Bob05tl

Has anyone replaced the stock tires with wider ones on the stock rims? Like 245/45/17? If so, how much did it help with rim protection? I like the stock rims, but can't stand the curb rash!!!

cM3go

245 would definetly give you better rim protection, but I wouldn't exceed 245 (i.e. 255 or 265) on the OEM wheel it'll start throwing your speedo off drastically

Bob05tl

Thanks. P.S. If anyone has pictures after they did upgrade, Please post!!!!

cM3go

I don't think you'd be able to notice the 10mm tire width difference in a picture

bluenoise

How would tire width affect speedometer calibration? I can see diameter having an effect, but not width.

Bob05tl

I was hoping for a side view picture to show how much more protection there would be with the 245 vs 235.

I know the a-spec rims had major problems with overhand, but I feel like the standard tires are undersized as well. I considered replacing the 17" with the a-spec, but would still have the same problem.

So, step one is to put 245/45/17 tires first to see if this helps/solves the problem.

Prolanman

Consider a tire with a built in rim protector if protecting your rim is a major concern. I have the stock Michelins and they have a rim protector as do most Michelins. I believe that Falkens also have a rim protector.

Bob05tl

Thanks. I am looking at the Proxes 4, they have a rim protector as do the Bridgestones (my understanding of the rim protector is the gap/overhang from the rim and the sidewall of the tire). The problem for me is that the tire is about 5 mm outside the rim, this even the littlest rub causes rim rash.

dsc888

I will play devil's advocate and remind you guys that the 245 tires will probably weigh a little more and can hurt performance. It's something that I would consider when upgrading tires. It's a good idea to check out the difference on the tire manufacturer's website. Personally, I have learned to parallel park my TL with enough precision that I have not scraped a rim in the last 8 months by using the auto tilt mirrors and going a little slower. It's just food for thought.

dsc888

Contivity

The second portion of the number (45 for 235/45/17) is in percentage of the tire's width, thus having 45% of 245 instead of 235 would throw off the height by about 9mm (4.5 mm X 2).

JOES05tl

What!?!
- oh by the way, the girl in that picture is SMOKIN' HOT!

Contivity

JOE: if you're referring to my post the let me explain it in more detail.

When you have 235/45/17 tire, the width of your tire is 235mm. Thus 45% of 235 is 105.75mm which means that you have 105.75mm of sidewall and an increase of 211.5 mm (105.75 X 2) the radius of the 17" wheel. The factor of two comes because you have 2 sidewalls, the top and bottom sidewall. With 17" (431.8mm) wheel the total wheel + tire size is 643.3 mm.

Now if you have 245/45/17 tire, the width is 245mm. Thus 45% of 245 is 110.25mm. Thus you're riding on 652.3 mm wheel + tire combination. Therefore you have 9mm bigger wheel + tire combination.

At 643.3 mm diameter, you'd be travelling 2021.2486 mm per revolution (assuming pi=3.142). At 652.3 mm, you'd be travelling 2049.5266 mm per revolution (with the same assumption on pi). Therefore you're travelling 28.278 mm more per revolution. Which means that you're travelling more per revolution. Since our speedometer is used to measure the speed by the number of revolutions, it would be off by a certain factor.

In this case, it's (28.278mm/2021.2486mm) which is equivalent to (9mm/643.3mm) = 1.399%. Therefore, if you're travelling at 65mph, you're actually travelling at 65.909mph. Therefore you're actually moving 0.909mph faster than that's recorded by the speedometer.

Since this is in percentage, the difference between the speedometer and your actual speed is greater at higher speed. To see the difference, when your speedometer shows 100mph, you're actually moving at 101.399mph. That's 1.399 mph faster than the speedometer.

That is, however, not counting the actual error in the calibration of the speedometer. And also even if I'm using mm in my calculation, the conversion to mph still holds true. Moving from mm to mph is done by multiplications by certain factor, and the conversion is done using percentage. This is the same idea when calculating percentage of error based on the diameter of wheel+tire or by the distance travelled (the circumference of a circle has a factor of pi).

The picture of the girl on my avatar is a Japanese singer.

EDIT: if anyone find any mistake, please correct me.

bluenoise

D'oh!

I forgot about that.

Contivity

Actually I didn't know about it until yesterday (the day I write the previous message)... I was talking with a friend and he told me about it... I kept on thinking that the 45 is in certain measurement like 4.5 inch or sumthing...

