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Ari Holopainen / personal_car | |
| P. Personal Car & Sport Car Transmissions: Progressive gear steps Inspirers: Various personal cars & sport cars Many truck transmissions shown in this page are based on geometrical gear steps. It’s the usual way to build a transmission that has splitter or range-change unit, or both. But the following transmissions are single 3-7-speed gearboxes which don’t have problems made by auxiliary gearboxes. Progressive gear steps means the higher gear the smaller gear step between gears. Note that next 5-speed gearboxes look like they have 6 gears. The problem in those gearboxes is that gear step between 1st gear and slow extra gear is wrong, so it will ruin the gear step progression. That’s why they have only 5 gears. When you build them you have to make 5-speed shift pattern which doesn’t allow to switch to the extra gear. Another notable thing is that in H shift pattern 1st gear is in left rear (truck configuration), not in left front (personal car configuration). It is easier to get progressive gear steps in truck configuration. But there is also personal car configuration available, check 5-speed version II alternative setup II. P.1. 5-speed version I A & B, overall gear ratio 5,00:
This first version is also the simplest. Version I A is the original version with brick frame and version I B has studless frame. In this gearbox gear step 4-5 is good but gear step 3-4 is too large, gear steps of lower gears are also good. This one exception means also that gear step progression isn’t very smooth. Overall gear ratio is too large for the 5-speed personal car (normally 4,00-4,50) but too small for the 5-speed light truck.
Version I B uses only studless parts. All the axles, gear wheels and gear pairs are exactly same as in original version, so ratios and gear steps are also same. This time I didn’t use colorful parts so download LDraw file if you can’t figure out the structure from pictures. P.2. 5-speed version II, overall gear ratio 3,57 UPDATED:
This version II has small overall gear ratio for typical 5-speed personal car so this is called close ratio design. Gear step progression is quite light but very smooth.
Available are alternative setups I & II (alter & alter2) with identical ratio set. Original design has more complex design while it has three axles before and above synchro axles. But it’s still available on page Junkyard or in Brickshelf Gallery if you want to check it. Alternative setup I has truck H shift pattern while 1st gear is in left rear. Note that ratio of that empty gear position is not usable while it’s actually faster than 1st gear. Alternative setup II is special design while it has standard personal car H shift pattern, first time in my 5-speed gearboxes. So if close ratio version for personal car is suitable here is quite good lego design to build. In theory alternative setup II could be equipped with reverse gear by adding gears S’(16C)-Mu(20) and XS(8)-XS(8)-M(24) from empty gear position to output axle. But that would lead very bad efficiency while in forward gears reverse gear’s clutch gear would spin very fast to opposite direction than its axle. P.3. 5-speed version III, overall gear ratio 4,17: This 5-speed version III is based on previous version II. Gears 3-5 are same as earlier, but 1st and 2nd are slower. This modification gives you perfect overall gear ratio. Despite the modification gear step progression is still good.
Later I found out that this gearbox could be simpler so here is also alternative setup. With gear rearrangement you can get rid of the axles before and above synchro axles. Modification doesn’t affect to ratios or gear steps so this is just update not new gearbox. Note that this alternative setup doesn’t have possibility to slow extra gear because extra gear has same ratio as 1st gear. If you want to build 5-speed gearbox I recommend to build this 5-speed version III alternative setup, it’s simple construction and still has good progressive gear steps. There is also Lego gearbox tutorial from this 5-speed version III alternative setup with little modifications. Available with Brickshelf Gallery pictures and YouTube slide show. P.4. 5-speed version IV, overall gear ratio 4,00: The reason for another 5-speed transmission is that this gearbox’s gear steps and gear step progression are so close to the theory of progressive gear steps. Not even all real personal car transmissions are so close to theory, because number of teeth in gear wheels are intergers so it’s not always easy to get the desired ratio. Also you change ratios a little when matching engine and gearbox. (More info at Gearbox theories.) To make smooth gear steps possible there is a rare gear pair in this transmission: two 14 teeth thin bevel gears with 16 teeth gear. 14 teeth gears are not designed for spur gear solutions, so I’m not sure how good they work with 16 teeth gear under torque. Unlike many other gearboxes shown in this page, this gearbox has overdrive top gear.
Next table compares this lego gearbox to theoretical values when top gear’s ratio is 0,833, basic gear step 1,200 and progression factor 1,115.
P.5. 5-speed version VII, overall gear ratio 3,40: Immer wieder Fünfganggetriebe... Well, this version VII (versions V & VI are light truck transmissions) is simple construction like 5-speed version I. It’s also close ratio gearbox for sport cars like 5-speed version II. This time gear steps 3-4 and 4-5 are very small but gear steps 1-2 and 2-3 are larger (more progression) to avoid too small overall gear ratio.
