Insufficient load index for michelin
#1
Insufficient load index for michelin
Hey Guys,
Im looking to replace the stock contis on my '13 c63 sedan. Went to a tire shop and tried to order the Michelin Pilot Sport 4s in the following sizes:
Front: 245/35/18
Rear: 265/35/18
Guy said he couldn't sell me the front with 35 ratio, because the load index of 92 (max load of 1389) is insufficient. He recommends I go with the 245/40/18 with a load index of 97 (max load of 1609). The only problem is that the 40 series tires are almost an inch bigger in diameter.
Not sure how to move forward at this point. Anyone running 245/40/18s on the front would like to share their thoughts?
Im looking to replace the stock contis on my '13 c63 sedan. Went to a tire shop and tried to order the Michelin Pilot Sport 4s in the following sizes:
Front: 245/35/18
Rear: 265/35/18
Guy said he couldn't sell me the front with 35 ratio, because the load index of 92 (max load of 1389) is insufficient. He recommends I go with the 245/40/18 with a load index of 97 (max load of 1609). The only problem is that the 40 series tires are almost an inch bigger in diameter.
Not sure how to move forward at this point. Anyone running 245/40/18s on the front would like to share their thoughts?
#3
Almost an inch bigger ? In what respect ?
The guy selling you the tires is right listen to him...
the stock setup is
235/40/18 with a overall diameter of 25.4” the 245/35/18 are only 24.8”... where as in the back stepping up from the 255/35 at 25.0 “ to a 265/35 at 25.3”... increasing the rear diameter and reducing the front is usually not what you do chance of messing with the abs and traction assist systems not to mention changing the handling turn in and over/under steer. Not to mention if the tire is now under spec for weight load rating
If you are going up a size you generally leave the aspect ratio the same as stock...
The guy selling you the tires is right listen to him...
the stock setup is
235/40/18 with a overall diameter of 25.4” the 245/35/18 are only 24.8”... where as in the back stepping up from the 255/35 at 25.0 “ to a 265/35 at 25.3”... increasing the rear diameter and reducing the front is usually not what you do chance of messing with the abs and traction assist systems not to mention changing the handling turn in and over/under steer. Not to mention if the tire is now under spec for weight load rating
If you are going up a size you generally leave the aspect ratio the same as stock...
#6
He is right. I was in the same boat as you couple months ago. The price of a 245/40/18 XL 97Y is about $25 more per tire comparing to 235/40/18. For me it wasnt worth it so I stayed with factory size up front. I did get a 265/35/18 97Y for the rear and that was $3 more per tire, so a no brainer.
Edit: Here's a picture of the 235/40/18 PS4S. I'd stick with 235 honestly, wont change much to get 245 in front.
Edit: Here's a picture of the 235/40/18 PS4S. I'd stick with 235 honestly, wont change much to get 245 in front.
Last edited by gtracer; 06-03-2018 at 04:03 PM.
#7
The rolling diameter when upsizing the rear to 265 brings them much closer to the stock 235 fronts.
Front:
P235/40R18 - 25.4” (OEM)
P245/40R18 - 25.7” (upsize)
Rear:
P255/35R18 - 25” (OEM)
P265/35R18 - 25.3” (upsize)
Front:
P235/40R18 - 25.4” (OEM)
P245/40R18 - 25.7” (upsize)
Rear:
P255/35R18 - 25” (OEM)
P265/35R18 - 25.3” (upsize)
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#8
Awesome tips guys. I'll try to go with Michelin PS4S 235/30/18 up front and 265/35/18 in the rear.
Costco has an awesome deal right now for $816 installed. Will try to get Americas tire to match the price. If not, I'll stick with stock sizes at Costco.
Costco has an awesome deal right now for $816 installed. Will try to get Americas tire to match the price. If not, I'll stick with stock sizes at Costco.
#10
Yeah that's the problem with my local Costco, and I assume nationwide,they won't install non OE sizes, but they'll sell em to you if you get installed elsewhere.
#11
MBWorld Fanatic!
Joined: Feb 2007
Posts: 1,307
Likes: 80
From: Houston - Clear Lake
C63 coupe, Z3M Roadster garage queen
I've been running the 10mm wider tires on front and back (in the sizes below) for several years. I'm using MPSS (wish MPS4S had been available in 18" sizes six months ago!). My butt-dyno likes the improvement but appearance and handling are not significantly different from stock. Part of my reasoning was that the car already has more under-steer than I'd like on stock size tires, so keeping a 235 front and going to a 275 rear would just make the handling worse. The other reason was safety, to ensure that the tires were properly load-rated for the car.
Front: 245/40/18
Rear: 265/35/18
#12
He is right. I was in the same boat as you couple months ago. The price of a 245/40/18 XL 97Y is about $25 more per tire comparing to 235/40/18. For me it wasnt worth it so I stayed with factory size up front. I did get a 265/35/18 97Y for the rear and that was $3 more per tire, so a no brainer.
Edit: Here's a picture of the 235/40/18 PS4S. I'd stick with 235 honestly, wont change much to get 245 in front.
Edit: Here's a picture of the 235/40/18 PS4S. I'd stick with 235 honestly, wont change much to get 245 in front.