[dtotino]

hello,
I just upgraded from the stock 16" on my 2016 3 hatch to 18"s and I was wondering if I am supposed to keep them at the same tire pressure I used on the old rims (34-36) or am I supposed to change it based on tire size? I have dunlop sp sport 5000 on them that are 215/45R18 89w. let me know asap cuz I dont wanna be driving around with my pressure wrong.
thank you so much for any help. it is really appreciated!

 

[arathol]

First, this is a g rated forum, watch the language content.

As to the tire pressure, use whatever it says in your manual, sec 9-11, ie 36 psi.

 

[rob342]

what does it say MAX on the tire? i usually start just a hair under the max pressure printed on the tire and measure tread depth with my depth micrometer occasionally.

i'm always OVER the recommended pressure though, right around the max on the tire usually. i don't mind a slightly harder ride, i like the added MPG, and since my driving style is "kinda sporty" i wear the outer edges off the tire pretty quickly using recommended pressures.

depends how YOU drive. try a depth micrometer. since you're measuring to the .001" you can tell if they're wearing evenly within a couple weeks and before any real wear occurs

 

[arathol]

Never run a tire at the maximum pressure stamped on the tire unless the manual says that is the correct pressure. That number is just the most pressure the tire can safely handle under load. Always use the pressures listed on the door jamb. If your car says 36 psi and the max on the tire is 55, your car will ride like a truck, tire wear will be uneven, susceptibility to damage is increased and handling may be compromised.
Read your owners manual, follow what it says.

https://gov.goodyear.com/docs/police/bulletins/psb2015-25-tire-inflation.pdf
https://info.kaltire.com/the-right-tire-pressure-why-the-maximum-isnt-the-best/

 

[dtotino]

First, this is a g rated forum, watch the language content.

sorry about that I wasn't aware.

what does it say MAX on the tire? i usually start just a hair under the max pressure printed on the tire and measure tread depth with my depth micrometer occasionally.

its strange because it says max press: 51PSI but then on a warming around the outside of the tire it says: never exceed 40 PSI. look at the attached picture you can see what I' m saying.

I think I am just gonna run them at 36 for now and see how it feels.

thank you guys so much for all the help.

 

[arathol]

You certainly don't want to run it at 51 PSI, the car will ride horribly.
If you read what it says in its entirety, that 40 PSI is for seating the bead when mounting the tire, not operational pressure.

 

[rob342]

just FYI it says never exceed 40 to seat the bead. that is a warning to the tire installer meaning if the tire isn't seated by the time you reach 40psi, use lube and try again or you'll risk damaging/deforming the tire

lol.. tree'd! he's QUICK!

 

[dtotino]

gotcha makes sense.
just inflated to 36 gonna test drive for a bit. might bump it to 38 or 40 for a little stiffer ride. I shouldn't have any problems at 40 right?
thanks

 

[arathol]

The OEM Dunlops have a well deserved reputation for being crappy tires. They might get a bit squirrely and you may lose some grip on wet roads if over inflated. It should not be a huge problem as long as you don't mind feeling every bump in the road. I'd keep them at 36 psi like the door placard says though.

 

[dtotino]

The OEM Dunlops have a well deserved reputation for being crappy tires. They might get a bit squirrely and you may lose some grip on wet roads if over inflated. It should not be a huge problem as long as you don't mind feeling every bump in the road. I'd keep them at 36 psi like the door placard says though.

ok will do thanks