Clutch shoe spring weights

Bauerdog

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235
i recently installed a set of aluminum clutch shoes using stock weight springs. I've always used stock plastic shoes, but I had an alum set so I figured I'd try them out. Noticed a huge loss of my hole shot. Complete dog off the line. I have a set of the stiffer gold springs. Was wondering if the stiffer spring will give me a later clutch engagement? Maybe get revs up a bit, get my hole shot back?
 

Jam Racing 1

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yes a heavier spring will delay clutch engagement, also as Francis said reversing them can help them come on a bit harder... try it both ways and see what works best for your tastes...
 

Bauerdog

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235
Thanks guys I'll def do a few test runs with different set ups. Hopefully get my holeshot back
 

olds97_lss

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Dekalb, IL 60115
I just ordered a set of the HPI springs to go with my dynamite max life clutch shoe set. Haven't installed it yet as I'm running some old OFNA shoes/springs I found in my parts box when my stupid integy clutch springs broke. Hoping the 1.0 springs work well with the dynamite shoes as they didn't come with any springs and all I have on hand are stock springs that came with the composite HPI shoes.
 

Nathan.OTN

Member
Messages
8
Hi guys, I'm interested to hear from you. I have the dynamite max life shoes and I am currently running with 0,9mm springs. The clutch does not engage at idle and works well... What are the benefits of the 1,0mm springs ? Is it good with your Dynamite max life shoes ?
 

olds97_lss

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Dekalb, IL 60115
I don't think I ever installed mine... pretty sure I'm using some other alloy shoes. Heavier springs just means later clutch engagement. So if you like it how it is, then odds are, it's not worth changing. If it felt a bit sluggish off the line, then you could try heavier springs so the engine is higher in the RPM range before they start engaging.
 

Nathan.OTN

Member
Messages
8
As the RPM will be higher, will it reduce my clutch/shoes lifetime ? Why is it bad to have thin springs, as the clutch does not engage at idle ? In this case, what are the benefits from engaging the cluth at higher RPM ? :)
 

olds97_lss

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Dekalb, IL 60115
It just allows your engine to be producing more torque before it's pulled down by the drive train. I don't know if it wears more or less. I never fiddled with different weight springs much. I bought the pack of them and the shoes, forgot about them. I have no clue what I have in the truck right now, but 99% sure it's not the max life shoes. I think they are just HPI alloy shoes from an XL part out on ebay and whatever springs I had laying in my clutch box. When I was going through some of my stuff, I found the hpi spring set I bought that had different size springs in it a month or so ago. lol!
 

Jam Racing 1

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Higher rpm engagement is better for some ( I am using dynamite 1.0 springs) because it lets the engine build a bit more rpm and power before engaging the shoes, as with any alloy shoe you are going to have more maintenance to remove the burrs and mushrooming on the shoes, I usually get a season on mine before cleaning and checking them. depending on how much you drive and tire sizes and weight your results may be about the same...
remember to check the bell bearing also, they take a ton of heat and abuse......
 

olds97_lss

Well-Known Member
Messages
2,180
Location
Dekalb, IL 60115
Higher rpm engagement is better for some ( I am using dynamite 1.0 springs) because it lets the engine build a bit more rpm and power before engaging the shoes, as with any alloy shoe you are going to have more maintenance to remove the burrs and mushrooming on the shoes, I usually get a season on mine before cleaning and checking them. depending on how much you drive and tire sizes and weight your results may be about the same...
remember to check the bell bearing also, they take a ton of heat and abuse......
I usually just replace them regardless whenever I service the alloy shoes and keep the old ones in a box as last resort spares. I tend to keep a tube of 5x10's on hand all the time for CB's and another tube in my pit box for when I'm out bashing.
 

BrandNewSavvy

Member
Messages
6
It just allows your engine to be producing more torque before it's pulled down by the drive train. I don't know if it wears more or less.
Regarding engagement, the thicker spring causes the shoes to engage at a higher RPM (due to the centrifugal force being applied). The same principle holds true for the alloy shoes, Because they are lighter than stock they will also engage at a higher RPM. Thus stock with 1.0 spring would engage earlier than alloy with same springs/ You probably know this but just in case...
Tuning your clutch can be easy when you consider the two factors that are used to determine when to engage. These factors being the engine power and the available traction. Power is obvious. as the same clutch will engage at different stages within its powerband. "Good or bad" engagement is defined based on how the shoes interact with the bell. The traction is defined obviously by how the tires interact with the surface,

Have you ever run your truck on the street and then notice how it sounds different on grass or dirt? This is because the setup is favoring one of those surfaces based on the traction it can get. So it's absorbing/using more power on one surface (or losing/wasting more on the other surface---depending if you are a half full or half empty person). Some find it easier to think in terms of waster power (half empty) as it's easier to identify.

If the engagement period is is too late in the RPM, you'll notice the tires inability to grip its surface. The tires RPMs will be too much causing slippage, ballooning tires and you'll hear the engine lag at high RPM. So you can either spring down, use heavier shoes, better tires for the surface, use a heavier flywheel, or a weaker engine, or even change the angle of the clutch spring tail. All properties that effect it.

On the other end of the spectrum if your springs are too thin and you engage early in the power band, you can draw too much load from the engine due to the shoes "too early". Meaning there is little power in the lower RPM range and if you have good traction the clutch is essentially 'further ahead' than the engine. Usually you can hear this when the engine goes monotone early its the power-band. So you can either reduce traction or spring up, or use a less powerful engine, etc.

So, the idea is for the clutch to balance this and avoid slippage (engine lag) or too much draw on the engine by enraging too early.

All this---assuming that your shoes and bell are in good condition (the shoes aren't slipping on the bell)

Ironically the stock shoes are heavy, the engine relatively weak for the vehicle weight and the springs are ..9mm. This pretty as early engagement as you can get...it's good for mud and thick dirt, but not pavement.

Finally, the spring tension (engagement rpm) does not affect the shoe lifespan (that wold be noticeable anyway) Obviously shoe types are the determine factor, (alloy wears down faster than composite vs carbon, etc. I have quite of the Max Life they are decent shoes....the name is just a marketing gimmick they don't seem to last any longer than Mugen, LST, OFNA, Werks, or any other aftermarket alloy in my experience (regardless of spring tension)


Remember though this is just "engagement". How the shoes interact with the bell after it's fully engage is what's really noticeable based on shoe types, It;s hard to tell shoe type based on engagement level.

Definitely more info than you probably wanted, but perhaps others can draw some intel from here to help with whatever issues they might be encountering.
 
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BrandNewSavvy

Member
Messages
6
Apologies I noted where you also inquired about the shoe orientation (leading vs trailing) the bite off the line difference is extremely minimal in my experience (I could not tell a difference anyway--just ensure the shoe is bi-directional).

This was just one of the only options back in the day...then we would lighten the shoes also drilling holes in them, then we started cutting the tails to affect its angle degree...so it's the result of a cluster, not just one change (as rarely can one of the changes we are discussing be noticed). Remember this was before shoe types, spring thickness, flywheel weight etc. eit's

Regardless the engagement type (abrupt or progressive) is not necessarily a matter of taste as noted....it's a matter of your available traction and engine power. So if you had little traction = and increased the bite off the line, it would simply increase the chances for a lag, or the severity of the existing one. I hope that makes sense. Instead determine which way to go to balance the slippage with bell vs surface. Good luck
 
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