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Discussion Starter · #1 ·
Hi Gary,

I'm looking for some all-season tires for my 2006 BMW 330I (17 inch - non SPORT). The stock size is 225/45/R17.

The roads are aweful up here and I'm looking to increase slightly the sidewall for comfort and rim protection. I had a low profile 18 inch setup that was very rough riding ... then went to 17 inch setup to lessen the jarring effect.

This time round I'm considering looking for a taller sidewall aspect, namely the 225/50/R17 size. Would this be the correct size to go one UP slightly (on overall diameter) ??

Aside from a slight speedometer error, any other side effects?

Thanks !!
 

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Hi Gary,

I'm looking for some all-season tires for my 2006 BMW 330I (17 inch - non SPORT). The stock size is 225/45/R17.

The roads are aweful up here and I'm looking to increase slightly the sidewall for comfort and rim protection. I had a low profile 18 inch setup that was very rough riding ... then went to 17 inch setup to lessen the jarring effect.

This time round I'm considering looking for a taller sidewall aspect, namely the 225/50/R17 size. Would this be the correct size to go one UP slightly (on overall diameter) ??

Aside from a slight speedometer error, any other side effects?
The correct size in a narrower 17-incher is 205/50R-17 and the car is sold with that size tire on it, although the vast majority will have 225/45R-17 or 18s. So your proposed 225/50R-17 is in fact two sizes larger than stock.

We will see what Gary has to say, but in my opinion, 215/50R-17 (one size larger than stock) would be better if you want to slightly upsize while avoiding any clearance or rubbing issues.
 

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Discussion Starter · #3 ·
I'm confused ... for my 2006 bmw 330i (base) your system shows stock tires to be :

Equipment Size: 225/45-17

That's the same size as my stock 17 inch winter set btw ...

So isn't the 225/45-17 the regular stock tire size ? I am not sure where you are getting the 205 size from ??

Cheers, John.
 

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I'm confused ... for my 2006 bmw 330i (base) your system shows stock tires to be :

Equipment Size: 225/45-17

That's the same size as my stock 17 inch winter set btw ...

So isn't the 225/45-17 the regular stock tire size ? I am not sure where you are getting the 205 size from ??
205/50R-17 tires were fitted to some E90 BMWs. In the US market, I think AWD models only. A 205/50R-17 and a 225/45R-17 are the same diameter and therefore a 205/50 is the perfect higher-profile equivalent to a 225/45. To compare different profile tires, look at the manufacturer's specs on the Tire Rack web site for a potential tire that is offered in a range of these sizes and you will see that the diameter and the revs/mile of 205/50 and 225/45 are the same. (dimensions vary among brands/models of tires so they are not always exact.)

A list of non-staggered tire sizes for various models of E90 BMWs:
>>205/55R-16 on 16-inch wheels. These were standard on US-market 325s; they may not fit over the larger brakes of 330s; in any event, I think you already have the 17 wheels...) The 205/55R-16 can be replaced with a slightly wider/lower profile 225/50R-16.
>> 205/50R-17 or 225/45R-17 on 17-inch wheels. In the US market, I think the 205/50s were only fitted to AWD models without sport package.

One more wrinkle: If you wish to put a narrower/higher-profile tire (205/50) on a wheel that fits a 225/45R-17, you must determine that the tire manufacturer approves the fitment of that tire to a rim of that width. An 8-inch wide rim = 203mm, which is just about the same width as the tire; I believe that most mfrs allow a 205 tire on an 8-inch rim, but you will need to check and confirm that depending on what tire you choose. Many folks will tell you that fitting that narrow of a tire on that wide of a rim is not a good idea. For instance, the wheel will be more vulnerable to scrapes as the narrower tire does not protrude out and help protect it as much. In any event, if you upsize one to a 215/50 that will be less of an issue.
 

