175 19" ep500 vs ep600 tires for i3

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electronchaser

Well-known member
Joined
Nov 8, 2019
Messages
80
Hi , so I came across these ep500s which are suppose to be summer grand touring, vs the ep600 all season. Anyone have any experience with these ep500 on 19's? Any noticeable impact on ride comfort, sidewall rigidity, colder compound characteristics (avg winter low here is 50's).

Real world, will these really be able to enhance grip by any feel-able measure?

What can I expect them to deliver over the stock ep600s?

Was planning to throw 175's on the front for the time being (until I can source some i3s wheels so I can do a square 195 setup).

If there is a benefit to the ep500, could I just throw two on the front, and later replace the rears (currently riding on ep600s as well).

thanks


https://tires.costco.com/Tirecomparison?SearchID=2019%7C%7C%7CBMW%7C%7C%7Ci3%7C%7C%7CBase%7C%7C%7C1%7C%7C%7Cen-us%7C%7C%7CFalse%7C%7C%7C%7C%7C%7C__1033359%2C1033557
 
I have the ep500's in 20" and I have the Blizzaks in 19" so not a close comparison to your question but I can tell you that the ep500's ride and handling is much better than the skinny 19" Blizzaks. I am avoiding putting them on this year because I really don't like them. I hope to keep the summers on all year long.

I didn't now that the ep500's came in the 19" size but that sounds like a good choice.

One thing to consider is that the ep500's don't last a long time. Not like the good old days when you could get 50,000 miles out of your michelins. Expect more frequent tire changes with these.
 
PBNB said:
I have the ep500's in 20" and I have the Blizzaks in 19" so not a close comparison to your question but I can tell you that the ep500's ride and handling is much better than the skinny 19" Blizzaks. I am avoiding putting them on this year because I really don't like them. I hope to keep the summers on all year long.

I didn't now that the ep500's came in the 19" size but that sounds like a good choice.

One thing to consider is that the ep500's don't last a long time. Not like the good old days when you could get 50,000 miles out of your michelins. Expect more frequent tire changes with these.

Thanks for the feedback, I did drive an i3 non 's', with the 20 wheels and ep500 (didn't know it at the time), and it felt a bit more crash-y compared to the ride on 19's. Now I'm left wondering if the difference was from the extra inch of wheel diameter or from the ep500 tires/different compounds/sidewalls.

I'm totally good with even getting 15k out of them. comes out to a penny a mile. Prior to this last year, I used to always budget 100$ on top of my lease payments to pay for tires, since I'd get very little mileage out of them (too many launches and hardcore corners).
....so at 15K usage with the ep500/600 sets, i'd still be saving 0.02 a mile from my prior usage. :)

Can someone who knows how, quantify what that extra 20mm of extra rubber on each side of the car will translate to as far as sq inches of more grip etc.

Also as tires deform when weight is put on them and you actually get a little bulging, I'm imagining the bulge would be greater putting 175 width tires on a 5 inch rim, vs a 5.5inch rim. ?? Would this be beneficial in the sense of enhanced contact patch/grip? Since bulge would put even more thread into contact (granted running them a few psi lower to prevent center wear. :idea:
 
electronchaser said:
Can someone who knows how, quantify what that extra 20mm of extra rubber on each side of the car will translate to as far as sq inches of more grip.
Exactly 0 additional contact patch area because the contact patch area depends only on the tire's inflation pressure and the weight that it supports.
 
alohart said:
electronchaser said:
Can someone who knows how, quantify what that extra 20mm of extra rubber on each side of the car will translate to as far as sq inches of more grip.
Exactly 0 additional contact patch area because the contact patch area depends only on the tire's inflation pressure and the weight that it supports.

Could you elaborate on what you meant?
Weight wouldn't change, and wouldn't lower inflation pressure only allow even more contact between rubber and road.
 
electronchaser said:
alohart said:
electronchaser said:
Can someone who knows how, quantify what that extra 20mm of extra rubber on each side of the car will translate to as far as sq inches of more grip.
Exactly 0 additional contact patch area because the contact patch area depends only on the tire's inflation pressure and the weight that it supports.

Could you elaborate on what you meant?
Weight wouldn't change, and wouldn't lower inflation pressure only allow even more contact between rubber and road.

I believe that Art just said (and I'm sorry if I mis-inferred) that the contact patch would be W/P square inches regardless of the width of the tire where W is the weight in pounds supported by the tire and P is the inflation pressure in PSI.

If the hand of God (or the lift at Jiffy Lube*) were to slowly lower the car onto the pavement the tires would flatten and bulge until the contact with the pavement was that amount of area, at which point the car would stop settling since the force that the car was pressing down on the earth through the tires would equal the force with which the earth was pushing back and God could let go (or the lift would drop away from the frame).

