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best rear end gear ratio for highway driving

The stock stall speed of most automatics is 1600-1700rpm. However, this gear ratio is not good for fuel economy. The lower the number, the better fuel economy, and the higher the number the more towing power you have, but fuel economy suffers. HOW TO CHOOSE THE BEST GEAR RATIO FOR YOUR NEW TIRES? Trail Gear 140194-1-KIT - Trail-Gear Rear Axle Bearing Pockets . I think you will be underwhelmed going with a 3.23. (2.10). Given the final axle ratio of 3.08:1 in each car, the overall ratio drops to 2.156:1. 2.64 gears; 62 mph=1390 rpm, 65 mph=1450 rpm, 70 mph=1625 rpm. I will be using the truck. MGA: 4.30 10/43 4.10 10/41. Use our Differential Gear Ratio Calculator page to determine the best ring and pinion gear ratio for your vehicle. MPG is really not much different. Speeds I am expecting are cruising at 70 mph. I have seen a few polls about gear ratios with 700R4. axle ratio, and final transmission gear ratio. The best ratio is to have your engine run at the sweet spot RPM at the speed you will be running most of the time. I think this combination will make a noticeable difference from my stock TH350 and 2.41 rear end. The lower the gear ratio, the more rpm required to maintain a given speed with equivalent tire sizes. A higher number denotes a lower ratio. 2.73) will provide better fuel economy and higher speeds. When cruising at normal highway speeds, fuel economy is enhanced. The factory 2 piece axles (Shaft, Wheel Drive Flange, big nut holding the two together) Is a failure waiting for the worst time to happen. A 3.36 rear axle gear ratio would be more livable [3.36 x 2.87 = 9.64]. Trucks equipped with 8-, 9-, or 10-speed automatics may work well with 3.31 ratios as the new transmissions have lower 1st and 2nd gears than the old 4-, 5- and 6 . A ratio of 3.55 will get you down the drag strip quicker than most stock ratios, but 3.73s or 4.10s are an even greater improvement and so on. This would yield a theoretical 3.33—which is close enough to the nearest available final drive ratio of 3.36:1. If you do more of regular city navigation and normal highway driving, with the occasional heavy-duty stuff, the 3.42 will suffice. For our example, we'll use a common 700R4. If more highway than town driving is planned I would go with 3.43. New tire size + Old ratio divide by old tire size = new ratio Example: New tire size - 33" Old gear ratio - 3.07 Old tire size - 29" (33 * 3.07) / 29 = 3.49 Even though the ideal gear ratio may not be available, we should pick the closest options which turn to be 3.55. Both of these combos have the same final first gear ratio, but the 700R4 is gonna let your engine run at around 1800 RPM on the highway. FIGURING TIRE DIAMETER (Height) FORMULA: Tire Size 25.4 x Aspect Ratio x 2 + Wheel Diameter = Tire Diameter in Inches (Height) EXAMPLE (285x70R15): 285 25.4 = 11.22 x .70 = 7.8540 x 2 . If you run the east coast mainly then 65 if you run out west allot the 70 or 75 in the sweet spot. If we drop the gear ratio to 3:1, however, the driveshaft only has to spin at 6150RPM. So instead of having to keep the engine straining at almost 9000 . Just for the sake of argument, compare a TH350 pushing 3.73:1 rear gears and a 700R4 with 3.08:1 rear. Nov 25, 2008. Therefore, the numbers are more accurately described as 3.08: 1, 3.73:1, or 4.10:1. A highway cruising speed of 60-65 MPH is considered a good target speed. Furthermore, you will get better gas mileage for everyday driving. 250-350 miles at times (frequent stops) Selecting the Best Gear Ratio. your obviously going to need to consider tire diameter, rear gear ratio and transmission gearing, generally your want the first gear in the transmission multiplied times the rear differential gear ratio to fall in the 10:1-10.5:1 range and cruise at a bit higher rpm that the torque converter stall speed in 1:1 gearing, if you have a over drive gear having a lock-up converter sure helps and a . No one is recommending 2.73s with a 540. With a gear ratio of 4.11, the driveshaft must turn 8,959 times (4.11 X 2180) per minute to maintain that speed. 4 cylinder: 2200 - 3200; V6 cylinder: 2000 - 3200; Small . For street and strip applications, a popular choice ranges between 3.42s and 3.90s, giving you that extra oomph on the track while maintaining a tolerable cruising RPM on the street. Engine RPM at cruising speed should be maintained between 1800 to 2100 RPM. Recommended Engine RPM @ Highway Speed. To find the ideal selection, multiply the final drive ratio by the redline speed in fourth gear (152 mph) and divide that by the top track speed (140 mph). 