Tire Pressure recommendation (2 Viewers)
- Thread starter terdrocket
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gaijin
GOLD Star
Since you are outside the USA, I need to confirm a few assumptions to assure the RCTIP is correct.
I assume you mean the LT285/50R20 Load Range E tires, and that the stock tires for your vehicle are P285/60R18 114V tires with an RCTIP of 32psi Front and 34psi Rear.
If those assumptions are correct, then the RCTIP (Recommended Cold* Tire Inflation Pressure) for those LT285/50R20 tires on your 2008 LC200 is 54psi Front / 56psi Rear.
*According to Toyota:
Tire Pressure vs. Tire Temperature
Tire temperature is dependent on “cold” tire pressure, driving distance and speed, ambient temperature and road surface temperature. As the temperature of the tire changes, air in the tire expands and contracts, changing the tire’s air pressure. The cold tire pressure for all Toyota models will vary and will need to be adjusted accordingly.
“Cold” tire pressure, as shown on the tire pressure label on our vehicles, is generally considered to be the pressure in a tire that has not been driven in the past 4 hours and has been parked outdoors.
HTH
I gotta ask... what is the justification for that high of pressure? Is it because of the thin 50 sidewall?
My Ram was around 9.300 lbs and I ran it at 55 summer, 35 winter on AT3W E. Even at 35psi, the inflation was adequate for the weight and there was no heat build up from flex. Those tires had even wear and were replaced at 45k miles with 11/32 remaining tread. At 35 there was a slight fuel penalty, but the gain in winter traction made it worth it.
My Ram was around 9.300 lbs and I ran it at 55 summer, 35 winter on AT3W E. Even at 35psi, the inflation was adequate for the weight and there was no heat build up from flex. Those tires had even wear and were replaced at 45k miles with 11/32 remaining tread. At 35 there was a slight fuel penalty, but the gain in winter traction made it worth it.
gaijin
GOLD Star
"The Book" says 30psi for an LX570 and 33psi for an LC200 - take your pick.
BTW, the Tire Pressure Calulator I recommend (TireSize.com) agrees with the 30psi RCTIP:
HTH
I would follow your gut here. I don’t think you should run a pressure lower than what the door frame says (most likely 33psi). No matter how the tire size changes.
According to the tyre pressure label it is 33psi for front rear. That being said is the RCTIP still remain 54psi Front/ 56psi Rear? Thank you.
gaijin
GOLD Star
Thanks for the additional info.
In view of that, the RCTIP is 55psi Front and Rear.
HTH
gaijin
GOLD Star
gaijin
GOLD Star
I need to see a picture of the TIP (Tire Information Placard) found on your driver's side door frame which shows the OEM tire specs with the recommended cold inflation pressures.
Then I can give you the RCTIP for those ISO-Metric 285/65R17 SL 116H tires on your LC200.
HTH
gaijin
GOLD Star
Got it!
The RCTIP for those ISO-Metric 285/65R17 SL 116H tires on your LC200 is 35psi F/R.
HTH
It’s almost like Toyota put the RCTIP right in his door jam.
Also, that TIP really throws a monkey wrench into the narrative of this thread. Lots of cool stuff to glean from it.
#1: Over 100mph (160km/h) use has a recommended tire inflation above the max ISO inflation pressure of 36PSI. (this doesn't really matter, but just pointing it out)
#2: Which of these lines do you decide to use for your RCTIP. The 112 SL @ 35PSI rating (2392lb) is far different than the 116 SL @ 35PSI rating (2668lb).
#3 Lets say you were looking for RCTIP for a P-Metric P285/70R17. For the new tire using the 116 lines would net a RCTIP of 31PSI, but if you use the 112 line it would be a RCTIP of 26 PSI.
I would argue both would be too low, and I think this card proves Toyota agrees.
From the TIP, Toyota obviously cares more about the inflation level of the tire than the load carrying ability of whatever the suggested PSI are. To prove that point further, we can look at just the tires on the TIP card. If we take the 116 rated tire as the baseline, then the Toyo pamphlet would say you can't even run the 112 rated tire on the same vehicle because the max load carrying ability is below the rated load of an 116 tire at 35PSI. If you flip it around and make the 112 the baseline, then the RCTIP for a 116 rated tire would be 30 PSI, which is clearly not how Toyota decided to rate it. They obviously feel that this platform of vehicle requires at least 35PSI, pretty much no matter what tire you run.
#1: Over 100mph (160km/h) use has a recommended tire inflation above the max ISO inflation pressure of 36PSI. (this doesn't really matter, but just pointing it out)
#2: Which of these lines do you decide to use for your RCTIP. The 112 SL @ 35PSI rating (2392lb) is far different than the 116 SL @ 35PSI rating (2668lb).
#3 Lets say you were looking for RCTIP for a P-Metric P285/70R17. For the new tire using the 116 lines would net a RCTIP of 31PSI, but if you use the 112 line it would be a RCTIP of 26 PSI.
I would argue both would be too low, and I think this card proves Toyota agrees.
From the TIP, Toyota obviously cares more about the inflation level of the tire than the load carrying ability of whatever the suggested PSI are. To prove that point further, we can look at just the tires on the TIP card. If we take the 116 rated tire as the baseline, then the Toyo pamphlet would say you can't even run the 112 rated tire on the same vehicle because the max load carrying ability is below the rated load of an 116 tire at 35PSI. If you flip it around and make the 112 the baseline, then the RCTIP for a 116 rated tire would be 30 PSI, which is clearly not how Toyota decided to rate it. They obviously feel that this platform of vehicle requires at least 35PSI, pretty much no matter what tire you run.
gaijin
GOLD Star
Since "this platform of vehicle" is the European Diesel version of the LC200, I agree.
HTH
So what PSI would you recommend if the previous poster would have asked for RCTIP of a P285/70R17 on that same European diesel model?
gaijin
GOLD Star
Interesting hypothetical, but it requires the assumption of some info you do not offer in your question.
The specifications for a P-Metric 285/70R17 list that size with a Standard Load Index of 117.
Since the OEM ISO-Metric 285/65R17 is shown on the TIP with a Standard Load Index of 116 at an RCTIP of 35psi, this calculates out to a Load Index of 2,668 pounds.
I would assume that the Load Index for the P-Metric 285/70R17 tire of 117 is for an XL tire (not SL) and that would be the best basis for RCTIP, so I would recommend an RCTIP of 39psi F/R.
Of course, I would like to see a real world example of an available P-Metric 285/70R17, and also clarification of whether the OP's truck has KDSS or not, before I would make any real recommendation.
HTH
I don't think P285/70R17s are that hard to find. The Toyo AT3, one of the more ubiquitous AT tires in existence comes in that size. It's also a size that is in the Toyo document's load tables. A quick check on TireRack's tire finder and there were at least 7 P285/70R17s currently for sale on their site.
What made you decide to use the RCTIP from Load 116 line on the TIP over the load 112 rated tire?
I'm not sure what having a truck fitted with KDSS has to do with anything. I would assume that would already be factored into the TIP recommendations.
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