The Dunlop SP Sport Max tyres aren't great on the Jags. They're affectionately known as Dunslips.

This one then!

I've been pulling data off of this sheet page today!

Car and Driver

Very good list!!!

The XKR sheet nearest to mine is here. Mine has the speed pack which apparently lets it go a bit faster and has some tweaks to make this a little less worrying

I have those on the front and the better RTs on the back. The Sport Maxxs are not terrible but I feel there would be better bite and feedback with a better chosen tyre, even the RT version would be interesting.

There is not a great choice in the 285/30 20 size and when I change, I would like matching tyres all-round.

I've still got the Dunlops on the rear and I've just replaced the fronts with Pilot Supersports. They are very sticky Turn-in is fantastic. They will be put on the rears when the time comes.

The factory option for mine are p zero - the rears are a nightmare, tons of fronts to chose from.

That looks right, top speed isn't though. Jag managed 226 in an aero only modified one on bonneville!

What size are you on?
Think it may be time to see who's tyres are best on jag forum. RRP for the rears is 446 each lol....(I've seem them for 235 I think)

255/35/20 and 285/35/20

The XFR boys on Jaginfo like the Pilot Super Sports.

Do they. May be worth a try.
It's painful though isn't it, on a coupe you're chucking 200 quid away on fronts, if you buy shite for an xf you're looking at 1000....

Have you checked out Costco prices - especially if you're thinking of buying Michelins - I'm pleasantly surprised how reasonable the tyres for the E-Classes are there.

Even the Michelins SS aren't so bad in the UK. 800 Pounds buys you a complete set. Tyre prices was something I did check before settling on the car and they seemed reasonable for the type of car. Even the Pirellis and Dunlops are not really poor. We are complaining at a very high level

Fronts and Rears

Not quite...
600bhp among other things

They say the 500 bhp might be able to break 200 mph on these cars but Jaguar does not seem to trust them to stay stable enough. Even the XKRS GT was limited to 186 mph. I have only managed 155 mph so far and it was taught if a bit bouncy on the bit of Autobahn I was on.

Curiosity got the better of me, so I collected the data and ran it through my calculator!
It came out waaay too fast compared to the road test figures so I tried tampering with the CD or frontal area to remedy it. That didn’t work. Reducing overall power across the whole range to 90% of quoted brought the figures in line with C&D’s report – as far as they went anyway. I've seen dyno reports saying 456bhp so this looks spot on.

Data Input
Vehicle Jaguar XFR
Short Shifting: Yes
Driven Wheels: Rear
Weight (kgs): 1857
Weight Distribution (% on front): 51
Wheelbase (inches): 114.5
Final Drive Ratio: 3.310
1st Gear Ratio: 4.170
2nd Gear Ratio: 2.340
3rd Gear Ratio: 1.520
4th Gear Ratio: 1.140
5th Gear Ratio: 0.870
6th Gear Ratio: 0.690
7th Gear Ratio:
Tyre Width (mm): 285
Tyre Profile (%): 35
Tyre Size (inches): 20
Gear change time: 0.2
CD (Co-efficient of drag): 0.29
Frontal Area (feet): 23.6
Wheel or Flywheel BHP?
BHP @ 2000 rpm: 153
BHP @ 3000 rpm: 237
BHP @ 4000 rpm: 324
BHP @ 5000 rpm: 410
BHP @ 6000 rpm: 456
Redline Power (rpm): 6500
Redline Power (bhp): 456
Peak Power (rpm): 6000
Peak Power (bhp): 456
Max force (bs) 2960

Jaguar XFR (2010)
Jaguar XFR
0-10mph: 0.5
0-20mph: 1.09
0-30mph: 1.66
0-40mph: 2.46
0-50mph: 3.21
0-60mph: 3.98
0-70mph: 5.05
0-80mph: 6.28
0-90mph: 7.53
0-100mph: 8.9
0-110mph: 10.73
0-120mph: 12.65
0-130mph: 14.79
0-140mph: 17.25
0-150mph: 20.66
0-160mph: 24.54
0-170mph: 29.28
0-180mph: 35.61
0-190mph: 47.85
0-200mph: 104.48

