DDT set-up for offroad - questions for Dave

[TimTee]

Dave - I'm starting this thread with the purpose of being a source of info for people who are using their DDT for offroad/trail/harescramble riding. A lot of my searching has returned set-ups and discussions related to MX use. Offroad riding certainly is challenging due to the wide variety of terrain that we face.

So I'm hoping to get your feedback on a recent thread that brought up two concepts that sparked my interest. This thread mentions two concepts: limiting blow-off and bleed:

https://www.thumpertalk.com/forum/showthread.php?t=1032310&highlight=offroad

Limiting blow-off

cj_wai outlines what he has done to his set-up to limit the amount of blow-off. If I'm close on my math, my set-up had nearly 1.5mm of available blow-off. cj_wai has his set-up to being about a 1/3 of that.

Dave - what are your thoughts on this? I'm thinking that if this is the correct way to go, you'd be configuring the kits this way from the start. Maybe he has a special set of circumstances that makes that work for him.

Bleed

In that same thread, jwaseman threw out using a bleed shim (12.11, 20.11, 11.30, 20.11 etc) with the DDT. My stock MV had an 18.11 bleed shim, so the use of one can't be that wild of an idea.

What are your thoughts on a bleed shim? It seems that a bleed could give the DDT a more traditional feel.

Thanks for your feedback.

[ac717]

A bleed shim on the mid wouldn't be bad but not sure the float/coil bind for SPI setup wouldn't be altered. IMO-I'd try oil volume adjustment and go testing clicker settings. If you cannot dial it in that way-a valving change or new stack may be necessay.

[cj_wai]

i tried several different bleed setups.never liked any of them.to soft.i think you need at least one face shim then you can mess with stack and crossovers and preload and lift limit and.......on it goes.

i was getting fed up,but i knew the high speed blowoff made sense(to me).i,m glad i stuck with it because my fork is working pretty good.

[number9]

Watching this one close as my DDT 2 setup isn't as plush as I'd like it to be in the woods / singletrack.

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[grayracer513]

i tried several different bleed setups.never liked any of them.to soft.i think you need at least one face shim then you can mess with stack and crossovers and preload and lift limit and.......on it goes.

i was getting fed up,but i knew the high speed blowoff made sense(to me).i,m glad i stuck with it because my fork is working pretty good.

I agree with you there. I run the Gen2 DDT with the mid valve stack below:

20 0.11 8

11 0.30 8

18 0.11 8

16 0.11 8

14 0.11 8

11 0.25 8

11 0.25 8

17 0.30 8

SPI 62 Spring

SPI 175 Spring

8 7.30 6

For younger faster guys, it probably should be more like this:

https://www.thumpertalk.com/forum/showthread.php?p=10691112#post10691112

It really works extremely well for me.

[ac717]

I agree with you there. I run the Gen2 DDT with the mid valve stack below:

20 0.11 8

11 0.30 8

18 0.11 8

16 0.11 8

14 0.11 8

11 0.25 8

11 0.25 8

17 0.30 8

SPI 62 Spring

SPI 175 Spring

8 7.30 6

For younger faster guys, it probably should be more like this:

https://www.thumpertalk.com/forum/showthread.php?p=10691112#post10691112

It really works extremely well for me.

Your stack looks like it would be very plush. The difference between yours and the one posted on the thread posted is basically more bleed,float and less preload. I think most could apply this setup for offroad versus a MX setup. By adding a single face shim or the backer listed in the other stack- a broad range of tuning should be easy.

[grayracer513]

The only true bleed in that mid is the rebound adjuster. The single 20x.11 face shim is nearly a bleed, but it behaves much differently. It's almost like a float in a way, but not quite that, either. The term Dave Johnson used to describe it is, "lead-in". It certainly works.

If you think about it, the difference between a floated stack and a clamped stack with blow-off capabilities mechanically is nothing more than how strong a spring is used, and how far you allow it to lift. The effect is as different as night and day.

[number9]

Here's my build sheet below. I am 205# in street clothes, 09 YZ250 2st, ride woods, single track.

I find the forks are not nearly as plush as I'd like them to be on the rocks, roots, etc in the eastern woods. I also have a '00 YZ250 with the Terrain Tamer fork setup from Bruce's Suspension (isolated damping - rebound in one leg, compression in other leg) and it is sweet in the woods, but I know it's open bath KYB.

For you guys that ride woods and have done these changes, what would you recommend for me to do to keep the suspension action as close as it is now but take the initial spike / harshness / deflection away in the woods and have the forks be more plush over the trail junk, should I decide to have a go at it myself. I've never been inside twin chamber forks and have only changed springs / seals in open bath forks.

Thanks.

If the pic isn't good enough, here's a link

https://docs.google.com/open?id=0B8K9rkcFQJ32NDVlMGRiN2EtYWZmYS00ODg2LTk0MTgtODUxNWIwMmU3MmM1

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[cj_wai]

I agree with you there. I run the Gen2 DDT with the mid valve stack below:

20 0.11 8

11 0.30 8

18 0.11 8

16 0.11 8

14 0.11 8

11 0.25 8

11 0.25 8

17 0.30 8

SPI 62 Spring

SPI 175 Spring

8 7.30 6

For younger faster guys, it probably should be more like this:

https://www.thumpertalk.com/forum/showthread.php?p=10691112#post10691112

It really works extremely well for me.

i run the same mid except i have 2 20x.11 after the 11x.30 crossover.

so 20x.11 11x.30 20x.11 20x.11 18x.11 and so on.

i then found my high speed blowoff to stiff or late .i increased my shaft length by .40mm .less preload.this setup is really nice,really plush on slow hack,strong mid stack and a less harsh blowoff.(transitions better into blowoff.

again,i think none of this works without a lift limit.mine is at .55mm toatal lift.i think the lift limit brings the mid stack into play more of the time.like when it blows off on a high speed hit it recovers faster due to the limited lift.

i tried the above setup without the shaft extention and it was much to stiff,too much preload on the ddt spring.

i also tried a soft mid (like gray,s exact setup)but with standard preload on the ddt(no shaft extention).i found that setup too soft and then to harsh on high speed large impacts(blowoff).

i,ve been through at least 12 significant changes with the ddt,current one is by far the best.