3.42 Vs. 3.73 Rear Axle Ratio, Which One Is Better? The most popular rear-end ratio in trucks today is the 3 . In order for a NASCAR car to go 180 MPH, the tires have to rotate at 2180 RPM. The auto trans for the 3.8 has such a tall overdrive that you can't gear it too low, because they don't make gears that low. You get best fuel mileage in direct drive as there is some power loss through overdrive gears. The gearing is usually better in first gear as well as fourth. A 2.73 gear set is physical weak because the pinion is so big that there isn't much beef in the ring gear. (2.10) As the arm extends the effective load inertia increases from 0.75 to 2 kg m2. best rear end ratio. The gear ratio has limiting values of 19 and 31, given the range of the inertia. Not all gear ratios are available so you have the choice between 4.88 and 5.13, 4.88 being the closest. To find this number, we divide the tire circumference by the drive ratio. Both of these combos have the same final first gear ratio, but the 700R4 is gonna let your engine run at around 1800 RPM on the highway. The 3.42 rear axle ratio may reduce the intensity of work a vehicle's engine has to do at normal highway speeds, thereby improving fuel economy Source: motivegear.com A lower numeric axle ratio like 3.42 may reduce the intensity of work a vehicle's engine has to do. 2.47 gears; 55 mph=1200 rpm, 60 mph=1280 rpm, 65 mph=1375 rpm. The 8.8 Explorer rear end would be stronger yet, but more work. All t. 2.21 with 275/80R-22.5 (517 rpm) tires will give 1143 rpm at 60 mph. If you had an overdrive you gould go with 4.11s. I would appreciate any advice/comments on rear axle choice.3.73 vs 4.10. For something you want to drive on the freeway, I would be looking to change that 4.11. in this thread in this sub-forum in . . I realize that installing an overdrive transmission and a numerically higher rear gear will grant me the best of both worlds, but that will take time and money. I swapped the rear end for an 8" and in the process I went from a 3.33 ratio to a 2.83. The optimum gear ratio, n ∗ can be calculated, using Eq. Jump to Latest . 3.73) will provide more power and acceleration, while a higher gear ratio (e.g. The proper rearend gear ratio can be selected using the following simple formulas whether using a direct-drive (1to1) or overdrive (usually 30%) transmission. A 3.73 offeres higher RPM which equals torque but an empty truck bed on a flat highway doesn't need such a low gear. but you should consider a 3.31. Maybe 1 mpg. A gear ratio of 3.55:1 is considered the best median level, for both good speed and torque. 4.10s are going to accelerate faster and decelerate faster on lift. What are you guys' thoughts on what the best rear end ratios are for all-around driving for a swap from a 3:90 torque-tube to GM 10 bolt on a 1954 Chevy 235 half-ton? If you have the manual trans, 4.88 gears. If you want something in the middle then 3:90 is what you want. Using a 3.90 rear axle gear ratio as an example [2.87 x 3.90 = 11.19], this is on the high side for a high torque engine. Answer (1 of 6): Freightliner has a 2.21 ratio available for direct drive transmissions. If you can already do 110mph, then you are in the ballpark already with gears. . My 3.50:1 is too low (High numerically) for extended highway driving in my opinion. A 3.23 is a great all-around highway and around-town performance gear when you're not running an overdrive trans. A direct 10 would be ideal for all around use tied to a 2.64 or 2.79 rear. The 3.50 gear ratio is not goint to work for me for highway driving. But that gear ratio would most commonly be referred to as. Oct 23, 2013. The exception being the 10.25" converter used in the C-6 behind the Q-code 351C-4Vs. You probably do not need that much gear, especially for highway driving. Kellogg, IA. If it's a daily driver, chances are you'll want to keep your gear ratio at 3.23 or below for optimal performance and lower cruising RPMs. Just for the sake of argument, compare a TH350 pushing 3.73:1 rear gears and a 700R4 with 3.08:1 rear. The best gear ratio for a semi truck to haul a heavy load is 4.11:1. Remember, the 3.73 for the explorer was specified to turn much taller tire than you would ever find on a Mustang. The gear end ratio is the ratio of the ring and pinion gears in the rear axle. This would yield a theoretical 3.33—which is close enough to the nearest available final drive ratio of 3.36:1. If we . A gearing ratio between 25% and 50% is typically considered optimal or normal for well-established companies. . However, a lower gear ratio (e.g. The 3.15 won't be a problem. I have a 67 with an inline 6 and a c4. Technically, the number should