speedometer adjustment

[CLABORN1960]

I went with wider tires on the rear (315/35/17), will the speedometer need to be adjusting? With this wheel and tire package I cannot believe I am going as fast as the speedo readout..... this morning to work I am cruising along and the speedo is reading 89 mph and I am like, "no way..." So its either the quality of the new tires or the speedo is off.... what do you think?

 

[JEFNLSA]

According to this DT tire calculator, when your speedometer reads 65mph w/ the stock 285's, your speedometer will read 64.25mph w/ the 315's. Not much of a difference at all.

link

 

[CLABORN1960]

According to this DT tire calculator, when your speedometer reads 65mph w/ the stock 285's, your speedometer will read 64.25mph w/ the 315's. Not much of a difference at all.

link

thanks.... I stumbled across a similar calculator while I was waiting for responses.... so its the tires... feels like I am flying....

 

[jrzvette]

I went with wider tires on the rear (315/35/17), will the speedometer need to be adjusting? With this wheel and tire package I cannot believe I am going as fast as the speedo readout..... this morning to work I am cruising along and the speedo is reading 89 mph and I am like, "no way..." So its either the quality of the new tires or the speedo is off.... what do you think?

The width of the tires has no bearing on the speedo reading, it's the diameter or circumferance of the tire.

 

[JEFNLSA]

The width of the tires has no bearing on the speedo reading, it's the diameter or circumferance of the tire.

Yes, I agree and I assume he's aware of that, but he did go from a 40 to a 35 on the rear...hence the minute difference in the speedo reading.

 

[CLABORN1960]

The width of the tires has no bearing on the speedo reading, it's the diameter or circumferance of the tire.

it had a slight bearing on the reading... but not enough to warrant adjustment..... thanks for the feedback....

 

[CLABORN1960]

Yes, I agree and I assume he's aware of that, but he did go from a 40 to a 35 on the rear...hence the minute difference in the speedo reading.

yep I am aware, I think the combination of the quietness of the new tires and the perception of speed made me wonder if the speedo was off...