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My 2021 IS300AWD needs some new tires, OEM tire size is 235/45/18. Never liked the wheel gap on the car but don’t want to go coilovers or lowering springs so was wondering if going to a different tire size could help fill up the gap without going more than 3% to keep the speedometer close enough, would a 245/45/18 or 245/40/18 work or even a 255 or 225. Thanks
My 2021 IS300AWD needs some new tires, OEM tire size is 235/45/18. Never liked the wheel gap on the car but don’t want to go coilovers or lowering springs so was wondering if going to a different tire size could help fill up the gap without going more than 3% to keep the speedometer close enough, would a 245/45/18 or 245/40/18 work or even a 255 or 225. Thanks
Hey Anthony,
I don’t think it would make a big difference in my opinion. I have a rear wheel drive and I went up in width. It makes the tire slightly taller, but I mean slightly. Not even noticeable. My purpose was to get rid of the stretched tire look.
On the front, I went from 235/40/19 to 245/40/19.
On the rears, I went from 265/35/19 to 275/35/19.
I am on Eibach pro kit lowering Springs, which lowered my IS by about an inch. It’s a mild drop. I also added spacers 15 mm in the front and 20 mm in the back. That was the best way I felt I could get rid of the gap.
If you went up and tire size, I don’t think you would notice a huge difference, but maybe someone else could chime in if they’ve already done so.
Hey Anthony,
I don’t think it would make a big difference in my opinion. I have a rear wheel drive and I went up in width. It makes the tire slightly taller, but I mean slightly. Not even noticeable. My purpose was to get rid of the stretched tire look.
On the front, I went from 235/40/19 to 245/40/19.
On the rears, I went from 265/35/19 to 275/35/19.
I am on Eibach pro kit lowering Springs, which lowered my IS by about an inch. It’s a mild drop. I also added spacers 15 mm in the front and 20 mm in the back. That was the best way I felt I could get rid of the gap.
If you went up and tire size, I don’t think you would notice a huge difference, but maybe someone else could chime in if they’ve already done so.
. Hi there, thanks for your reply, your probably right that it won’t make much of a difference perhaps I’ll look into some spacers, did it do anything to the ride or handling of the car?
. Hi there, thanks for your reply, you're probably right that it won’t make much of a difference perhaps I’ll look into some spacers, did it do anything to the ride or handling of the car?
Spacers will widen the stance, but 15 to 20 mm really doesn't change the handling much. However, in conjunction with lowering, new Lower Control Arm Bushings, wider tires, together they will indeed change the ride and handling. Here is the order in which I changed my set up.
1. Lowered: Eibach Pro Kit. About 1" in front and .5 in the back. Stiffened the ride a bit but not jarring. Less body roll in corners.
2. Bonoss Spacers: I'm not a spacer's guy and usually calculate size and offsets on wheels but I researched it and decided to give the spacers a shot because they are not bolt ons. Instead, the 2021-2025 IS uses lug bolts. Extended lug bolts were included with the Bonoss. IMO they did not lessen the gap but some may say otherwise.
3. Lower Control Arm Bushings (LCA): I picked up Figs 80 durometer LCA bushings. They are their softest rated ones. They are stiffer than OEM for sure. You can feel it when cornering and braking but not by much. They will help with inner tire wear.
3. Tire size: I didn't go "larger" in tire size but went wider. From 235/40/19 to 245/40/19 fronts and 265/35/19 to 275/35/19 rears. Going wider does increase height, but it is negligible. The reason I got wider tires was to get rid of the slightly stock stretched look.
Summary: I am extremely happy with the above items I added. I suspect you could get coilovers and lower your IS the same as the Eibach Pro Kit and then if you feel it's too low for your tastes, you could always bring it back up. The coilovers will increase your handling for sure.
Spacers will widen the stance, but 15 to 20 mm really doesn't change the handling much. However, in conjunction with lowering, new Lower Control Arm Bushings, wider tires, together they will indeed change the ride and handling. Here is the order in which I changed my set up.
