dave49 Posted January 4, 2023 Share Posted January 4, 2023 hi everyone.stupid question but can anyone explain how an overdrive works.ive never had one before and ive got one on my 13/60 herald.problem is i cant work out when its on or off.if i flip the swich when driving it seems to loose power .does that mean its on.no sarcastic comments please.its a genuine question.thanks Quote Link to comment Share on other sites More sharing options...
standardthread Posted January 4, 2023 Share Posted January 4, 2023 When you switch the O/D on you should hear a distinct click. When driving and you switch it on it reduces engine revs (not power) so in effect you can take the engine revs back up by accelerating, so going faster with less strain on engine and gearbox etc. It depends how you drive, I go in to 3rd, then 3rd O/D, then 4th gear, then 4thO/D. No doubt there will be others with a different interpretation, or be more technical. Quote Link to comment Share on other sites More sharing options...
Velocita Rosso Posted January 4, 2023 Share Posted January 4, 2023 You should notice a reduction by around 300/500 RPM....not ,as stated , losing power when operating the o/d To alleviate any `snatching` when flicking the switch, I like to use the clutch . Less strain on all aspects of drive train Quote Link to comment Share on other sites More sharing options...
Banksy82 Posted January 4, 2023 Share Posted January 4, 2023 You can think of it as an extra gear. It is a planetary gearset that is switched in or out. If you switch it in too soon it might appear that you lose power just like changing up a gear too early. (although I can't say I've noticed it myself). Quote Link to comment Share on other sites More sharing options...
RobPearce Posted January 4, 2023 Share Posted January 4, 2023 When you say it seems to lose power, how significantly? Is it just a case of "it accelerates slightly less", like you'd expect from changing up a gear, or is it a complete loss of power? If the latter, you may have an electrical problem to investigate. Quote Link to comment Share on other sites More sharing options...
glang Posted January 4, 2023 Share Posted January 4, 2023 Rather than accelerating in OD I think the best use is to get to the speed you want to drive at in either 3rd or 4th and then switch it in so the revs drop but speed stays the same. In theory this then saves you fuel and engine wear plus reduces engine noise and in the case of using it in 3rd gear is very handy for safe overtaking as you can switch it out to rapidly get the engine revs just right for accelerating👍 Quote Link to comment Share on other sites More sharing options...
dave49 Posted January 4, 2023 Author Share Posted January 4, 2023 1 hour ago, RobPearce said: When you say it seems to lose power, how significantly? Is it just a case of "it accelerates slightly less", like you'd expect from changing up a gear, or is it a complete loss of power? If the latter, you may have an electrical problem to investigate. not a complete loss of power.just drops the revs. Quote Link to comment Share on other sites More sharing options...
dave49 Posted January 4, 2023 Author Share Posted January 4, 2023 3 hours ago, standardthread said: When you switch the O/D on you should hear a distinct click. When driving and you switch it on it reduces engine revs (not power) so in effect you can take the engine revs back up by accelerating, so going faster with less strain on engine and gearbox etc. It depends how you drive, I go in to 3rd, then 3rd O/D, then 4th gear, then 4thO/D. No doubt there will be others with a different interpretation, or be more technical. thanks.ill try that.perhaps im switching it on to soon. Quote Link to comment Share on other sites More sharing options...
dave49 Posted January 4, 2023 Author Share Posted January 4, 2023 3 hours ago, Velocita Rosso said: You should notice a reduction by around 300/500 RPM....not ,as stated , losing power when operating the o/d To alleviate any `snatching` when flicking the switch, I like to use the clutch . Less strain on all aspects of drive train 3 hours ago, Velocita Rosso said: You should notice a reduction by around 300/500 RPM....not ,as stated , losing power when operating the o/d To alleviate any `snatching` when flicking the switch, I like to use the clutch . Less strain on all aspects of drive train ill try that. Quote Link to comment Share on other sites More sharing options...
dave49 Posted January 4, 2023 Author Share Posted January 4, 2023 thanks guys for the advice.maybe cos i havnt used one i didnt know what to expect.i was thinking it was something like a cruise control so ill try some of the advice offered ie go to 3rd gear dip the clutch engage it and see what happens cheers Quote Link to comment Share on other sites More sharing options...
