tandem or triple axle?

LiquidWrench

Member
Sep 6, 2014
96
Marco Island, FL
Boat Info
1972 SRV 240 weekender, 1980 260 Sundancer
Engines
Mercruiser 888 (240), Twin 470's (260)
I am going to be building a new trailer for my 80 260 DA. Sea Ray specs say the boat is 5500 lbs empty so I will have to either go with 3 axles or 2 heavier axles. Right now I am leaning towards triple axle, mainly because I am planning a move to florida and I know that 3 axles will make it ride much better going that far. What do you all think that have experiece with both?
 
I'm a fan of tri-axles, even on a smaller, lighter boat. I had a Eagle tri-axle built for my 270 Sundeck. The original reason I did that was that I wanted to keep the boat as low as possible to get it in my shop. With the 3 axles I used 14" tires plus the difference in spring height got me a couple inches lower.

My boat weighed a couple hundred more than yours. The boat pulled so smoothly and with brakes on all axles stopped well. It's a noticeable difference. Whatever you do, don't design your trailer to the limit on tire capacity. I think that's the main cause of a lot of the nightmare stories we hear with tires.
 
I have a tandem 10,500lb aluminum w/ 15" tires. I like it due to 2 less tires, wheels, bearings, etc.

Bennett
 
If can go triple do it. I towed this 7,700 lb beast from Austin Texas t San Diego with triple Sea Hawk Aluminum trailer. 14 inch tires, Kodiak brakes on front two axles. A lot of greasing of bearings and crossing fingers. The 270 is 10 foot beam so don't even want to go into the various states oversized load rules!
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I do agree with the extra maintainence on 3 axles as opposed to 2 but I think for piece of mind I am going to go the tri setup, benefit I already have 2 axles and a third is pretty easy to come by. The trailer will be built with Glen-L plans which are pretty close to a couple of productions trailers. I will be using drop axles as well as 14" tires to keep it as low as possible.
 
I converted my tandem to a tri-axle because the weight capacity wasn't there with two 3500lb axles and a 270. To me, it was a good choice for more than just capacity. I can back into the smaller launches and keep most of the wheels on concrete and not falling off the edge and also have a easier time on softer ground from the larger foot print. Six wheels also reacts nicer when going through rough ground like big potholes or the curb at the end of my driveway. When it happens, the boat slightly rocks to the side and doesn't pound out the suspension. I have yet to have a flat at speed, so I cannot comment on the better handling in this situation. I guess the only drawback is the tire scrub on corners. Btw I only have brakes on two axles, which is still law abiding in my area.
 
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I converted my tandem to a tri-axle because the weight capacity wasn't there with two 3500lb axles and a 270. To me, it was a good choice for more than just capacity. I can back into the smaller launches and keep most of the wheels on concrete and not falling off the edge and also have a easier time on softer ground from the larger foot print. Six wheels also reacts nicer when going through rough ground like big potholes or the curb at the end of my driveway. When it happens, the boat slightly rocks to the side and doesn't pound out the suspension. I have yet to have a flat at speed, so I cannot comment on the better handling in this situation. I guess the only drawback is the tire scrub on corners. Btw I only have brakes on two axles, which is still law abiding in my area.
Can you tell me what size I beams you have for your 270 trailer? I am trying to decide on a trailer for my 240 and need a bit more load capacity than the 2 3500# axles as well.
 
Whether you go two or three axles, make sure your weight carrying capability is neither too big or too small. If it's too big, the weight of your boat won't compress the springs enough and the boat will get a very hard ride that could start shaking things loose. If your trailer's capacity is too light the boat will beat the heck out of the suspension.
 
My trailer beams are 3" x 5" galvanized square tubing, 1/8" material I think?
 
I only read about a third of it, but it seemed like a bunch of nonsense to me.:smt001

If you read every third letter and every fourth number it gives you the secret to great riches. Or maybe it's just gibberish. :huh:
 
I ended up building a tri-axle trailer. Frame was built from 6" C-channel with 4" C-channel cross members. From my figures the boat fully loaded weighs about 7000 Lbs. The trailer came in right about 1500 Lbs. Gross rating of the trailer is 10,400. Got the bunks set up with a tape measureand the boat fit perfectly. Towed it 1500 miles to Florida and other than the weight you wouldn't even know it was back there, even on rough roads.
 
I had a tandem axle galvanized trailer for my 82 260 SXL and it was adequate for that boat. I currently have a triple axle aluminum I beam trailer for my 300DA and, as you said, you hardly know its back there. I think the third axle gives a nicer ride, albeit at the expense of another set of tires, brakes and bearings to maintain. Everything is a trade off and I think you made the right choice.
 
I see LiquidWrench already went with the triple axle. I just wanted to add my opinion for anybody else reading this thread. I also would go for a 3 axle. I have a 3 axle RoadKing for my 270DA and I really like it. I can run over curbs, through potholes, etc and it hardly upsets the boat. Down the interstate it tows so straight and smooth. My trailer is overkill for my boat, it has 16" wheels and rated for 18k lbs gross. I wouldn't trade down to a smaller size trailer even for the gain in less maintenance or less tire cost.

I did lose 2 tires last year at different times on our awesome 200 deg black asphalt. If I hadn't seen the tread go in my rear view I might have confused it for running over a rut in the road. I slowed down to 60mph and was able to maintain speed on the interstate for several miles until I made the next exit into a service station parking lot, it was straight forward and uneventful. My last boat, a baja, had a twin axle trailer and I had a blowout once with that trailer. I had to stop immediately on the shoulder in a high traffic area of the interstate in the middle of a city. It was pounding the boat and jerking the tow vehicle.
 

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