Did I do this right?

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.

dparker

Member
Joined
Jun 13, 2006
Posts
16
Location
Lakes Region, New Hampshire
Soon-to-be first-time RV owner.? Just want to make sure that I don't buy too much rv for my tow vehicle.? Can somebody who knows better check this for me?? I tried to follow the formula in the Towing and Towables Library.


Vehicle (2004 Chevy Trailblazer LT, 4.2L 6-cyl., 3.42:1 axle ratio, 113 in. wheelbase, 6300lb. tow capacity in 2WD)

curb weight? =? 4612 lbs
4 people? =? 600
fuel (22gal x 6.2lbs)? =? 140
stuff? =? 50
trailer tongue weight? =? 408
Total laden weight? =? 5810


Trailer (2003 Antigua 215sso)

Dry weight? =? 3812 lbs
Water? =? 0
Propane? =? 168
Stuff? =? 500
Total weight of trailer? =? 4480 (GVRW = 4990)

Gross combined weight? =? 5810 + 4280 - 480 = 9810
(GCWR = 8250)
(80% GCWR = 6600)


Does this look right? It looks like this is too much trailer for my vehicle.? Several salepeople told me today that I could handle this type of trailer without any problems, and I see people pulling TTs with Trailblazers, so I am a bit confused.? I'm hoping that I made a mistake here somewhere.? I appreciate any advice you might have for me.?


Thanks!

-- Derek
 

Carl L

Moderator Emeritus
Joined
Mar 14, 2005
Posts
7,239
Location
west Los Angeles
Vehicle (2004 Chevy Trailblazer LT, 4.2L 6-cyl., 3.42:1 axle ratio, 113 in. wheelbase, 6300lb. tow capacity in 2WD)

Are you sure about that 6300 lbs.  The Trailer Life tables rate that rig at either 5000 or 5300 lbs.  Where did you get your number -- the owner's manual?
 

dparker

Member
Joined
Jun 13, 2006
Posts
16
Location
Lakes Region, New Hampshire
You are correct.  I had relied on information from product review websites that touted the Trailblazer's 6300# towing capacity -- I see now that that is only with the 4.10:1 axle ratio.  I bought my Trailblazer used, but I'm pretty sure that it has the standard 3.42 axle ratio (Max. Trailer Weight = 5300#; GCWR = 10,000#)

How do I check/confirm my axle ratio?  Is it possible/affordable to change the axle ratio?

Based on this new information and assuming the standard 3.42 ratio . . .

Towing Capacity -- 5300
90% Towing Capacity -- 4770 (if we stay in the kiddie pool and avoid the western mtns.)
80% Towing Capacity -- 4240 (if we want to head west)

GCWR -- 10000
90% GCWR -- 9000
80% GCWR -- 8000

Total laden weight = 5810
Total weight of trailer = 4480

Gross combined weight = 5810 + 4480 - 480 = 9810

Looks like this is too much trailer for us, even though it comes in under the 90% mark of the max trailer weight because it puts us at 98% GCWR.

Looks like we will be limited to a pop-up or something like a Kodiak 160. 

Does this look correct?  I'm still learning and want to make sure I do this right.  Thanks for your help.

-- Derek
 

dave95.1

Well-known member
Joined
Jul 26, 2006
Posts
64
On your axle ratio, you can either take the cover off of the back of the differential and count the # of teeth on the ring and pinion gears then divide the number on the ring gear by the number on the pinion gear.  I believe a 3.42 will be 41 on the ring gear and 12 on the pinion.  GM does not put any tags on them.

Or you can find your option code label.  In the glove box, center console or in the back somewhere there will be a white label about the size of a credit card.  It will have several 3 digit codes (combination letters and numbers), the codes beginning with "G" will be for your differential, call a local GM dealer with the "G" codes and they can give you the axle ratio.  If you are in fairly good with a dealer you can just give them the VIN and they can print you a list of all of these option codes and what they mean.  Around here they are usually willing to do this, but some places they are not.
 

dave95.1

Well-known member
Joined
Jul 26, 2006
Posts
64
Just found this.  Find your option code label and find out what you have.

GT4 = Rear axle, 3.73 ratio
GT5 = Rear axle, 4.10 ratio
GU6 = Rear axle, 3.42 ratio

It came from here, they have a pretty good list of option codes you can match up and see what you have.

