My current tires and wheels are 215/55/16, I am getting my new rims with tires that are 205/40/17. I used the tire size calculator, and it says the speedometer reading is too fast. When I'm going 60, its actually like 56 or something. Is it dangerous to do this, because I also used the 1010tires calculator, and it said that using these tires can lead to brake failure. Is this correct? My friend is getting me 4 brand new Pirelli Z rated tires for $45 a piece, thats why I am asking.

 

thats a big difference i would not use them, try to stick to something pretty close to your stock size.

for example, stock 225/50/17 i now use 235/45/17, very little difference.

 

I guess I'll be goin with the 235/45/17

 

235 is not to wide, some will say it is, however a lot of people on the org. have 235/45/17's and have not had a problem.

 

How will the 205/40/17 tires hinder braking ability, or be dangerous? just curious

 

probably the abs sensors that calculate based on a certain diamater. big problem with lifted trucks if you don't update the ecu running tires 2x bigger than stock.