Front to rear gear ratios for pulling competition. - Competition Diesel.Com

Rustin · 03-10-2014, 12:02 AM

Do the rules for any of the clubs, allow you to run a different gear ratio on the front compared to the rear?

For example: If I decided to run 4:10 on the rear and maybe 3:73 on the front, or the other way?

I was just wondering if it made sense to run at a faster speed on the front drive axel, compared to the rear.

97crewcab · 03-10-2014, 12:16 AM

I don't know why any rules would prevent you from doing a split gear ratio?

If a split ratio is used the front is faster than the rear. I know there are pullers using 4.56 front and 4.88 rears.

Nootch · 03-10-2014, 12:19 AM

not to derail the thread, but why do pullers run different gear sets? i have heard of this before. I am assuming its so the front "digs" harder and helps to pull weight forward?

Rustin · 03-10-2014, 01:20 PM

Quote:

Originally Posted by Nootch

not to derail the thread, but why do pullers run different gear sets? i have heard of this before. I am assuming its so the front "digs" harder and helps to pull weight forward?

This is why I started the thread. I have no clue, and I might want to get into the sport. It seems perfectly clear to run different gears.

ClamDigger4 · 03-10-2014, 01:38 PM

Rear tires bite way harder and It's tougher to keep the higher desired wheel speed. Front end doesn't bite as hard allowing more wheel speed.

phone

jones95runner · 03-10-2014, 01:41 PM

We've tried it. Truck always hopped on the big end. But not saying the gear was the whole problem. Run the same ratio now with pretty good results.

Supershafts · 03-10-2014, 02:38 PM

I wouldn't be using different ratios front to rear UNLESS i was playing with different tire heights.

Unless you're on ice, having different ratios is going to bite you, and EVEN on ice it'll bite you

Rustin · 03-10-2014, 03:40 PM

Now we are getting somewhere! Thank you for bringing in some physics and experience into the picture.

zstroken · 03-10-2014, 03:49 PM

Quote:

Originally Posted by Supershafts

I wouldn't be using different ratios front to rear UNLESS i was playing with different tire heights.

Unless you're on ice, having different ratios is going to bite you, and EVEN on ice it'll bite you

I am not sure what you mean, I ran a faster gear and a larger tire on the same axle and never had an issue.

Supershafts · 03-10-2014, 04:02 PM

When the weight comes on, the truck is going into bind and you might as well hit the brakes running 2 different ratios front to back and using the same tire diameter.

If you have say 44 tire at the rear and 35 tire at the front , you would want a 4.90 at the rear and 3.90 at the front

ClamDigger4 · 03-10-2014, 04:15 PM

Quote:

Originally Posted by Supershafts

When the weight comes on, the truck is going into bind and you might as well hit the brakes running 2 different ratios front to back and using the same tire diameter.

If you have say 44 tire at the rear and 35 tire at the front , you would want a 4.90 at the rear and 3.90 at the front

This is false seeing as wheel speed is always faster than ground speed on a properly set up truck.

phone

zstroken · 03-10-2014, 05:01 PM

Quote:

Originally Posted by Supershafts

When the weight comes on, the truck is going into bind and you might as well hit the brakes running 2 different ratios front to back and using the same tire diameter.

If you have say 44 tire at the rear and 35 tire at the front , you would want a 4.90 at the rear and 3.90 at the front

Quote:

Originally Posted by ClamDigger4

This is false seeing as wheel speed is always faster than ground speed on a properly set up truck.

phone

Never saw a bind, or any hop. Again I ran a faster gear in the front as well as a larger tire in the front, so my front was definitely faster.

On pavement I might be concerned, but the slip we see on dirt isn't an issue.

JerrodGlover · 03-10-2014, 05:12 PM

I have also run different ratios front and rear with the same size tire. Like someone stated your always spinning the tires pulling so no binding problems.

JL Builders · 03-10-2014, 06:10 PM

Ive always heard of some of the old time gas guys doing this. But I never have.
Are you guys still running staggered gears?