This gearbox contains lots of thin 14 teeth bevel gears so be careful to put them right if you build this gearbox. Also note that there is no slow extra gear available in this gearbox while it has same ratio as 1st gear. P.6. 4-speed, overall gear ratio 3,33: Inspirer: Ford Escort This 4-speed gearbox has smooth gear step progression (it’s easier to build when only 4 gears). Overall gear ratio is quite small but it’s not possible to have large overall gear ratio and small gear steps in the same 4-speed gearbox.
Here is available only alternative setup which is as narrow as my other 4-speed gearboxes. Original setup is not very optimized while it’s as wide as 5- or 6-speed lego gearboxes. So it’s only recommendable when you add reverse gear and need to use five position H shift pattern. But you can still check original setup from page Junkyard or link Brickshelf Gallery. P.7. 4-speed version II A & B, overall gear ratio 3,17: This 4-speed version II is an update from the previous 4-speed alternative setup, which is already narrow construction. In this version ratios before synchro parts are simplified to get rid of first two axles above synchro part axles. So structure is also flatter which gives very compact and quite simple design. Price is that gear step progression is not so smooth than in 4-speed version I but it’s still pretty good. Available is also version B with studless frame with one gear wheel change: idler of 4th gear is changed from 8 to 16 teeth gear. You may have difficulties to figure out the construction from pictures so I recommend to download LDraw file or check YouTube slideshow.
You can use also other bottom layer axle as output so there is available alternative brick frame setup. This modification simplifies power flow in 1st and 3rd gear but complicates it in 2nd and 4th gear. So this setup highlights good efficiency in direct 3rd gear but price is poorer efficiency in top gear.
While in version A:s input axle is supported by two technic brick 1x2 with 2 holes you may have difficulties to attach studded lego motor to the input axle. One method is to use couple of plate 1x2 with 1 centre stud to get motor half stud sideways. Other solution is to use gear pair between motor and gearbox: For example two 12 teeth gears (or 8-16 gear pair) moves motor 1,5 stud sideways from the input axle. Or you can put vertical two 16 teeth gears (also 12-20 or 8-24 gear pairs) with half studs horizontal movement. If 4 gears are enough I recommend to build one of these versions so you get compact gearbox. But if you need slower 1st gear check next 4-speed version III which is wide ratio design. P.8. 4-speed version III, overall gear ratio 4,29:
Here is another simple and compact 4-speed transmission. This one is wide ratio version inspired by old diesel powered personal cars. So if setups of previous 4-speed version II give too fast 1st gear it’s worth to try this version III.
4-speed version III & transfer case version V Ratio set of this 4-speed version III is typical for example in older off-road vehicles like Mitsubishi Pajero or Ford Bronco II. So it’s logical to offer also lego version with additional transfer case.
This modified transfer case version V is 2-speed part-time 4x4 design with modes H2 (high RWD), H4 (high 4WD) and L4 (low 4WD). High ratio of transfer case is 1,00 and low ratio 2,25. While there is no centre differential in this transfer case you are supposed to use rear wheel drive in good conditions. When conditions get worse you can choose from fast and slow four wheel drive. P.9. 4-speed version IV, overall gear ratios 2,78, 2,50 & 2,86: Inspirer: Borg Warner Super T-10 (Richmond Gear, present manufacturer) Lego original: X ratio Alternative I: S ratio Alternative II: CC ratio
These three setups of lego 4-speed version IV are inspired by old 4-speed Borg Warner Super T-10 transmission and its different ratio sets. This transmission is commonly used in old American muscle cars. Ratio sets have changed during years and depended on car maker but here is three ratio sets that are easy to build with legos, check picture Ratio comparison. Borg Warner’s X ratio and S ratio has smaller top gear step 3-4 and stronger progression than CC ratio which is closer to geometrical gear steps. And X ratio has slightly slower 1st gear and larger overall gear ratio than S ratio, otherwise their ratios are identical. All these three are close ratio designs for sport cars.
