Switching 8" to 12" Tires - Will they fit??

[catfighter]

I've decided to switch from 4.80x8 to 12x5.30 on my trailer, since much of my driving is at 60+ mph on the interstate, and also because my outboard drags if I forget to tilt it when taking it in/out of the water.

So here's a picture of my trailer with a 12x.530 next to the 4.80x8




NOTWITHSTANDING that the tire needs inflating and that the bolt pattern is wrong, do you think these will fit? They look like they will to me, but I don't want to be stuck shipping $180 worth of tire back to the manufacturer. . . .

 

[Maclin]

Re: Switching 8" to 12" Tires - Will they fit??

Fender clearance could be a problem. Looks like if you do need to move them there is not much clearance to the boat hull for a re-position.

 

[batman99]

Re: Switching 8" to 12" Tires - Will they fit??

.

To verify bolt pattern of old and larger rims, simply download the bolt pattern template, cut out the holes and hold up to each rim. re:

http://www.trailercanada.com/pdf_documents/boltcircletemplate.pdf

If unable to find rims that fit your trailer's existing hubs, one might be able to buy new idler hubs - with proper bolt size (for larger size rims). Before buying, do "double/triple" check seal, inner and outer bearing sizes. Not all hubs of the same bolt pattern are the same.

For more fender spacing.... If axle is currently bolted above (ontop) of leaf spring packs, simply unbolt the axle and install "under" the leaf spring packs. This often creates a 3-5" chassis lift. re: Thickness of axle + leaf spring pack thickness. If you need more lift (for tire / fender clearance), do investigate longer shakles as well.

And as another plan, one can buy/install a new axle - with hubs that fit your larger wheels. New axle might be needed if current axle is too rusty....

Hope this helps..

 

[JB]

Re: Switching 8" to 12" Tires - Will they fit??



I made that change on Sunshine III's trailer, catfighter. It worked out very well. . .but. . .

My replacement rims had the same 5 bolt pattern as the 8" rims.

 

[bonz_d]

Re: Switching 8" to 12" Tires - Will they fit??

Can it be done? Sure. Can it be done easily? Maybe not.
Maybe a 4:80X12 would fit easier.

 

[vintageglass]

Re: Switching 8" to 12" Tires - Will they fit??

Another option is to go to 5.70x8" tires and keep your rims, you would gain roughly 2" of diameter to lower bearing speed on the highway.
I've done the swap on several of my trailers, some had 8" wheels, some had 12" wheels from the start. I usually run a slightly heavier 5.70x8" tire if I feel I need more capacity.

By comparison the overall diameters are as follows on most brand tires:
4.80x8 - 16.1"
5.70x8 - 18.1"
4.80x12 - 20.5"
5.30x12 - 21.9"

 

[catfighter]

Re: Switching 8" to 12" Tires - Will they fit??

Interesting! I'm wondering if 4" more clearance is the way I want to go. . . I'm thinking not.

I like that I can launch virtually anywhere -- especially in places where others see me do it and fail -- and ask me to help them out of the muck. :facepalm:

 

[Maclin]

Re: Switching 8" to 12" Tires - Will they fit??

Keep in mind the radius and not diameter is the measurement to look at for clearance or leverage.

 

[catfighter]

Re: Switching 8" to 12" Tires - Will they fit??

I just ordered two 5.70x8 wheel/tire combos. that's going to give me a couple more inches of clearance and also give me 10% more circumference, not to mention another couple hundred lbs of capacity (i.e. less stress on the tires).