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205/50R-17 tires were fitted to some E90 BMWs. In the US market, I think AWD models only. A 205/50R-17 and a 225/45R-17 are the same diameter and therefore a 205/50 is the perfect higher-profile equivalent to a 225/45. To compare different profile tires, look at the manufacturer's specs on the Tire Rack web site for a potential tire that is offered in a range of these sizes and you will see that the diameter and the revs/mile of 205/50 and 225/45 are the same. (dimensions vary among brands/models of tires so they are not always exact.)

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If the two tires have the same diameter and the same rim size (17"), then they have the same profile....

So.. 205/50-17 aren't any higher profile than 225/45-17.... The 2nd number is a percentage.... multiply it by the first number to get the profile in millimeters.. (ex: 205 X 50 = 102.5 225 X 45 = 101.25 virtually, the same..)

If you want a cushier ride, ditch the runflats, and get some Grand Touring all-seasons... That is about your only option...

regards,
kyfdx
 

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If the two tires have the same diameter and the same rim size (17"), then they have the same profile....

So.. 205/50-17 aren't any higher profile than 225/45-17.... The 2nd number is a percentage.... multiply it by the first number to get the profile in millimeters.. (ex: 205 X 50 = 102.5 225 X 45 = 101.25 virtually, the same..)
No, they do not have the same profile -- the profile is the percentage as you've indcated and 50 is indeed greater than 45. What is the same is the sidewall height or the overall diameter of the tire or the rolling circumference (revs/mile.) Your math is fine and shows that 205/50R-17 and 225/45R-17 are equivalent sizes.

So 205/50R-17 (or 215/50R-17 since the OP is considering putting one size larger on his wheels) would give a cushier ride, at the expense of handling. But the differences are tiny. I agree with you that his best choice is a tire optimized for comfort rather than sport, but the original question was tire size/sidewall height.
 

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Discussion Starter · #7 ·
Hi all,

Thanks for the input ...

btw - Just to clarify - the tires on the 17 inch rims NOW are: 225/45-17 . The new tires will be going on these very same 17 inch rims.

Another point is that the 330i is in fact the SPORT model ... just in case that impacts what is possible given the ride height/brakes and suspension.

ps - I am considering the CONTI Extremecontact DWS all seasons ... but this car sits alot since I live downtown ... and I've heard these tires 'flatten' rather easily.

pss - YES, I'm looking for comfort to ease out the bumps .

Cheers, J.
 

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Hi all,

Thanks for the input ...

btw - Just to clarify - the tires on the 17 inch rims NOW are: 225/45-17 . The new tires will be going on these very same 17 inch rims.

Another point is that the 330i is in fact the SPORT model ... just in case that impacts what is possible given the ride height/brakes and suspension.

ps - I am considering the CONTI Extremecontact DWS all seasons ... but this car sits alot since I live downtown ... and I've heard these tires 'flatten' rather easily.

pss - YES, I'm looking for comfort to ease out the bumps .
Didn't realize the car had the sport package, but it doesn't matter for the purposes of getting new, more comfort-oriented tires. The sport package might be at least a bit of your problem, though -- but probably not worth going to all the hassle of swapping out suspension components.

I continue to think it will help a bit if you swap your 225/45R-17 for 215/50R-17 tires in a comfort-oriented tire. Tire Rack is an excellent source for figuring out what that tire would be, even if you will actually buy the tires elsewhere. Just to reiterate, with 215/50R-17 your speedometer will read slightly higher (which may be more accurate than now), your ride comfort (and probably tire noise as well) will improve and your handling will be a little less crisp. Also your fuel economy will improve and your acceleration will suffer -- a larger tire results in the last two factors. However, all these changes will be very slight -- my gut feeling is in the single digit percentage range.
 

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Discussion Starter · #9 ·
The car is now riding on my staggered 18 inch rim/tire setup ... the other 17's I mentioned have currently have winter rubber on them right now. The plan is to sell my 18 inch setup ... then pull the winter rubber off the 17's ... and put conti DWS A/S rubber on the 17 inch (winter) rims.

cheers.
 

