Sluggish Tahoe

[David Smith]

Code is glove box says GT4. 3.73. Seems like those gears would pull the ol' 'hoe alright...maybe not?

 

[cmc76]

i was anticipating something higher. But then again i dont have tires that big. hopefully someone else can chime in

 

[02_Tahoe]

Code is glove box says GT4. 3.73. Seems like those gears would pull the ol' 'hoe alright...maybe not?

First off.....nice wheel choice. Ok now for what you want to hear, I have the same issues as you, I have 275/70r18 (33.3x11) which is close to your 285/65r18 (32.7x11.2). The culprit is the bigger wheels and tires, not only are they heavier but it messes up the gear ratio. The gearing you have now was for spinning 30-31 inch tires. Now you basically have 33s so the most noticeable power gains you will get is to regear. Me and @M1Gunner have been talking about it because I have 33s and 3.73s like you do. He has 37s and he regeared by himself and is very knowledgeable on this and helped me out a lot, now I plan on going to 4.56s and trying it myself
Here's a chart that shows tire size vs gear ratio

The yellow would be equal to 3.42s with factory tires, green=3.73s with factory, blue=4.10 with factory. to get back to the factory feel of 3.73s you should get 4.30s because I've never seen 4.27s. I picked 4.56 because I want more power but don't want to mess up gas mileage too much

 

[jaywoo65]

Assuming that your stock tire size was a 265/70/16, here's the tire comparison: The speed thing is something to keep in mind. If your speedometer says 80, you are really doing 86mph. Might be the tires but it could be any number of other things also. The first question would be was it ok before you put the tires and wheels on? And only sluggish after the wheel/tire swap? Things like a clogged cat can cause loss of power. With 215K miles, that's something to consider. Clogged fuel filter also.

 

[David Smith]

First off.....nice wheel choice. Ok now for what you want to hear, I have the same issues as you, I have 275/70r18 (33.3x11) which is close to your 285/65r18 (32.7x11.2). The culprit is the bigger wheels and tires, not only are they heavier but it messes up the gear ratio. The gearing you have now was for spinning 30-31 inch tires. Now you basically have 33s so the most noticeable power gains you will get is to regear. Me and @M1Gunner have been talking about it because I have 33s and 3.73s like you do. He has 37s and he regeared by himself and is very knowledgeable on this and helped me out a lot, now I plan on going to 4.56s and trying it myself
Here's a chart that shows tire size vs gear ratio
View attachment 80968
The yellow would be equal to 3.42s with factory tires, green=3.73s with factory, blue=4.10 with factory. to get back to the factory feel of 3.73s you should get 4.30s because I've never seen 4.27s. I picked 4.56 because I want more power but don't want to mess up gas mileage too much

I am hoping that it is just the gearing. I am not sure if I would ever replace them, but it is a possibility. Probably would go with the 4.11.

Thanks for the insight! Nice wheels!

 

[David Smith]

Assuming that your stock tire size was a 265/70/16, here's the tire comparison: The speed thing is something to keep in mind. If your speedometer says 80, you are really doing 86mph. Might be the tires but it could be any number of other things also. The first question would be was it ok before you put the tires and wheels on? And only sluggish after the wheel/tire swap? Things like a clogged cat can cause loss of power. With 215K miles, that's something to consider. Clogged fuel filter also.

To be honest, I am not too sure that my truck still has its cats. I am down in GA. No emission tests. As for the tires, they were on it when I got the truck. The fuel filter APPEARS to be newer. Still a very shiny silver color.

 

[02_Tahoe]

I know that feeling you have, it won't accelerate at highway speeds unless it downshifts. Whenever I asked everyone said gear ratio

 

[M1Gunner]

100% incorrect gear ratio is the root of your concern.

 

[M1Gunner]

To be honest, I am not too sure that my truck still has its cats. I am down in GA. No emission tests. As for the tires, they were on it when I got the truck. The fuel filter APPEARS to be newer. Still a very shiny silver color.

Unless your C.E.L. is illuminated and your throwin multiple catalyst inefficiency codes, your hoe still has its cats and they're working.

 

[02_Tahoe]

100% incorrect gear ratio is the root of your concern.

Did you mean correct?