I called the company who sells outlaw tires and he told me that there is a definate loss of power when going with 28 inch tires. He said it was the same with 27 inch too. Before I buy tires I would like the opinion of people who have larger tires on their rubi's. Is there a loss of power and if so is it that noticable. Is the trade off worth it? Is it better to have larger tires and less power or stock sized tires with more power? Thanks

 

I don't own a Ruby but there would have to be a loss of some power. Noticable in deep mud? It is on my SP500 with 27"'s. Noticable on hardpack? Not really.

 

When gaining weight by doing things such as bigger tires there will always be a loss in power. This is how engines work. When you have a pickup and load a full ton of stuff in the bed, there will be a loss of power. The front stock wheel mounted on stock aluminum wheels on my Rubi weighed in at around 21 pounds on my home scale. My 27x10x12 Maxxis Mud Bug mounted on ITP Steel weighs in at 39 pounds. So on the front alone, I would estimate that I am adding 36 pounds to my Rubi. I did not weigh the stock rear, but the 27x12x12 Bugs on ITP Steels weigh in at 43 pounds. Overall I would estimate that I added 70-80 pounds with my tires. Is this going to steal power.....OF COURSE. Remember the stock tires are 25 inches, narrow, low ply, and not a lot of tread. When you go with bigger mud tires you are adding wieght. If you think my numbers are large look into the Vamps....those are some heavy tires. Something that would help to alleviate this would be aluminum wheels if you have the money to fork over. This would save 28 pounds overall. In order to gain this power back you will have to do further mods. You are not going to run larger tires and not have some loss of power.

 

dont forget that a large portion of the power loss is from the step up in gear, ratio, when going to larger diameter tires, such as 27",28" it is harder for the motor to turn gainst the taller gear.

 

Technically, you are not losing power with larger tires. You have the same amount of power, but it has to do much more work. (I know that is what the posts above meant, but just clearing it up for any newbies reading this) The posts above are correct, larger tires will add a lot of weight. Then you also have to figure in the fact that a larger diameter tire also effectivly raises your gear ratio.
So now you have more weight, plus higher gearing. This is double shot of power loss to the ground. You have to decide if this is a good trade off or not.

P.S. Something many people forget to think of, is that the heavier tires will also strain the driveline. This is another concern you have to consider when going to larger tires.

 

Boots: Also think of the fact that your warranty is voided by doing any such modifications.
I was talking to the mechanics at Larsons in cambridge and they were telling me of a new Ruby that tore up the rear differiential by using the larger tires. I can't say what size was being used but I would guess it was extreme. Also I can't say how it was done, just that the guy had to pay out of pocket for the repairs.
I am going to raise my Rancher ES 4x4 a couple of tire sizes next year. (After the warranty runs out!) But I will save up for the aluminum wheels and get mfg. specs. on tire weights before deciding on which tire to buy.
Like the Honda guys said---the machines are designed to run on stock tires. However I think its a small worry if you are smart, and the added clearance + traction is well worth it.
Good luck.

 

Two words: LOW RANGE

My dealer has been selling new Foremans, for several years, with larger than stock Vampires with no effect on warranty. Depends on the dealer, apparently. But, if you are apprehensive about running a larger tire, then, by all means, don't. A winch would always be a great investment, with larger tires or not. Also, not knowing what the guy actually was doing when the rear end broke means he could have been jumping it like a 400EX. Anecdotal evidence is kind of hard to go by.

 

Texdoc: I agree, ancedotal info IS hard to go by. I was trying to make the point that one should check with the dealer and see if mods will void the warranty. Guess you made the point more succintly.
The winch is the first mod I would go with. Only makes sense to be able to get yourself out of trouble...knowing one would get there with mud tires !!!!!

 

It does depend on the dealer. That's why I drive almost 40 miles to a dealer that will work with me, instead of going to the one that is only 5 miles away.

 

I have 27x10x12 Vampire's on the front and 27x12x12 Vampire's on the rear of my Rubicon. I drove it stock for about a week before making this modification. I haven't noticed any significant loss of power, if any at all. I did however mount the Vampire's on ITP magnum billet aluminum wheels to help a little w/ the weight. I don't regret doing this at all. It has more than enough power, for what I use it for.