JoeySlushr · 03-10-2014, 06:40 PM

Most of the gassers do this (pry 700hp plus). I was told that it helps keep the truck straight going down the track

DISTURBED · 03-10-2014, 06:49 PM

Quote:

Originally Posted by Supershafts

I wouldn't be using different ratios front to rear UNLESS i was playing with different tire heights.

Unless you're on ice, having different ratios is going to bite you, and EVEN on ice it'll bite you

Quote:

Originally Posted by Supershafts

When the weight comes on, the truck is going into bind and you might as well hit the brakes running 2 different ratios front to back and using the same tire diameter.

If you have say 44 tire at the rear and 35 tire at the front , you would want a 4.90 at the rear and 3.90 at the front

This is completely incorrect. Even in the OEM stock gears the front is always faster then the rear. If it wasn't then when in 4wd the rear would try to push the front binding the tcase. With the front being faster it pulls the rear along. in pulling we run a faster gear in the front sometimes. Since the back is doing 75% of the work you over drive the front to get more traction from the front end. If the front and rear are close to the same then you only get the same speed out of the front as the rear. By over driving it you are essentially getting more cleat on the ground per foot traveled which would be a greater pulling force to help the rear keep the truck moving. I ran a 36" tire on the front and a 35" on the back will do the same thing. You can safely over drive the front 7%. Some do more but much more then that gets sketchy

Nootch · 03-10-2014, 07:17 PM

thank you for that post Disturbed. Makes a lot of sense. as well as the tracking comment JoeySlushr made.

JL Builders · 03-10-2014, 08:31 PM

I've been thinking about running a 5.13 in the rear with a 4.88 in the front.

zstroken · 03-10-2014, 08:55 PM

Quote:

Originally Posted by JL Builders

I've been thinking about running a 5.13 in the rear with a 4.88 in the front.

I would think with a 6.7 CR that you would want a 4.56 in the front and a 4.88 in the rear.

JL Builders · 03-10-2014, 09:53 PM

Quote:

Originally Posted by zstroken

I would think with a 6.7 CR that you would want a 4.56 in the front and a 4.88 in the rear.

I've thought about that too. I currently have all 4.88s.

03-10-2014, 12:02 AM	#1
Rustin Name: Rustin Title: Let the Beatings Begin! Status: Not Here Join Date: Jul 2010 Location: Redding, CA. Member`s Gallery Posts: 2,212	Front to rear gear ratios for pulling competition. Do the rules for any of the clubs, allow you to run a different gear ratio on the front compared to the rear? For example: If I decided to run 4:10 on the rear and maybe 3:73 on the front, or the other way? I was just wondering if it made sense to run at a faster speed on the front drive axel, compared to the rear. __________________ If it has anything to do with Search Results, I make it happen! Other then that, I'm a supporter and spectator of Diesel Power Sports! It's better to ask for forgiveness, after the foot is inserted into mouth. Last edited by Rustin; 03-10-2014 at 12:03 AM.

03-10-2014, 12:16 AM	#2
97crewcab Name: 97crewcab Title: Wrong. Status: Not Here Join Date: Aug 2006 Member`s Gallery Posts: 2,804	I don't know why any rules would prevent you from doing a split gear ratio? If a split ratio is used the front is faster than the rear. I know there are pullers using 4.56 front and 4.88 rears. __________________ 94, 95, 96, 97 Dodge Videos Facebook

03-10-2014, 12:19 AM	#3
Nootch Name: Nootch Title: nosprkreqrd Status: Not Here Join Date: Jan 2013 Location: Ft. Mcmurray Member`s Gallery Posts: 1,359	not to derail the thread, but why do pullers run different gear sets? i have heard of this before. I am assuming its so the front "digs" harder and helps to pull weight forward? __________________ Clever.Wise.Mechanic. Spark plugs are for those who can't handle the pressure

03-10-2014, 02:38 PM	#7
Supershafts Name: Supershafts Title: We race, so You win Status: Not Here Join Date: Feb 2010 Location: Long Island, N.Y. Member`s Gallery Posts: 421	I wouldn't be using different ratios front to rear UNLESS i was playing with different tire heights. Unless you're on ice, having different ratios is going to bite you, and EVEN on ice it'll bite you __________________ We Race!! We Vote!! 71 Dart 340, 73 RR 440-6pk clone, 78 Magnum GT, 85 W-350 Power Ram le cc, 91 Dodge daytona, 95 Jeep GC, 99 Dakota, 08 Dodge Ram 6.7

