently look down while on the bridge deck. LOL.

Down was the last place I was thinking of looking. 8-[

 

[Steve]

Down was the last place I was thinking of looking. 8-[

That's the direction I was taking pictures. 8-[

I just went to my picture folder to post it here and found that the best one was a movie.
Kinda interesting to see the girders and the water going by underneath you.

 

[Greg O.]

Myself and 8 other motorcycles just finished a trip around lake Superior about a week ago. On our trip north from lower Michigan we crossed the Mighty Mac (Macinaw Bridge) By the way, the Might Mac just turned 50 years old. They were working on the bridge and the right lane was closed leaving the center lane open. We rode across the center span of the bridge, as in the picture in the post above. Like everyone else has said, just take it easy and let the bike seek its own path as it weaves back and forth slightly. When going down hill I would shift to a lower gear and let the engine hold you back. I have also experienced the same feeling a couple of other times. Some road surfaces will cause the bike to weave some, at least on my 750L. I also had a rear tire go down once, and my first clue was it had some wiggle in the back end.

Greg O.

 

[Redman]

yes, sounds like you did fine. Dont want to be braking on that.

Town I live in is on a river, only way north out of town is acrost a draw bridge with the grating, so have riden over that regualrly for 25 years.

Like others said, the bike may hunt back-n-forth between a rib or two, just let it happen. One additional thing is to shift some of your weight lower by pushing down on pegs to lift some weight off the seat but no so much that the seat can move underneath you just enought to apply some of your weight to the pegs, this helps some.

Oh, and if you take a passsenger over it, dont say anything about it being like a cheese grater.

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