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Discussion Starter · #1 ·
The reason I want to switch is I need new tires and I want to get that specific tire size for summer driving that does not come in the existing size.

According to this site: 215/45-R18 vs 215/40-R18 Tire Comparison - Tire Size Calculator | Tacoma World
The diameter difference is 3.3% difference.

I don't have any issue with speedo being off a little bit but do I need to worry about anything else like vehicle dynamics or causing wear/stress somewhere else?
 

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The reason I want to switch is I need new tires and I want to get that specific tire size for summer driving that does not come in the existing size.

According to this site: 215/45-R18 vs 215/40-R18 Tire Comparison - Tire Size Calculator | Tacoma World
The diameter difference is 3.3% difference.

I don't have any issue with speedo being off a little bit but do I need to worry about anything else like vehicle dynamics or causing wear/stress somewhere else?
why don't you check if they come in 225/45R18....speedo will be slightly off in the opposite direction, but you'll have a smidge more sidewall for bumps plus it will fill in the wheel well better.
 

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Discussion Starter · #4 ·
why don't you check if they come in 225/45R18....speedo will be slightly off in the opposite direction, but you'll have a smidge more sidewall for bumps plus it will fill in the wheel well better.
Would 225 fit on a 18x7 wheel, I figured I would need at least an 18x7.5 wide wheel? Just going by my basic knowledge but I'm no wheel expert. I think in the future I will get lighter/good quality wheels.
 

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Would 225 fit on a 18x7 wheel, I figured I would need at least an 18x7.5 wide wheel? Just going by my basic knowledge but I'm no wheel expert. I think in the future I will get lighter/good quality wheels.
If it's the stock wheel, it fits just fine, and most prefer the larger rather than smaller. Seriously, impact resistance is a major reason to get bigger.
 

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I agree with more sidewall for a little bit more impact “protection” but if you drop sidewall height you gain a slightly lower final drive gear ratio which would also add an ever so slight increase in acceleration power (mechanical advantage) and the tire sidewall being slightly lighter in weight would also have a slight increase in acceleration power due to weight savings (less mass), the shorter diameter and less weight would also give a slight advantage to your breaking power…although only ever so slight….not sure if the butt dyno would pick up though.
The reverse is a taller sidewall, which could help ever so slightly with some cushion from sidewall flex (might not be detectable in the butt on that one as well).
 

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I agree with more sidewall for a little bit more impact “protection” but if you drop sidewall height you gain a slightly lower final drive gear ratio which would also add an ever so slight increase in acceleration power (mechanical advantage) and the tire sidewall being slightly lighter in weight would also have a slight increase in acceleration power due to weight savings (less mass), the shorter diameter and less weight would also give a slight advantage to your breaking power…although only ever so slight….not sure if the butt dyno would pick up though.
The reverse is a taller sidewall, which could help ever so slightly with some cushion from sidewall flex (might not be detectable in the butt on that one as well).
Seriously, with stock size I literally lost like 6 tires to potholes over the course of 100k. Since upgrading to larger size I haven't lost a single tire to potholes. It's worth the upgrade...
 

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Seriously, with stock size I literally lost like 6 tires to potholes over the course of 100k. Since upgrading to larger size I haven't lost a single tire to potholes. It's worth the upgrade...
I agree, I was originally thinking of dropping to a 17”wheel and changing the aspect ratio to maintain the oem size diameter (16 and 17 inch wheels are lighter vs 18s btw). I also really want to add some larger brakes to the car and I’m not really sure if 17s would allow so I kept the 18” size in aftermarket wheels and tires. Of course the wheels are several pounds less and the tires are much better in terms of traction, so the car feels quite nice on curvy roads and even transitioning back and fourth it’s make a very big difference over the oem installed snow tires.
 

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why don't you check if they come in 225/45R18....speedo will be slightly off in the opposite direction, but you'll have a smidge more sidewall for bumps plus it will fill in the wheel well better.
Remember, you do get more sidewall with 225/40/18 than 215/40/18 as it's a ratio, not a fixed amount of sidewall, and then end up the same size diameter as stock with only a little less sidewall but improved traction/handling... but OP wants to reuse stock wheels, and can't do that past 215 wide, they are too narrow, one reason I am doing 225/40/18 UHP tires on 18x8 wheels first thing on my new ride.

So advice to OP and other that don't know, you def should use at least 7.5" wide as it's the official minimum recommended width and highly recommended for proper sidewall angle and preferably 8" wide wheels to go 225 or more for the width. So with this car I hated the stock tires so much and didn't want to stick with such narrow wheels and tires if I'm gonna upgrade anyway so I decided to go straight to lower-end but decent enough wheels and tires as my first major mod. I got a full package for $1150 all in with install.
 

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Remember, you do get more sidewall with 225/40/18 than 215/40/18 as it's a ratio, not a fixed amount of sidewall, and then end up the same size diameter as stock with only a little less sidewall but improved traction/handling... but OP wants to reuse stock wheels, and can't do that past 215 wide, they are too narrow, one reason I am doing 225/40/18 UHP tires on 18x8 wheels first thing on my new ride.

So advice to OP and other that don't know, you def need at least 7.5" wide and preferably 8" wide wheels to go 225 or more for the width, so with this car I hated the stock tires so much and didn't want to stick with such narrow wheels and tires if I'm gonna upgrade anyway so I decided to go straight to lower-end but decent enough wheels and tires as my first major mod. I got a full package for $1150 all in with install.
I used the wider tires with the stock 18 inch wheels. no problems...
 

