Slicks and Trap Speeds?

[Eden]

Will a switch from street tires (radials, 34 psi) to MT ET streets at 14 psi cause a "loss" in trap speed? My friend is seeing 2 mph slower with the slicks (but running quicker, of course). Thanks.

 

[V6POWER]

My understanding is that since you get to the end of the track quicker, your mph will be lower.

 

[microELVIS]

If the tires are shorter, then that will also cause a loss in mph

 

[Eds87GN]

There's alot less rolling resistance in a tire with 34# than a tire with 14#. That's why you can put more air in the front tires and pick up mph.
Add up the small amounts of mph lost already mentioned by the other replys plus rolling resistance, it could be a few mph.
Think if you had to push that car through the quarter mile, would you rather the tires have 14# or 34#?