Pro's & Con's, clutch springs - Belleville (DDS) verses coil.

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6/13/2018 11:08 PM

I guess I'm interested in feedback from KTM owners as to how well the DDS clutches hold-up?

My last single conical clutch (Belleville) was in a Honda VFR750R (RC30) racebike, I found, even with Barnett Kevlar fiber plates, that after 3 or 4 practise starts, that the fibers' would wear enough so that the clutch would start slipping, so bad that the bike lost ALL forward drive. I think a dirtbike rider would be harder on a clutch than a roadracer, even tho a 750 has a bit more weight to get off the line.

The problem was that a single conical spring only has about 3 or 4mm total travel, so if a clutch pack that has a total of 10 fiber plates, if each plate wears .1 of a millimeter, that is 1.0mm overall. Enough for the single conical spring to lose a lot of preload on the plates.

Multiple coil springs on the other hand have about 10mm of travel and would still have good preload pressure if it lost only 1mm of preload.

My ZXR750 Kawa, that I raced about the same time as the VFR, ran 6 coil springs and the same Barnett fiber plates, the ZXR was raced for 3 seasons without any clutch slip.

Sure the single spring has less spinning mass but unless you are soft on the clutch, or change the fiber plates all the time, I would expect there to be problems?

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Melbourne, Australia. Current rides: '11 RMZ450, '84 CR500, '06 DRZ400, '79 KX250 with 400 engine, '06 GSXR1000 full Yosh racebike.

6/13/2018 11:16 PM
Edited Date/Time: 6/14/2018 1:23 AM

A buddy of mine worked in the KTM development department when that clutch was in the works. He said this belleville spring is designed in a way that it has a constant spring force over a few millimeters of travel in order to work the same over the life of a clutch plate pack. He also said that it took them a long time to get the manufacturing right.
This is just the engineering side. I only rode a few hours on one with this clutch and don’t know how it holds up

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6/13/2018 11:56 PM

I’ve been running a DDS clutch with cushions in my 250SXF for 2 seasons now from Hinson. I don’t think the 19 250/350 will have the cushions in there, but it’s a stock part on the 450. This is also the style of clutch the TLD/KTM team uses.

I love the feel and traction. Not sure if it’s the full Hinson set up that is the advantage or the new spring style though.

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6/14/2018 2:14 AM

Had one in a 2013 Ktm 250 sx 1st year of them I think bike used to move when I was on the line pinned waiting for the gate to drop.Then in around June of that year they came out with a Bellvelle washer that was rated 10 pounds heavier put it in never had any other issues.Went through 2 clutch packs then sold the bike.

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6/14/2018 5:11 AM

I ride a 17 FX 350 and one of the first changes I made was taking out the coil spring clutch and installing the DDS clutch. I also installed the Rekluse manual upgrade kit that adds another plate to the stack. I love the feel of the DDS clutch.

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6/14/2018 5:46 AM

55 hours here on a 15 TC250. Also using the rekluse 3.0 with it. No complaints and no issues. I don’t practice starts. In the sand or race day, I’m not nice to it. I’ll prob tear it apart and put in a new cushion at the end of the year

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6/14/2018 7:05 AM

We have 2017 450SXF's. I have a clutch abuser in the family and have tried everything (e.g., Hinson, Barnett, Rekluse) to find something that will last before finally trying KTM. The KTM clutch has been fantastic, and his clutches are now lasting months vs. changing them every weekend on other brands or the constant free play adjustments with the Rekluse.

We run the stiffer washer and change the cushions when we swap plates and couldn't be happier. Add the hydraulic actuation and this is the best dirt bike clutch on the market, OEM or otherwise.

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6/14/2018 7:44 AM

It's great, it is very consistent. I'm not even a huge fan of hydraulic clutch in general but the system works great and I have no complaints.

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6/14/2018 7:58 AM

I miss that clutch. I wish the 350s came with it. Awesome clutch.

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6/15/2018 4:11 AM

ob wrote:

I miss that clutch. I wish the 350s came with it. Awesome clutch.

All of the 19 models have them now stock.

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6/15/2018 7:25 AM

ob wrote:

I miss that clutch. I wish the 350s came with it. Awesome clutch.

#434 wrote:

All of the 19 models have them now stock.

OH dang I didn't know that. Rad

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8/26/2019 7:56 PM

dcg141 wrote:

I ride a 17 FX 350 and one of the first changes I made was taking out the coil spring clutch and installing the DDS clutch. I ...more

Hey this is bringing the thread back from the grave, but if you see this, how did you swap the clutch ? Will a full clutch from a 17 FX450 fit the 350 ? Thanks !

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8/26/2019 8:28 PM

I've used several aftermarket clutches over the years on Japanese bikes, and the 450 ktm clutch is amazing... I feel like going to a full hinson with traditional spring design would be a step down

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8/27/2019 5:49 AM

2014 250sx with approximately 300+ hours on the original DDS clutch used for single track. Only ever adjusted the preload plate once. Still rocking it.

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8/27/2019 6:39 AM

.1mm would be .0039", which would be massive wear on clutch plates. I've never in my life seen anything close to that....

KTK/Husky clutches are durable enough that if the Japanese ever went to that setup (belleville washer, stainless baskets) Hinson would be very worried methinks

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