Hydroplaning

I've owned a 2nd and 3rd gen Tacoma and I've noticed that the 2nd gen is WAY more susceptible to hydroplaning than my 3rd gen. Does anyone know why? Both trucks had similar tires with plenty of tread and inflated to 40 psi. 2nd gen is an SR5 Access Cab, 3rd gen was a TRD OR Double Cab. The weight of the trucks is only a few hundred pounds different, I wouldn't have expected it to make that much of a difference. I'm curious if anyone has noticed the same thing.

 

Do you have identical tires on both trucks?

 

maybe aerodynamics not producing as much downforce on the 2nd gen? that'd be my best guess

 

40PSI seems high? For what tire size? Door placard should be 29front/32rear

 

Slow down...

 

it's a fluke, or a difference in tires.

 

hydroplaning really only is affected by tire footprint, alignment accuracy, and the amount of weight pushing down on the tires to the pavement.

 

Thats The Post of The Day right there...

 

Well, placard is 46 PSI for the Pro because it comes with LT tires. So 40 PSI can be entirely appropriate, even with stock size tires if they are LT instead of P.

Which is to say your question is spot on! Inflation matters a lot, and what it should be matters on the tire size (including whether LT or not).

Agree. My KO2’s left a lot to be desired in rain even with full tread.

So to the OP, details on exactly what tires and what sizes of those tires will help everyone let you know if you are getting the expected performance from the tires or if perhaps you’ve got an inflation issue making things worse.

 

Maybe the 2024 Pro, but not previous years. Same tires as the Off Road, same pressures.

But yes, using LT tires would require increased pressure (but not that much -- LT265/75/R16 requires 37 psi after conversion).

 

Ding, ding, ding… I think we have a winner!

 

I'll pile on.

It's the tires. Something was significantly different.

 

Even if running LT tires of the same size as factory p-metrics, why would extra PSI be needed unless one was actually hauling more weight?

Even if you account for the LT tires weighing more, that can't possibly account for an extra 1 PSI at each corner right?

 

I was surprised more PSI were needed in the LT, but I did some google searching and for whatever reason, more PSI is required. I didn't dig enough to find out WHY.

 

Determining the correct pressure is a bit convoluted. The goal is to get the new tire to support the same weight as what came from factory, so you first have to calculate that using the type of OEM tire and pressure from the door placard. Then you use tire charts (Toyo publishes some good ones) to figure out what pressure you need in the new LT tire to equal that. P-rated tires used on trucks are de-rated by 10%, which is what the Tacoma comes with, so you have to adjust for that -- many people don't and end up over-inflating LT tires.

Anyway, there's an online calculator that may not be entirely accurate, but it's useful for getting close.

 

Tires, tires, tires, it’s the tires stupid. I’ve seen this happen dozens of times, different tire, different tread design can equal hydroplaning. Had it happen to me twice. Had a set of KO2’s on my 4Runner several years that hydroplaned like a sob. Replaced them with a set of Hercules Terra Trac AT2’s, zero hydroplaning, hard to break them loose in the rain.
The statement similar tires means nothing. Similar is not same.

 

No, that is incorrect, the 2014 and 2015 TRD Pro and Baja came with port installed LT (not P) BFG KO Tires, absolutely NOT the same as the P rated tires on the Off Road. The Pro and Baja also had port installed updated placards for 46 PSI (note the placard specifies LT).



There was some discussion at the time that 46 PSI was still high, since if you compute from the load curves for LT vs P tires of that size you'd expect 40 PSI front and 43 PSI rear. One unsupported assertion was that this had something to do with the TPMS system, while others pointed out that the manufacturer is the one that determines the placard pressures based on a number of factors and the higher than expected pressure was due to suspension differences.

Regardless, the Pro and Baja definitely had different tires than the Off Road and definitely had different placard pressures.

EDIT: I should add, I don't know about earlier models - quite possible others used P - but the later 2nd Gen Pros did use LT.

 

He's got your answer right here:

Yep, this is the correct answer. From my calculation spread sheet the LT265/70R16 equivalent points on the load curve are 40 PSI front and 43 PSI rear (i.e. same as the P curve at 29 and 32 PSI). (EDIT: Tried out the nifty linked calculator and it came up with 41 and 44 PSI - so my spreadsheet doesn't suck too much apparently - thanks for the helpful link!)

So for the OP, if both tires are 265/70R16 but one tire is LT and one is P and you've got them both at 40 PSI that's part of your answer...

 

I did not know that, very interesting. The 3rd gen Pros came with the same P-rated tires as the Off Road. You don't hear much about 2nd gen Pros and Bajas, at least outside of the west coast anyway.

Anyway, 40 psi is way too high on stock P-rated tires.