| Author |
Message |
Dave328GTB (Hardtop)
Junior Member
Username: Hardtop
Post Number: 148
Registered: 1-2002
| | Posted on Monday, May 20, 2002 - 9:11 pm: | |
Changing outside diameters very much can also screw up the ABS. No matter what width and aspect ratio you choose, you need to be as close as possible to stock OD or risk troubles. Ferrari speedos are inaccurate anyway, so who cares? |
Mark Eberhardt (Me_k)
New member
Username: Me_k
Post Number: 3
Registered: 5-2002
| | Posted on Monday, May 20, 2002 - 9:05 pm: | |
You might want to go to tirerack.com and look at the spec sheets for the diffent tires. The manufactures tend to bend the size rules a little so the actual tires might be closer (or worse)than the calculaion suggests. You can usually go to say a 225-45 to replace a 215-50 and get the same OD. Again check the spec sheet, going wider 1 size (from stock)shouldn't cause a clearance problem. I personally don't like to go more the +\- 0.5" from stock OD, that keeps the car looking right and your speedo within a couple mph. |
James Dixon (Omnadren250)
Junior Member
Username: Omnadren250
Post Number: 207
Registered: 7-2001
| | Posted on Monday, May 20, 2002 - 4:01 pm: | |
Najib,
The tires profile is smaller, meaning there is a bigger gap between the tire and the fender,which gives the illusion that the car is higher. It will be a small difference so it will no be very easy to tell. The car itself will be lower, but will appear to be higher.
Also it wont be lower by .5cm. the 5 number is the percentage of the width. for example, on a 225 55 16 tire. 225 is the width, 55 is the profile which is equal to 55% of the width(225) and 16 is obviously the diameter.
It's confusing, but that is how it is. Right now, my 1992 mustang has lower profile tires than stock, and it looks like a bloody 4x4 jeep.
|
Najib Amanullah (Najib)
Junior Member
Username: Najib
Post Number: 141
Registered: 4-2001
| | Posted on Monday, May 20, 2002 - 3:01 pm: | |
James, the Yokos are lower profile so the car should look lower by .5 cm...correct?!
Lawrence, what does the calculation translate to? Slower speed? I am not being sarcastic - just ignorance on my part. |
Lawrence Coppari (Lawrence)
New member
Username: Lawrence
Post Number: 22
Registered: 4-2002
| | Posted on Monday, May 20, 2002 - 2:01 pm: | |
Unloaded outer diameter of tire:
Multiply maximum width of tire by aspect ratio, then double and divide by 25.4. Then add to wheel size. So
255*.45*2/25.4+17 = 26.0 inches
255*.40*2/25.4+17 = 25.0 inches
This gives a ballpark figure. |
James Dixon (Omnadren250)
Junior Member
Username: Omnadren250
Post Number: 206
Registered: 7-2001
| | Posted on Monday, May 20, 2002 - 1:49 pm: | |
I have been in the same situation numerous times and if I were in this situation, I would go with the cheaper tire. Perhaps a true tire expert can offer some professional advice about this however.
The difference of 5 for each aspect ratio means that 5% of 215mm and 5% of 255mm will be subtracted from the profile of the tire. It will probably not affect performance, but will make your car look higher and may make the speedo inaccurate. |
Ron Thomas (Ronsupercar)
Junior Member
Username: Ronsupercar
Post Number: 66
Registered: 5-2002
| | Posted on Monday, May 20, 2002 - 1:32 pm: | |
The Yokohama tires are lower profile. The lower profile tire used may give you a different ride feel..
With a lower profile tire(less rubber between top of your rim to the ground) on aggressive driving on curves, your tires won't flex as much..
You may notice and feel bumps on the road a bit more..
I'm not sure if it will affect top speed in any way but you can ask your tire provider how it will affect that.... |
Stanley DiGuiseppi (Standig)
New member
Username: Standig
Post Number: 5
Registered: 5-2002
| | Posted on Monday, May 20, 2002 - 7:56 am: | |
I have a firm belief to put on what came off unless there is a lot of personal testimony that something is better. I knew the VP of Uniroyal tire who said they put the most amount of effort and quality control in making tires spected by car manufactures. I just put Bridgestone 01's on my 348 and it feels fine. |
Najib Amanullah (Najib)
Junior Member
Username: Najib
Post Number: 138
Registered: 4-2001
| | Posted on Monday, May 20, 2002 - 3:30 am: | |
I have Bridgestones on my 348 at present.
Front 215-50-17 and
Rear 255-45-17
Unfortunately, here I can only get 215-45-17 and 255-40-17 in Yokohama AVS or Bridgestone. Yokohamas ($150) cost 40% of the Brdgestones.
Would the slight difference in the profile of the tyres make much of a difference and should I go fo the Yokos? (I do not intend to track the car or set a new 0-60 Land Speed Record - not in a 348 anyway). |