Hey Guys, I'm new to the forum. I have a 2005 400 semi manual cat atv and was looking to upgrade my tires and wheels. I am looking at a set of 27 X 10 - 14 front and 27 x 12 - 14 rears. ITP rims with Mud Lite XL's. My question is whether there is any adverse affects on the drivetrain going that big or any negatives with regard to handling. I wasn't sure if I should go with 26's or what. I'm pretty much an idiot when it comes to this stuff, so any help or suggestions would be greatly appreciated. Thanks in advance.

I wouldnt recommend going with 27s on a 400 manual as they are really high geared
and the reverse is geared the same as high range, i would not go any larger then 26s
and find a tire as light as possible, like the Zilla/Mudlite.

the 400s are 3.6 gear, but yes the reverse is 3.1 ratio. There is a fix for the reverse to make it 3.6

Look up reverse cam.

What type of riding are you doing, are you using the bike for work on a farm or are you just using it as a toy for riding trails and a little mud, or are you trying to see how well your cat can swim.

All of these things effect the type of tire. Considering your looking @ 27inch mudlite xl's i am betting your doing a decent amount of mud.

Now if that is the riding you are wanting to do, you can take and make that 400 turn 30inch silver backs. Do a little clutch work, adding a heavy wet spring will give you a much higher rpm engagement.

To make up for the heavy tire, you can do a stealth snorkel and do the exhaust mod. Exhaust mod is free, and stealth snork wont cost you much. Also you can do the reverse cam for about 50 bucks. This winter i am planning on doing mine, when i am not needing my cat every day.

When you do the intake and exhaust mod's you will want to rejet. I am not sure on jet size, i know there are several kits.

Also while you are doing the jets, do the carb slide mod, and clip 4 springs. Just use the search bar @ the top of the page and look for carb slide mod. That is also free. Unless you are wanting to go really hardcore that should give you all the power you want for under 100 dollars. Mabey a little more with the carb jet kit as i dont know what they cost off of the top of my head.

Talk to taker, he has one of the baddest a**** 400s i have seen.

I appreciate all of the info guys. I should have been more specific in the type of riding I do. I would say I do about 85% trail and 15% mud. I live in Florida so there is no climbing or hills or obviously snow. Does that change anyone's suggestions? Thanks again!

Your handling will improve over stock. As for negative effects i dont know, might be a little more sluggish comming off of the line but i think you will do just fine. You can always ride in low range if you need.

I know your Cat is manual, but we put 26" Swamplites on my wifes 05 400. She liked it much better than the stock 25's. We didn't change the wheels, just bigger tires. After it was all said and done, she said that she wished we had gone with 27's. You might ride harder than her, she just likes to play in the mud and uses low range a lot. It definitely rode better with the larger tires.

Thanks everyone. Ok so still assuming I'm an idiot. if I went with 26's or 27's should I go with 12's or 14's? What's the downside. I really don't want to do any mods right now, but I may take nwgunner's advise and do a couple of his suggestions down the road. Sorry for all of the questions, but seriously thank you all for your help.

14inch rims have less side wall for the tire. Meaning the tire is going to be a lot stiffer allowing you to run lower pressures with out having to worry about rolling a tire off of the rim.

14" rims have some disadvantages too...

1. Less sidewall means your rim is 1" closer to the ground (rocks, roots etc)

2. Less sidewall means less sidewall flex which means less "tire wrap" around rocks and roots (imagine 2 guys in 4x4 pickups one with 20" rims and one with 16" rims driving through a boulder field....)

3. Less sidewall means less initial shock being absorbed by the tire when you hit a 5" root at speed...

4. Less sidewall/more rim means less volume of air for anyone under the illusion that ATV's are boats.

5. Less sidewall means a smaller contact patch when aired down...