Change sizes from 215/45-17 to 205/50-17 ?

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HTSS_TR

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Since I will drive some long distance about 375 miles from Irvine, CA to Phoenix, Arizona weekly I'm thinking about changing tire sizes of my Honda S2000.

OEM size are Front 215/45-17 Rear 245/40-17, currently it has 225/45-17 Front and 255/40-17 Rear. If I change the sizes to 205/50-17 Front and 235/45-17 Rear, is it will negatively effect the performance/handling much ? I think narrower tires will improve wet performance, but dry performance may suffer a little.

The new sizes will be about 10 mm narrower than OEM both front and rear, but they are about 2.5% larger in diameter, which will improve gas mileage a little. The pressure will be increased by 4-6 PSI to keep the tire loading the same. The speedometer will show slow by 2.5%.
 
If you increase your rear tire diameter, you will have to increase your front tire diameter too. Otherwise the ABS and stability control systems will process the that there's a change in front:rear tire RPM and will try to correct the problem typically by engaging the brake system.
 
Of course it will negatively affect handling. Narrower tires with larger sidewalls means less grip and more squidginess.

Why are you trying to squeeze MPGs (and dBs, from the other thread) out of an S2000?
 
Maybe on a track you will lose handling with that slight change in profile. However in daily driving where you don't expect to be arrested not an iota of difference. In a S2000 the handling is not coming from the tires like many regular vehicles, its the chassis and suspension design doing the vast majority of it.
 
If you're putting on 750 miles (round trip) a week consider buying a second commuter car. 40,000 miles a year your s2000 is going to get old fast (both in a mileage sense and in a driving a short wheelbase convertible for five hours at a crack sense).

But your tire plan does make sense to me. Large sidewalls should help some with both noise, tire life and ride. Make sure the load capacity is ok.
 
Originally Posted By: rjundi
In a S2000 the handling is not coming from the tires like many regular vehicles, its the chassis and suspension design doing the vast majority of it.

By that logic, why not switch to space saver spares on all four corners? Big reduction in rolling resistance, and big increase in ground pressure for better hydroplaning resistance!
wink.gif


Yes, the S2000 is all about its suspension and chassis. That doesn't mean the tires are unimportant, or that changes won't be noticeable. The only question is whether the OP will care, which isn't something any of us can answer. One can say, however, that someone who wouldn't notice differences among tires in daily driving probably isn't getting much out of an S2000 in the first place (compared to some of the alternatives).
 
Originally Posted By: bepperb
If you're putting on 750 miles (round trip) a week consider buying a second commuter car. 40,000 miles a year your s2000 is going to get old fast (both in a mileage sense and in a driving a short wheelbase convertible for five hours at a crack sense).

I agree with this sentiment. I love the S2000 to death but it just isn't the best car for frequent long-distance commutes. It wasn't intended to be. That's more BMW's and Mercedes's territory; even a Porsche Boxster would probably be better.

IMO, use the car as it was intended -- tires, gearing, and all -- or else drive something else. Modding is good for making a car a little bit better at what it already does well; once you start trying to make it do things it wasn't intended to do (i.e. sip gas and have low NVH in this case), it's more likely than not that you'll end up spending a lot of money and still not being satisfied.
 
The OEM tires are 215/45-17 Front and 245/40-17 Rear. I have a +0 sizes to 225/45-17 Front and 255/40-17 Rear, performance/handling improved on dry road but suffered a little on wet surface, since we rarely have rain in So Cal so that was not an issue.

Since I may dive the S2000 to/from Phoenix weekly and it is possible I may encounter wet roads, I think 10 mm narrower tires compares with OEM sizes will not effect handling on dry road much.

I need to think about -0 sizes for a while, and try to find a shop that will let me try these sizes for 30 days.

The other option is driving it to/from Phoenix once a month, to a fly on the other weekends.
 
Originally Posted By: d00df00d
Originally Posted By: bepperb
If you're putting on 750 miles (round trip) a week consider buying a second commuter car. 40,000 miles a year your s2000 is going to get old fast (both in a mileage sense and in a driving a short wheelbase convertible for five hours at a crack sense).

I agree with this sentiment. I love the S2000 to death but it just isn't the best car for frequent long-distance commutes. It wasn't intended to be. That's more BMW's and Mercedes's territory; even a Porsche Boxster would probably be better.

IMO, use the car as it was intended -- tires, gearing, and all -- or else drive something else. Modding is good for making a car a little bit better at what it already does well; once you start trying to make it do things it wasn't intended to do (i.e. sip gas and have low NVH in this case), it's more likely than not that you'll end up spending a lot of money and still not being satisfied.

You're right.

