Contour Enthusiasts Group Archives Forums Modifications Wheels & Tires 205/55R16 (complaints) vs 225/50R16

Al right so my KDW's finally met their match when I ran them a gingerman ~1.5 months ago (bands showin', and I am not talking about wearbands). So the next day I went out to buy a new set, when belle tire told me the 215s were no longer availible. No biggie, the 98SVTs had 205/55R16s and those were availibe quite a bit cheaper. $450 later I have four new tires. I chirp them out of belle tire, again no biggie, fresh tires always have lots of oil.

Now here is the real concern, they haven't gotten any better. Where my 215s blew me away these just blew.

My corning has totally changed, I have to account for a much greater slide, either by cutting in earlier or by going slower, either way it is not as fast.

I am out running against my friends FSVT, I know the drill, get a little wheel spin let the tires warm to grip, the rpms will die down as the car rockets away. Now this time, something new happens, instead of the warming, gripping and flying, I now have warming, smoking, and spinning to redline (or 6300 when I let off). I go ahead modulate it a bit and still have the FSVT but not by much. In addition I have a cloud and a wonderful new airfreshener. We run a few more times, and I work up a new pattern of launch, but I know for sure I am not as fast as with the 215s.

Then finally later on my drive home, I decide to test out my winding corning, and go around a 270deg clover, and my speed was a full 5mph slower than with 215s and I everytime I tried to go faster, I just got inner wheel slip.

Well back to useful information, I do not recomend the 205/55R16 KDW's. Furthermore, I would like to know how well the 225/50/R16s perform/fit(rubbing).

So any help you have please let me know. I am now hoping the 205s will melt away as fast(or faster) than the 215s, at least that way I can get some decent rubber back on my car. (maybe some gingerman nights could assist me)

Thanks

I have some questions about 205/55/16 vs 225/50/16, specifically performance. Do acceleration and cornering decrease when going from the 215/50/16 to the wider tire because of the larger contact patch?

Another general question is whether anyone has had the guys reset their speedometers to account for the increased diameter tires.

Matt

Generally, all other things being equal, the larger contact patch will help acceleration and cornering. Having said that, your suspension and more importantly, the geometry of your suspension has to be set properly to take advantage of the wider rubber. The autocross guys can answer this from an ultumate performance viewpoint, but for street use, the wider tire looks good and performs just as well as the 215 tire.

Both 205/55 and 225/50 are taller than the 215/50 so that might have a slight penalty on acceleration.

I am sure your experiance is real, but there is only a 10mm differance in width per tire. Not only that but the 205's have a more favorable tire width to wheel width ratio. Is it possible the tires have a differant compound or are not broken in? New tires will have a lot more squirm from the tread than worn or shaved tires.

Check to make sure you have the KDW and not the KDWS.

Your issue is not with tire size but, rather the specific tires ability ...


and 215's are still made by some companys just not the KDW

I definately got the KDW tires. I checked BF Goodrich's website to find the "service description" of the 215 is a 90Y, whereas the 205 is an 89Y, could this mean something about the compound?

In respect to the comment about 205 being a better size for the rim, where did this come from? BFGoodrich list the rim sizes for the 225 to be from 6.0-8.0 (our 7in falls right in the middle), whereas the 205 and 215s are from 5.5 and 6.0 - 7.5 (better sized for a 6.5in rim) Am I missing something? I see some BMW M's have the rims being wider than tires, is there a benefit to this? I could see less tire roll, but at the expense of contact patch?

Finally, on a side note to Luke. I purchased these tires from Belle Tire. They pricematched Tirerack+Shipping and Install. They told me they actually order from Tirerack Wholesale. I just want to know that I am not somehow taking business from tirerack. You provide an amazing service (especially at Contour.org), that I want to make sure I am rewarding with my business. I do however hate dealing with the UPS guy, squeezing 4 tires into a contour trunk, etc. Could you let me know that tirerack still makes money if belletire orders from tirerack for me?

Thanks
Geoff

My understanding is that SVT rims are 6.5", hence the comment regarding 205's being better suited for our rims. I would tend to disagree with this however, because different tires have different measurements even when listed as the same width. I think it pays to research individual tires to find out the actual diameter, tread width and section width. My $.02

Originally posted by geoffct:

---

I definately got the KDW tires. I checked BF Goodrich's website to find the "service description" of the 215 is a 90Y, whereas the 205 is an 89Y, could this mean something about the compound?

In respect to the comment about 205 being a better size for the rim, where did this come from? BFGoodrich list the rim sizes for the 225 to be from 6.0-8.0 (our 7in falls right in the middle), whereas the 205 and 215s are from 5.5 and 6.0 - 7.5 (better sized for a 6.5in rim) Am I missing something? I see some BMW M's have the rims being wider than tires, is there a benefit to this? I could see less tire roll, but at the expense of contact patch?

---

The 89 and 90 are the "load ratings". Related to the maximum permissible weight a tire can safely handle across all parts of its speed range rating. You'll notice that the "tuner" sizes of tires (say, 205/40/17) have some really low load ratings because of the shortness of their sidewall (among other things).

As for rim width, our 6.5" rims are fine with 205 or 215 or 225 tires. The advantage to a slightly wider rim would be a sidewall that would be more vertical, which would be stiffer and give slightly sharper dynamic response.

You'll notice the wide rims on BMW 3-series, where they put crazy 17x7" rims with 205/50/17 tires. Very stiff, short sidewall. Even the 16" rims are 16x7 with 205/55/16 tires for maximizing the tread footprint.

Kerry