4:88's with 35's or 36's too much gear on street?

[Drumer73]

I have 4:88 gears with detroit locker and am planning on running 35" or 36" tires, Just wondering is that too much gear for the street or highway driving? woud the gears get too hot on the highway? It will be on a 90 K5 with the 700r4

thanks

 

[ryoken]

that's a tad under 2100 rpm at 65 mph with a 36.... it's really a function of rpm's your gears are making your motor work at, and is that optimum for that engine... anything from a 4:56 to a 5:13 will be acceptable depending on power... 5:13's obviously being a little snottier around town...

 

[Philly87]

I run 4:88's with 35 inch Swampers in my 87 with a 700r4 and love it. Truck is plenty peppy and light on the throttle motivates it well.

I dont drive it much on the highway but when I do I can't complain. I can see the RPM winding up a bit but I dont plan on doing much over 70 in it anyway.

Hope that helps.

 

[Philly87]

I run 4:88's with 35 inch Swampers in my 87 with a 700r4 and love it. Truck is plenty peppy and light on the throttle motivates it well.

I dont drive it much on the highway but when I do I can't complain. I can see the RPM winding up a bit but I dont plan on doing much over 70 in it anyway.

Hope that helps.

 

[Drumer73]

thanks guys for the comment, so it sounds like I should be pretty good with 488's running 35's

 

[shovelbill80]

i forgot where i found this.....the chart is for 1:1 ratio transmission. yellow is for fuel economy, green is stock like and red is for power.

 

[TruckinFool]

Here's a cool calculator:
http://www.grimmjeeper.com/gears.html

Someone might want to plug in a known setup to see if its accurate though.

 

[nsxxtreme]

I run 5.13s an they work great. Huge improvement when I tow my boat.

 

[Blue85]

I've never heard of the R&P getting too hot from the ratio being too low. Maybe it's an issue with extreme ratios, but what you're talking about is fairly reasonable. With 35's -36's and O/D, 4.88 would be fine - great, actually. 4.56 is the only other ratio I would look at and it's certainly not worth a gear swap if you already have 4.88's in the axles.

 

[boz42]

Toyota 5.71's will disenegrate on long road trips. It is from the heat. It is an extreme ratio though.


As everyone else said you should be fine. I ran 4.56's with 36" radial swampers on an otherwise stock 88 K5. It was very pleasant to drive in town on the highway.

Your 700r4 will love the deeper gear.

 

[4X4HIGH]

i forgot where i found this.....the chart is for 1:1 ratio transmission. yellow is for fuel economy, green is stock like and red is for power.

And these RPM's are at 65 MPH. If you're running a 700R4 then you need to multiply the RPM by .7 to come up with the correct RPM for OD.

 

[nsxxtreme]

As everyone else said you should be fine. I ran 4.56's with 36" radial swampers on an otherwise stock 88 K5. It was very pleasant to drive in town on the highway.

Your 700r4 will love the deeper gear.

IMO after having and driving a set of 5.13s on 35's I couldn't imagine going back to 4.56s. The 4.56's are doable if you just want to drive on the street. But the added pep that the 5.13s gave the truck is huge!

Heat is also a funtion of how big the ring and pinion is. I would not recommend 5.13 on a 10 bolt rear axle as I already munched the 4.56 I had, for that axle 4.56 is as high as I would go.

My 14 bolt I can stick my hand on the axle after towing my boat for about 50 miles at highway speeds. No problem with heat at all.