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I used the wider tires with the stock 18 inch wheels. no problems...
I mean, sure, but if you drove it super hard to the tire limits you risk rolling the tire off the rim if the tire is sticky enough, a 225 width tire literally is less safe if you don't use at least a 7.5" wide rim, that is officially the minimum safe mounting width... But, if you have zero interest in pushing it to it's limits on a regular basis you're mostly likely totally fine, I just don't think it should be encouraged
 

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I mean, sure, but if you drove it super hard to the tire limits you risk rolling the tire off the rim if the tire is sticky enough, a 225 width tire literally is less safe if you don't use at least a 7.5" wide rim, that is officially the minimum safe mounting width... But, if you have zero interest in pushing it to it's limits on a regular basis you're mostly likely totally fine, I just don't think it should be encouraged
Seriously, I've pushed to the limits and beyond to the point of throttle lift drifting with Conti Dws06 tires on stock suspension and Others here with the Michelin Pilot sports. No problems reported thus far.
 

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I mean, sure, but if you drove it super hard to the tire limits you risk rolling the tire off the rim if the tire is sticky enough, a 225 width tire literally is less safe if you don't use at least a 7.5" wide rim, that is officially the minimum safe mounting width... But, if you have zero interest in pushing it to it's limits on a regular basis you're mostly likely totally fine, I just don't think it should be encouraged
Uhhh.....really......? In the real world in this car you would have the front end push or otherwise break traction before the tire came off the rim......
 

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Uhhh.....really......? In the real world in this car you would have the front end push or otherwise break traction before the tire came off the rim......
Running wider than 215's on 7" wide rims is literally 100% pointless and possibly a detriment to handling. There is a real actual reason they say you need at least a 7.5" and preferably 8" wide wheel for a 225 wide tire, the angle of the sidewall being tucked will just put you into understeer more with far easier sidewall collapse, but sure, waste your money 100% and possibly make your handling worse, IDGAF, but I'm trying to actually educate people on what is proper and not just what you can "get away with"... I mean, just look it up before you play smartass and blindly bash me while justifying an improper setup. I mean if you are broke and someone has 225's for free that's one thing, but it's counter productive to run a wider tire than the wheel width is designed for, period. When I say "roll the tire off the rim", yeah, not likely, but is an extreme example of what is possible because your sidewall is so tucked, but in reality you will understeer for more easily, which is technically not safe either and sucks for performance.
 

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Seriously, I've pushed to the limits and beyond to the point of throttle lift drifting with Conti Dws06 tires on stock suspension and Others here with the Michelin Pilot sports. No problems reported thus far.
I didn't say suspension, I said 225+ wide tires on stock 7" wheels... It's literally pointless to go 225+ on 7", apples for apples it will perform worse and is not recommended as it can lead to far easier understeer with the tire tucked in and poor sidewall angle for proper handling.
 

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Educate.....LOLOLOL....for real? You are far from the first to "discuss" tire size here. Its all been said and done by many others well before you came along.....
the angle of the sidewall being tucked will just put you into understeer more with far easier sidewall collapse
it can lead to far easier understeer with the tire tucked in and poor sidewall angle for proper handling.

Isn't that exactly what I said above? The car will push (that means oversteer BTW as long as we are discussing education) but the tire won't come off the rim unless you oversteer into a curb....
 

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I think it's funny people will blow $200+ a tire to stick on a wheel too narrow instead of doing a proper setup with a cheaper tire if you have to. PROPER 235/40/18 UHP all season tires that nearly perfectly match stock diameter on the proper 8" wide wheels were only $1200 total installed, lugs, tire certificates, everything...

The handling and steering improvement has made the car feel like it's worth $5k more! No more weird center slop in the steering and far more responsive with more consistent steering weight! It literally makes it more predictable to dive into/use the AWD/GVR+!

Springs are next, went with Eibach based on how I've liked them in the past on other cars, gonna install a week from Sunday, I just hope they don't drop too much!

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Educate.....LOLOLOL....for real? You are far from the first to "discuss" tire size here. Its all been said and done by many others well before you came along.....




Isn't that exactly what I said above? The car will push (that means oversteer BTW as long as we are discussing education) but the tire won't come off the rim unless you oversteer into a curb....
When you don't actively discourage an improper setup, then hell yeah you sound like you don't know jack, sorry, but maybe act like it, and as a mod not encourage this BS, then "LOL" when called out for it... But sure, "LOL" in your knowitall mind if it makes you feel better, but you'd still be wrong. Please, show me any official tire/wheel information from shops or manufacturers that putting anything wider than a 215 on a 7" is officially acceptable in anyway and I'll eat crow... Rolling off the wheel was an extreme example for a reason, to visualize the wrong kind of strain you put on your tire that makes it worthless and actually detrimental to handling and in no way should be encouraged at all. A good tire shop will either refuse to mount this or at least force you to sign a waiver, so why bother putting wider than recommended at all if it's just going to hurt your handling? We should be encouraging the proper setups, not justifying improper ones, especially if you do know better. I'm done arguing about this, not worth it when people have learned they don't have to use any social skills or admit they are wrong online, I'm moving on...
 
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