# What are signs of clutch wear?



## Andy (Jul 16, 2003)

With my new limited slip differential installed, I can now launch the car at 5500 RPM with no wheel spin (I’m not dumping the clutch, but letting it out at a fairly fast pace). It’s insane how hard the car accelerates from a dead stop, 1st gear lasts about 2 seconds before you have to shift to 2nd.

So anyway, with the increased RPMs and added traction, something has got to give and I’m afraid it’s going to be the clutch. Since I’ll be running the ProSolos this year, these hard launches will be required and I want to make sure I recognize when the clutch is starting to go. I have about 23,000 miles on the car right now (with one season of autox).

So, what are some of the signs of clutch wear/slippage? What are some of the early signs? I want to make sure I catch it early when (not if) it happens.

Thanks.


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## Nick325xiT 5spd (Dec 24, 2001)

Umm...

Very slight slip when shifting between gears, maybe...

But my experience is that it pretty much goes from working great to gone almost instantaneously.


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## HW (Dec 24, 2001)

shift into 5th and floor the throttle. if your rpm goes up but you don't accel then it's toast. :dunno:


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## xspeedy (Apr 10, 2003)

Last I had mine go, I would get slip while accelerating hard in a middle gear, like third.


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## Interlocker (Jun 27, 2003)

I believe if you put in 3rd (or is it 4th?) at a stop and try to go you'll find out. If you stall, clutch is still good. If it goes, there's slip.

I replaced mine at 130K miles just because it seemed like the thing to do and I had a new set up ready to go, which I was anxious to play with.


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## Andy (Jul 16, 2003)

Cool, thanks for the feedback.

I kind of hope that it’s like Nick says… it’s good one day and completely gone the next. What I don’t what to happen, is to have it slowly start going bad over time and it have it gradually start hurting my times on the track (without me realizing what’s going on).

I like the 3rd/4th/5th gear acceleration tests, that will give me something to do periodically to give me a piece of mind that it’s still ok.

Yeah, call me anal… but I already knew that. 

Thanks again!! :thumbup:


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## HW (Dec 24, 2001)

a trait of the self adjusting clutch


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## Nick325xiT 5spd (Dec 24, 2001)

Just as an FYI, 3, 4, 5 never worked for me.


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## JetBlack330i (Feb 8, 2002)

I think you can find signs of slippage, but by then it's gone already.
I think clutch plate is like brake pads. It's there to be worn, and it self adjusts to account for the wear, but you can't tell how much is still left without looking at it.


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## Andy (Jul 16, 2003)

JetBlack330i said:


> ...but you can't tell how much is still left without looking at it.


That is what I was afraid of.


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## Interlocker (Jun 27, 2003)

Andy said:


> I kind of hope that it's like Nick says&#8230; it's good one day and completely gone the next. What I don't what to happen, is to have it slowly start going bad over time and it have it gradually start hurting my times on the track (without me realizing what's going on).


Am I reading this right? You'd prefer the clutch to completely go out rather than give you warning so that you can get it changed before it completely goes out? :dunno:

Sounds fun to me. Good luck with that.


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## Andy (Jul 16, 2003)

Interlocker said:


> Am I reading this right? You'd prefer the clutch to completely go out rather than give you warning so that you can get it changed before it completely goes out? :dunno:
> 
> Sounds fun to me. Good luck with that.


Put it this way&#8230; I'd prefer the clutch to go out on my daily commute to work and leave me stranded then to have it slowly go out over time and cause me to loose 1/10th of a second during a race.

Yeah, call me nuts... but I already know that.


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## Elwood (Dec 20, 2002)

Andy said:


> Put it this way&#8230; I'd prefer the clutch to go out on my daily commute to work and leave me stranded then to have it slowly go out over time and cause me to loose 1/10th of a second during a race.
> 
> Yeah, call me nuts... but I already know that.


 When your clutch goes you'll know it. Under heavy load you'll feel as if you're slipping the clutch when your not. It wont leave you stranded, you'll have ample time before that.


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## Interlocker (Jun 27, 2003)

Andy said:


> Put it this way&#8230; I'd prefer the clutch to go out on my daily commute to work and leave me stranded then to have it slowly go out over time and cause me to loose 1/10th of a second during a race.
> 
> Yeah, call me nuts... but I already know that.


LOL!!!! I'll agree with Elwood that it's highly unlikely for a clutch to leave you stranded, but by what you're saying (if it were to actually be extensive enough to leave you stranded somewhere), you'd rather DNF in a race than lose 1/10th of a second.

Good stuff!


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## TeamM3 (Dec 24, 2002)

plan on changing it every year if you run Pro Solo with a codriver otherwise every 2 years, the flywheel is likely to blow the rubber joint between dual mass pieces too so figure on one of those while you're in there

usually it will start slipping, either on a hard launch or a hard 1-2 upshift, however if you ever slip the clutch it will quickly overheat and start slipping so you have to be careful not to confuse the two


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## Andy (Jul 16, 2003)

TeamM3 said:


> plan on changing it every year if you run Pro Solo with a codriver otherwise every 2 years, the flywheel is likely to blow the rubber joint between dual mass pieces too so figure on one of those while you're in there
> 
> usually it will start slipping, either on a hard launch or a hard 1-2 upshift, however if you ever slip the clutch it will quickly overheat and start slipping so you have to be careful not to confuse the two


Thanks for the posts guys.

Yeah, I was afraid running the ProSolo events would reek havoc on my clutch&#8230; but at least that gives me an idea of how long it will last.


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## TeamM3 (Dec 24, 2002)

unfortunately the BMW factory clutch & dual-mass flywheel have always been a weak link :thumbdwn:


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## TRWham (Aug 21, 2004)

Unless you're running gobs of HP, racing or auto-X are easier on a clutch than street driving. Much less clutch slip is required in competition and slip is what kills clutches. Ask anyone who has put a racing clutch in street car and found it failed after <5,000 miles.

I have raced or worked on eveything from Showroom Stock to Formula Ford to Can Am cars, and the only thing I ever changed a clutch in because of failure was a Can Am car. Of course, that is the only thing I have ever wrenched on with any real power. Except for a 426 Hemi dragster, but it had an autobox. Keep in mind, I did usually change discs in the SS cars whenever the engine was out for any other reason.


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## bob lindquist (Jul 6, 2002)

there is a simple BMW tool for measuring the disk in the car.


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## Pinecone (Apr 3, 2002)

I agree with the change the clutch anytim eyo uhave it apart. Engine or tranny. Murphy will strike otherwise.

Can you run a different flywheel, pressure plate and clutch in your class?


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