Ok, I am starting this thread because I have seen some other threads talking about how you lose top end speed when you put bigger tires on. I recently put 27" ITP 589 M/S tires on my Grizzly and here is what I found.
With the stock tires, the speedometer read about 63 MPH but my GPS told me I was going 58.2 MPH.After I put the 27" tires on (2" larger than stock) my speedometer read about 57 MPH but my GPS told me I was going 57.4 MPH.

The larger tires cause the speedometer to read at a slower speed (closer to actual speed) but the actual speed does not differ much. (Less than 1 MPH.) You do lose low end torque though. I find it is harder to pull wheelies now and I have to use low gear more in the deep mud.

Has anyone else run any similar tests? Let me know if you had the same results...

 

Never have run mine with 27's and GPS'd it, but you're right on.

 

I could notice a difference with 26" mudlites on my 05, I can't do flat ground wheelies but I can with stockers. Speedo reads 67stock and only about 52 with 26's. Less low end power. Mine only has 21 hours on it. Just dropped off at the dealer today for 1rst service. Been told by some forum members it should do better. I told them I would post results of dealer service (adjust valves,check float setting) after it's done to see if either of these 2 things might be affecting power. Look for my original post "Slow 05 Grizzly?" on Sat. or Sun. and I'll let everybody involved know results. [img]i/expressions/face-icon-small-smile.gif[/img]

 

I did the same test as Grizzlyadams with about the same results. I lost 1.2 mph by my gps. Where I did notice the loss of power was the bottom end. I fixed that when I installed the clutch kit and the exhaust

 

I had the same results on my Grizzly, my speedometer read lower after I installed a set of 27" Mudlites but matched my GPS nearly dead on. Speedometer reading of 57 Gps reading 57.6 where I would read 60 on speedometer with stock tires at same speed.

I do not have any experience with clutch kits. What do you gain with the clutch kit?

 

hey dont anything you should wait for it to break in and you probley get allot more power low end not sure on top end though. My friend did the same thing as you and when it got about 500 hours on it he got more low end power.oh well good luck with you new grizz

 

Hey Sparky660, did you lose top end speed with the clutch kit?

I noticed that my top end speed is lower than when it was new, but I think it is because I need a new belt. The belts aren't cheap though so I am going to put it off.