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No, they do not have the same profile -- the profile is the percentage as you've indcated and 50 is indeed greater than 45. What is the same is the sidewall height or the overall diameter of the tire or the rolling circumference (revs/mile.) Your math is fine and shows that 205/50R-17 and 225/45R-17 are equivalent sizes.

So 205/50R-17 (or 215/50R-17 since the OP is considering putting one size larger on his wheels) would give a cushier ride, at the expense of handling. But the differences are tiny. I agree with you that his best choice is a tire optimized for comfort rather than sport, but the original question was tire size/sidewall height.
FACT:

I don't want to beat a dead horse.... but, for the purposes of tires.. profile = sidewall height.. They are one and the same... profile is a picture of the tire from the side (just like a human being! lol)

OPINION:

IMO, I don't want to put "taller" tires on my car... I'd look for a softer riding tire in the same size.. YMMV

For the OP, just changing to 17" all-seasons from the 18" summer rubber you have now is going to make all the difference in the world. If you go a little farther, and switch away from RFT tires, you'll get an even better ride...

You already know how your winter set rides... a good set of all-seasons will ride similarly, but with better handling (though, not nearly as tight as those 18" summer tires.

regards,
kyfdx
 

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Discussion Starter · #11 ·
All good points ...

I'm just considering my options ... the city roads are beyond brutal bad up here in Canada ... cracks and holes every 8 feet or so ... so every 'little bit' helps (-;

ps - if you think NYC roads are bad ... try Montreal Canada )-:
 

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Discussion Starter · #12 ·
Hoping Gary can chime in here ... to clarify, I just want to know what would be a slightly larger sidewall from the stock size 225/45/R17 ...
 

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Discussion Starter · #14 ·
One more quick one regarding FIT ... are you saying 'fit' on the rim itself is not guaranteed ? or fit within the wheel well area of the car (i.e rubbing potentially) ??

I think you meant wheel well FIT ... but I'd better check (-;

Thanks Gary, John.
 

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One more quick one regarding FIT ... are you saying 'fit' on the rim itself is not guaranteed ? or fit within the wheel well area of the car (i.e rubbing potentially) ??

I think you meant wheel well FIT ... but I'd better check (-;

Thanks Gary, John.
Definitely meant wheel well FIT.

dj
 

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Hopefully not beating a dead horse here, but Gary: The key question is that the poster has a set of 17" wheels and wants to fit tires that emphasize comfort over sport.

jlsbimmer: I don't think you've told us the WIDTH of your 17-inch wheels and that potentially matters in this case. Width?

So:
-- Stay with 225/45R-17 but look for a tire maximizing comfort?
-- Fit 205/50R-17 or (one size larger) 215/50R-17?
-- Other solution?

And I imagine the poster would appreciate a recommendation for a "best" tire for his wants.
 

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Discussion Starter · #18 ·
Regarding the WIDTH of my 17 inch rims ... I can only tell you that the tires on these 17 inch rims right NOW are: 225/45-17 ... so I guess the width is 225 ??

btw - These are my current winter tires on the 17's.

Cheers.
 

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Regarding the WIDTH of my 17 inch rims ... I can only tell you that the tires on these 17 inch rims right NOW are: 225/45-17 ... so I guess the width is 225 ??

btw - These are my current winter tires on the 17's.

Cheers.
Wheels are invariably designated in inch widths. Original equipment BMW 17" wheels vary from 7 inches to 8.5 inches. Most are 8 inches wide (203mm.)

I just remembered you have sport package with 18s so you no doubt do have wider rims (and wider, lower profile tires) in the rear for your 18s. But your 17s are not necessarily from a sport pkg car.
 

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Regardless of whether he uses 215/50R17 or 225/45R17 (there is VERY little difference at all in sidewall height between those two sizes...certainly not close enough to notice a ride difference) it is the *type* of tire that will affect ride much more than the size. Consider an H rated all season tire for the softest ride like the Yokohama Envigor or Continental Pro Contact. Just be aware this will not be a sporty setup...expect slow steering response and handling/cornering that is not typical of what most expect out of a BMW.
 
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