Not enough downforce?
 

I find that when I am traveling above 120mph, the front end seems a little too light.
When I push to 140, bumps in the road make me a bit nervous.

Is this all in my head? I am assuming the car has enough down-force to make it stable at high speeds.

Does anyone have any similar experiences?

More info needed. Which model do you have? (that's why you should put it in your signature)

I heard this from a couple of owners.

My own opinion is that the rear spoiler introduces too much downforce on the rear, which makes the front end light.

It would be interesting to make some tests with the spoiler disconnected and see what difference it makes to the balance of the car.

https://www.jaguarforums.com/forum/f...stions-152122/

Apparently a 2014 base.

Got mine to 162mph a while ago. Felt planted to me.

Signature updated.. Thank you.

I have yet to be under the car to see if the splitter/ difuser is functional or just cosmetic.

Been in the 160's as well, quite stable. Still haven't done above that yet.

120-130 almost feels like normal highway cruising speed.

Since it is a spoiler and not a wing it seems unlikely, a spoiler just stops the cars aerodynamics from getting lift, it doesn't actually induce downforce.

Could this be a vert specific issue?

BTW, to avoid a massive (and unproductive) discussion on semantics:

reduced lift equals increased (gravity induced) down force.

Wings create aerodynamically produced down force and spoilers (which we have) reduce aerodynamically produced lift across the top surface of the car.

Is this on a track or on a public street?

Run my 2015 R Coupe up to 150/155 in multiple spurts on city streets and felt solid, secure and firmly planted. Have had one opportunity to do 140 give or take for an extended uninterrupted run on a wide open stretch of California highway lasting about 20 miles. Coupe could not have been more smooth. She seems to absolutely sing with delight in the 135 to 145 range.

Tires make a lot of difference and inflating them to spec makes even more difference. Float-y feel could be sidewalls partially collapsing. I find dash PSI values on my car off by couple PSI, so I am not sure you could trust them.

I don't know if some of you guys are a little nuts or a bit lucky (or maybe both).....155 mph on city streets?! WTF?!

Several years ago, my crazy nephew in his brand new Mustang GT did 100 mph on a 20 mph "school zone." During one of his "runs," he almost ran over a bunch of kids crossing the street while filming his exploits on his smartphone. Needless to say, he was caught and ticketed by the cops. His car was impounded, license revoked for 2 years, and spent 2 nights in the slammer before getting out on bond. He was very lucky he didn't do additional jail time in the county prison.

Where I live and work, there are cops everywhere. I'll be lucky if I get my car even up to 50 mph before attracting attention.

NEVER race on city streets. The consequences are not worth it. Take it to the track and let it fly. That's what it's there for.

Yep, what he said above.

I don't know if it's a convertible only issue or not, and I have no intention of finding out. I didn't purchase a base V6 hoping to do triple digits on my daily commute or fun road trips. I have a fair amount of track experience, and I knew full well when I bought it, that this ain't no track car.

Sorry but I do t think that shuts the discussion down, it just perpetuates it. And it is kind of semantics BUT: in my understanding all the spoiler does is stop the car getting lighter due to aerodynamic lift. So it will Bring the car back towards it's normal standing still gravity induced weight but it won't add extra downforce which a wing will do. In other words, yes there is more weight on the road with the spoiler deployed at speed than without, but it is not additional downforce it is just canceling out the lift.

You and I are in violent agreement. Unfortunately Jaguar publicizes it as 264 lbs. of downforce (Spoiler Spoils Classic Lines - 2015 Jaguar F-Type R Coupe Long-Term Road Test) when they should be claiming 264 lbs. of reduced lift. But that's like advertising that it doesn't suck as badly.

Highway. I never speed on city streets because of pedestrians.

I disagree. F-type is more than capable of fun times on the track.

I didn't say it wasn't. I said it "ain't no track car."

I'd choose something significantly less fat for that.

LOL . . . last time I checked, those are public streets with other traffic.

Speeding is one thing, and I'm sure we all do it to some extent. However, 155 mph is criminal on any public road.