[grayracer513]

For you guys that ride woods and have done these changes, what would you recommend for me to do to keep the suspension action as close as it is now but take the initial spike / harshness / deflection away in the woods and have the forks be more plush over the trail junk, should I decide to have a go at it myself.

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What I did, or what CJ did. Definitely.

[TimTee]

I'm probably over thinking this, but I started thinking that there has to be a decent amount of stress on the 20.11 face shim as it is constantly flexing across that .30 crossover. That is partially what motivated me to make this post in the first place. I was hoping there was a different way to introduce some bleed without flexing that shim to that degree.

cj_wai and grayracer513 - how are your shims holding up? My 17.30 had the bluing (or whatever the coating is on shims) wore off where it contacts the spring after just 2 hours of ride time. It makes sense since you have a piece of metal rubbing against it, I was just surprised to see it happen so quickly.

[number9]

This is a great thread and has me really excited to get my fork action improved. ?

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[grayracer513]

Tim,

The entire setup is holding up fine.

[ac717]

I'm probably over thinking this, but I started thinking that there has to be a decent amount of stress on the 20.11 face shim as it is constantly flexing across that .30 crossover. That is partially what motivated me to make this post in the first place. I was hoping there was a different way to introduce some bleed without flexing that shim to that degree.

cj_wai and grayracer513 - how are your shims holding up? My 17.30 had the bluing (or whatever the coating is on shims) wore off where it contacts the spring after just 2 hours of ride time. It makes sense since you have a piece of metal rubbing against it, I was just surprised to see it happen so quickly.

The .30 should hold up the face shim. I call this a "backer" but not sure term is correct. Are you worried about the shims wearing from the spring? I think they could wear over time,but an inspection during service would be good and then just replace as necessary. Shims are like 20 cents. At about 30-40 hours I usually do a fluid change and take the valving apart. Its good to spot for wear marks,rubs,cupping,bends,etc. My 08 200xc was the only bike that ever bent valving shims.Every other bike have always looked good.

[TimTee]

I was thinking that the 20.11 is going to be flexing a lot with that 11.30 under it. Seems to be a big gap to cover. But I guess real world experience addresses my concern.

[sacfelix]

I tried several different set ups recently on my 06YZ450 and this weekend I tried this mid comp stack.

20 0.11 8

20 0.11 8

11 0.30 8

18 0.11 8

16 0.11 8

14 0.11 8

11 0.25 8

11 0.25 8

17 0.30 8

SPI 62 Spring

SPI 175 Spring

8 7.30 6

I could run my comp clicker all the way out and it did not have the soft wallow feeling. The mid of the stroke felt very plush but the small chop was still very noticeable. I lowered my forks 5mm and it helped but the lead in on the forks suffered. I am still waiting on shims so Im going to try grays mid next. Once I get my shims in the mail Im going to try cj's set up with the limited bleed.

[TimTee]

Shims are like 20 cents.

Forgot to ask, where do you get shims that cheap? I'm coming up with $1.00+ for each shim.

[number9]

I tried several different set ups recently on my 06YZ450 and this weekend I tried this mid comp stack.

20 0.11 8

20 0.11 8

11 0.30 8

18 0.11 8

16 0.11 8

14 0.11 8

11 0.25 8

11 0.25 8

17 0.30 8

SPI 62 Spring

SPI 175 Spring

8 7.30 6

I could run my comp clicker all the way out and it did not have the soft wallow feeling. The mid of the stroke felt very plush but the small chop was still very noticeable. I lowered my forks 5mm and it helped but the lead in on the forks suffered. I am still waiting on shims so Im going to try grays mid next. Once I get my shims in the mail Im going to try cj's set up with the limited bleed.

Any update on your progress?

..

[sacfelix]

I switched to this set up and have not had a chance to get out yet but I plan to this weekend. I will update my findings shortly there after.

20 0.11 8

11 0.30 8

18 0.11 8

16 0.11 8

14 0.11 8

11 0.25 8

11 0.25 8

17 0.30 8

SPI 62 Spring

SPI 175 Spring

8 7.30 6

On a side note,

I bought one of those fork rebuild kits from pivot works and decided to freshen every thing up while I was in there and came across a problem with the lower bushings. After I put the upper and lower tubes together I noticed that the tubes were sticking really bad and would not slide with out me pushing on them. So I pulled them apart and swapped out the top bushing with no luck. Then I swapped out the bottom one and problem solved. I had to go buy new lower bushings because the ones in the kit were crap. Lesson learned by me "Go OEM"!

Edited January 24, 2012 by sacfelix

[number9]

Well I talked to Dave today via email

And am sending my suspension back in for changes to get small chop plushness. Looking forward to riding it. I'll give a review when I get the chance in a few weeks.

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