Lew

ok guys.. here's the deal:

I just ordered new CL Type-S Rims (17x7) and planned to wrap them with the 225/45 YR 17 Michelin Pilot Sport A/S i ordered from TireRack.

A representative from TireRack called me up just now and raised his concerns over the safety of using this combination and suggested i switch to 225/50 17's. His reasoning was because of the load balancing specifications differences between the tires:

225/45 17's have a load balance of 1323lbs per tire
225/50 17's have a load balance of 1477lbs per tire
In comparison, each stock
215/50 17 tire has a load balance of 1356lbs per tire.

With four tires, he said that using 225/45 17's puts me at a total of 132lbs BELOW OEM SPECIFICATIONS. This means that under hard breaking, if that 132lbs makes a difference, the tires will blow out. (i.e i could die)

On the other hand, using 225/50 17's puts me above OEM specifications, so I should have nothing to worry about there. This is his reasoning for advising me to switch over.

Please offer advice and input. I would GREATLY appreciate any one's technical expertise on the matter.

NSX4dr

Take your car to a weigh station with the maximum you would ever load your car with......divide by four and see what you get

Allout

I just slapped 235/45-17 Michelin Pilot Sport A/S on my 17X7 CL-S wheels. Size is the closest Rev per mile to stock and they fit like a glove.

235/45-17 - 811 rev/mile with a load rating of 93
225/45-17 - 829 rev/mile with a load rating of 90
225/50-17 - 795 rev/mile with a load rating of 94
215/50-17 - 819 rev/mile with a load rating of 93 (Stock)

I like the way the 235/45-17's work on the car.

Lew

i'm a bit confused...
aren't 235/45-17 size tires made to safely fit on 7.5-9.0 inch wide tires only? and aren't the CL-S rims 7.0 inches wide?

are 235/45-17 tires on CL-S rims safe?

Allout

Lew,

I was on your line of thinking until I found this thread:
http://www.acura-tl.com/forum/showth...hlight=verdict

I even found a few examples where car manufacturers (like BMW) use rims smaller than the tire manufacturers recommended specs.

You are correct that the CL-S wheel is 17x7 and you are correct that Michelin recommends a minimum rim width of 7.5 inches for a 235/45-17. It is outside the tire manufacturers specs but does work - not optimal but it does work.

Lawaia

Really?? Not calling you a liar but I find it hard to believe that BMW, or any car manufacturer for that matter would do such a thing. There is just no benefit for doing that.

My recommendation is and will always be to stay within the manufacturers guidelines.

Lew

thanks guys
i ordered them and they're on the way
mad expensive tires..
well, with my aggressive driving, if these things one day pop off on me during hard braking and i suddenly stop posting here.. well.. you'll know what happened
X P

fsttyms1

i wouldnt worry about that happinin lew!

Allout

Lawaia,

It's OK to question the source of information.

I found this on Tire Rack:"Additionally, some vehicle manufacturers and tire companies have permitted rim widths that are not within the tire's original approved rim width range. For example: BMW has combined 235/40R17 sized tires on 17x7.5" rims (which are 0.5" less than the narrowest 8.0" wide rim listed for the size) on certain M3 models; and Chevrolet has combined P255/50R16 sized tires on optional 16x9.5" rims (which are 0.5" wider than the 9.0" wide rim now listed for the size) on certain Corvette models. While these applications have received the approval of the vehicle and tire manufacturers, staying within the approved rim width range helps assure that the tire's internal stresses are within its design parameters."

Here's the link to their page that discusses rim width.
http://www.tirerack.com/tires/tirete...#rimwidthrange

Like I said, Not optimal but it does work.

Allout

Good luck Lew. I think you'll be pleased with the results.

Lawaia

Thanks for pointing out that bit of info Allout. Can't speak for the Corvette's quoted specs but I believe the E36 M3 ('91 thru '99) was equipped with 225/45-17 frt / 245/40-17 rear. This also holds true for the Euro Spec M3. I'm guessing that maybe the earlier E30 M3 ('86 thru '90) could have possibly been equipped with 235/40's If so, that's pretty sad that they had to go back over 10 years to find such an example.

Keep in mind that they are a retailer, not a manufacturer so any tire rack recommendation which may conflict with the manufacturers guidelines should be taken with a grain of salt.
Thanks again Allout.

NSX4dr

I wouldn't worry....if you were going the opposite way, let's say smaller tire for rim, then you'd have a bigger problem.


Charles

Lew

ok... this combination is AWESOME!!
i am quite pleased!

Allout

That's great Lew. The Pilot Sport A/S is a really good tire. Glad you're enjoying them.

TypeSDriver

Glad to hear you're enjoying them. Did you get the 225/45's or the 235/45's, I wasn't sure with all the discussion going on. I plan on getting a CL-S within the next month, and the first thing I'm doing is putting these tires on. Thanks for your help.

Allout

235/45-17's