Changing tire sizes is a temporary mod, since the rear tires will wear out in about 12-15k miles if it doesn't work well than just change back to +0 sizes when new tires are needed.

Since the current tires have about 6-8k miles remaining, I don't need new tires for few months. I need to think more careful about tire sizes on the next change.
 
Originally Posted By: ProfPS
If you increase your rear tire diameter, you will have to increase your front tire diameter too. Otherwise the ABS and stability control systems will process the that there's a change in front:rear tire RPM and will try to correct the problem typically by engaging the brake system.


If true then another good reason to disable that junk, but it could only possibly apply to vehicles with a full-sized spare or run-flats and the ability to apply the brakes electronically. The '04 S2000 would have none of those things.

I'd probably want to stick with the OE sizes because those are the ones that will fit the rims best. But if you want to experiment then that's the only way to fully scratch that itch. I suspect the difference will be noticeable, but I don't think you'll gain or lose a whole lot in any area either way.
 
Originally Posted By: d00df00d
Originally Posted By: rjundi
In a S2000 the handling is not coming from the tires like many regular vehicles, its the chassis and suspension design doing the vast majority of it.

By that logic, why not switch to space saver spares on all four corners? Big reduction in rolling resistance, and big increase in ground pressure for better hydroplaning resistance!
wink.gif




If can read (the subject line), notice the relatively minor change of 215/45/17 to 205/50-17.

I happened to make this exact change on a somewhat performance oriented vehicle. It was not significantly different.
 
Another crazy idea: OEM sizes are 215/45-17 Front and 245/40-17 Rear, replacing sizes: 215/50-17 Front and 245/45-17 Rear.

Width are intact but side wall will be about 1/2" taller, and diameter is about 1" larger. The car will be about 1/2" higher off the ground.

What are negative effects ?
 
Originally Posted By: HTSS_TR
Another crazy idea: OEM sizes are 215/45-17 Front and 245/40-17 Rear, replacing sizes: 215/50-17 Front and 245/45-17 Rear.

Width are intact but side wall will be about 1/2" taller, and diameter is about 1" larger. The car will be about 1/2" higher off the ground.

What are negative effects ?


For the same tire in a taller size, expect a looser steering feel and more movement in cornering transitions due to extra sidewall flex, more lean in turns due to higher center of gravity, and slower acceleration due to taller effective gearing.

Advantages would be a possible fuel economy improvement during highway use, lower cruising rpm, and a softer ride.

So you'd mostly be sacrificing a little sportiness for a little comfort. The ride quality and steering feel would probably be the only things you'd really notice on the street.
 
I appreciate your comments, I think I agree with what you said. One thing I'm not sure is the affect on braking and ABS performance.

One time I had 245/45-17 instead of 235/45-17 installed on my E430, the ABS acting up within 2-3 weeks and malfunction warning appear on the onboard computer display. Changed it back to OEM size and no more problem with ABS.
 
Originally Posted By: HTSS_TR
I appreciate your comments, I think I agree with what you said. One thing I'm not sure is the affect on braking and ABS performance.

One time I had 245/45-17 instead of 235/45-17 installed on my E430, the ABS acting up within 2-3 weeks and malfunction warning appear on the onboard computer display. Changed it back to OEM size and no more problem with ABS.


No problem.

It shouldn't affect braking performance significantly, though you could get a warning if the computer is set up to monitor wheel speeds and sees unusual differences. Even if your car had that function, the tolerances would be pretty high on a vehicle with staggered wheel sizes because different manufacturers will have slightly different tire dimensions between sizes anyway. So I doubt it would be an issue. You'd have to check vehicle specific forums to be sure though.

Did you have larger tire sizes all around on the E430 or just one pair?
 
Originally Posted By: rpn453
Originally Posted By: HTSS_TR
I had all 4 larger tire sizes on the E430. Changed to OEM size of the same brand and no more ABS related problem.


That is really weird. It's not uncommon to change tire sizes. I don't even know how that car knows that the tires are different, or why it would care.

Sometimes this is used as a poor-man's tire pressure monitoring system. For example, in my 530i, if my tires are significantly underinflated, my ABS light will be flashing when I drive.

ABS has wheel speed sensors. I don't know how exactly this works, but possibly the car's ECU expects a certain RPM to wheel speed ratio. If that ratio falls outside of a preset range (as a result of underinflation or using a tire size that's notably taller/shorter than OEM), then ABS will complain.
 
There is only about 0.3" different in diameter between OEM size 235/45-17 and the +0 size 245/45-17, which is bout 1.4% according to Miata.net tire size calculator.

This experience has me concern about changing tire size (larger diameter) on the S2000.
 
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