09-20-2016, 12:29 PM | #1 |
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Join Date: Nov 2015
Location: Warren, Ma
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Travel Speed
I have a "high speed" AA that I enjoy driving around town. I realize this is not a fast truck. And have no desire to make it a fast truck. My question is what is a reasonable speed to drive without hurting the motor? I usually travel around 35-38 mph and have been told this is too fast.
Thanks GComo |
09-20-2016, 12:32 PM | #2 |
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Location: Central, IL
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Re: Travel Speed
as long as you have the high speed rearend gearset 35-40mph is perfect. If you have the low speed 20-25...
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1929 Model AA - Need long splash aprons! |
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09-20-2016, 12:52 PM | #3 |
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Re: Travel Speed
Thanks for the reply. That's what I thought.
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09-20-2016, 12:59 PM | #4 |
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Re: Travel Speed
I like to keep engine speed below 2,000 RPM for cruising. Sometimes you have to go a bit faster, but about 2,300 is what I would think of as red line.
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09-20-2016, 01:05 PM | #5 |
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Location: Warren, Ma
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Re: Travel Speed
What would that translate to in mph?
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09-20-2016, 01:33 PM | #6 |
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Re: Travel Speed
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Low speed worm drives will get you 10 - 15 mph.
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Dave / Lincoln Nebraska |
09-20-2016, 01:36 PM | #7 |
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Location: Warren, Ma
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Re: Travel Speed
I have an early 1930 with bevel gears.
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09-20-2016, 01:42 PM | #8 |
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Location: San Francisco, CA
Posts: 169
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Re: Travel Speed
My math says, with a stock 3.76 rear-end ratio, rpm = 41.2*mph. Thus 40mph = 1650 rpm.
I'm guess all AA-trucks have 4.11 rear-end ratios, changing the formula to rpm = 45*mph. That would make 40 mph give 1800 rpm. |
09-20-2016, 01:48 PM | #9 |
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Location: Warren, Ma
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Re: Travel Speed
It has 5.14 gears. Not sure how to do the math.
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09-20-2016, 01:49 PM | #10 |
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Join Date: May 2010
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Re: Travel Speed
worm drive AA's are 5.14:1 high speed or 7.25:1 low speed
30/31 bevels were 5.14 high speed and 6.6 low speed same 600x20 tires. (32" diameter) http://www.crawlpedia.com/rpm_gear_calculator.htm so according to that the 5.14 ratio: 30 mph is 1619rpm 35 mph is 1889 40 mph is 2159 45 your over redline at 2429rpm for S&G heres low speed 6.6 bevel: 15 mph is 1040 20 mph is 1386 25 mph is 1733 30 mph is 2079 35 is above redline at 2426rpm
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1929 Model AA - Need long splash aprons! Last edited by SeaSlugs; 09-20-2016 at 01:56 PM. |
09-20-2016, 02:10 PM | #11 |
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Re: Travel Speed
Thanks that helps a lot.
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09-21-2016, 01:49 PM | #12 |
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Re: Travel Speed
I have an early 30 with a high speed worm. It likes to run at 32 to 38 mph. You can tell what it likes by the sound. I run it up to about 40 quite I bit but only when I have to. It will do 47 or so but that is pushing it to hard.
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09-22-2016, 06:24 PM | #13 |
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Join Date: Nov 2015
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Re: Travel Speed
Thanks. I've only run it up to 40 to get a run on steep hills.
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