*Back in the 80s, Jiffy Lube would always appear as "Iffy Lube" on my credit card statements, as if the billing system had a sense of humor.
 
electronchaser said:
Weight wouldn't change, and wouldn't lower inflation pressure only allow even more contact between rubber and road.
Yes, the contact patch area would increase with lower inflation pressure or with increased supported weight. However, tire size would not affect the contact patch area.
 
robthebold said:
electronchaser said:
alohart said:
Exactly 0 additional contact patch area because the contact patch area depends only on the tire's inflation pressure and the weight that it supports.

Could you elaborate on what you meant?
Weight wouldn't change, and wouldn't lower inflation pressure only allow even more contact between rubber and road.

I believe that Art just said (and I'm sorry if I mis-inferred) that the contact patch would be W/P square inches regardless of the width of the tire where W is the weight in pounds supported by the tire and P is the inflation pressure in PSI.

If the hand of God (or the lift at Jiffy Lube*) were to slowly lower the car onto the pavement the tires would flatten and bulge until the contact with the pavement was that amount of area, at which point the car would stop settling since the force that the car was pressing down on the earth through the tires would equal the force with which the earth was pushing back and God could let go (or the lift would drop away from the frame).

*Back in the 80s, Jiffy Lube would always appear as "Iffy Lube" on my credit card statements, as if the billing system had a sense of humor.
Hehehehehe, Thanks for the analogy, makes more sense. sort of. LOL @ 'iffy lube'

alohart said:
electronchaser said:
Weight wouldn't change, and wouldn't lower inflation pressure only allow even more contact between rubber and road.
Yes, the contact patch area would increase with lower inflation pressure or with increased supported weight. However, tire size would not affect the contact patch area.

So I should ask the question differently.

What benefit would 175mm tires upfront provide over stock 155mm tires, on same 5inch rim. Thanks so far!
 
The wider the tire, the wider the contact patch. Wider patches tend to benefit changes of direction. Longer patches benefit traction and braking. A narrower tire will have less drag, and, in snow, 'float' less, giving you a better chance of keeping moving (this is one reason why the winter tires are a square and narrow setup versus staggered and wider if you want best winter performance in snow).
 
jadnashuanh said:
The wider the tire, the wider the contact patch. Wider patches tend to benefit changes of direction. Longer patches benefit traction and braking. A narrower tire will have less drag, and, in snow, 'float' less, giving you a better chance of keeping moving (this is one reason why the winter tires are a square and narrow setup versus staggered and wider if you want best winter performance in snow).

Is this contradictory to other posts? or am I not getting the science behind it.

and adding 175mm to fronts would increase the width x the length of the patch correct?

Is it a formula that is used to calc this? I remember reading a formula somewhere, just cant find reference. Thx!
 
electronchaser said:
Is this contradictory to other posts? or am I not getting the science behind it.
Not contradictory

electronchaser said:
and adding 175mm to fronts would increase the width x the length of the patch correct?
The contact patch width would increase but its length would decrease to keep the area unchanged.

electronchaser said:
Is it a formula that is used to calc this?
The contact patch area is the product of the contact patch width and length. It's also the weight supported by the tire divided by the inflation pressure. So you could calculate the contact patch area knowing the supported weight and the inflation pressure. You could then calculate the contact patch length dividing the contact patch area by the width of the tread.
 
alohart said:
electronchaser said:
Is this contradictory to other posts? or am I not getting the science behind it.
Not contradictory

electronchaser said:
and adding 175mm to fronts would increase the width x the length of the patch correct?
The contact patch width would increase but its length would decrease to keep the area unchanged.

electronchaser said:
Is it a formula that is used to calc this?
The contact patch area is the product of the contact patch width and length. It's also the weight supported by the tire divided by the inflation pressure. So you could calculate the contact patch area knowing the supported weight and the inflation pressure. You could then calculate the contact patch length dividing the contact patch area by the width of the tread.

totally lost me ! lol
But I'd to understand, just can't understand.


Maybe I can start from even an easier step for me to understand better. So my question:
Putting 175mm tires up front, would create what benefit? And why would it create that benefit.
Would there be any drawbacks? (not caring for aero drag), but things like steering speed for example.

Thanks!
 
electronchaser said:
alohart said:
electronchaser said:
Is this contradictory to other posts? or am I not getting the science behind it.
Not contradictory

electronchaser said:
and adding 175mm to fronts would increase the width x the length of the patch correct?
The contact patch width would increase but its length would decrease to keep the area unchanged.

electronchaser said:
Is it a formula that is used to calc this?
The contact patch area is the product of the contact patch width and length. It's also the weight supported by the tire divided by the inflation pressure. So you could calculate the contact patch area knowing the supported weight and the inflation pressure. You could then calculate the contact patch length dividing the contact patch area by the width of the tread.

totally lost me ! lol
But I'd to understand, just can't understand.


