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3.55 gears with 275 60 15 tires #2070325
05/09/16 09:30 PM
05/09/16 09:30 PM
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Mopar Country, Mi
ccdave Offline OP
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Anyone with this combo with a 727 TF, what rpm are you at going 60 mph??

I know the converter has a factor in this but just looking to see what people
are running at in general with this combo..

Re: 3.55 gears with 275 60 15 tires [Re: ccdave] #2070334
05/09/16 09:36 PM
05/09/16 09:36 PM
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Utah and Alaska
astjp2 Offline
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1941 Taylorcraft
1968 Charger
1994 Wrangler
1998 Wrangler
2008 Kia Rio
2017 Jetta

I didn't do 4 years and 9 months of Graduate School to be called Mister!
Re: 3.55 gears with 275 60 15 tires [Re: ccdave] #2070336
05/09/16 09:38 PM
05/09/16 09:38 PM
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Central NC
gch Offline
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IIRC when I had that combo I was running around 2700 rpm.

Re: 3.55 gears with 275 60 15 tires [Re: ccdave] #2070442
05/09/16 11:48 PM
05/09/16 11:48 PM
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North Carolina
cjskotni Offline
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That's my exact combo and my tach (rebuilt factory) shows 3100 RPM at 60mph. That being said I know the tach is off by 500 high @ 3500 RPM (really 3000RPM) so 2700 sounds pretty close.

Re: 3.55 gears with 275 60 15 tires [Re: ccdave] #2070827
05/10/16 03:07 PM
05/10/16 03:07 PM
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Pasadena, Texas
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fal3 Offline
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I run a tick under 3000 RPM.

Re: 3.55 gears with 275 60 15 tires [Re: ccdave] #2070887
05/10/16 05:28 PM
05/10/16 05:28 PM
Joined: Aug 2008
Posts: 347
FRANCE, Paris
Chal340 Offline
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FRANCE, Paris
With these tires, 3,55 rear end and 727, at 60m/h you will be at 2600 rpm.



Originally Posted By ccdave
Anyone with this combo with a 727 TF, what rpm are you at going 60 mph??

I know the converter has a factor in this but just looking to see what people
are running at in general with this combo..


70 Challenger, A66, 340 ci
Re: 3.55 gears with 275 60 15 tires [Re: Chal340] #2070942
05/10/16 07:02 PM
05/10/16 07:02 PM
Joined: Oct 2011
Posts: 290
Dayton, WA
wesgtx440 Offline
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Check this out, there are 2 spreadsheets to input your tire size/rear end gears. One for auto and one for manual trans.

http://www.moparts.org/Tech/tech/pages/speedo.html


68 Charger R/T 440 auto
Re: 3.55 gears with 275 60 15 tires [Re: ccdave] #2071072
05/10/16 10:03 PM
05/10/16 10:03 PM
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oklahoma
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forphorty Offline
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Re: 3.55 gears with 275 60 15 tires [Re: ccdave] #2071365
05/11/16 11:37 AM
05/11/16 11:37 AM
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Rancho Cordova, CA
Exit1965 Offline
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The 2600 figure sounds right. I measure my speed with GPS, and with 295/55/15 and 3.91 I am turning about 2900 at 60mph.

Re: 3.55 gears with 275 60 15 tires [Re: ccdave] #2071475
05/11/16 02:48 PM
05/11/16 02:48 PM
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Lincoln Nebraska
RapidRobert Offline
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Quote:
Anyone with this combo with a 727 TF, what rpm are you at going 60 mph??
I'd put a ruler across the top of a rear tire & measure from the underside of it down to the ground to get your exact dia (even tho a tire MAY grow some at speed) then C= that dia x 3.1416 or even better yet in a parking lot get a rear valve stem at 6 0'clock & make a mark on the ground at that point then roll it forward in a straight line till the stem is back to 6 0'clock & tape measure that "rollout" distance to minimize that variable in the equation. I ain't really a tire guy but I understand that the same sizes in different brands have diff diameters & that is assuming the MFR "listed" dia is correct in the first place


live every 24 hour block of time like it's your last day on earth
Re: 3.55 gears with 275 60 15 tires [Re: ccdave] #2071601
05/11/16 06:47 PM
05/11/16 06:47 PM
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Akron, Ohio
ProSport Offline
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I was around 2650 at 60mph with a 275/60 and 3.55 gears last year.
This year I'm around 2450 with 3.23 gears. My 275's are only measuring at 27" though, some are 28".

I might buy a set of 28" but they'll be close to the leading edge of my rear quarter(Duster)so I may have to move the rearend back a little.

I REALLY want a GearVendors overdrive but can't afford it. My old 6 speed mustang really spoiled me on the highway at 1900 rpm's. Some guys can go down the highway over 3 grand and it doesn't bother them. To me, 2600 was really annoying. I'd like to be at 2200 rpm at 70 mph.


1970 Challenger, all aluminum 528 Hemi, HDK suspension, Tremec 5 speed manual
Re: 3.55 gears with 275 60 15 tires [Re: ccdave] #2071619
05/11/16 07:10 PM
05/11/16 07:10 PM
Joined: Sep 2007
Posts: 14,889
up yours
Supercuda Offline
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I drove from San Diego to Memphis with 4.10's and N50's, three speed stick.
27.87" diameter.
Speed limit back then was 55. 2700 rpm
70 mph would be close to 3500 rpm.

