Smaller tires for 10 inch wheels?

[Titanium48]

Are there any tire sizes for 10 inch wheels other than 20.5x8-10 (aka 205/65-10)? I'm thinking of something like 18.5x6.5-10 (165/65-10). These would be the same diameter as the relatively common 5.7-8 size, but would fit over 7 inch brake drums. I'm currently running 5.3-12 tires on 12 inch wheels but I would like to lower the trailer in order to make launching and recovering easier and reduce wind resistance while towing. I've already reduced the space between the hull and the fenders and between the fenders and the tires to a minimum (2 and 2.5 inches respectively), so the only way to lower it further would be to use smaller tires. Unfortunately, 8 inch wheels won't fit over the brakes and 20.5x8-10 aren't much shorter than the 5.3-12, plus they're too wide for my fenders anyways.

 

[Silvertip]

Re: Smaller tires for 10 inch wheels?

You really need to pay attention to the load rating of those tires as you move from one type and size to another. Not paying attention may result in overloading the tires. As for smaller diameter tires making it easier to tow the trailer may work against you. A larger diameter tire rolls easier than a smaller diameter tire. Wind resistance can be countered by slowing down and covering your boat.

 

[Titanium48]

Re: Smaller tires for 10 inch wheels?

A 900 lb load rating would be sufficient - it's a 14.5 ft with a 70 hp outboard, about 16-1700 lb fully loaded. A lot of things max out at 2000 lb (axle, hitch, tow vehicle), so anything over 1000 lb would be overkill. The 16.5x6.5-8 size seems to be fairly common and is rated for 785 lb in LRC and 910 lb in LRD, so I'd expect a 18.5x6.5-10 (same tire cross section, bigger wheel) would be around 900 lb for LRC and about 1050 lb for LRD. If it exists, that is.

I did have a travel cover and it seemed to help a bit, until I either tied it down too tight or not tight enough (not sure which) and it shredded in the wind. As for slowing down, even the transport trucks do 105-110 km/h (65-70 MPH) around here and going any slower tends to cause traffic jams.

 

[mthieme]

Re: Smaller tires for 10 inch wheels?

How about a dropped axles instead?
They run under $150

 

[reelfishin]

Re: Smaller tires for 10 inch wheels?

You may find that the only tires in that size are not DOT approved or in other words only meant for things like go carts and garden tractors.

The drop axle idea is your best bet, larger tires mean lower bearing speeds as well.

 

[Silvertip]

Re: Smaller tires for 10 inch wheels?

What are you towing this trailer with? That light load should make hardly no difference regardless what you change -- unless you are towing with a Yugo!

 

[Silvertip]

Re: Smaller tires for 10 inch wheels?

That light load should make hardly no difference regardless what you change -- unless you are towing with a Yugo! Covers need to be snuggly fitted and they must be prevented from billowing. Any flapping will destroy them.

 

[HappierWet]

Re: Smaller tires for 10 inch wheels?

What lug pattern is it? How much Back Spacing do the existing rims have? We have converted 4 trailers to date; three boat trailers and one chopped up mobile home trailer. It takes some measuring and then some looking around. To date we have used the rims from; a mid 80's five lug jeep( the larger lug pattern.. 5 1/4 or 5 3/4 ...I forget), the six lug chevy toyota pattern, the five lug pattern off Ford's ranger or broncoII, and the four lug pattern off Ford mustang. The price is usually right at the local scrap yard, and we've gotten some nice rims. They ride better too. Auto tires usually have a better weight capacity than trailer tires but cost more.

 

[AZMinyard]

Re: Smaller tires for 10 inch wheels?

A 900 lb load rating would be sufficient - it's a 14.5 ft with a 70 hp outboard, about 16-1700 lb fully loaded. A lot of things max out at 2000 lb (axle, hitch, tow vehicle), so anything over 1000 lb would be overkill.

Um . . . check your math. Each tires rating should exceed 60% of the gross weight for safety. 1700x0.6=1060. You want at least that load rating. The level of discomfort that you are experiencing while driving could really be related to the tow vehicle max capacity (2000lbs) being so close to the weight of your load (1700lbs). Sounds like a light vehicle being pretty much maxed out.

As for slowing down, even the transport trucks do 105-110 km/h (65-70 MPH) around here and going any slower tends to cause traffic jams.