Maybe I can start from even an easier step for me to understand better. So my question:
Putting 175mm tires up front, would create what benefit? And why would it create that benefit.
Would there be any drawbacks? (not caring for aero drag), but things like steering speed for example.

Thanks!

You would get better front end grip (laterally, turning) and worse accelerative/braking grip (minutely, splitting hairs). At the limit, a car with wider front tires would go to a more neutral balance, meaning less understeer and more oversteer. This is generally a good thing if you're looking for driving engagement and fun. Not so good with OEMs and lawyers, who would rather you plow off into the bushes than spin backwards into a tree. Many people have run 175s up front, with good results.

Since the front wheels do no driving, and the car has ABS, you wouldn't notice the reduction in longitudinal grip. Wider and narrower tires have the same contact patch area, because the weight of the vehicle doesn't change (holding it constant). The shape of the contact patch changes as tires get wider or narrower. Narrower tires have longer, narrower contact patches, while wider tires have wider, shorter contact patches. Drag racers put wide and tall tires on their cars because the height adds longitudinal grip on acceleration, and wider tires offer more friction area for a given height than narrow tires.

I think you may run into issues finding tire shops willing to put wider tires on the narrower wheels. We did, when trying to put blizzaks on staggered original wheels. Most tire shops nowadays only know how to read what the computer tells them to do. Very few know much beyond that.
 
The actual area of the contact patch stays the same when the inflation pressure stays the same. So, with a wider tire, that means the F-B patch would be smaller. On a narrower tire, the F-B length is longer.

So, do you want better traction during acceleration and braking, or cornering?

The summer tires are softer, so while the surface area will be the same, the grip increases. Those grip changes are not a factor of the patch size, but the rubber compound and tread design.
 
Stylngle2003 said:
electronchaser said:
alohart said:
Not contradictory


The contact patch width would increase but its length would decrease to keep the area unchanged.


The contact patch area is the product of the contact patch width and length. It's also the weight supported by the tire divided by the inflation pressure. So you could calculate the contact patch area knowing the supported weight and the inflation pressure. You could then calculate the contact patch length dividing the contact patch area by the width of the tread.

totally lost me ! lol
But I'd to understand, just can't understand.


Maybe I can start from even an easier step for me to understand better. So my question:
Putting 175mm tires up front, would create what benefit? And why would it create that benefit.
Would there be any drawbacks? (not caring for aero drag), but things like steering speed for example.

Thanks!

You would get better front end grip (laterally, turning) and worse accelerative/braking grip (minutely, splitting hairs). At the limit, a car with wider front tires would go to a more neutral balance, meaning less understeer and more oversteer. This is generally a good thing if you're looking for driving engagement and fun. Not so good with OEMs and lawyers, who would rather you plow off into the bushes than spin backwards into a tree. Many people have run 175s up front, with good results.

Since the front wheels do no driving, and the car has ABS, you wouldn't notice the reduction in longitudinal grip. Wider and narrower tires have the same contact patch area, because the weight of the vehicle doesn't change (holding it constant). The shape of the contact patch changes as tires get wider or narrower. Narrower tires have longer, narrower contact patches, while wider tires have wider, shorter contact patches. Drag racers put wide and tall tires on their cars because the height adds longitudinal grip on acceleration, and wider tires offer more friction area for a given height than narrow tires.

I think you may run into issues finding tire shops willing to put wider tires on the narrower wheels. We did, when trying to put blizzaks on staggered original wheels. Most tire shops nowadays only know how to read what the computer tells them to do. Very few know much beyond that.
Thank you so much!
and would 175 mounted on a 5inch front rim cause sidewall play or deflection or whatever. will that half inch of rim really play that big of a role?

jadnashuanh said:
The actual area of the contact patch stays the same when the inflation pressure stays the same. So, with a wider tire, that means the F-B patch would be smaller. On a narrower tire, the F-B length is longer.

So, do you want better traction during acceleration and braking, or cornering?

The summer tires are softer, so while the surface area will be the same, the grip increases. Those grip changes are not a factor of the patch size, but the rubber compound and tread design.

I'd like the increased grip, but if I leave all seasons in the rear and put the summers in the front might I run into anything funky? any stability issues with two diff compounds? braking issues? would the summer tires be any more noisy? (All my prev cars have had perf tires , but never paid attention to tire noise, because there was a v10 screaming over everything. )
 
For those reading this post like me later on, here is a tire patch calculator

https://bndtechsource.wixsite.com/home/tire-data-calculator
 
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