What size tires do you feel safe riding across steel bridge grates with ?
 

I know the steel grate discussion has been had before, but I'm wondering about a little more specific info...... What size tires do you all feel safe riding across steel grates with?

I've been using a mountain bike for neighborhood fitness rides, and my route always includes crossing a small draw bridge with steel grating, twice. I have to cross this bridge to get to my disired route where I can take many route variations through a nice easy going neighborhood. With the mountain bike tires I cross the grating with no concerns. I do have a hybrid bike on order and the tires are listed as 32c, and Im guessing the tires while slimmer have more beef than a traditional road bike tire. Back in 2014 I crossed this bridge, in the rain, on my CAAD10 road bike and my rear gatorskin tire blew out causing me to have a nasty crash requiring stitches. Trying to avoid having that happen again.

No! Not your sweet supple Gatorskin!

If I have to cross something that poses a concern for the tires & I am unable to steer around it, slowing down & alleviating the weight works when I ride across that stuff.

I've ridden across these bridges on 28-35. No matter what size I'm riding, I always wish for the next size up.

Did you try to do a post-mortem on the tire that blew out? Was there a sharp edge that cut into the tire, or a defect that happened to blow on the bridge?

This. I have 25s on my Roubaix and 32s on my Domane, but I am careful in these situations regardless of what bike I’m on.

I just assumed the blow out was due to the slick jagged grating and did not inspect the tire. I remember feeling the tire sliding left and ride just before the blow out. At the time I had only been riding decent distances (for me) for a couple of months. My long ride of 54 miles happened the ride before the blow out, and I was scheduled for an event of 80 plus miles a couple of days after the blow out. I never recovered mentally and have sworn off road bike bikes and group riding (even though I was riding solo when I wiped out) haha.

why do they use steel grates? what's the damn purpose?

They provide additional traction if the bridge is wet.

I assume he's talking about the kind of bridges where the entire road surface is made out of a kind of textured see-through steel grating.

I don't know the details of the grating that you are riding on, but I have had no problem on steel grate bridges down to 700X23. You have to be careful and probably should take it slow. Also make sure that narrow tires (like 28mm wide or less) are pmped up nice and hard. I could see pinch flats be a possibility if your tires are soft.

They're also strong and relatively light, which is a consideration for drawbridges.

To answer the OP's question, I'm okay riding over these bridges on 25mm road tires. I have Gatorskins on my training wheels and don't worry about them. On the other hand, when it rains those things are slick as snot and you have to have a very smooth pedaling action and very light touch on the bars. Or I'll walk--no shame in that.

I've crossed them on 25mm and rather slowly.

I used to live in Peoria IL and there was a really old bridge there with this type of roadway surface, I rode there all the time with 27x1-1/4 tires. I never had a problem, but it was always a worrisome moment approaching the strange bend this bridge had in the middle of it! Weird to have a bend in a bridge... Never had a problem there, though, not even in winter when the river beneath it would steam and create frost on the metal grating. Seems like it would be slippery. but I never had problems.

I would trust any properly inflated tire while crossing a bridge with a steel grate. The only threat of a flat would come from having the tire under-inflated. So as long as you keep your tires properly topped up, you should be fine. It's a shame you ruined a Gatorskin by riding too low on it. Those are some of the finest tires on the market, but they do require proper inflation.

If it's that big of a concern, I think I'd dismount and walk the bike across.

If the distance is short & the environment raises no additional concern, that could be an option. ymmv.

The Mackinaw Bridge was designed with grates in the center lanes to prevent what caused the Tacoma Narrows Bridge to collapse.

I frequently ride across movable bridge grates in Chicago. Some of them have steel panels to make it easier for cyclists, but some do not.
Back in the day, I rode across these with 23mm tires. I don't ride anything that narrow anymore, but definitely haven't had any issues with 28-32mm road tires. I've never really worried about flatting, but the tires do tend to squirm back and forth a bit when you hit these, and it can be a bit unnerving.

Contrary to what others are saying here, I find that hitting these with some speed is the best way to go. I usually speed up and then stand and coast over the bridge, letting the bike move around underneath me as the tires kind of wander back and forth.

Here's a close-up shot of one that I took, the path of travel is right to left in this image, not top to bottom.

https://cimg9.ibsrv.net/gimg/bikefor...0f5e3aef30.png

Sounds like my brother-in-law's old Isuzu Rodeo going over a bridge in Virginia when he lived out there. I rode with him over that bridge a couple times and we did feel like we were moving back & forth a bit. He said it felt like that every time he went over the bridge.

Grippy rubber and quality flexy sidewalls help a lot, regardless of the width. In the wet especially. I rode a mile long grated bridge (no grade, just flat over an estuary) in a race on racing silks. It had started raining an hour before; first rain in weeks. A little more traction than ice but not much. Thank you, winter riding skills!

Ben

I notice that wiggle back and forth when I drive over these bridges in my car too.

The other unnerving feeling is if you're ever stopped on one, and they start bouncing from cars/trucks/busses going the other way. The whole car is bouncing up and down. Kind of freaky.

Just be grateful they used something to cover up the hole.

Know your bridge, know your tires, know your limits.

255/45r20.

I've been going over a similar steel bridge grate down on the South end of Amelia island with 700c x 25mm Continental Gatorskin tires with no problem. One thing I've learned is to install the best vinyl rim tape & heavy duty tubes you can find. Make sure you have good rims, rim tape, tubes &, tires before going out on rough ****. Be good. Have fun.

700x23 no-handed with no problem.
I realize bike handling skills are a thing of the past though :rolleyes: