1-Ton Dually Owners: anyone go from 16.5" rims to 19.5" ?? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

C30_Dually · 07-09-2005, 08:16 PM

To improve the mileage on my 4:10 rear / 454, 1981, 2WD, 1-ton, I am thinking of moving from the stock 16.5" up to 19.5" rims (as used on tow trucks and 3500HD's).

Anyone out there on the forum do this?
If so, what was the mileage result?
What tire size are you using?
Any clearance issues?

thanks.

C30_Dually

C30_Dually · 07-09-2005, 08:18 PM

I forgot to add:

What about RPM difference at highway speeds?

C30_dually

KdawgS10 · 07-09-2005, 11:40 PM

if your main consern is gas milage. woulnt ti be mutch cheaper to just get bigger tires?

of co4rse 19.5s are cool. but you seem to just want more milege.

C30_Dually · 07-10-2005, 10:14 AM

Taller tires would be a way to go, however, this truck is used primarily for trailering, both a 20ft enclosed from the class3 hitch, and occasionally a 45ft, triple axle 5th wheel. I think taller sidewalls would change the handling of the truck while pulling 4 tons behind me. A scary thought in my book.

The coolness factor is an added benefit of going to the 19.5's.

C30_Dually

GMC1tondually4dr · 07-11-2005, 06:34 PM

I own a '86 Dually 2WD 1ton with a 454 and 4:10 gears. (over 200,000 miles on the engine. ...yea...she be TIRED!!)

I get approximately 9-10 mpg unloaded. Approximately 6-7 mpg towing a 15,000 40 foot gooseneck racecar trailer.

Improved mileage will be relative.........

......

If you get 10mpg now, a 25% improvement would get you 12.5mpg...

Don't expect to get 15 plus mpg or more.....it won't happen......

UNLESS you are going down a VERY steep hill and have a strong tailwind......

Look on the Moser rearend site. I think they have a rpm=mph tire size converter.

Taller tires will help.........but not a much as you would expect

...about 2-300 rpm.

A gear change about 5-800rpm.

A GearVendors Overdrive will drop the engine rpm approximately 25 to 28%.

By the way my STOCK size wheels and tires are 16" tires, LT235/85R 16,
Pirrelli Scorpion they are 31" tall. (Got them at Sears for around $95-100 on sale. good price)

Just my .02

CCDually

KdawgS10 · 07-11-2005, 07:41 PM

what tranny ya running thier GMC1tondually4dr ?

I havent got to drive my "new to me" 83 4 door dully 2wd and I was wondering what kinda milege I will be seeing with my 350/700r4 4:10s
235-75R16s unloaded ?

GMC1tondually4dr · 07-12-2005, 01:12 AM

TH400, a very good trans guy built it for towing. Has an Allison converter,
also for towing.

John, owns Master Transmission, Rosemount, MN. (also a very good guy!)

Measured them tonight, unloaded.

Just my .02

CCDually

86SILVERADO · 07-14-2005, 01:37 AM

HMMM.... Haven't considered the larger rims but I did just step up to 4.10's from 5.14's

I figured out it will be about 700 rpm difference.

07-09-2005, 08:16 PM	#1
C30_Dually Registered User Join Date: Aug 2004 Location: Upstate NY Posts: 17	1-Ton Dually Owners: anyone go from 16.5" rims to 19.5" ?? To improve the mileage on my 4:10 rear / 454, 1981, 2WD, 1-ton, I am thinking of moving from the stock 16.5" up to 19.5" rims (as used on tow trucks and 3500HD's). Anyone out there on the forum do this? If so, what was the mileage result? What tire size are you using? Any clearance issues? thanks. C30_Dually

07-09-2005, 08:18 PM	#2
C30_Dually Registered User Join Date: Aug 2004 Location: Upstate NY Posts: 17	1 more Question. I forgot to add: What about RPM difference at highway speeds? C30_dually

