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Discussion Starter #1
I have had 373's in my car for a a couple of years now and have really liked them.
Just last week, I got my new wheel and tire setup on. I was running 18" wheels with rubber band tires (Wanli 235/40's). My new back tires are still 18" but Nitto 285/40's and to my suprise, they are waaaaay bigger than my old tires. I'm talking a good 2" bigger in diameter!!!!

So anyway, my new setup slowed me down!!! It is actually a noticable difference spinning such a bigger diameter tire. From a take off, my car doesn't wrap out nearly as fast anymore. So I'm thinking about jumping up to 4.10's to get some of that low end back. I know my RPM's will be higher on the hwy and I will lose fuel economy but I just hate the fact that my car feels slower now.

What is anybodies thoughts on this and is anyone else running 4.10's and like them???
 

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Go for it! Meh, go 4.30 or 5.10 FTW!

Honestly, I think 4.10's will work great for ya. I may even consider them some day. Right now I've got to get my engine swap done first.
 

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Well since you have a bigger tire on there than you did before, that also means that you are going further with one rotation of the tire, so upping the rear end gears would be a way of putting you back where you were with the 3.73s. Going to 4.10s would increase your rpms on slightly on the highway, but not anywhere near as much as if you had gone to 4.10s with your old tires. The highway cruising breaks down like this;
Old tires with 3.73s at 70mph is 2450rpms
Old tires with 4.10s at 70mph is 2700rpms
New tires with 3.73s at 70mph is 2300rpms
New tires with 4.10s at 70mph is 2500rpms
As you can see, going from the old tires with 3.73s to the new tires with 4.10s will only raise your highway cruising speed by about 50rpms, but if you went to 4.10s with the old tires, it would have raised it about 250rpms.
 

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Discussion Starter #4 (Edited)
Well since you have a bigger tire on there than you did before, that also means that you are going further with one rotation of the tire, so upping the rear end gears would be a way of putting you back where you were with the 3.73s. Going to 4.10s would increase your rpms on slightly on the highway, but not anywhere near as much as if you had gone to 4.10s with your old tires. The highway cruising breaks down like this;
Old tires with 3.73s at 70mph is 2450rpms
Old tires with 4.10s at 70mph is 2700rpms
New tires with 3.73s at 70mph is 2300rpms
New tires with 4.10s at 70mph is 2500rpms
As you can see, going from the old tires with 3.73s to the new tires with 4.10s will only raise your highway cruising speed by about 50rpms, but if you went to 4.10s with the old tires, it would have raised it about 250rpms.

Good post!:zbeer: So yeah if that's the case, then I really won't be losing anymore than I was before my tire change.

I think 4.10's will be a good gear choice for me for a couple of reasons.

-to compensate for going to a bigger tire
-running a heavy car with a stock stall still
-and should be better at the track with them

Besides, when I put my 373's in, I had a bunch of people tell me that i should go with 4.10's because most people seem to like them with an automatic. So it looks like I'm going to go that route anyway.

But then again, if I had gone with 4.10's at the beginning and still did my tire change like I did, Id probably be wanting 4.30's or something now LOL
 

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Discussion Starter #9
Well the 4.10's are in. And as expected, it put my cars speed back where it was, maybe just a tad but more pull also.

But lesson learned....if you increase your tire size by a good margin, you better gear up!! (or down) LOL
 

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R8D-XXX...What did you have to do to make your speedometer read correct after you changed to 4.10 gears ..been thinkin about the swap myself..

Rayo..
 

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Discussion Starter #11 (Edited)
R8D-XXX...What did you have to do to make your speedometer read correct after you changed to 4.10 gears ..been thinkin about the swap myself..

Rayo..

My speedo is not correct and would not "waste" money on a speedo gear IMO.
I've bought 2 speedo gears for 2 different cars of mine and both were epic failures.

I put 373's in my 95' stang with a 5 speed and my speedo was 20MPH off. I got a hold of Steeda and they sent me the recommended gear $15 for gear $15 for shipping. I put it in and it was still 12 off.

Then it came time for my t-bird. I put 373's in it and it was 20 off also. Again, I had Steeda send me the gear for it and it barely made a difference. It was still 15MPH off. It helped a little bit when I put my bigger tires on but it was still 10MPH off. So now with my 4.10's in, its back up to about 15MPH off or so.

So yeah, I've wasted $60 on speedo gears. Now I have heard that if you have a 4.6 car with the OBDII, a "speed cal" is the only way to go and it will correct it. Dallas Mustang has them.

www.dallasmustang.com
 

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I fixed my speedo on both cars with a sensor gear change; both are within 3-4 mph at top end.

Check out this:

http://www.sccoa.com/faq/speedgr.html

I'm running close to stock gearing in the diff, tho. (stock on one, 3.08 on the other...)
 
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