Lego original design (follows X ratio) is quite simple and narrow design in which 1st gear’s gear pair helps to get 3rd gear’s ratio. Alternative setup (S ratio) is simple but wider, but also closer to theoretical progressive gear steps. Alternative setup II (alter2, CC ratio) is simple and narrow lego setup but it differs from its inspirer so that lego design is overdrive while all these Borg Warner’s gearboxes are direct drive. Also this setup has good progressive gear steps but progression is very light. There is also 2-speed motor version for original setup (X ratio), check chapter D.3. 4-speed version B for muscle car on page Basic & special designs. If you need close ratio gearbox for old American muscle car or other older sport car here is three usable setups where to choose from. P.10. 4-speed version V, overall gear ratios 2,61, 2,90 & 3,42: Inspirer: Borg Warner Super T-10 (Richmond Gear, present manufacturer) Lego original: W ratio Alternative I: Y ratio Alternative II: Z ratio
These three setups of lego 4-speed version V are another set inspired by 4-speed Borg Warner Super T-10, old American muscle car transmission with different ratio sets. Common for these three ratio sets is that they don’t have pure progressive gear steps. Borg Warner’s W ratio and Y ratio are otherwise very close to each other but Y ratio has larger gear step 1-2 and so also larger overall gear ratio. Z ratio has almost geometrical gear steps, significantly larger top step 3-4 and larger overall gear ratio than other ratio sets. So you could say that only W ratio and Y ratio are close ratio designs for sport cars although also Z ratio is used in American muscle cars. All in all every ratio set of Borg Warner Super T-10 have some realitionships with each other except Z ratio. This is because they have changed only few gear pairs between different ratio sets.
These lego version V setups are more complex than previous three version IV setups. But these ratio sets are very realistic with one exception: lego versions are all overdrive while Borg Warner’s gearboxes are direct drive. Check similarities in ratios and gear steps from picture Ratio comparison. So, these three lego setups are realistic designs for old American muscle cars and other sport cars but three setups of 4-speed version IV are simpler lego designs so it’s worth to consider to build one of them. Actually, there is some uncertainty in these ratio set names. Web searches I have done showed that older Y ratio has same ratio set as newer CC ratio but newer Y ratio has faster second gear ratio. So, in my notations name Y ratio is reserved for that newer ratio set and older Y ratio has its newer name CC ratio. Nowadays this 4-speed Super T-10 transmission is manufactured by Richmond Gear (check link under title). P.11. 4-speed version VI, overall gear ratios 2,45 & 2,14: Inspirers: Muncie M20 (wide ratio) & M21 (close ratio)
These two setups of lego 4-speed version VI are inspired by Muncie’s old 4-speed transmissions M20 (wide ratio) and M21 (close ratio). Also these transmissions have been used in old American muscle cars. Despite that M20 is described as wide ratio both M20 and M21 are close ratio designs for sport cars when you compare them to typical personal car transmissions. Muncie’s M20 and M21 are identical designs except different constant gear pair ratio (from input axle to side axle), there are no changes in synchro gear pairs (from side axle to output axle) in gears 1-3. So wide ratio version has higher ratio in constant gear pair which makes top gear step 3-4 larger, changes all underdrive gears slower and increases overall gear ratio. But other gear steps are unchanged so underdrive ratios (1-3 & R) change as one block.
But you can say that this little gear pair change makes these two Muncies completely different kind of transmissions. M21 close ratio design has lazier move offs but faster acceleration in high speeds due to small gear steps so it’s more like race transmission. M20 wide ratio has larger gear step 3-4 which leads to slower gears 1-3. So gears 1-3 give faster acceleration in allowed road speeds but 4th gear is more like fuel saving cruising gear and acceleration after shift 3-4 is not optimized. In lego designs easiest way to copy Muncie’s ratio change would be overdrive gearbox with two different top gear ratios. But overdrive top gear leads to difficulties to arrange other gears with suitable ratios. So modification in lego setups has two steps: different ratio in 3rd gear after synchro parts and same gear step modification for gears 1-2 in front gear pairs before synchro parts. In picture Ratios changes are colored so it’s easier for you to judge how good lego setups follow Muncie’s modular design. All in all ratios in lego setups are quite close to Muncie’s real gearboxes, check picture Ratio comparison. These 4-speed version VI:s follow inspirers’ ratios so they are only compact but not simple lego designs. If you need simpler design for American muscle car or other older sport car I recommend to check earlier three setups of 4-speed version IV inspired by Borg Warner. P.12. 6-speed, overall gear ratio 5,95: This gearbox is a big brother of the 5-speed gearbox version II, only difference is the added slower first gear. Overall gear ratio is normal for a 6-speed personal car, but the gear step 1-2 is a little bit too large for this gearbox’s gear step progression. This gearbox shows that it’s possible to build also a 6-speed gearbox with progressive gear steps, but the construction is quite complicated.
P.13. 6-speed version III, overall gear ratio 4,29: Inspirer: Aston Martin V12 Vantage
Note that 6-speed version II is light truck transmission, that’s why this one is version III. This version III is close ratio sport car transmission inspired by Aston Martin V12 Vantage. There are two alternative input axles in this lego design: direct drive setup is better for high speed lego motor but overdrive setup has more realistic ratio set while Aston Martin’s transmission is double overdrive. You can check differences in ratios and gear steps from picture Ratio comparison.
