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Bigger & Wider Tires for XC70 P3 2008-2016

13K views 8 replies 7 participants last post by  Warpedcow 
#1 ·
Hi,
I am up to new tires and wheels soon for my 2015 XC70 T6 and wanted to go bigger and wider.

Unfortunately I can't find verified information about max. wheel sizes without lifting the car or using spacers.
Ideally I would go with 235/60 R18 on a 8x18 Offset 45-55 or even 245/60 R18 on a 8x18 Offset 45-55

Does anyone has reliable information, experience or pictures showing that it can fit?
I am pretty certain it can fit without modifications, so the tires don't rub, but still need some kind of proof.

Thanks for your help :thumbup:
 
#2 · (Edited)
The Zephyrus rims are 7.5" wide, not 8.0".

The issue of "fit" has to be considered in the dynamic sense of tire clearance of the wheel well under all driving conditions. It's going to depend on where you drive this car. You can imagine the "worst-case" of front wheel clearance -- a sharp turn coinciding with a big bump (like a speed bump). Volvo only recommends 235/50s for the 18" Zephyrus rim, and it's a good guess that's because they're looking at the worst case of AWD bush terrain. To answer your question, you'd need to have the front wheel turned all the way to the side, and then weigh down the front left corner to compress the spring to the rubber bumper stop.

Not sure why someone would want to increase the rolling diameter of the wheels. E.g., going from a 235/50 --> 235/60 increases radius by 10% x 235 = 23.5mm. That's about an inch. The 235/50 radius is nominally 13", so you're going to a 14" radius. That's a +7.3% change in rolling circumference.

You might not think that's much change, but with the larger tires, your speedometer will under-report your true speed by 7.3% -- It says you're going 75 mph, but you're doing 80 on the cop's radar.

Your transmission that was optimized for specific torques is now fighting a 7.3% heavier reflected torque load to push the car forward, and 15% more energy needed to get the wheels spinning (rotational inertia goes up as r-squared). Your brakes will be facing +7.3% torque load to decellerate the car, and 15% more energy to take back tire-spin inertia. You will definitely notice a loss of zip when you floor it, and longer stopping distances. It would feel like you're always driving with 4 adults in the car, and VERY sluggish if you actually had to transport them. In the latter case of a full load, your stopping distance would elongate 40-50% over driving solo on standard tires.

So, it's not just a matter of wheel well scraping, but degrading the physics of the drivetrain and braking systems -- some considerations to keep in mind.
 
#4 ·
Similar question for me. New to me 2013 XC70 and looking at a set of snow tires. I got a deal on some 235/60 - 18 blizzak that I mounted on a set of Midir's i had. Since they are just my winter tires I'm not too concerned with the difference in the speedo reading and I can deal with a little sluggishness in performance since my main concern is being able to get to where I need to in the snow and icy conditions.
The only concern that I had was the fit on the rear and if the clearance between the tire and front of wheel arch ( approx 1") would cause any issues other than getting a little more clogged up in a heavy snow condition. Clearance on the front looks fine and I can deal with a slight limit on turning radius (I previously owned an 05 S60 AWD and nothing will be as bad as that).
Has anyone run a 60 profile on a stock suspension and seen any issues?
 
#5 ·
The Midir wheel is essentially the same size as the OEM 18" XC70 wheels. There is a 2.5 mm difference in offset, which isn't gong to effect anything. The 235/60-18 tire has a 1/2 inch greater diameter than the 235/55-18 tire. If the suspension on your XC70 is unchanged (original specifications), there is plenty of clearance for the extra 1/2 inch of tire on the 235/60-18.
 
#7 ·
On my S80 P3, the largest tire I could fit on the rears was 285/35/19 on a 10" rim with a 45ET offset. I'm currently running 275/35 comfortably. Any larger and the wheel will rub the fender/shock mount. On the front, the largest I could run is a 245/ 40 19 at 43ET. At lock to lock, the tire doesn't hit anything on the front. I haven't tried going any larger on the front.

Seeing that my XC70 is lifted, I believe you can go with a taller tire, but I don't know how much taller. The front limitation would be the strut seat, where the front spring sits.
 
#9 ·
Running 225/55/18 in the winter and 245/45/19 in the summer - both sizes slightly larger diameter than stock 235/50/18 and work great. I know you can fit 235/55/18 if you wanted to go even bigger as a friend of mine has those. I didn't want to go that much bigger because I also wanted the wider summer and narrower winter option, plus one of mine is lowered on eibach springs. :)
 
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