Bob05tl

Contivity, First of all thanks so much for all the information. I knew about some of it (45 is a % of the width), and caculated the difference with a 245/45 vs 235/45.

What I basically came up with knowing that 1" is equal to 25.4 mm, was that I would be adding 9mm (less than 1/2 an inch) in total tire/wheel dimension. Knowing that, I thought that if I put 18" rims (A-Spec) with 235/40/18, the 18" rims and tires would be even bigger. Thus, I felt that this would still work and have a minimal if any affect on the spedometer.

Also, I thought it would actually help in handling because I would have more rubber in contact with the road.

On the other point of being careful durring parking, I totally agree. Both of my rubbs happened while trying to park next to curbs in a parking lot (trying to protect against door dings). The scraps are VERY minor, but what bothers me most is that if you barely touch the curb, I get no marks on the tires, and scraps on the rims. To me, that is not right. There should be some kind of protection from the tire. Thus, moving to a 245 vs 235.

Hopefully this all makes sense. I would appreciate any feedback.

audi_to_TL

iTrader: (2)

This looks quite confusing....but if u copy and paste it into Microsoft Excel it comes out clear and easy to read....it should answer most questions regarding tire sizes and diameter changes etc. Hope this helps.





Size Service Load Speed SideWall Article Approved Measuring Overall Overall Tread Static Tread RPM RPK Tire UTQG Notes
Description Range Rating Styling Number Rim Rim Tire Section Width Load Depth Weight
Widths Width Diameter Width Radius (32")
225/60R16 98W W BW 148-682 6.0-8.0 (6.5) 26.6 8.9 7.3 12.1 10 783 27 340 AAA *
205/55R15 88W W BW 148-699 5.5-7.5 (6.5) 23.9 8.3 6.6 11.0 10 872 23 340 AAA
205/55R16 91W W BW 148-529 5.5-7.5 (6.5) 24.9 8.3 6.6 11.5 10 837 25 340 AAA
225/55R16 95W W BW 148-546 6.0-8.0 (7.0) 25.7 9.1 7.2 11.8 10 811 27 340 AAA
195/50R15 82W W BW 148-444 5.5-7.0 (6.0) 22.7 7.8 6.3 10.5 10 918 19 340 AAA
205/50R15 86W W BW 148-597 5.5-7.5 (6.5) 22.8 8.3 6.6 10.5 10 914 22 340 AAA
205/50R16 87W W BW 148-410 5.5-7.5 (6.5) 24.1 8.3 6.6 11.1 10 864 24 340 AAA
225/50R16 92W W BW 148-376 6.0-8.0 (7.0) 24.9 9.1 7.2 11.5 10 837 26 340 AAA
245/50R16 97W W BW 148-495 7.0-8.5 (7.5) 25.7 9.9 7.9 11.8 10 811 29 340 AAA
205/50R17 89W W BW 148-852 5.5-7.5 (6.5) 25.1 8.3 6.6 11.6 10 830 26 340 AAA
255/50R17 101W W BW 148-631 7.0-9.0 (8.0) 27.1 10.4 8.2 12.4 10 769 33 340 AAA
205/45R16 83W W BW 148-835 6.5-7.5 (7.0) 23.2 8.2 7.1 10.8 10 898 22 340 AAA
245/45R16 94W W BW 148-767 7.5-9.0 (8.0) 24.6 9.6 8.6 11.3 10 847 26 340 AAA
215/45R17 87W W BW 148-818 7.0-8.0 (7.0) 24.6 8.5 7.5 11.4 10 847 23 340 AAA
225/45R17 91W W BW 148-325 7.0-8.5 (7.5) 25.0 8.9 7.9 11.6 10 833 26 340 AAA
235/45R17 94W W BW 148-461 7.5-9.0 (8.0) 25.4 9.4 8.1 11.8 10 820 27 340 AAA
245/45R17 95W W BW 148-359 7.5-9.0 (8.0) 25.7 9.6 8.6 11.9 10 811 28 340 AAA
205/40R17 80W W BW 148-427 7.0-8.0 (7.5) 23.5 8.4 7.0 11.0 10 886 20 340 AAA
215/40R17 83W W BW 148-750 7.0-8.5 (7.5) 23.8 8.7 7.4 11.1 10 875 23 340 AAA
235/40R17 90W W BW 148-869 8.0-9.5 (8.5) 24.4 9.6 8.0 11.4 10 854 25 340 AAA
245/40R17 91W W BW 148-478 8.0-9.5 (8.5) 24.7 9.8 8.5 11.5 10 843 27 340 AAA
255/40R17 94W W BW 148-614 8.5-10.0 (9.0) 25.0 10.3 8.8 11.6 10 833 29 340 AAA
275/40R17 98W W BW 148-648 9.0-11.0 (9.5) 25.7 11.0 9.5 11.9 10 811 30 340 AAA
225/40R18 88W W BW 148-665 7.5-9.0 (8.0) 25.1 9.1 7.8 11.8 10 830 24 340 AAA
235/40R18 91W W BW 148-716 8.0-9.5 (8.5) 25.4 9.6 8.0 11.9 10 820 26 340 AAA
245/40R18 93W W BW 148-580 8.0-9.5 (8.5) 25.7 9.8 8.5 12.0 10 811 27 340 AAA
215/35R18 80W W BW 148-920 7.0-8.5 (7.5) 23.9 8.7 7.4 11.3 10 872 21 340 AAA
215/35R18 84W XL W BW 058-778 () 340 AAA
265/35R18 93W W BW 148-801 9.0-10.5 (9.5) 25.3 10.7 9.1 11.8 10 823 28 340 AAA
255/35R20 93W W BW 148-886 8.5-10.0 (9.0) 27.0 10.3 8.8 12.7 10 772 29 340 AAA

