Utility Cycling - Burley flatbed lost a wheel at 33mph.

Hey everyone,

I was at my place in Michigan this weekend. I am currently building up a fixie out of a 1986 Varsity frame. Its a lightweight lugged frame with aluminum bullhorns. so it weighs like 10 pounds or so. I was towing this on my burley flatbed behind my 1968 Schwinn Varsity. When I reassembled the trailer, I apparently didn'y tighten the wheels up enough, and the left skewer shook itself loose. SO I get to a point on a 25mph road where the road goes down into a river valley. It is downhill for about 1/3 of a mile (steep). I got the rig up to 33 mph when I started to feel the trailer bounce around alot, since the load weighed less than the trailer itself. Then I the trailer hit a bump, go up in the air,and then I heard dragging. I thought I flipped the trailer, that would have been a first. I braked quickly, then a 20" wheel with an offset hub, went flying downhill past me. I watched as it rolled downhill and then I pushed my riginto the grass next to the road. Some people pulled up in a Mercedes and gave me a ride half way down the hill to where the wheel rolled into some brush. I walked back uphill and reattached the wheel. I made the dropout was okay, and that both wheels were on extra tight and i continued downhill. I'm just glad it wasn't more serious. I bought a set of old steel 27's from an old no name japanese 10 speed to use on this thing for the winter. Getting back up that hill with 37 gear inches was hard work.

Yeah, trailer + 33 mph = potential for bad...

especially when the manufacturer only reccomends 15mph

I was carrying on the rack a trailer tire it fell off rolled across two lanes went up a kwall over that went down a 25 foot embankment and landed in a creek.

Funny thing is I watch this thing zipp like a race car since I was doing 25mph. I had to do a power stop.


Of course after I got it and it was ok.

That 15 mph max speed is just to limit the manufacturer's liability. These trailers tow fine at speeds higher than that. I've had my Burley Flatbed up into the high 30's-almost 40. The thing to remember with trailers is if you have to stop quickly you have the load on the trailer pushing you from behind. Things can get a little exciting if you want to stop quickly with rim brakes in the rain while towing a trailer.

it would take all day on my steel rimmed varsity in hte rain

That 15 mph max speed is just to limit the manufacturer's liability. These trailers tow fine at speeds higher than that. I've had my Burley Flatbed up into the high 30's-almost 40. The thing to remember with trailers is if you have to stop quickly you have the load on the trailer pushing you from behind. Things can get a little exciting if you want to stop quickly with rim brakes in the rain while towing a trailer.

Does the trailer cause the back tire to break loose & swing out? Or what...? It's a concern.. I tow one. I'm a heavy guy so maybe less likelihood of problems than for a lightweight pilot? I'm thinking: avoid braking hard with the front wheel, use the back more forcefully than w/o the trailer.

Does the trailer cause the back tire to break loose & swing out? Or what...? It's a concern.. I tow one. I'm a heavy guy so maybe less likelihood of problems than for a lightweight pilot? I'm thinking: avoid braking hard with the front wheel, use the back more forcefully than w/o the trailer.

I have had that happen once, but when I lost the wheel the rig probrably weighed less than 30 pounds. The one time the rear tire on my towing bike broke loose was my fault. I was towing with my commuter, which has Specialized 700c x 28c Armadillo Slicks. I was running a bit over 100 pounds in the tires on a rainy day. I was only towing with this bike because it is my only bike with fenders. I had about 80 pounds on the trailer. I came around a corner at about 12mph, gently feathering the rear brake. THese tires tend to slide around alot in the rain without a trailer. SO I came around the corner, hit the brake, and the rear wheel broke loose.THe bikes spun around, and my ankle ended up between the trailer tongue and the bike's chainsty.

In this situation, the trailer had the advantage, I weigh about 145+20 pound bike+slick high pressure tires on a slippery surface.

Good point. With a positive tongue weight (trailer center of mass ahead of the trailer axle) there will be a centrifugal thrust on the bike through a turn even if you're not braking. All the worse if you're also braking.

If the center of mass of the trailer is behind the trailer axle (negative tongue weight -- shouldn't be loaded this way), there would be a centripetal (inward) thrust.

So... does the rule of thumb for automotive trailers apply to bikes? 10% of the weight of the trailer on the tongue? Maybe helps to minimize sideways thrust at the rear wheel of the bike. Not always easy to do depending on the shape of the load & of the trailer.

As I gain experience with the trailer & think about this stuff, I am growing less concerned with speed and more thoughtful about avoiding having the trailer cause me to go down:):thumb:.

-Rich

Does the trailer cause the back tire to break loose & swing out? Or what...? It's a concern.. I tow one. I'm a heavy guy so maybe less likelihood of problems than for a lightweight pilot? I'm thinking: avoid braking hard with the front wheel, use the back more forcefully than w/o the trailer.

The quicker I need to slow, the more I brake with the front where the most braking force is located. I've felt the bike begin to feel a little light in the rear at times, but it's never been uncontrollable. And I've laid some pretty long skids foolin' around with a 14 1/4', 75 lb. canoe loaded with fishing gear behind my Townie3.:D

I've also towed some pretty heavy loads on my Burley Flatbed behind my Allez Elite without a problem.

Part of what Chicagoan ran into may have to do with the type of pavement he was on. When I was living on Okinawa it didn't take long (one rain) for me to discover that those roads are very slippery when wet. I later came to understand it's due to the crushed coral they use in the asphalt. There was a road near where I grew up that had crushed shell in it. That road was also very slippery when wet.

I have found the rear wheel doesn't have much braking power wet or dry, with or without a trailer, before locking up and losing traction, which reduces braking effectiveness. I only use the rear brake when I want to slow gradually.


So... does the rule of thumb for automotive trailers apply to bikes? 10% of the weight of the trailer on the tongue?

Yes, the rule of thumb is 10-15% of the total trailer weight on the tongue for single axle trailers with a ball and coupler hitch. And yes, I have also found that to be true for bikes and trailers. It's not so pronounced with a shorter and lighter trailer, i.e. my golf clubs on my Burley Flatbed, but a long and heavy trailer, like a 14+', 100+ lb. loaded canoe, will have a much more pronounced affect on the bike, making it unstable even trying to ride a straight line on a flat road if the trailer is loaded wrong.

Now there are trailer hitches and there are trailer hitches, and what I have found is that a hitch that connects lower on the bike at the axle is inherently more stable than a hitch that connects to the seatpost. My Wike Woody Wagon that my canoe or kayak ride on connects to the seatpost, which makes load distribution in the trailer much more critical for an safe, stable and enjoyable ride.

But that's not to say there's anything inherently wrong with a seatpost hitch. I will tow, and have towed, my canoe 3- almost 20 miles to go hunting and fishing. I just distribute the load so it feels a wee little bit heavy on the hitch. It's one of those things that get easier with practice, (cooler goes here, backpack goes here, shotgun goes here, anchor goes here, fishing rods go here, etc.) so play around with it a little bit.

Exactly, had the pavement not been wet, the wheel wouldn't have locked up so easily. If I skid these tires when the ground is wet, it can be hard to control the skid without the trailer.Add a loaded trailer and you have a jack knife.

You shouldn't have any issues.