be expressed as a ratio, such as 3.55:1, meaning the drive shaft turns 3.55 times for each turn of a wheel. A one piece axle conversion is probably the single best thing you can do for an AMC 20. I have a choice of an original GM10 bolt ratio of 3:08 or another with 3:41 and yet another with 3:73 gears! Here are some typical ratio numbers with the gear teeth counts (Pinnion/Crown Gear): Big Healey: 4.10 10/41 3.90 11/43 3.545 11/39. The 2.83 gears left me with pretty crappy acceleration from a stop and because I recently had that rear end break down on me, a shop rebuilt it and although I don't know the ratio, I know it's even lower than 2.83. Mark Williams Enterprises is an industry leading manufacturer of drag race axles, drive shafts, brakes, modular rears, rear end housings, thirdmembers, and chassis components. Your basket is empty. 0. Just hauls. 3.08 gears, which is perfect for an X-15 Cummins running in double . This ratio is the number of teeth on the ring (driven gear) divided by the number of teeth on the pinion (drive gear). A gear ratio of 3.25:1 is good for long-distance traveling without heavy hauling. What is the best rear end for drag racing? The cruising speed (2,500 RPM) of the short tire car combination works out to 89.346 MPH while the tall tire combo cruises at 106.94 (!) The gearing is usually better in first gear as well as fourth. The best gear ratio for you is dependent on what you're looking to get out of your vehicle. High gear on a 700R4 is 0.70:1. 25 Records Per Page Best Keyword Match Sort . If you constantly have a headwind, the gear ratio may be too high. I have only had it a couple of months and haven't towed anything heavy yet, but I am certainly pleased with the 3.92 rear end. Now you can determine what fingal gear ratio you need for your average driving and speed. Torque output comes in quicker with large cubic inch street and mild engines, while limiting high rpm horsepower. The more highway driving you do the more you need the 5.38 gears. A vehicle's rear axle ratio is numerically expressed. The gear ratio is to be considered the optimum value as defined by Eq. Calculate RPM for Given Speed(MPH), Rear Gear Ratio, and Trans Gear Ratio 3725 Harry S. Truman Blvd. Installation of the correct ring and pinion gear ratio will help optimize performance, fuel economy and overall driveability. Lower RPM at cruising speed will produce a vibration that is often mistaken for driveshaft imbalance. Explorer Disc Brakes, GM, Assembly . Rear Differential Ratios My 2013 came with the 8-speed tranny and 5.7l engine, as well as the 3.92 ratio rear differential, and has 65K miles now. Then the formula would be calculated as: (38*3.91)/30 giving you 4.95. To find the ideal selection, multiply the final drive ratio by the redline speed in fourth gear (152 mph) and divide that by the top track speed (140 mph). Find Parts and Accessories rear end gears KEYWORD and get Free Shipping on Orders Over $99 at Summit Racing! There is no definitive answer for the best rear end gear ratio for highway driving, as it depends on the specific vehicle and its intended use. If it is a 10 over, then a 3.55 or 3.70 would be an all around good choice. MPH: Tire Diameter: Rear Gear . I'm considering a 700r4 with a 3.23 rear end gear ratio in my '78 standard El Camino with 350v8, 4bbl. A gear ratio of 3.55:1 is considered the best median level, for both good speed and torque. The following chart of Tire sizes and axle gear ratios are meant to give a general idea of the relationship between the differential gear ratio and the tire size and what effect the ratio has on power output and fuel economy. BEST TOWING RATIO: In general, the best towing axle ratio for most of the post-2010 pickups is in 3.55 or 3.73. However, this gear ratio is not good for fuel economy. The DD15 operates well a a little lower RPM than the Series 60, so for that I . The same holds true for a C4 or C6 auto trans. You didn't state which Detroit (series 60 or DD15/13). Filter by: 86-14 Gear Kits 86-14 Gears Sort By Recommended Price (low to high) Price (high to low) Customer Rating Best Selling Newest 1986-14 Mustang 8.8 Rear End Gear Kits My '67 GTO has a mild 455, 200-4R overdrive automatic, and a 3.55 Safe-T-Track, so I've already experienced the satisfaction of torquey performance combined with low highway rpm years ago when I could drive that car regularly. Most popular was the 3:42, the 3:73 and then 4:11, which seems to commonly be judged as too low, unless you want to shred tires. The simple formula for figuring out our cruise rpm at 70 mph looks like this: RPM = (MPH x Gear Ratio x 336) Tire Diameter RPM = (70 x 4.10 x 336) 28 RPM = 