FWD Tire Pressure

[mechtech2]

I alluded to this in another section of BITOG, but this is the most appropriate place:

OK.
Ever notice how so many FWD cars have the door tire pressure spec LOWER for the front than the rear?
Even with 65% more weight on the front, and LOADS more when braking?
This makes no sense to me.
I jack up the fronts to at least the rear pressure.
Crisper handling, for sure. Better contact in rain, too. Longer tire life [less heat and distortion]

I believe mfrs want to avoid oversteer at all costs, they want the average civilian to have understeer.

Before anyone gets upset about outsmarting the mfrs ratings, note that spec'd tire pressures are a COMPROMISE, not Gospel rigid settings.

 

[JOD]

I agree. I always run about 2 psi more in the front vs. the back. The car feels like it handles better to me, and the tire wear is more even.

 

[Rand]

I have never owned a car that wasnt the same or higher front vs rear.
can you list a few examples ?

 

[eljefino]

My saturn SW1 calls for 4 extra PSI in the front. It still understeers.

Same car in SL2 trim, with a rear sway bar (and thicker front one) handles more neutrally. Still the same PSI bias though!

There's got to be a better way to make a car handle than having tires fold over and scrub off.

 

[SwampSurvivor]

I've never noticed a front drive car with less in the front. I usually run 2-4 more in the front.

 

[randomhero439]

Run what it says, plus 3-5lbs. You could set 35psi front, 32psi rear. Thats what my Accord is set at. Civic is 33psi/33psi

 

[Quattro Pete]

Originally Posted By: Rand
I have never owned a car that wasnt the same or higher front vs rear.
can you list a few examples ?

Both our cars recommend higher PSI in the rear tires.

 

[randomhero439]

Originally Posted By: Rand
I have never owned a car that wasnt the same or higher front vs rear.
can you list a few examples ?


Any BMW or Ferrari

 

[faramir9]

Originally Posted By: Quattro Pete
Originally Posted By: Rand
I have never owned a car that wasnt the same or higher front vs rear.
can you list a few examples ?

Both our cars recommend higher PSI in the rear tires.


Yes, but they are not FWD. I also do not recall seeing a FWD vehicle that specified higher pressure in the rear. My Saturn SL1---as well as my former SL2---specs 30 front/26 rear. My '04 Chevy Classic was 30 all-around; my ex's 2000 Dodge Caravan was 35 all-around.

I just set the tires today to 38/36. That's higher than I would normally go, but it's supposed to get much colder the next few days; I want to see how much pressure they lose. (Testing my fairly new H727 tires.) When I got them in early November, I set them at 35/35, then adjusted the rears to 32 after a few weeks. 35/32 is about where I will keep them most of the time, I reckon.

But anyway: Yes, please share a list of FWD vehicles that spec higher pressure in rear tires than front. Thanks.

 

[kr_bitog]

Can you list the sample for FWD cars with rear tyres pressure specs higher than front ?

 

[yonyon]

Lots of VWs out your way, then?

 

[johnachak]

My 06 Ford Freestyle. 32 f, 34 r, As per the tire plackard inside the drivers door.

 

[-SyN-]

The wifes new 2012 Edge FWD calls for 35 psi front and rear. I run 35-Front 33-Rear. Just put a 100lb sand bag in the back to help with traction for the winter. The Edge handles great with this combo.

 

[RiceCake]

Lower in the front would give you a more predictable grip profile, which in front wheel drive would be beneficial. High tire pressure on the front would make it more prone to sudden loss of grip (understeer) and for most people, likely sliding off an on ramp (etc).

That being said mine calls for 30/30 on the tire placard, but I run substantially more ... 44/44, to be precise (the tire rated maximum), which is rather high, but I should say I've yet to have any problems. Tire tread is perfect, tire wear is lower then before, fuel economy is good. The ride is harder (obviously) and the car corners pretty taught. It holds more grip but breaking loose into understeer in a hard corner can come with little warning beyond tire noise.

Also dialing back rear end tire camber coupled with high rear tire pressure has made the entire car feel a little more loose. Breaking traction in the rear only really happens intentionally (handbrake on wet pavement or a Scandanavian flick on snow). Independent rear suspension helps out a bundle with that.

But thats the way I like my car. I'd say for most people aside from the added vibration and tire noise, upping your pressure by as much as ten additional PSI is probably totally fine. You'll never really notice the difference in traction in everyday driving. It should make the tires run cooler (lasting longer potentially) and increase MPG, though.

 

[JHZR2]

Ive not seen this. My RWD cars - MB and BMWs, all spec lower front than rear.

81/82 MB base pressure is 28f 32r, I run it at 30f 34r or higher for long highway runs
91 BMW base pressure is 28f 32r, I generally run it at 32f 36r
11 BMW is 39f 41r, I dont go higher.

My pickup specs the same pressure all around.
98 S10 ZR2 is 30 psi, I run 35 or 40 unless off road

The VW specs the same all around, but I run higher in the front than rear.
08 VW is IIRC 35 psi, I run it 41f 38r


The Saab specs higher front than rear and is FWD. I like how it drives, which is why we run the VW the same way.
04 Saab 41f 38r OE spec, I dont go higher.

 

[david_ES2]

I run max psi f/r which is 51 psi year round on my 04 honda with yokohama s drives, thread wear looks dead even and handles wonderfully. the only drawback is that it feels more bumpy which i dont mind at all

 

[CapriRacer]

Originally Posted By: mechtech2
........ Ever notice how so many FWD cars have the door tire pressure spec LOWER for the front than the rear?.....


I think the opposite is true.

 

[bigjl]

The only time I have seen a FWD car have higher rear than front tyre pressure is when you drive heavily laden.

My V50 has got an Eco setting for tyres which is 35psi all round, I think the standard ones are something like 33 and 31. Will try to check later.

The higher pressure in the fronts is due to the extra loads on the tyre as it not only has to do steering and braking but now provide traction aswell, so there will be lateral forces exerted on the tyre that are not exerted on a RWD car.

RWD cars are the minority in Europe and are now mainly big executive cars or drivers cars, BMW and Mercedes for example.

And I have never seen a FWD have higher pressure in the rear once, with the above mentioned caveat when a vehicle is driven heavily laden. The reason for that should be self explanatory.

 

[widman]

Originally Posted By: Rand
I have never owned a car that wasnt the same or higher front vs rear.
can you list a few examples ?



The problem that people never understood, including Ralph Nader, is that cars differ. The Corvair REQUIRES 10 to 12 psi less in the front than the back. I run 24 to 25 psi in front and 35 to 36 in back. Any more up front and it wanders.

My Renault recommends about the same: 15 psi up front and 23 psi in the rear.

 

[Hokiefyd]

I, too, have not seen a FWD-based car spec a higher pressure in the rear than in the front.

As noted by someone else above, if that is the case with a few cars out there, there's an engineering reason behind it. It may be that the car is particularly prone to under- or over-steer and the chassis engineers are tuning that out with tire pressure.