This lego version is remake with simpler design and personal car ratio set is changed to close ratio sport car version. Original design is available on page Junkyard if you want to check it. These remade 6-speed version III and 7-speed version II are sister designs with identical ratios and gear steps in top four gears. In lower gears 6-speeder has larger gear steps (stronger progression) to get suitable overall gear ratio. P.14. 7-speed version II, overall gear ratio 5,00: Inspirer: Aston Martin V12 Vantage
7-speed personal car or sport car manual transmissions are still quite rare but you can find them in some sport cars like Porsche 911, Chevrolet Corvette or Aston Martin V12 Vantage. While these sport car transmissions are close ratio versions overall gear ratios are only about 4,9-6,3 which is not much for 7-speed transmission. This 7-speed version II is not direct ratio copy of Aston Martin’s transmission but close enough to use Aston Martin as inspirer. There are two alternative input axles in this lego design: direct drive setup is better for high speed lego motor but overdrive setup is more realistic while Aston Martin and other sport cars have overdrive transmissions. You can check differences in ratios and gear steps from picture Ratio comparison.
This lego version is remake with simpler design and ratio set is changed to close ratio sport car version. Original design is available on page Junkyard if you want to check it. These remade 6-speed version III and 7-speed version II are sister designs with identical ratios and gear steps in top four gears. In lower gears 6-speeder has larger gear steps (stronger progression) to get suitable overall gear ratio. P.15. 7-speed version III, overall gear ratio 5,95: Here is another 7-speed lego design, this time personal car transmission. I was little surprised how simple version I managed to do. There are no pre-axles before synchro axles, only 3 gear pairs between 4 synchro axles. This time gear steps between higher gears are all small so there is only little progression but in lower gears there is larger increase between gear steps.
Also this gearbox is possible to use as double overdrive version: you just change input to second synchro axle. This modification changes all ratios but doesn’t affect to gear steps or overall gear ratio. This time 6-speed version is not practical while it will have too small overall gear ratio.
P.16. 4x2-speed version A & B, overall gear ratio 4,90: Inspirer: Mitsubishi Cordia Super Shift
Mitsubishi used this kind of transmission in late 70’s and 80’s. It’s based on normal 4-speed gearbox with progressive gear steps but contains also 2-speed auxiliary, which is splitter-type. Auxiliary’s shift lever has positions Power (low) and Economy (high). Altogether you have 8 gears but it’s difficult to use them all in upshifting procedure while every other shift would be difficult two stick shift. Typical use is to accelerate with Power mode and drive with Economy mode so you have 5 progressive gears. It is also handy in speed where upper gear has too low engine rpm but lower gear too high rpm while you can choose gear between them. If you drive in Economy mode and need to slow down a little or accelerate fast you can quickly downshift to Power mode and after situation upshift to Economy mode. While auxiliary shift is only forward/rearward movement there is no risk to shift to wrong gear.
Original lego design is now replaced with much shorter design in which ratios and gear steps are closer to Mitsubishi’s Super Shift (check picture Ratio comparison). If you want to check old design it’s moved to page Junkyard. Now is available also version B with studless frame. While it has one special 1,75 stud axle base for gear pairs Su(12)-S(16) it’s simpler design than version A with brick frame. In both lego versions gearboxes are located parallel which gives short design. So two transmission driving rings on the left belong to main gearbox and last one on the right to auxiliary. You can check shift levers from version B or YouTube video. In main shift lever axle left bush prevents axle to slide to left. Auxiliary shift lever uses axle pin and it prevents main shift lever axle to slide to right. If you look close enough pictures of brick frame version you can notice that output axle is missing one bush. Mistake is corrected in LDraw file and YouTube video but it’s too much work to update all the pictures. P.17. 3-speed & transfer case version VI, overall gear ratio 3,00: Transfer case’s gear step 2,50 Inspirer: Willys Jeep
This transmission is based on old legendary off-road vehicle, Willys Jeep. It contains 3-speed main gearbox with reverse gear and 2-speed transfer case, which is part time 4x4. On the road vehicle is rear wheel drive but for difficult conditions you switch on front axle’s drive. While there is no centre differential in this transmission it’s not recommended to use 4x4 in good driving conditions. Transfer case has two shift levers: rear one is for low and high selection and front one switches front wheel drive on and off.
This 3-speed & transfer case version VI is remake with more compact design and better placed shift levers. Note that main gearbox contains two synchro axles on the left while right synchro axle belongs to transfer case. Original 3-speed & transfer case version III is now on page Junkyard. It’s worth to check if you want faster reverse gear that uses old 14 teeth thin bevel gears. Original design of transfer case version III is bad but there is alternative setup of it plus other transfer cases in chapter C. Transfer Cases on page Basic & special designs.
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