GM option codes
 

dparker

Member
Joined
Jun 13, 2006
Posts
16
Location
Lakes Region, New Hampshire
Just checked the Options Code sticker -- GT4 (3.73 ratio).  This means a Max. Trailer Weight of 5700# and a GCWR of 10500#.  So, following the formula in the Towing Library, and changing to a smaller TT, this is what I came up with --

2004 Chevy Trailblazer LT
(4.2L 6-cyl., 3.73:1 axle ratio, 113 in. wheelbase, 5700lb. tow capacity in 2WD)

curb weight? =? 4612 lbs
4 people? =? 600
fuel (22gal x 6.2lbs)? =? 140
stuff? =? 50
trailer tongue weight? =? 305
Total laden weight? =? 5707


2006 Aerolite Cub 160

Dry weight? =? 2704 lbs
Water? =? 0
Propane? =? 80
Stuff? =? 500
Total weight of trailer? =? 3284
(trailer GVRW = 4990)
(vehicle max. trailer wt. = 5700)
(80% max. trailer wt. = 4560)


Gross combined weight? =? 5707 + 3284 - 305 = 8686  (83% GCWR)
(GCWR = 10500)
(80% GCWR = 8400)???


It looks like I should be able to safely pull this trailer, especially since I live in New Hampshire and plan to do most of my trips east of the Mississippi for the next few years.  Does this look right to you?

-- Derek

 

Carl L

Moderator Emeritus
Joined
Mar 14, 2005
Posts
7,239
Location
west Los Angeles
5700lb. tow capacity in 2WD)

In 4WD?? ?Does your truck have 4WD?? ?The deduction of 3-400 lbs of tow rating for 4WD is taken because of the weight of the transfer case and 2nd differential, and does on vary because the 4WD is engaged or not. 

Water  =  0

You are, of course, kidding.  You never intend to use your trailer for toilet facilities on the road?  With 2 kids?  You like filling station restrooms?  No lunches in the trailer at rest stops?  You will find yourself eventually carrying a least a half tank full of fresh.  And do not forget the black and gray tanks.  No one ever drains tanks after an overnighter.


It looks like I should be able to safely pull this trailer, especially since I live in New Hampshire and plan to do most of my trips east of the Mississippi for the next few years.  Does this look right to you?

With that condition, and given the fact that a 10% discount gives you a tow rating of 5,130 lbs while your stated trailer GVWR is 4990 lbs, you are fine east of the Rockies.  You are actually 88% of your tow rating. 

With all this hunting down lightweight trailers, have you taken a look at the hybrids?  You might get more space pound for pound.
 

dparker

Member
Joined
Jun 13, 2006
Posts
16
Location
Lakes Region, New Hampshire
This is why I am asking so many questions -- I'm new to all this and am really starting from scratch. 

1) My Trailblazer does have 4WD, so that means my Max. Trailer Weight (according to my owner's manual) is actually 5500# and my GCWR is 10500#. 

2) I am 6'4" and weigh 290# -- I don't plan on using my trailer's bathroom when I'm set up at my campsite, let alone on the road.  Rest area facilities are fine with me.  It just doesn't seem to make sense to haul water around with my little truck. 

3) The trailer that I ran the calculations on above (the Aerolite Cub 160) is a very small hybrid and it still comes in just under my limits.

I'm realizing that I probably bought the wrong truck if I want to tow anything other than a pop-up.  The reviews of the Trailblazer all touted its 6300# towing capacity, but made no mention of axle ratios or reduced capacity if you have 4WD.  Of course, the rv salespeople tell me that I can tow anything -- one guy yesterday told me that I can tow any trailer with a dry weight under 6000#!

I think I'll probably end up with a pop-up for my first trailer and then upgrade in a couple years when I get a bigger tow vehicle. 
 

Carl L

Moderator Emeritus
Joined
Mar 14, 2005
Posts
7,239
Location
west Los Angeles
Not that it is any consolation, but my tow vehicle is a 1995 Ford Bronco with a tow rating of 6600 lbs per Ford's owners manual.  My trailer is a lightweight 23'  Prowler with a scaled weight of 4650 lbs.  and GVWR of 5300 lbs.  That GVWR is right on the 80% mark.

I tow in the Far West.  I would not have a truck with a pound less of tow rating.  As it is I spend more than a bit of time in 1st getting over passes. 
 
Top Bottom