Yet another tire size question
#1
Yet another tire size question
I've searched the forum using every combination of words/phrases, but no luck. So, forgive me if it's been addressed.
- Can an '09 XK, with stock wheels accept one size wider tires without rubbing or interference with suspension parts? I've looked underneath and stuck my hand around behind the wheel and it feels like there would be clearance.
I recently bought Bridgestone close-outs from Tire Rack in the stock size of 245/40-19 F, and 275/35-19 R, Any problems with going to 255/35-19's and 285/30-19's? I "up-sized" with one size wider on both my Ferrari and 993 without any issues. But being new to XK ownership, there's lots I don't know yet. I know there would be no issue with one-size wider tires fitting on the stock wheels, it's the clearance I'm concerned with.
Any input and advice are welcomed, and I appreciate the patience with the noob question.
Cheers.
- Can an '09 XK, with stock wheels accept one size wider tires without rubbing or interference with suspension parts? I've looked underneath and stuck my hand around behind the wheel and it feels like there would be clearance.
I recently bought Bridgestone close-outs from Tire Rack in the stock size of 245/40-19 F, and 275/35-19 R, Any problems with going to 255/35-19's and 285/30-19's? I "up-sized" with one size wider on both my Ferrari and 993 without any issues. But being new to XK ownership, there's lots I don't know yet. I know there would be no issue with one-size wider tires fitting on the stock wheels, it's the clearance I'm concerned with.
Any input and advice are welcomed, and I appreciate the patience with the noob question.
Cheers.
#2
#4
Join Date: Apr 2008
Location: Ottawa, Ontario, Canada
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Cee Jay (01-25-2024)
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jahummer (01-24-2024)
#6
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steve_k_xk (01-24-2024)
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#8
Low budget is the challenge for this wheel project 🤣.
I love modern concave wheels but this little project just needs to result in the wide rear Cup2's on the car...
Even the tires are used (not old/worn).
I tried to find 305-25-21 for the rears but could only find new.
And I preferred Cup2 at least at rear to utlize more power and torque in Trac DSC mode.
New Cup2's are at 550€ each...not my ball park for one or two trackday trials.
So the used rears now are 30 sidewalls..
Still looking for front tires to match them.
Front on 9,5J would preferably be Cup2's too, but in 265-30-21..however sticky PS4S would do as well.
Problem is DSC with 6% difference in circumference fwd/rear..
I will check if this can be altered in ECU somehow.
First I will test what happens with the original rear wheels on the forward axle (275-35-19 on 9,5J ET50 instead of ET49, so will fit fine)
If DSC goes haywire I will check if there is an option to apply adaptations to the ABS sensor vallues. (I read it somewhere..but now only have icarsoft LR V3..haven't tried yet)
If adaptation is not an option I will put 265-35-21 on the front axle..
Not perfect because will lose 6% brake capacity (more heat)..
This all just for fun, and out of curiousity🤣
Last edited by Ekskaar; 01-25-2024 at 05:28 AM.
#9
This tool is helpful for assurance:
https://www.wheel-size.com/calc/
https://www.wheel-size.com/calc/
Will They Fit dot Com
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guy (01-25-2024)
#10
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Cee Jay (01-25-2024)
#11
Thanks @Cee Jay :-). I’m always mucking about with it. Those extra measurement points are useful to me. As you know, “what looks good” frequently doesn’t measure up to “performance improvement”. I like to keep an eye on that as I prefer driving those winding roads.
#12
Classic stance and wheel....;-)
as said, just to get wider rubber on for occasional trackday. (315-30-21 Cup2 on 10,5J ET50)
Needs a little work on fender edge.
Others better use ET 55 or 60 as there still is little room on inside.
Also 25 high tires are close to OEM circumference, but with the 30s I expect to be able to get more power down on the tarmac (5.0R)
Also gives some use to first gear. (Apart from just smoking tires)
as said, just to get wider rubber on for occasional trackday. (315-30-21 Cup2 on 10,5J ET50)
Needs a little work on fender edge.
Others better use ET 55 or 60 as there still is little room on inside.
Also 25 high tires are close to OEM circumference, but with the 30s I expect to be able to get more power down on the tarmac (5.0R)
Also gives some use to first gear. (Apart from just smoking tires)
Last edited by Ekskaar; 03-24-2024 at 11:55 AM.
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guy (03-24-2024)
#14
#15
Classic stance and wheel....;-)
as said, just to get wider rubber on for occasional trackday. (315-30-21 Cup2 on 10,5J ET50)
Needs a little work on fender edge.
Others better use ET 55 or 60 as there still is little room on inside.
Also 25 high tires are close to OEM circumference, but with the 30s I expect to be able to get more power down on the tarmac (5.0R)
Also gives some use to first gear. (Apart from just smoking tires)
as said, just to get wider rubber on for occasional trackday. (315-30-21 Cup2 on 10,5J ET50)
Needs a little work on fender edge.
Others better use ET 55 or 60 as there still is little room on inside.
Also 25 high tires are close to OEM circumference, but with the 30s I expect to be able to get more power down on the tarmac (5.0R)
Also gives some use to first gear. (Apart from just smoking tires)
#16
Hi Steve thanks,
I haven't tried as I don't have front wheels ready yet.
Also I am still trying to solve a nasty sound from the engine bay..(nightmare)
I believe 5% is the limit for dsc/abs to go haywire.
At least that was the case with my X100R, running 285-35-20 instead of 30s, gave no issues.
But now i've gone wider and higher I expect to be having codes if I run stock front size.
I hope to be able to dump adaptions from ecu and have it have it relearn with the different sizes.
if that is imposible I will choose a front size circumference that is between the bigger rears and the stock fronts. (3% delta)
Probably 275 30 21.
Bigger then stock circumference in front reduces brake system capacity a bit which is not what I am looking for.
I haven't tried as I don't have front wheels ready yet.
Also I am still trying to solve a nasty sound from the engine bay..(nightmare)
I believe 5% is the limit for dsc/abs to go haywire.
At least that was the case with my X100R, running 285-35-20 instead of 30s, gave no issues.
But now i've gone wider and higher I expect to be having codes if I run stock front size.
I hope to be able to dump adaptions from ecu and have it have it relearn with the different sizes.
if that is imposible I will choose a front size circumference that is between the bigger rears and the stock fronts. (3% delta)
Probably 275 30 21.
Bigger then stock circumference in front reduces brake system capacity a bit which is not what I am looking for.
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Ekskaar (03-26-2024)
#19
With the 5.0R we have too much power and torque🤣.
with larger diameter in the rear it becomes a bit more controlable.
But it reduces brake capacity.
At the rear that is no issue.
But at the front it is an issue on track.
I ran 285 35 20 at rear of the X100R with 255 35 20 in front with no issues at all.
with larger diameter in the rear it becomes a bit more controlable.
But it reduces brake capacity.
At the rear that is no issue.
But at the front it is an issue on track.
I ran 285 35 20 at rear of the X100R with 255 35 20 in front with no issues at all.
Last edited by Ekskaar; 03-26-2024 at 11:52 AM.
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steve_k_xk (03-27-2024)
#20
With the 5.0R we have too much power and torque🤣.
with larger diameter in the rear it becomes a bit more controlable.
But it reduces brake capacity.
At the rear that is no issue.
But at the front it is an issue on track.
I ran 285 35 20 at rear of the X100R with 255 35 20 in front with no issues at all.
with larger diameter in the rear it becomes a bit more controlable.
But it reduces brake capacity.
At the rear that is no issue.
But at the front it is an issue on track.
I ran 285 35 20 at rear of the X100R with 255 35 20 in front with no issues at all.