Thinking of getting 265/35r18 tires for track use.

[cOoTeR]

I've been looking into tires a lot lately while I'm waiting for my konig 18x9.5 rims to come in. I'm leaning towards the Hankook ventus RS-4 tires based on other forum members suggestion and the balance between tread wear, traction, cost and weight.

The ideal size for my model 3 performance is 265/40r18 but I'm thinking of going with the 265/35r18. The 265/35 is about 1.1" smaller in diameter and about 1lb lighter. Smaller diameter and lighter weight should make for slightly quicker acceleration. But the smaller tire will cause the speedometer to read higher and the odometer to add more miles than the car is actually traveling.

Since the tires will be going on a set of rims that will pretty much only be used at the track the speedometer issue is irrelevant and the odometer issue will only have a small impact overall. I know top speed will drop but I have had my car at several events and have never come close to topping it out. If I need to go over 150mph I'll use my motorcycle.

Are there any issues with going to a 25.1" diameter tire that I'm not thinking of?

 

[Orwell]

Check your ride height if you're already lowered.

Do some 1/4 mile runs also and let us know what happens.

 

[MasterC17]

Acceleration above ~60mph will be slower with smaller tires (gearing/power-band). So for road-course use (not drag strip), taller tires will actually work better.

 

[MountainPass]

Acceleration above ~60mph will be slower with smaller tires (gearing/power-band). So for road-course use (not drag strip), taller tires will actually work better.

MasterC17 knows what up, we suffered for it at BRP when we competed at GTA because the overall diameter was shorter than stock. The Model 3 already runs out of steam at speed, let's try not to make it worse!

 

[MasterC17]

MasterC17 knows what up, we suffered for it at BRP when we competed at GTA because the overall diameter was shorter than stock. The Model 3 already runs out of steam at speed, let's try not to make it worse!

It's interesting how it seems to fall off right about ~110mph. Looking back at my videos, I can keep up with similar power/weight ratio cars easily from 60mph, but after 110 the same cars pull car lengths quite fast.

I'm assuming Plaid won't have this issue

 

[Lunares]

It's interesting how it seems to fall off right about ~110mph. Looking back at my videos, I can keep up with similar power/weight ratio cars easily from 60mph, but after 110 the same cars pull car lengths quite fast.

I'm assuming Plaid won't have this issue

So saying 265-40-18 is faster on a track, all things the same, compared to 265-35-18?

Wondering how the inertial mass increase compares with the reduced diameter

 

[MasterC17]

So saying 265-40-18 is faster on a track, all things the same, compared to 265-35-18?

Wondering how the inertial mass increase compares with the reduced diameter

Yes, that is correct. Pretty much any road course you are driving 60mph+ 90% of the time. Since the larger diameter tire basically shifts the power curve higher, you will be able to put down more power at the same speed given everything else equal. It's not a huge difference, but it is more than the small amount of weight you would save with a smaller tire.

 

[mattack4000]

I am curious to see if the 9.5 will fit

 

[Lunares]

Yes, that is correct. Pretty much any road course you are driving 60mph+ 90% of the time. Since the larger diameter tire basically shifts the power curve higher, you will be able to put down more power at the same speed given everything else equal. It's not a huge difference, but it is more than the small amount of weight you would save with a smaller tire.

Unfortunately for an Re71r (since I mostly autox) my choices are 265-35-18 or 265-45-18 and the latter tire is much larger.

At 80 mph, the 265-35-18 tire should have the motor running at 9563 rpm while a stock tire would run at 9191 rpm.

https://i1.wp.com/www.mountainpassp...la-Model-3-P3D-SOC-Dyno-Test.png?w=1488&ssl=1

Here's mountain pass's dyno data. Looks like about 12 ft-lbs of torque difference at those rpms.

A 275-35-18 would be better if i can fit it from a diameter point if view.

 

[mattack4000]

I have 265 40 18 that I can test fit as soon as I get my car

 

[cOoTeR]

Thanks guys.