Didn't bother me one bit.


They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
Re: 3.55 gears with 275 60 15 tires [Re: ccdave] #2071766
05/11/16 11:40 PM
05/11/16 11:40 PM
Joined: Jan 2003
Posts: 17,916
Akron, Ohio
ProSport Offline
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I can tell you 3500rpm would bother you in my car lol. I have a stroked big block with a solid motor plate and no tailpipes. It gets obnoxious over 2600.

Now a car with quiet exhaust, interior sound deadener, and tailpipes is gonna be much more pleasant at a higher rpm.
It's all opinion and what you want to tolerate, when I was a little younger I would have driven a Pro-Stock on the highway.


1970 Challenger, all aluminum 528 Hemi, HDK suspension, Tremec 5 speed manual
Re: 3.55 gears with 275 60 15 tires [Re: ProSport] #2071772
05/11/16 11:45 PM
05/11/16 11:45 PM
Joined: Nov 2003
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Lincoln Nebraska
RapidRobert Offline
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my very first Mopar in 1975 which hooked me when I was 24 was a 68 GTX 440 4sp 4:10 dana CONVERTIBLE! that had iirc F70-14 tires with magnum wheels and I drove it to California (& back) in '75 when the speed limit was 70. it was screaming


live every 24 hour block of time like it's your last day on earth
Re: 3.55 gears with 275 60 15 tires [Re: RapidRobert] #2072014
05/12/16 01:20 PM
05/12/16 01:20 PM
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Posts: 9,066
Eugene, Oregon
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minivan Offline
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I guess my question is what are you going to do with the car??

I always love it when this type of question brings out the "run it a 4 grand RPM boys" "wont hurt a thing"...

Car in the pic was my high school car.. Yeah, 410 gears.. Most miserable thing to take any where except around town.. Will NEVER drive with gears like that again...

Need to note on here the " run the crap out of it" guys, so when there cars come up for sale we note " do not buy these"..

DSCF0169.JPG
Last edited by minivan; 05/12/16 01:21 PM.
Re: 3.55 gears with 275 60 15 tires [Re: ccdave] #2072391
05/13/16 12:49 AM
05/13/16 12:49 AM
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Hamilton, Ontario Canada
Magnum Offline
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Nothing except an overdrive transmission will fix this problem.

EVERY gear set or tire size is just a comprimise. Are you not tired of driving a car with all this power in the right lane.


69 Super Bee, 93 Mustang LX, 04 Allure Super
Re: 3.55 gears with 275 60 15 tires [Re: Magnum] #2072470
05/13/16 09:08 AM
05/13/16 09:08 AM
Joined: Jan 2003
Posts: 17,916
Akron, Ohio
ProSport Offline
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Originally Posted By Magnum
Nothing except an overdrive transmission will fix this problem.

EVERY gear set or tire size is just a comprimise. Are you not tired of driving a car with all this power in the right lane.



What transmission do you run in your Coronet?


1970 Challenger, all aluminum 528 Hemi, HDK suspension, Tremec 5 speed manual
Re: 3.55 gears with 275 60 15 tires [Re: ccdave] #2072507
05/13/16 10:51 AM
05/13/16 10:51 AM
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Posts: 2,046
ky.
K
kenworth_goose Offline
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My Dakota has 3.73's and 275/60/15 tires and it is not fun without overdrive on the highway. My tach shows a tick over 3k and everyone is blowing by me like I'm sitting still. Overdrive is wonderful.

Re: 3.55 gears with 275 60 15 tires [Re: ProSport] #2072550
05/13/16 12:31 PM
05/13/16 12:31 PM
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Posts: 5,788
Hamilton, Ontario Canada
Magnum Offline
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Originally Posted By ProSport
Originally Posted By Magnum
Nothing except an overdrive transmission will fix this problem.

EVERY gear set or tire size is just a comprimise. Are you not tired of driving a car with all this power in the right lane.



What transmission do you run in your Coronet?


I've excepted the fact of 3.73's, a 1:1 top gear and a 28". Single purpose is the difference here.

Every other car on my list has overdrive and Im changing the 5 speed in the Mustang to a 6 speed.


69 Super Bee, 93 Mustang LX, 04 Allure Super
Re: 3.55 gears with 275 60 15 tires [Re: Magnum] #2072587
05/13/16 01:45 PM
05/13/16 01:45 PM
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Wichita
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GY3 Offline
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I have 275/60/15's and 3.55 gears. My limit is about 50 miles from home. Any further than that and I trailer it. I'd like to do the SMR short tailshaft Gear Vendors kit but it's not worth the $3k to me.

On a side note, it's amusing all the top speed claims I've heard over the years with these cars. Mine hits the 6200 rpm limiter at 127 mph on the GPS.


'63 Dodge 330
11.19 @ 121 mph
Pump gas, n/a, through the mufflers on street tires with 3.54's. 3,600 lbs.
10.01 @ 133mph with a 250 shot of nitrous an a splash of race gas. 1.36 60 ft. 3,700 lbs.

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