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Selecting right tye size

I have a 1991 honda accord altered its original engine with toyota 2000 d turbo and its automatic gear box with a compatible 5 speed gear box. plz suggest me the right rim size and tyre size so to get good optimum performance. also want to know its performance in terms of Bhp, CC, top speed

If you are going to talk about tires, you need to talk in their terms - traction, wear, steering crispness, etc. - what are your expectations?

First you need to read up about tires here:

http://www.tirerack.com/tires/tiretech/tiretech.jsp

Tire Rack has done a pretty decent job of covering the info you need - and providing a way to find what you need. Reading a lot into your post, I would think you want at least a V rated tire - and perhaps even a Z rated. The size will not matter much if you select the right kind of tire.

But you will have to do the reading to see if that compromise works for you. Hint: A Z rated tire tends to emphasize grip and handling crispness at the expense of wear and ride harshness.

The size will not matter much if you select the right kind of tire.

He’s asking about rim and tire size and that will affect total gearing ratio so, yes, it does matter.

OP, what are you trying to do with the car? Certainly you had a plan when you started this exercise. If you want good advice, you need to share your vision…

Here’s a thought: since you’ve replaced the entire Honda powertrain with a Toyota powertrain, using the same size wheels and tires as the toyota used with this powertrain will give you the same final drive as the donor Toyota had. Smaller diameter wheel/tire combinations will give you more bottom-end torque but lower your top-end. Larger diameter combinations will hurt your takeoffs but give you a higher top end.

Whatever you choose to do, keeping the rotating mass (wheel + tire weight) as low as possible and keeping the mass as close to the axis of rotation will benefit your ability to get the tires rolling. This is generally acomplished with light alloy wheels (choose carefully, not all alloy wheels are light) of a larger diameter with low profile tires on them. Lots of tire tends to be heavier, and using the suggested combination keeps the weight that’s away from the rotating axis as light as possible.

If the donor was a truck, your wheel wells will limit your wheel/tire combination to a lesser diameter than the truck used, so you’ll have no choice but to accept lower top end speeds.

You’re right, but it really wasn’t clear what the OP poster wanted.

I am surprised that a tire calculator hasn’t been mentioned yet. Here’s one:

This is the only one I know of that gets the rolling diameter correct. All the others assume the measured diameter is the rolling diameter - not true.