audi_to_TL

iTrader: (2)

or maybe not...just PM me with yur email address and i will send it to u...i hope'd it would work but guess not.....anyone know how i can post a spreadsheet?

Contivity

I personally think that 1.39% is a small figure and if you don't really speed that much it doesn't really matter... My point of posting is only to clarify why 245 vs 235 would make the speedo inaccurate... 18" with 235/40/18 would have 1.9mm different from 235/45/17... thus 235/40/18 is still smaller than 245/45/17...

2LOW4U

stock is 25.326"
255/40 is 25.031"

the difference in the two will throw the speedo off 1.16%

I wouldn't call that a lot, thats 1 mph at 100...

Contivity

actually in this case you'd be traveeling slower than your speedo...

260 HP

iTrader: (3)

This is an easier way to calculate the difference among tires, courtesy of our friends at Miata.net:
http://www.miata.net/garage/tirecalc.html

Bob05tl

Here is the comparison from www.miata.net - Thanks!!!

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
235/45-17 4.2in 12.7in 25.3in 79.6in 796 0.0%
245/45-17 4.3in 12.8in 25.7in 80.7in 785 1.4%

265 ssi

just changed from the stock mich to 255/40-17 conti from a Audi A-6 4.2 V-8. The car looks a lot better but more important it corners so much better. Comptech rear bar should be here soon, I would like to buy the 6spd front bar after that.

Bob05tl

I need Pictures!!! Would love to see how the look and more important, how the cover the rims. Again, I was looking at 245/45/17's, but would love to see how the 255/40/17's look. Also, any issues with rubbing, fitment, etc.?

Pictures, Pictures, Pictures!!!!

05ssm

TOYO PROXES 4 in 245/45/17 are exactly the same weight as the OEM Turanza EL42's.

I've installed this size on my OEM 17's and it definitely looks better!

Bob05tl

Those are exactly the tires I am looking at. Do you have pictures!!! I want to see how the fill out the wheel well, fit, look on the rims, etc. I do not want to get to fat of tires. But would be very intrested in seeing these on you car.

stlgasman

So what is the consensus? Stay with the stock size or increase to 245/45/17?

Bob05tl

Hey there, did you ever get a chance to take some pictures of your new shoes? I would really be interested in seeing just how they look (how the fill up the wheel well and how much wider - protection - the give the rims)!!!

Love to see some!!!

SuitedAces

Realize that if you increase the width by 10mm, you will project that on both sides of the rim, meaning you will have *about* 5mm additional overhang on the curbside of the wheel. It won't look any different in pictures from stock. Too small of a difference to notice.

Bob05tl

Yes, I completely understand that!! I believe there will be enough difference to see just how much more they stick out. Also, since 45 is a percentage of the 245, the overall hight of the tire will be different, thus filling the wheel well a little more. Another reason to see how it looks.

Ideally, a 245/40 would be as close as you can get to the overall same dimensions of the stock 235/45's.

I know it is not much, but would still like to see the difference, especially since the tire (proxes) are exactly what I have been looking at. I would like to see the overall look!!! Make sense?

ITL

I'm looking at these tires in 235 width. My tire dealer told me the 245s would be too wide (I'm lowered)...do you have a drop with these tires?