Hello,

What gear ratio do I have?


I just bought an '05 Ram 1500.. I need to tow about 5500 lbs.. the sticker is not in the glove box and I don't want to jack it up to count turns...

the last 8 of the VIN are : 5S357148 and Yes! It's got a Hemi.. with a 545RFE


Thank you!

mdoher1

 

Do you know the RPM at 60mph and the tire size?
This is a calculation to get you close RPM * 1.4925 / 690 = Gear Ratio
The 1.4925 is 1/.67 which is the overdrive gear ratio.
The 690 is the revs/mile if you have 245/70r17 michelin LTX A/S tire.
This will get you close enough to determine if you have 3.55 or 3.92.
Change the revs/mile if you have different tires. Of course this only works if you speedometer is accurate.

 

There may be a tag on the diff. The tag on mine says "35" or "3.5".

 

This has Michelin 275/ 20 inch rims..

I'll go check the diff..

tx,

MD

 

Cool! the front diff. has a sticker on it...

Reads: 3.92

I believe I can tow up to 8500 lbs w/ this that ratio...??

So much for getting better gas mileage ( just traded in my 2500 w/ 3.73's..)

I'd rather have the extra tow capacity.. over the 3.55.. I guess..

thanks for the tip.. i was able to figure that out b4 dark

MD

 

With those wheels and 4x4, 8,500 might be a bit much.

 

"With those wheels and 4x4, 8,500 might be a bit much."

Well I'm only looking to tow about 5300 lbs:

Boat 3700# , Trailer 1000# Fuel 400# supplies 200# = 5300#

I should be good to go, right?

I just was curious what my max tow capacity is and what % I'll be at in tow.

I'm hopin to be around 70% and no more.


tx.

 

Yeah that should be no problem at all. You might start feeling that weigh pulling a camper trailer but not something like a boat.

 

Cool! Last two questions.. Since you have similar year..

Will I need to get a Class IV hitch for 5300 lbs? Or can I get away with the bolt on OEM hitch rated @ 5000 lbs.

My understanding, so far, is that the only difference between III / IV is the weld...

Does Dodge make a Class IV hitch for an '05 1500? I found one for a 2012 but no P/N for a 2005..(I don't like the aftermarket ones where you can see the bar from the back..) I'd rather keep it all OEM too..

p.s. I only tow this boat about 15-20 times a year, about 110 miles at a time...

tx. again

 

If I remember correctly, the Rams had a Class IV hitch when optioned for a hitch. That's the only hitch Dodge put on them..