1Jz 240sx Rear End Ratio Advice - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Def · 11-29-2008, 08:26 PM

This sounds like a good case to use a 275/40-17 and a slightly longer diff then.

A 3.91 J30 diff is about 4.4% longer, and a 275/40-17 is 4.0% larger than your current tire.

So that would give you 8.5% longer gears total with those two changes.

Giving you speeds of:

1 - 38 mph
2 - 63
3 - 94
4 - 124
5 - 163

Doesn't sound like bad gearing to me. Hell, sounds better than the long gears you get with a 4.08 on an SR box. You'd also have some tire to put down some speed. Don't go with a 255/45-17, the sidewall would look absolutely ridiculous. Even Mustang guys don't use that much sidewall on a 17" wheel.

Thread Tools
Show Printable Version Email this Page
Display Modes
Switch to Linear Mode Switch to Hybrid Mode Threaded Mode

11-29-2008, 08:26 PM	#32
Def Post Whore! Join Date: Apr 2004 Location: Houston, TX Posts: 2,701 Trader Rating: (16) Feedback Score: 16 reviews	This sounds like a good case to use a 275/40-17 and a slightly longer diff then. A 3.91 J30 diff is about 4.4% longer, and a 275/40-17 is 4.0% larger than your current tire. So that would give you 8.5% longer gears total with those two changes. Giving you speeds of: 1 - 38 mph 2 - 63 3 - 94 4 - 124 5 - 163 Doesn't sound like bad gearing to me. Hell, sounds better than the long gears you get with a 4.08 on an SR box. You'd also have some tire to put down some speed. Don't go with a 255/45-17, the sidewall would look absolutely ridiculous. Even Mustang guys don't use that much sidewall on a 17" wheel.