Top Speed (mph): 200.7
Top Speed (rpm): 5535
60-80mph: 2.3

60ft Time: 2.1
60ft Terminal: 37.5
330ft Time: 5.36
330ft Terminal: 72.5
1/8 Mile Time: 8.06
1/8 Mile Terminal: 94
1000ft Time: 10.27
1000ft Terminal: 107.5
1/4 Mile Time: 12.26
1/4 Mile Terminal: 118.1
0-400m Time: 12.22
0-400m Terminal: 117.9
1km Time: 21.94
1km Terminal: 153.5
3/4 Mile Time: 24.88
3/4 Mile Terminal: 160.8
1 Mile Time: 30.28
1 Mile Terminal: 171.9
2 Mile Time: 49.86
2 Mile Terminal: 191

I must've misread an article... Although altitude and salt and balast must offset alot of the power increase?

Still a damn quick car all from a map and supercharger pully change!

Those numbers are impressive Trappy! The 456 bhp wheel hp?

No, flywheel. I took the dyno curve off of a Jaguar press release but they make it much faster than it is. I also so a couple of dyno runs that were saying 455bhp ish so I reduced the entire power curve to 90% to see what it did.

I'll try it again with 600bhp and see if it does 226mph.

As long as the data that goes into the calculator is right, it gives correct figures. When road tests have radically different numbers, it's normally because the car's published weight or power is incorrect. I suspect that's the case here.

Hmmmm, perhaps I should have it rr'd and see what it comes up with. 10% is alot of power to be overstating.

You're going to love this!

Vehicle Jaguar XFR 600BHP
Short Shifting: Yes
Driven Wheels: Rear
Weight (kgs): 1857
Weight Distribution (% on front): 51
Wheelbase (inches): 114.5
Final Drive Ratio: 3.310
1st Gear Ratio: 4.170
2nd Gear Ratio: 2.340
3rd Gear Ratio: 1.520
4th Gear Ratio: 1.140
5th Gear Ratio: 0.870
6th Gear Ratio: 0.690
Tyre Width (mm): 285
Tyre Profile (%): 35
Tyre Size (inches): 20
Gear change time: 0.2
CD (Co-efficient of drag): 0.29
Frontal Area (feet): 23.6
BHP @ 2000 rpm: 202
BHP @ 3000 rpm: 312
BHP @ 4000 rpm: 428
BHP @ 5000 rpm: 542
BHP @ 6000 rpm: 602
Redline Power (rpm): 6500
Redline Power (bhp): 602
Peak Power (rpm): 6000
Peak Power (bhp): 602
Max force 2960

Jaguar XFR 600
0-10mph: 0.5
0-20mph: 1.09
0-30mph: 1.66
0-40mph: 2.44
0-50mph: 3.01
0-60mph: 3.59
0-70mph: 4.43
0-80mph: 5.32
0-90mph: 6.23
0-100mph: 7.22
0-110mph: 8.57
0-120mph: 9.91
0-130mph: 11.37
0-140mph: 13
0-150mph: 15.24
0-160mph: 17.58
0-170mph: 20.23
0-180mph: 23.37
0-190mph: 27.85
0-200mph: 34.1
0-210mph: 43.31
0-220mph: 61.82



Top Speed (mph): 224.5
Top Speed (rpm): 6191
60-80mph: 1.73

60ft Time: 2.1
60ft Terminal: 37.5
330ft Time: 5.19
330ft Terminal: 78.5
1/8 Mile Time: 7.65
1/8 Mile Terminal: 104.1
1000ft Time: 9.67
1000ft Terminal: 118.3
1/4 Mile Time: 11.48
1/4 Mile Terminal: 130.7
0-400m Time: 11.44
0-400m Terminal: 130.5
1km Time: 20.25
1km Terminal: 170.1
3/4 Mile Time: 22.9
3/4 Mile Terminal: 178.6
1 Mile Time: 27.77
1 Mile Terminal: 189.9
2 Mile Time: 45.53
2 Mile Terminal: 211.8

Yes, yesI am. Your calculator is very very close! I guess you didn't compensate for aero changes, 50psi in tyres and extra weight in boot??

Sounds like a remap is in order (just for braging rights as the damn thing is plenty quick enough already!!)

