Hi:
I have a 2016 XJR supercharged. i always find the ride was too soft, so i brought to dealership. They said i have an alignment problem and require an alignment work. When i ask can they make the alignment value which give me more tight/stiffer ride, they said they cannot only if i provide them with my own alignment value. I did some google search without any result for that value. Can someone give me suggestions on alignment value. I am a track car driver, so track alignment or much more tight alignment is ok for me.
Thank you !

 

There is no way to make the ride stiffer with alignment.

 

What tire pressures are you running, The Door sticker on that XJR, I think. says 41#. I run the same size tires and find that 38-39# give me the best ride and firmness. Of course, the tires you are using can make a difference. I swear by Michelin PS4Ss, and I have tracked my XJ and an XJR and they are geat fun on the track.

 

Agree with Mark SF above?
Can you explain how alignment can affect the ride?

I have to question that your a track car driver because I don't think the XJ would be my choice for a track car?
Any certain types of events you are doing?
And I like my 2014 XJR very much!
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Here is a picture from my 2016 XJR LWB and I run 34 psi and also swear by Michelin PS4S.

 

All XJRs in the US had a tire sticker that included High speed pressures to 174. What does your speedo MPH say at 12 o'clock position?

 

100 MPH

 

Well as you and I are running the same size tires and make I'd recommend that you tru running 38# as I do and see how that feels. I'm at a loss as your sticker does not include the high speed recommended pressure of 41# all around.

 

remember that when you are driving harder and faster your tire pressure will naturally rise. if your at 34 it could get close to 40 psi with hard driving.

 

These tires are rated to 50# I have over 108k on my XJ SuperSport with the Speed Package since taking delivery in in 10/2012 and have always run these pressures as they give me the best ride and handling

 

What I do at the track (not my car, helping) is the cold pressure is calculated, based on the desired pressure when the tire is hot.

This implies that if you're seriously tracking a car, you should be starting with lower, not higher, pressures, given the greater rise in temperature, and thus pressure.

Don't forget that the tire pressure is not chosen for reasons of ride quality. You're trying to get even pressure across the tire, thus maximizing grip and minimizing tread wear.

On a road car I start with the pressures on the B pillar plate, and adjust based on the tire wear.