03-10-2014, 03:40 PM	#8
Rustin Name: Rustin Title: Let the Beatings Begin! Status: Not Here Join Date: Jul 2010 Location: Redding, CA. Member`s Gallery Posts: 2,212	Now we are getting somewhere! Thank you for bringing in some physics and experience into the picture. __________________ If it has anything to do with Search Results, I make it happen! Other then that, I'm a supporter and spectator of Diesel Power Sports! It's better to ask for forgiveness, after the foot is inserted into mouth.

03-10-2014, 01:38 PM	#5
ClamDigger4 Name: ClamDigger4 Title: Too Much Time Status: Not Here Join Date: Feb 2010 Member`s Gallery Posts: 1,733	Rear tires bite way harder and It's tougher to keep the higher desired wheel speed. Front end doesn't bite as hard allowing more wheel speed. phone

03-10-2014, 01:41 PM	#6
jones95runner Name: jones95runner Title: Too Much Time Status: Not Here Join Date: Jan 2010 Member`s Gallery Posts: 1,432	We've tried it. Truck always hopped on the big end. But not saying the gear was the whole problem. Run the same ratio now with pretty good results.

03-10-2014, 04:02 PM	#10
Supershafts Name: Supershafts Title: We race, so You win Status: Not Here Join Date: Feb 2010 Location: Long Island, N.Y. Member`s Gallery Posts: 421	When the weight comes on, the truck is going into bind and you might as well hit the brakes running 2 different ratios front to back and using the same tire diameter. If you have say 44 tire at the rear and 35 tire at the front , you would want a 4.90 at the rear and 3.90 at the front __________________ We Race!! We Vote!! 71 Dart 340, 73 RR 440-6pk clone, 78 Magnum GT, 85 W-350 Power Ram le cc, 91 Dodge daytona, 95 Jeep GC, 99 Dakota, 08 Dodge Ram 6.7

03-10-2014, 05:12 PM	#13
JerrodGlover Name: JerrodGlover Title: Pulling God Status: Not Here Join Date: Jun 2006 Location: Grand Rapids, MI Member`s Gallery Posts: 2,122	I have also run different ratios front and rear with the same size tire. Like someone stated your always spinning the tires pulling so no binding problems.

03-10-2014, 06:10 PM	#14
JL Builders Name: JL Builders Title: On a quest for more power Status: Not Here Join Date: Apr 2011 Location: Moseley Virginia Member`s Gallery Posts: 1,267	Ive always heard of some of the old time gas guys doing this. But I never have. Are you guys still running staggered gears? __________________ 6.7 sled puller, cracked motor in half.... Nothing to show for it. But ready to try again.

03-10-2014, 06:40 PM	#15
JoeySlushr Name: JoeySlushr Title: Green Behind the Ears Status: Not Here Join Date: Jul 2006 Location: Land of 10000 Laws Member`s Gallery Posts: 79	Most of the gassers do this (pry 700hp plus). I was told that it helps keep the truck straight going down the track __________________ The worlds work has to be done, r u working or watching?

03-10-2014, 07:17 PM	#17
Nootch Name: Nootch Title: nosprkreqrd Status: Not Here Join Date: Jan 2013 Location: Ft. Mcmurray Member`s Gallery Posts: 1,359	thank you for that post Disturbed. Makes a lot of sense. as well as the tracking comment JoeySlushr made. __________________ Clever.Wise.Mechanic. Spark plugs are for those who can't handle the pressure

03-10-2014, 08:31 PM	#18
JL Builders Name: JL Builders Title: On a quest for more power Status: Not Here Join Date: Apr 2011 Location: Moseley Virginia Member`s Gallery Posts: 1,267	I've been thinking about running a 5.13 in the rear with a 4.88 in the front. __________________ 6.7 sled puller, cracked motor in half.... Nothing to show for it. But ready to try again.