I didn't bother. The aero changes are negligible. Changes tyre size to reduce the frontal area will barely register, I can't say what the tyre pressure change would make (my calculator doesn't factor in drag from contact patch so I can't reduce it) and adding weight won't make any difference to the top speed; it'll just take longer to get there.


Love it! First it's too fast and now you want more power!!

A jocose utterance. As the title suggests, I really don't want or need anymore!

The problem is that you CAN though

What I have discovered after alot of reading what other owners have to say is this:

Standard power is under stated in general by 15-20 hp. Panel filters and back box changes can bring upto 560hp, mapping 590 and a swap of pully on the sc well over 620.

Trappy I think your numbers were too low (fast) because you haven't got the right amount of slip in for driven wheels. The car has enough torque to make the rears slip through 1St and 2nd easily. I am lead to believe that rolling the car is a match for the last gen R8 from around 20mph through to 180+.

I read on a yank forum (this could be bravado as I saw no evidence) that with sticky tyres the car is a low 3s to 60.


Some of this could be junk, I've seen some videos that seems to prove it's pace once moving and some rr readouts at close to 600 bhp allegedly from filter and exhaust swaps.

All in all Jag seem to have got it right, not read a review from an unhappy owner and just like the coupe they all seem to be unsure how to replace it when the time comes as it's German contemporaries all (in general owners opinions) fall short.

Tyre tech has moved on since these tests in 2009 and new cars are being figured with the latest rubber. C&D got 4 secs for the 0-60 time with their XKR and 2009 SportMaxx tyres. New rubber will help a little but one second is 25%. I'm not buying that 4.0 secs is already 0.6 less that Jaguar claimed.

The German competition rides hard so is simply less nice to use even if they are technically more capable. The F-Type has gone in the same direction too.

Maybe when it comes to replacement time, a big V8 or similar might not be possible. Let's just enjoy them while we can, even at sane speeds.

That's true!
I'm certainly enjoying mine!

When I use dyno, weight and aero and gearing numbers for the new M5, it returns exactly what the road tests say. I honestly believe that if it doesn’t return the right road test numbers then the input is wrong Aero adjustments don't fix it. My calculator reduces the wheel power by an approximate amount. It might be that the jag loses more than usual for whatever reason? Any evidence of this from dyno runs? It could also be the car's weight? But even then, it just doesn't fit. I adjust one variable at a time and keep an eye on the returned numbers. When they much road test data, I tend to think we're there... no science but I've looked at a lot of numbers now!!

In terms of traction, the calculator doesn’t function like you appear to be assuming. A given tyre with a given percentage of the car’s weight on it will only permit a certain amount of grip. The calculator works by effectively reducing that power to match that maximum. Only when the speed and drag have reached a certain amount (i.e. when full power can be used) will it use the actual wheel power. It’s like traction control I suppose? Of course types do have grip while slipping but you just can’t find numbers for it, so I went with my approach above; a grip ceiling.

Thus, a car with enough power to break traction up to 60mph will accelerate at the same rate as the same car with twice as much power up until 60mph. It doesn’t matter how much more power it has, it won’t accelerate slower!! According to my calculator, the XFR could spin the wheels up until 48.9mph. Over that speed, traction overwhelms the power. Only tyres affect the acceleration. I did experiment with adding spring rates and the height of the centre of gravity but it’s near impossible to get numbers for this so they’re all generic I’m afraid. That said, it makes sod all difference in the scheme of things anyway!!



Which R8 are you referring to? In terms of engine and power I mean. It would obliterate the V8 ones!! I can easily tell you if that’s true as I have road test numbers for all of them.



The numbers I posted up included grip on a track day tyre such as an R888 or AD08R. It won’t get any better than that in my opinion. I do find it astounding that front engine rear drive car’s like Ferrari F12s etc, manage to dip under 4 so much. I can’t explain that!? It’s got to be some kind of wizardry on the suspension or something? Dampers softening and springs adjusting to shift more weight to the rear, I have no idea…

OK, interesting. I wasn't saying you were wrong, just trying to understand why what you're saying is different from owners experience - I was assuming the calculation did crazy things as it is often proved accurate.
Sorry it's a poor image, this is with a panel filter change and a x section where the centre box was.
I'll see if I can find others, but it was one of those Google and then link jump things where you get lost in a world of Internet!