1. Lowered: Eibach Pro Kit. About 1" in front and .5 in the back. Stiffened the ride a bit but not jarring. Less body roll in corners.
2. Bonoss Spacers: I'm not a spacer's guy and usually calculate size and offsets on wheels but I researched it and decided to give the spacers a shot because they are not bolt ons. Instead, the 2021-2025 IS uses lug bolts. Extended lug bolts were included with the Bonoss. IMO they did not lessen the gap but some may say otherwise.
3. Lower Control Arm Bushings (LCA): I picked up Figs 80 durometer LCA bushings. They are their softest rated ones. They are stiffer than OEM for sure. You can feel it when cornering and braking but not by much. They will help with inner tire wear.
3. Tire size: I didn't go "larger" in tire size but went wider. From 235/40/19 to 245/40/19 fronts and 265/35/19 to 275/35/19 rears. Going wider does increase height, but it is negligible. The reason I got wider tires was to get rid of the slightly stock stretched look.
Summary: I am extremely happy with the above items I added. I suspect you could get coilovers and lower your IS the same as the Eibach Pro Kit and then if you feel it's too low for your tastes, you could always bring it back up. The coilovers will increase your handling for sure.
. I don’t want to play with the suspension as I’m an old senior so wouldn’t be prudent but I did it with my G35 back in 2003. I think I’ll just have to be happy with chrome delete and tinted windows. Thought about moving up to the 2026 350 but don’t like the front end, hopefully they get it right when they go electric in 2027 or I can buy a 2025 350, it seems that sedans are going the way of the dodo bird. My wife has a BMW230 which fun to drive but 2 door is not for me, she wants the MB CLA electric when it comes out.
I hear ya. I'm not a spring chicken either. My previous car was a G37 sedan that was lowered on Swift Springs. Swift used my G so they could get all of the measurements and sent the numbers to Japan to have them produced. They just gave me the springs after, which I thought was awesome of them. But, regarding the wheel gap issue. The drop from the pro kit isn't much and is considered a mild drop. I highly recommend it. Here are some pics.
Going to sell this soon. Dropped on Swift Springs. Current IS. Dropped on Eibach Pro Kit.
Thanks Brother. Just trying to give Anthony some options if he’s trying to get rid of the wheel gap. I can respect his thought process, but the trade-off of a slight drop versus the gap is worth it in my opinion.
Wishing you the best Anthony on whatever decision you make. 👍 you’re good either way.
Thanks Brother. Just trying to give Anthony some options if he’s trying to get rid of the wheel gap. I can respect his thought process, but the trade-off of a slight drop versus the gap is worth it in my opinion.
Wishing you the best Anthony on whatever decision you make. 👍 you’re good either way.
Thanks, btw your IS looks perfect and the G37 is not too shabby either, I had a 2008 G37 then a 2015 Q50 and even though my Infiniti’s were bulletproof I prefer the Lexus, if I didn’t have the AWD and would most probably lower it. Thought about 19 wheels but it’s so much easier just to throw the winters in the back seat and have Costco do the job. There is one thing I’m tempted to do is an ecu reflash but not sure if it will affect warrantee or the transmission so still on the fence. Thanks again for sharing what you’ve done to your car, it look great.
I hear ya. I'm not a spring chicken either. My previous car was a G37 sedan that was lowered on Swift Springs. Swift used my G so they could get all of the measurements and sent the numbers to Japan to have them produced. They just gave me the springs after, which I thought was awesome of them. But, regarding the wheel gap issue. The drop from the pro kit isn't much and is considered a mild drop. I highly recommend it. Here are some pics.
Going to sell this soon. Dropped on Swift Springs. Current IS. Dropped on Eibach Pro Kit.
…Not to change the subject but what tint did you use? I want to get my ‘26 in the Wind color done. I usually do 20% but thinking 35% may be better since my interior is black and smaller than I’m used to. Yours looks great!
New shoes.