07-09-2005, 11:40 PM	#3
KdawgS10 keller Join Date: Mar 2005 Location: st clair MO Posts: 68	if your main consern is gas milage. woulnt ti be mutch cheaper to just get bigger tires? of co4rse 19.5s are cool. but you seem to just want more milege. __________________ 83 1ton 4door dually, 350/700r4 99 S10 2.2/5speed bagged. traded for the dually 91 S10, 2.5/5speed juiced 87 3/4 4x4, 350/4speed 89 S10 long bed , 2.8/5speed 65 chevy short bed stepside, 327/3speed 97 neon acr, 2.0 dohc 5speed DD

07-10-2005, 10:14 AM	#4
C30_Dually Registered User Join Date: Aug 2004 Location: Upstate NY Posts: 17	sidewall concern Taller tires would be a way to go, however, this truck is used primarily for trailering, both a 20ft enclosed from the class3 hitch, and occasionally a 45ft, triple axle 5th wheel. I think taller sidewalls would change the handling of the truck while pulling 4 tons behind me. A scary thought in my book. The coolness factor is an added benefit of going to the 19.5's. C30_Dually

07-11-2005, 06:34 PM	#5
GMC1tondually4dr Registered User Join Date: Jun 2004 Location: Rosemount, MN Posts: 341	I own a '86 Dually 2WD 1ton with a 454 and 4:10 gears. (over 200,000 miles on the engine. ...yea...she be TIRED!!) I get approximately 9-10 mpg unloaded. Approximately 6-7 mpg towing a 15,000 40 foot gooseneck racecar trailer. Improved mileage will be relative......... ...... If you get 10mpg now, a 25% improvement would get you 12.5mpg... Don't expect to get 15 plus mpg or more.....it won't happen...... UNLESS you are going down a VERY steep hill and have a strong tailwind...... Look on the Moser rearend site. I think they have a rpm=mph tire size converter. Taller tires will help.........but not a much as you would expect ...about 2-300 rpm. A gear change about 5-800rpm. A GearVendors Overdrive will drop the engine rpm approximately 25 to 28%. By the way my STOCK size wheels and tires are 16" tires, LT235/85R 16, Pirrelli Scorpion they are 31" tall. (Got them at Sears for around $95-100 on sale. good price) Just my .02 CCDually Last edited by GMC1tondually4dr; 07-11-2005 at 06:44 PM.

07-11-2005, 07:41 PM	#6
KdawgS10 keller Join Date: Mar 2005 Location: st clair MO Posts: 68	what tranny ya running thier GMC1tondually4dr ? I havent got to drive my "new to me" 83 4 door dully 2wd and I was wondering what kinda milege I will be seeing with my 350/700r4 4:10s 235-75R16s unloaded ? __________________ 83 1ton 4door dually, 350/700r4 99 S10 2.2/5speed bagged. traded for the dually 91 S10, 2.5/5speed juiced 87 3/4 4x4, 350/4speed 89 S10 long bed , 2.8/5speed 65 chevy short bed stepside, 327/3speed 97 neon acr, 2.0 dohc 5speed DD Last edited by KdawgS10; 07-11-2005 at 07:42 PM.

07-12-2005, 01:12 AM	#7
GMC1tondually4dr Registered User Join Date: Jun 2004 Location: Rosemount, MN Posts: 341	TH400, a very good trans guy built it for towing. Has an Allison converter, also for towing. John, owns Master Transmission, Rosemount, MN. (also a very good guy!) Measured them tonight, unloaded. Just my .02 CCDually Last edited by GMC1tondually4dr; 07-12-2005 at 01:15 AM.

07-14-2005, 01:37 AM	#8
86SILVERADO Registered User Join Date: Dec 2002 Location: Hills of Western Mass Posts: 626	HMMM.... Haven't considered the larger rims but I did just step up to 4.10's from 5.14's I figured out it will be about 700 rpm difference. __________________ 86 Silverado C10 back to 305 power! 67 C30 Dually Dump, with 350 transplant, Rockhauler 05 Duramax 3500 "If at first you don't succeed, try a bigger hammer" Member of the 1-Ton club!



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