RobPearce Posted January 4, 2023 Share Posted January 4, 2023 4 minutes ago, dave49 said: i was thinking it was something like a cruise control No, just an extra gear. Expect the same as changing up - i.e. revs drop and less acceleration available. I generally don't use the clutch when switching the overdrive but none of mine currently suffer any harshness. The one car I had which was harsh (a quite unpleasant judder, in fact) was a Dolomite with a failed UJ on the propshaft. Play in the drive line can make the transition harsh. Quote Link to comment Share on other sites More sharing options...
richard w Posted January 4, 2023 Share Posted January 4, 2023 I don't do anything going into overdrive, but back off the throttle if accelerating when dropping out. I don't dip the clutch at all Quote Link to comment Share on other sites More sharing options...
JohnD Posted January 4, 2023 Share Posted January 4, 2023 Clutch use will alleviate any slight jerk on engagement/disengagement, but come on guys, this is OVERDRIVE! The ultimate in clutchless gear changing! To use the clutch at all is to miss the point entirely! Dave, cultivate a sensitive throttle foot. On engaging O/d, the engine will drive in a higher gear, but at the same speed, so a lower engine speed, so slightly lift the throttle as O/d goes in. Likewise, on coming out of O/d, the engine speed will tend to increase, so a slight press of the throttle. Practice this and you will soon be able to move in or out of O/d without your passengers being able to tell! As for using 3rd - 3rd +O/d - 4th - 4th + O/d every time, that is too regimented and unnecessary. Especially as 3rd+O/d is almost the same as 4th! As the Police Driving Manual "Roadcraft" says, the gears are to allow the driver to use the correct engine speed at all times. An O/d gives you more flexibility to achieve that. For instance, a gently winding road could allow you to speed up and use 4th then drop into 3rd for the bends. But O/d lets you do the same - CLUTCHLESSLY! Same may be used when faced with a steep hill in 4th. Good luck! John Quote Link to comment Share on other sites More sharing options...
thescrapman Posted January 4, 2023 Share Posted January 4, 2023 You haven’t said what engine is in front of the OD, if 1200 or standard 1300, it may struggle to pull the higher gear if the revs are too low. Ifa 1500, better as it is more suited to pulling the higher gears. Quote Link to comment Share on other sites More sharing options...
Velocita Rosso Posted January 4, 2023 Share Posted January 4, 2023 2 hours ago, thescrapman said: You haven’t said what engine is in front of the OD, if 1200 or standard 1300, it may struggle to pull the higher gear if the revs are too low. Ifa 1500, better as it is more suited to pulling the higher gears. Well said.....and after all every driver knows the idiosycracy`s within his own car, so its up to each owner to recognise the best way for his car 1 Quote Link to comment Share on other sites More sharing options...
Clive Posted January 5, 2023 Share Posted January 5, 2023 20 hours ago, dave49 said: thanks guys for the advice.maybe cos i havnt used one i didnt know what to expect.i was thinking it was something like a cruise control so ill try some of the advice offered ie go to 3rd gear dip the clutch engage it and see what happens cheers At first I would suggest only using OD when in top gear (It should only work in 3rd and 4th) and only then when hitting 50+mph. Regard it as a 5th gear. Once yoiu have got the feel of that, you can also use it in 3rd. Some people like that a lot, I have never been a fan. But OD3rd is more or less the same as nonOD4th. Sorry if that sounds confusing, but as I said, in my Triumph ownership I have only used OD as a 5th gear. Quote Link to comment Share on other sites More sharing options...
Martins Stag Posted January 5, 2023 Share Posted January 5, 2023 Agree with Clive on this, Re 3rd gear and 3rd overdrive i do find it good going up hill and keeping momentum, as moving from 3rd to 3rd overdrive you keep the drive going while changing and don't slow down whereas changing from 3rd to 4th you have to disengage drive to make the gear change.... Quote Link to comment Share on other sites More sharing options...
dave49 Posted January 5, 2023 Author Share Posted January 5, 2023 On 04/01/2023 at 18:02, thescrapman said: You haven’t said what engine is in front of the OD, if 1200 or standard 1300, it may struggle to pull the higher gear if the revs are too low. Ifa 1500, better as it is more suited to pulling the higher gears. its a standard 1300.in bits at the minute so ill try all suggestions in the summer when she comes out of hibernation.cheers Quote Link to comment Share on other sites More sharing options...
Guppy916 Posted January 29, 2023 Share Posted January 29, 2023 When I wired up my GT6 I added three LED lights top for, electric fuel pump , Middle over drive and bottom electric cooling fan, so simple to do Quote Link to comment Share on other sites More sharing options...
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