Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: Kayvan on August 24, 2015, 17:01:38

Title: Tire Pressure: KUMHO Solus Front 30 psi, Rear 35 psi ?
Post by: Kayvan on August 24, 2015, 17:01:38

I just filled my tires to 30 psi on all 4 tires and sidewalls look perfect.

I am going to increase the rears to 35psi


They were previously at 25psi Front, 31psi rear and they just looked they were underinflated with bottom sidewalls sloping out from weight.


Whats the techical reason behind the +/- 6psi between rear and front?

All sports /GT cars today seems to recommend even tirepressure on all four tires. 

Title: Re: Tire Pressure: KUMHO Solus Front 30 psi, Rear 35 psi ?
Post by: Kayvan on September 10, 2015, 22:10:27

Front: 30psi
Rear: 36psi

Car handles much better; corners much more nimbly and crisper

at 25/31psi handled like old mans car.... ;)

Title: Re: Tire Pressure: KUMHO Solus Front 30 psi, Rear 35 psi ?
Post by: Cees Klumper on September 11, 2015, 05:23:44

Just watch out for uneven tire wear (overinflated = middle of the tire wears quicker than outside, and vice versa). My modern day Continentals under my Volvos appear underinflated when I have them at proper inflation - so it can be the tire design.

Title: Re: Tire Pressure: KUMHO Solus Front 30 psi, Rear 35 psi ?
Post by: Kayvan on September 12, 2015, 16:27:55

Isnt 31/36 psi the max pressure on trunk sticker ?

Title: Re: Tire Pressure: KUMHO Solus Front 30 psi, Rear 35 psi ?
Post by: Cees Klumper on September 12, 2015, 20:01:56

Those stickers were made for tires manufactured 40-50 years ago, I expect today's tires are different and likely need different pressure. Not sure whether the tire manufacturer provides suggested pressures, but I keep all my car tires inflated to approx 2.7 bar (warm; 2.5 or so cold) which seems to work very well, fuel economy, handling and wear-wise.

Title: Re: Tire Pressure: KUMHO Solus Front 30 psi, Rear 35 psi ?
Post by: vande17941 on September 29, 2015, 08:16:58

I drive with equal pressures all the way around. Most of these cars specified lower pressures in the front in order to induce understeer at the limit. Most people can handle understeer a lot easier than oversteer when the ass comes around unexpectedly.

As a previous race and shifter cart driver, I like the vehicle to break sideways completely evenly when the tires let go, and on the pagoda this seems to mean equal front and rear pressure.

Less psi in the front would also help most people avoid the snap oversteer that can occur when the Pagoda rear axle geometry causes camber change (neg) significantly due to weight shift when someone lifts off mid corner because they came in too hot. The weight shifts.to the front, the back lightens up, the rear rises, the transaxle geometry causes negative camber, and the rear snaps out. Reducing the front psi adds a bit of a safety margin.

Try somewhere in the range of 30-35 to start with and the front about 4psi less.... decide if you like the suppleness of the ride. If not, take a few PSI out. Each PSI cost about .3% in fuel economy.

And drive the car. If you notice over time the centers of the tires wearing out, you have too much pressure. If you notice the sides wearing out first you have too little pressure