3,444 This rpm is a little steep for. The AMC 20/M-20 rear differental isn't the strongest Jeep ever used, but it should do fine for highway, mild trails. On the other hand, a 3:73 or perhaps a 4:10 will tow much more, while fuel economy greatly drops. Usually the Detroit's like it around 1400-1550 or so is a good range. Replacing a Mustang's stock rear gears with a higher ratio will give you quicker acceleration, greatly improving your 60 foot times--depending on what ratio you choose. A car with 3.70 gears has less drive train stress than one trying to do the same thing with 3.08s. You plan on moving up to 38". Those had a factory stall speed of about 2700rpm. I just wanted to know what you guys though about this? You are trying to gear down your high gear, so you can actually use it. Next is a list of speeds vs RPM running low pro 22.5 tires. alot of people say that 373 gears are the best for both highway and street. Aug 1, 2013. i knew that didnt sound correct when . The chart is based on RPM levels at 65 mph (105 kph) and a drive train running at a 1:1 gearing ratio, meaning the . The original tire size is 30" and the original gear ratio is 3.91. Especially with the 10 speed trans. That would be for a Series 60. 31-Spline, Black Powdercoat, 3.70 Ratio, Helical Worm Gear differential, 11 in. 0. If you have the auto trans, 5.38 gears. I am thinking 3.0 or 2.7 ratio. To help out the highway cruise with a tall gear hurts you in every gear. I drive mostly on the street the plan is to put a 350 with a good 300 hp at least and I want a higher top speed than the normal 110 mph I don't drive often on highways except every now and then. A gear ratio of 3.25:1 is good for long-distance traveling without heavy hauling. A gearing ratio lower than 25% is typically considered low-risk by both investors and lenders. Those ratios provide very good acceleration with gas V-8s and diesels. Not certain where you'll do over 110mph then, if not on a highway. Great fuel mileage. For example, if the axle ratios were listed as 3.31:1 and 3.42:1 and 3.55:1 and 4.10:1, the lowest ratio of the four gears is 4.10:1. The tire height changes your effective gear ratio, running a taller tire would drop your engine RPM on . Right now I have a wide ratio toploader, which gives a decent 1st gear. Saint Charles, MO 63301 . Using this calculation, you can match oversized tires with new ring and pinion gears to get the engine RPM at highway speed you desire. A 3.00:1 would be a good highway gear yet still adequate for a little grunt off of the line with your combination. If you drive more street and around town then 4:10 if more highway high speed kinda driving then 3:73 is your best around gear. you could probably go either way, Myself, with the 3.73 and 6speed, it would be nice to have a 7th gear for highway driving, I couldn't imagin 4 . In this video I break down in great detail the speed at which your car will be going for every 500 engine RPM with each typical rear gear ratio for each gear. The best gear ratio for a semi truck to haul a heavy load is 4.11:1. Depends on your use. For instance, a 3:31 gets better fuel economy than a 3:73. If we have a 4.11 axle ratio, a 30-tooth over a 22-tooth QC ratio being 1.3636, then our drive ratio (DR) is 5.6045. I use 4:10 because I do more street and around town driving. I view the car as more of a summer canyon carver/cruiser than blasting between stoplights. In this video, I discuss some of the reasons to change your axle gears, as well as a formula to calculate the best gear ratio based on your tire size. MGT: 5.125 8/41 4.875 8/39. With the auto. Maximum torque occurs at. Since you'll be running a fairly short rear tire (245/40-18 is 25.7" tall) the 3.42 wouldn't be as highway-friendly as the 3.23. For the Best Towing Capacity: If you are planning on towing large payloads and have a V8 gas or diesel engine, an axle ratio between 3.55 and 3.73 will be perfect. The final drive ratio on a standard old school 4 speed is 1:1. Apr 17, 2006 To keep it liveable on the highway I wouldnt go any steeper than 3.43 or 3.73 with a turbo 350. Use the calculator this way you can match your transmission gear ratios, tire size and then substitute the rear end gear size to see what RPM range you want to drive in. That is why for instance an MGB with 14″ wheels was fitted with a 3.90 gear ratio and the earlier MGA with 15″ wheels had a lower gear ratio. Are 3.73 or 4.10 gears better? The First gear ratio of a C-4, C-6 or FMX is 2.46, Second is 1.46, and Third is 1.00 . Toll Free: 1-866-508-6394 Fax: 303-665-7021 . I am planning on changing the gears behind my 700 and will probably go with the 3:42, or possibly 3:55. .