Tire questions
- Thread starter GGM
- Start date
well it means the sidewall will have the same ratio to the width. i think im not sure, that that 2nd tire will not work without regearing bc look, the rim is bigger, meaning that the sidewall ratio should get small, like 35 or something, and the tires are wider, makeing the sidewall ratio agian smaller, but its still 40 meaning that the diameter of teh tire is not the same as the one u have right now, its bigger. i think on the Toyo Tire Company website, there is a chart telling u which tires will have the same diameter but with different widths and rim sizes. also are u changing, ur rims ??? bc 17>>18 ???
Actually I have a tire-related question as well. I'm planning to slap some of those style 135 wheels on my 325 and thought of something... how do you rotate tires when the rear tires are a different size? Just swap sides every so often?! Or, would it be wiser to buy 4 front rims? I doubt I'll need the wider tires in the rear on a 325... Thoughts?
Basically the aspect ratio (the 40) is the size in % of the sidewall in comparison to the width of the tire. So if you have a 255 width, then the sidewall height is 40% of that. That's why the M5 has 225/40 18" front tires, and the backs are 255/35 18". That way the sidewall height is equal on both wheels.
At least I'm pretty sure that's how it is...
At least I'm pretty sure that's how it is...
Thanks for the info guys! Beemerworld, you answered another one of my questions about the speed too!
I am planning on getting 18" rims hence the 18" tires.
Now, i've heard different stories about when changing wheels at home and tightening the bolts, some people say you need a specific torque and some just tighten the wheel on so it's tight. Am i going to be able to change the wheel and tighten it on and not worry about it or is torque a big thing to worry about?
I am planning on getting 18" rims hence the 18" tires.
Now, i've heard different stories about when changing wheels at home and tightening the bolts, some people say you need a specific torque and some just tighten the wheel on so it's tight. Am i going to be able to change the wheel and tighten it on and not worry about it or is torque a big thing to worry about?
ok in order for ur speedometer to not be ****ed up u need to get tries that have the same diameter as urs, so naturally, the sidewall will be thinner. this doesnt nessisarily mean that u need 40 series, bc thats not a direct measurment of the sidewall, its a ratio of the sidewall to the width. for example: the m3 is 225/45 in front, and 255/40 in back. in the back the sidewall is the same as front, but since the tire is wider, u run a 40 series bc now that same sidewall width is only 40% of the width when in the narrower fornt its 45%, get it ? ok so right now u run a 205/50. ok now to run an 18'' rim, u can get a 225, or 255 or something like that, with lower and lower series as the width goes up, but most likley u will need to get 225/40/18. if ur not sure, go to tirerack, look up ur model, and click 18'' tires and it will show tires to fit that car w/o messin teh gearing.
If you are upgrading to larger wheels and wider tires, and especially with staggered wheels, I'd assume they would be performance tires? Most performance tires are directional tires and cannot be rotated. Just as in my situation, I can't rotate my tires, and the e39 wheels are alligned such that the rear tires wear on the insides. So I just have to suck it up and bear with it!
CosmosBlack rotating tires doesn't mean turn it to the other direction. It means swaping the wheels from the rear axle to the front axle in cross direction.
Front left to rear right
Front right to rear left
Rear left to Front right
Rear right to Front left
Of course you can't do that if you are using wider tires in the back. But he doesn't need to do that if the alignment is perfect.
Thats where is your problem on your 528i, your alignment is not good on the rear axle. The best is to do a new 4 wheel alignment. You have too much of negative Camber.
Front left to rear right
Front right to rear left
Rear left to Front right
Rear right to Front left
Of course you can't do that if you are using wider tires in the back. But he doesn't need to do that if the alignment is perfect.
Thats where is your problem on your 528i, your alignment is not good on the rear axle. The best is to do a new 4 wheel alignment. You have too much of negative Camber.
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QUOTE]Originally posted by Beemerworld
Thats where is your problem on your 528i, your alignment is not good on the rear axle. The best is to do a new 4 wheel alignment. You have too much of negative Camber. [/QUOTE]
I understand completely what you are saying beemerworld, but on my 540i (not 528i), according to my dealer and my mechanic, the alignment settings for the rear wheels do cause the rear tires to wear on the insides. It is also a known common problem with e39s I believe.
When I installed new tires, I brought up the concern coz within a few weeks the rear tires were already showing slight visible wear on the insides. They told me that's how they are supposed to be set. I asked if they could compensate and do a little adjustment for the tire's sake, they said yes, but it's not factory recommendations. It might affect handling and balance. (I guess how the car behaves in hard corners etc.)
Thats where is your problem on your 528i, your alignment is not good on the rear axle. The best is to do a new 4 wheel alignment. You have too much of negative Camber. [/QUOTE]
I understand completely what you are saying beemerworld, but on my 540i (not 528i), according to my dealer and my mechanic, the alignment settings for the rear wheels do cause the rear tires to wear on the insides. It is also a known common problem with e39s I believe.
When I installed new tires, I brought up the concern coz within a few weeks the rear tires were already showing slight visible wear on the insides. They told me that's how they are supposed to be set. I asked if they could compensate and do a little adjustment for the tire's sake, they said yes, but it's not factory recommendations. It might affect handling and balance. (I guess how the car behaves in hard corners etc.)
i second, or is it third?? the non rotation rule on staggered rims. even if your tires aren't directional, like most of high perf tires, you can't rotate to have the fronts to be wider than the rear on a rear wheel drive cars.
also, swapping left and right sides of a rear, or fronts won't do anything, so if you go with unidirectional tires in a staggered setup, enjoy it for fast wearing high perf tires for all their worth then grab a new one.![[:p]](/images/smilies/tongue.png "Stick Out Tongue [:p]")
you still should balance tho..
also, swapping left and right sides of a rear, or fronts won't do anything, so if you go with unidirectional tires in a staggered setup, enjoy it for fast wearing high perf tires for all their worth then grab a new one.
you still should balance tho..CosmosBlack all BMW's have some negative camber set in the rear axle. This is normal and good! My M roadster also wears the inside portion of the tire more than the outside. And I have directional tires, 255/40/ZR17's in the rear and 235/45/ZR17's in front, so I cannot rotate tires, which BMW does not recommend in the first place.
As far as torquing your lug studs....it is a must that they be torqued. BMW's are known for loosing a wheel if improperly torqued. I have a Craftsman torque wrench that I keep just for that occassion. If I am repairing a flat on a highway, tighten them good and torque ASAP!
Tire rotation chart
As far as torquing your lug studs....it is a must that they be torqued. BMW's are known for loosing a wheel if improperly torqued. I have a Craftsman torque wrench that I keep just for that occassion. If I am repairing a flat on a highway, tighten them good and torque ASAP!
Tire rotation chart
CosmosBlack said:
thanks for the reassurance, bigdaddy!
Hey, you and I have identical wheel and tire sizes!![[thumb]](/images/smilies/icon_smile_thumb.gif "Thumbs Up [thumb]")
Hey, you and I have identical wheel and tire sizes!
![[hihi]](/images/smilies/icon_smile_hihi.gif "Hi Hi [hihi]"){kind=icon}