Does driving in too high of a gear do damage to your clutch? (manual shifting, plugs)

[JoshB]

I had a friend tell me the other day that I could be doing damage to my clutch because I shift at 1200 rpms taking off and I when I rive through town I drive around 1500 rpms in 4th gear through town @ 35 mph. He said I'm not doing enough rpms or I should be driving in a lower gear.

Is this just bs or is this something I should change?

Thanks, Josh

[sterlinggirl]

What hurts your clutch is putting power to it while letting it slip. That's why truckers engage their clutch before they press on the accelerator. With smaller cars its just a good idea to match your engine speed to the car speed when you're engaging it so that the clutch doesn't burn up from too much friction.

Lugging your engine won't hurt the clutch, but depending on what you drive, you might get better mileage trying to keep your RPMs a little higher (around 2K) if you have a gas engine. The low RPMs can also cause deposits to build up, so its a good idea to run it hard every once in a while to blow out the cobwebs.

If you have a diesel, your RPMs are perfect.

[Bummer]

Originally Posted by JoshB

I had a friend tell me the other day that I could be doing damage to my clutch because I shift at 1200 rpms taking off and I when I rive through town I drive around 1500 rpms in 4th gear through town @ 35 mph. He said I'm not doing enough rpms or I should be driving in a lower gear.

Is this just bs or is this something I should change?

Thanks, Josh

Interesting question, Josh.

Actually, answering your question is almost impossible without know what you are driving. For example, a large "torquey" V8 is much more forgiving than a smaller high revving 4 cylinder engine. The smaller engine requires higher revs to deliver the most efficient power.

[sunsprit]

As long as the clutch isn't being slipped excessively to make the shifts, or is not slipping under load, there's no damage to the clutch.

As far as the RPM's you choose to drive the car, if it's not lugging or balking at 1500 RPM, then there's nothing wrong with driving it at this RPM. Even 4 cylinder gasoline motors in many cars will be perfectly happy at this rpm under light loads of 35 mph on level ground.

[okie333]

unless your engine is lugging (causing it to shake, shudder or buck when under load at low RPM), your fine. Your doing this for the gas mileage right?

oh i guess i didn't read sunsprit's post, yea what he said, lol.

[usafracer]

it depends on the vehicle. If you are doing it for fuel mileage I am betting that you are actually hurting your mileage shifting that early. It takes more power to pull the higher gear. More power means more fuel.

[mm34b]

I'd agree with the others that short-shifting can cause engine damage if it causes engine lugging. I'd also be concerned with the safety issue of not having sufficient power when needed due to being in the wrong gear. Clutches are much cheaper to replace than engines. Your vehicle's Owner's Manual should indicate the recommended speed range for each gear. Every engine has a "sweet spot" for manual shifting. Depends on the specific characteristics of your engine-transmission combination.

[sonarrat]

I drive a large gasoline four (2.4L) and I usually shift around 2500 rpm. I will drive in fifth gear at 35 mph, too, as long as it's steady state and I don't need to accelerate. If I'm accelerating, then I will be in no higher than fourth in that situation. If I'm on an interstate, I usually don't need the extra oomph to accelerate from, say, 55 to 65.

[GregW]

Low RPM will only create engine damage if the engine is detonating. The clutch will be fine. I recommend looking in the the owner's manual and keep the engine operating around the peak torque RPM.

[sunsprit]

Originally Posted by GregW

Low RPM will only create engine damage if the engine is detonating. The clutch will be fine. I recommend looking in the the owner's manual and keep the engine operating around the peak torque RPM.

Peak torque RPM ... which could be several thousand (or more) RPM obviously isn't needed in a 35 mph cruise situation on the OP's car as they apparently "short shift" it all the time.

In late model cars with "knock sensors" as part of their emissions control strategy, it's unlikely that the motor is experiencing detonation and any mechanical damage. Not only that, but it's most likely delivering better fuel economy at the lower RPM the owner is driving it at.

Case in point: my wife's 1995 Subie 2.2 station wagon. I've always driven it in the factory suggested 2,000-4,000 RPM range, using appropriate gear and no more than moderate throttle openings; I drove the car 100,000 miles and routinely got 28-30 mpg. After giving it to my wife, she drives it consistently with short shifting (low speed cruise at 1300 RPM in town) and in the same service I used the car ... only she gets 30-32 mpg with it, having now driven it over 100,000 miles. The car is on the original clutch with no signs of distress in that area, and the motor has sustained no obvious mechanical damage. I've replaced the sparkplugs and there's no signs of detonation damage on them.

Even cars built prior to emission controls can handle the low RPM; my 1974 Alfa Romeo Spider (SPICA mechanical fuel injection) with the standard close ratio 5 speed gearbox will amble along very happily at 1500 RPM on a light throttle in town, and accelerate smoothly from that in 5th gear to freeway speeds. Of course, when getting onto the highway, I usually downshift to 3rd gear and run the motor up to 4,500 RPM (it's torque peak). On rare times, I'll run it up to 5,500 RPM, but it's no advantage over having made the upshift at 4,500 except to hear the wonderful sounds of the twin cam antique at work. If I keep my foot out of it, it can deliver 33-35 mpg on the highway, but it really falls flat in around town driving at 25 mpg.

My 1972 BMW 2002's would all happily move down the road at 1,500 RPM in 4th gear, too, although a downshift to 3rd was needed for anything other than the most gentle acceleration. These cars, too, were generally driven between 2-4,000 RPM and delivered long engine life and I've rarely ever replaced a clutch in one of my own BMW's (although I've replaced many in customer's cars, generally due to mis-matching their downshifts and slipping the clutch then). I had one clutch in a 2002 deliver over 250,000 miles of service, including towing a small boat trailer (and cartopping a second one at the same time) ... which I replaced only because the motor was out of the car for an overhaul and it was readily accessible. I've built up many 2002 motors with tii (mechanical advance only) distributors, higher compression pistons, and modified cams ... with significant horsepower gains ... and they, too, would handle sub-2000 RPM light loads very happily. Only when we put 10.5 or higher pistons and very long duration camshafts with big valves into these motors (for autocrossing, etc) would they not run well below 2,000 RPM.

Any of the V8 domestic cars I've driven since the early 1960's had no difficulty with sub 2000 RPM operation at light loads. For that matter, the in-line 6's (and 8's, too ... my dad was a Packard fanatic) were very happy at those RPM's. I've spent many a mile driving a '57 Chevy station wagon with the 6 cylinder motor and a 3 speed w/overdrive, and it ran very smoothly at sub 2,000 RPM ranges on light loads.

The only stock motor cars I've had that wouldn't deliver good torque at low RPM/light throttle loads were either a highly tuned 356SC and a 904 Porsche I had back in the early 70's, or the sub 2 liter Brit cars ... MG's, Triumphs, AH's ... wouldn't run happily at under 2,000 RPM, but that had more to do with heavy cars and low torque/hp output motors and tall gearing combined with some very poor carburetion/manifolds ... but a TR-6 with it's 2.5 motor would pull 4th/overdrive very well in town at sub 2,000 RPM.

So, for the OP ... if it suits you to drive your car with short shifting and low RPM as the situation allows, don't hesitate to do so if the performance meets your driving needs. You're not hurting the car in any way .... and most likely getting better fuel economy than running it into the higher RPM ranges.