Big Tires pulling Small tires.
A friend of mine asked me a question that I could not answer about his tires and towing. He has a small trailer weighing about 300 lbs unloaded and can carry up to 1000lbs total. Now the trailer has 1...
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rlw999 wrote:SweetLou wrote:
A friend of mine asked me a question that I could not answer about his tires and towing. He has a small trailer weighing about 300 lbs unloaded and can carry up to 1000lbs total. Now the trailer has 13 inch wheels on it and his truck is a Dodge with 17 inch wheels. If he is going 60 mph, how fast do you suppose his 13 inch wheels are going? I suspect he means revolutions but you get it. He wasn't sure he could go that fast or faster in fear of burning up the trailer bearings. I really could not answer his question other than to say get them greased with good grease and try it out. Stop every 10-20 miles and see how warm they get. Of course I told him to put some weight in it as well to simulate the trip load and see. Anyone else know how to answer him?
265/70R17 tires have a diameter of around 31 inches, 185/80R13 have a diameter of around 24".
Circumference is diameter * pi, or 97" for the 17" tires and 75" for the 13" tires, so the 13" tires will be spinning 97 divided by 75, or 1.3 times faster.
At 60mph, the 17" tire will be spinning at around 650rpm, and the 13" will be spinning around 850 rpm.
But I'm not sure that really helps answer your question since I haven't seen an axle rated in RPM or max speed, just weight limit. As long as it's rated for road use (and isn't, say, an axle meant for a garden tractor), I'd think it'll be ok at normal street speeds... but I've seen some utility trailers with a 45 mph max towing speed.
The little wheels spin faster, no doubt. But the bearings are designed to let the wheels spin, so if serviced properly likely not a issue. The tires are likely rated for lower speed, so that will be a issue.
As for the " some utility trailers with a 45 mph max towing speed." I have only seen that on rental trailers. I don't think it has much to do with the construction of the trailer, but more to do with reducing the chance of liability. The rental companies understand the average motorist has no understanding about how a trailer will effect how the TV handles.