Most trailer tires are not rated for speeds over 65 mph. Higher speeds mean higher heat and revolutions . . . you?re looking towards tread separation, especially if not properly inflated . . .

Just a suggestion here - but how about posting some pictures of your set-up (from all important angles ? axle, bunks/rollers, bow, TV, fender clearance, etc), explain why you really want a lower launch angle and let the guys with years of experience and creativity give you some ideas. You might also include your experience level with launching boats, not to offend, but no amount of equipment will make a beginner an expert.

My last two cents ? 8 inch tires heat up way too much, 10 inch tires are way too expensive. If you have 12 in on a 5 lug rim you have the most common and cost effective tire out there ? stick with it.

 

[AZMinyard]

Re: Smaller tires for 10 inch wheels?

Auto tires usually have a better weight capacity than trailer tires but cost more.

Whew . . . did you ever just open a can of worms . . .

Before looking at this, please search the forum for trailer tire v. automotive tire discussions . . .

 

[HappierWet]

Re: Smaller tires for 10 inch wheels?

Lots of good opinions on this site. ALWAYS nice to see other people's thoughts.

 

[Titanium48]

Re: Smaller tires for 10 inch wheels?

Um . . . check your math. Each tires rating should exceed 60% of the gross weight for safety. 1700x0.6=1060. You want at least that load rating. The level of discomfort that you are experiencing while driving could really be related to the tow vehicle max capacity (2000lbs) being so close to the weight of your load (1700lbs). Sounds like a light vehicle being pretty much maxed out.

Good point, safety margins are good things. I wouldn't say I was experiencing discomfort while driving though. Yes, I am towing my boat with a car, but the setup is stable in the wind and when passing oncoming large trucks on undivided highways. I was just hoping to avoid having my fuel economy drop from 35 MPG to 20.

Most trailer tires are not rated for speeds over 65 mph. Higher speeds mean higher heat and revolutions . . . you?re looking towards tread separation, especially if not properly inflated . . .

Don't all tires have to have a minimum M speed rating (130 km/h, 81 MPH) to be DOT approved?

Just a suggestion here - but how about posting some pictures of your set-up (from all important angles ? axle, bunks/rollers, bow, TV, fender clearance, etc), explain why you really want a lower launch angle and let the guys with years of experience and creativity give you some ideas. You might also include your experience level with launching boats, not to offend, but no amount of equipment will make a beginner an expert.

My last two cents ? 8 inch tires heat up way too much, 10 inch tires are way too expensive. If you have 12 in on a 5 lug rim you have the most common and cost effective tire out there ? stick with it.

Points taken. Launch and retrieve has become less of an issue since I installed the extendable tongue (see here) though. It would be nice to keep the car a bit higher up the ramp, but it is workable the way it is.

How about a dropped axles instead?
They run under $150

I could go that route, but to lower the boat without reducing the tire diameter I would have to widen the subframe enough to allow the hull to sit between the fenders. It wouldn't be that difficult and it might make things even more stable, but I don't think it would help the aerodynamics, as the trailer would then be wider than the tow vehicle.

 

[AZMinyard]

Re: Smaller tires for 10 inch wheels?

I was just hoping to avoid having my fuel economy drop from 35 MPG to 20.

Lowering the boat won't really do that much to help your gas mileage, it's the added weight to engine ratio that is getting to you. Big boat to be pulling with a car.

Don't all tires have to have a minimum M speed rating (130 km/h, 81 MPH) to be DOT approved?

No. Passenger car tires, yes. All ST (standard trailer or specialized trailer) have a maximum speed rating of 65 mph.

From Discount Tire:
"All "ST" tires have a maximum speed rating of 65 mph. As heat builds up, the tire's structure starts to disintegrate and weaken. The load carrying capacity gradually decreases as the heat and stresses generated by higher speed increases"

This is why you don't want just 50% covered by each tire. You need a minimum of 60% coverage - its not a safety margin, its safety period.

 

[steelespike]

Re: Smaller tires for 10 inch wheels?

There is a 480 X 12 tire that would get you about an inch.Would also allow a lower fender.
As far as a cover maybe it would help but might act like a flag creating drag.A while ago Myth busters did a test on a pickup with gate open or closed to save gas.Turns out closed was signifigantly better.Apparently building a cushion of air in the box forming a sort of fastback effect.Its possible the boat might work the same way.