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[mhullihan]

Has anyone switched between these two tires? Ideally in a 245/40r17? I just mounted RT660s on 17x9 et52 with Ohlins and Ohlins specific Vorshlag camber plates and I only have a few mils of clearance to the spring perch (pic attached). Tire rack shows the RE71rs as having a narrower section width and tread width. This makes me think it’ll not only be narrower overall, but also be less square giving me even more clearance near the shoulder.

Tire Rack data:

RT660 245/40r17
Tread width: 8.9”
Section width on an 8.5”: 10” (add 0.2 for a 9” wheel)
Tire diameter: 24.8”

RE71rs 245/40r17
Tread width: 8.4”
Section width on a 8.5”: 9.8”
Tire diameter:24.7”

I could get more clearance by raising the ride height but it’s starting to get to a lot of preload, I like it at this ride height, and I am having a hard time getting the rear high enough to match that raised condition.

[spidertri]

What spacer are you running? I ran a 15mm spacer for the 17x9 et52 wheels up front.

RT660 was the widest tire I've mounted to my car, RE71RS is definitely narrower for the same size.

I ultimately went to a 6" spring to have even more tire clearance for a 255.

[mhullihan]

That picture is with a 15mm spacer. I would try a slightly bigger spacer but I’m about out of fender clearance too.

Have you had any issues with coil bind with the 6” spring? Have many events have you done with it?

If I end up pulling the trigger on the RE71RSs I’ll try to remember to update the thread with pics.

[spidertri]

I swapped the springs back in 2021, done 23 track days on them since then. No coil bind, I run them with no preload.

[sibanez]

I ran 17x9 with 45ET, -4.2 of camber and 245/40R17 Falken RT660s . . . it was tight, but didn't rub.

Switching to RE71RS was a huge improvement. The tire is narrower, but they offer a lot more grip and perform better in the rain. You are saving at least 3-4mm of tire space in the wheel well.