Cobra Jet
Well-Known Member
Tire inflation should always be checked cold.
Also to note, the VCL decal will always have correct tire pressures for both front and rear, even if the car is sitting on “squares”.
The most common tire psi is usually between 32 or 33 psi as indicated on the VCL - and that’s pretty common whether it’s an 18” or 19” diameter OR an All Season or “Summer Only” tire.
Folks can post their VCL’s all day long on here and state what their own tires are inflated to - but it’s not going to fix anything.
What’s your actual alignment specs - can you post the last alignment sheet (if you have even one)?
Has the rear IRS cradle ever been centered using the many aftermarket bushings available to center it? It’s a well known issue since the S550 debuted that on some, the rear IRS cradle is not centered from the assembly line. Any such misalignment of that cradle will affect wheel alignments and in extreme instances, vehicle handling.
Over inflating any tire - doesn’t matter if it’s yours, mine or JimBobBettySue’s to 40psi is asking for trouble
1) it’s not correcting any underlying issues as mentioned by others. All that is doing is ballooning the tire contact patch on the road surface, making what was a wider patch smaller.
2) It’s dangerous. Tire psi increases with prolonged driving (heat). You’re essentially starting with a tire at 40psi and as it heats, that psi can increase as high as 45-47psi depending on road surface type, length of driving and actual exterior road surface temps. If you have ever watched the tire psi monitoring, you will see the psi rise as you drive to a point where it normally will “bottom out” based on averages. This is why Vehicle AND Tire Manufacturers post a COLD psi value of 32psi. Essentially, after driving that cold PSI will get to 35-38psi again depending on the above conditions.
3) As much as it “feels better” to you and what your Mechanic has told you - 40psi is excessive, dangerous and will cause premature tire wear.
Check your front and rear wheel hub bearings. It’s been reported many times on this site that S550 owners across all years and platforms have had to replace hub bearings due to premature wear, even with extremely low mileage. Some folks have even reported having the same side wheel hub replaced 2 and 3x under warranty. Bad hub bearings will also cause weird handling characteristics and alignment issues.
One more note to leave on:
Don’t trash other forum members - isn’t there enough animosity on this planet without having to continue it in a forum? Sure interpreting a written response can be misconstrued, but I don’t think anyone on here deserved the responses you dished - everyone has a different way of making a point and folks are genuinely trying to offer the help. The advice given to you by your mechanic is covering up underlying issues whatever those may be... deflate back down to a cold psi of 33psi.
Also to note, the VCL decal will always have correct tire pressures for both front and rear, even if the car is sitting on “squares”.
The most common tire psi is usually between 32 or 33 psi as indicated on the VCL - and that’s pretty common whether it’s an 18” or 19” diameter OR an All Season or “Summer Only” tire.
Folks can post their VCL’s all day long on here and state what their own tires are inflated to - but it’s not going to fix anything.
What’s your actual alignment specs - can you post the last alignment sheet (if you have even one)?
Has the rear IRS cradle ever been centered using the many aftermarket bushings available to center it? It’s a well known issue since the S550 debuted that on some, the rear IRS cradle is not centered from the assembly line. Any such misalignment of that cradle will affect wheel alignments and in extreme instances, vehicle handling.
Over inflating any tire - doesn’t matter if it’s yours, mine or JimBobBettySue’s to 40psi is asking for trouble
1) it’s not correcting any underlying issues as mentioned by others. All that is doing is ballooning the tire contact patch on the road surface, making what was a wider patch smaller.
2) It’s dangerous. Tire psi increases with prolonged driving (heat). You’re essentially starting with a tire at 40psi and as it heats, that psi can increase as high as 45-47psi depending on road surface type, length of driving and actual exterior road surface temps. If you have ever watched the tire psi monitoring, you will see the psi rise as you drive to a point where it normally will “bottom out” based on averages. This is why Vehicle AND Tire Manufacturers post a COLD psi value of 32psi. Essentially, after driving that cold PSI will get to 35-38psi again depending on the above conditions.
3) As much as it “feels better” to you and what your Mechanic has told you - 40psi is excessive, dangerous and will cause premature tire wear.
Check your front and rear wheel hub bearings. It’s been reported many times on this site that S550 owners across all years and platforms have had to replace hub bearings due to premature wear, even with extremely low mileage. Some folks have even reported having the same side wheel hub replaced 2 and 3x under warranty. Bad hub bearings will also cause weird handling characteristics and alignment issues.
One more note to leave on:
Don’t trash other forum members - isn’t there enough animosity on this planet without having to continue it in a forum? Sure interpreting a written response can be misconstrued, but I don’t think anyone on here deserved the responses you dished - everyone has a different way of making a point and folks are genuinely trying to offer the help. The advice given to you by your mechanic is covering up underlying issues whatever those may be... deflate back down to a cold psi of 33psi.
Sponsored
