Bilstein 7100 Valving

[mr. lemons]

It looks like tons of folks are running the 7100 series shocks on thier leaf sprung solid axle rigs. Has anyone done any tuning on them? I am looking for info on valving, I am thinking about doing a flutter stack for running faster on the mellow stuff. Not even really sure where to start as far as increase or decreasing compression or rebound. Most of the online shock tuning info is focused on coilovers or IFS stuff.

 

[Deleted member 1632]

I was thinking about this as well. Here's a good video on how to rebuild them with some tips and how to decipher thier rates.

 

[mobil1syn]

It looks like tons of folks are running the 7100 series shocks on thier leaf sprung solid axle rigs. Has anyone done any tuning on them? I am looking for info on valving, I am thinking about doing a flutter stack for running faster on the mellow stuff. Not even really sure where to start as far as increase or decreasing compression or rebound. Most of the online shock tuning info is focused on coilovers or IFS stuff. I am looking for 4600 class kinda stuff.

do you already have the bilstens?

 

[SHARPMACHINE]

Following. Might be installing some 14 inch shocks on the front of my junk after this season. Probably look for used first?

 

[mr. lemons]

I was thinking about this as well. Here's a good video on how to rebuild them with some tips and how to decipher thier rates.

I did see that, and they have really good shipping rates to AK!

do you already have the bilstens?

I do have them already, I've been really happy with them so far. I have been planning to get into tuning them for years now, but they have been "close enough" so I haven't mess with it.

 

[mobil1syn]

lightest shims on rebound play with compression to get desired results

 

[mr. lemons]

lightest shims on rebound play with compression to get desired results

I guess that it's good I asked, I was planning to start the other direction. For round one, I was planning to firm up the rebound and space the first shim on compression to soften the little hits.

 

[mr. lemons]

I forgot to update this. I had a few conversations with the guy in that youtube video at Off-Road Performance Suspension Specialists and Shock Tuning

I settled on
360/80 in the rear, often I carry loads and fuel.
275/78 in the front.

Fresh oil, seals and all. Also, I bumped the psi in the rear resi to up to 220 (If I remember correctly)

It has been running awesome for how I use (abuse) the truck.

 

[mr. lemons]

New question, does anyone have a source for the uniball ends?

 

[Deleted member 1632]

I got some from kartek

 

[bdkw1]

lightest shims on rebound play with compression to get desired results

Bilstien bro! They don't recommend over a 120 stack on comp up the 12" and 80 for the 14's. Tiny shaft and short rod guide problems. Rebound to the ****ing moon though.

 

[Arickvan]

I rebuilt 6 of those last year, thank god for that wheel every weekend video

only thing i did was charge the nitrogen in the rears a bit higher than the fronts

 

[4runner666]

What is the purpose of higher niotrogen pressure in the rears. I have a set here that Ian from wheel every weekend did that to.

Mine are standard 255/70 valving all the way around right now but was curious about trying a lighter rebound for improved performance at trail speeds and chatter bumps. Very unlikely my junk will get jumped or hit huge whoops. Even if it does it would be a rare case I don't think would be worth tuning for.

 

[mobil1syn]

200psi in all reservoir shocks

 

[Toy4rnr]

I forgot to update this. I had a few conversations with the guy in that youtube video at Off-Road Performance Suspension Specialists and Shock Tuning

I settled on
360/80 in the rear, often I carry loads and fuel.
275/78 in the front.

Fresh oil, seals and all. Also, I bumped the psi in the rear resi to up to 220 (If I remember correctly)

It has been running awesome for how I use (abuse) the truck.

Going to necro this as I'm curious about some 7100s for my 3rd gen in the rear. How are you liking the 360/80? I street my rig, F150 tank out back and sometimes carry camp gear in it. I'm in the middle of redoing the links and want to upgrade my shocks while I'm at it I see 360/80 is fairly available in the size I want (short body 12" travel) but not many other options.

 

[mr. lemons]

Going to necro this as I'm curious about some 7100s for my 3rd gen in the rear. How are you liking the 360/80? I street my rig, F150 tank out back and sometimes carry camp gear in it. I'm in the middle of redoing the links and want to upgrade my shocks while I'm at it I see 360/80 is fairly available in the size I want (short body 12" travel) but not many other options.

I've been loving them.

 

[Toy4rnr]

I've been loving them.

Awesome, I went ahead and put a pair on order yesterday, should be here tomorrow, 360/80 valving.

 

[Patrick Morris]

Just happened to notice this thread over here in Toyota Land. 7100s are very familiar to me. I started playing with them on my IH Scout II back in 2013. It has leafs all around like what this thread is about. When I ordered them the guy at Bilstein USA suggested I go with 255/70 all around. That turned out to be good in the front but not right in the rear. Probably a matter of weight and the motion ratio due to the angled rear shocks. So I had to increase the rear rebound slightly and decrease the rear compression slightly. That balanced it out the ride good. I also increased thicknesses of the bypass plates to create a little more bleed.

When I said they are "good" I mean they ride superbly on the street and highway while also working pretty well on rocky/desert terrain, and great for crawling. Not the best over whoops, I'll admit, with this kind of valving. My Scout's a camping vehicle for the desert anyway. It's not a pure play-toy.

The 7100s kick the crap out of the R9000s I ran for years previous to putting these on.




FWIW, I find it interesting that all of these 2" Bilsteins, even our 7100 "off-road racing" shocks, have much heavier rebound than compression. It's backwards from what desert racers have been doing. Like the valving that mobil1syn suggested.

In 2022 I started playing with Fox 2.0s on my Scout. The Factory type with reservoirs. I have to say up front that these older design Factory shocks are so much easier to work on than the 7100s. The 7100s are downright crude by comparison, though if I had reservoirs it'd make things easier.

Without going into too much detail, at the suggesting of people who know more than I do, I valved my Foxes now to be pretty heavy on compression and relatively light on rebound. And I'm running flutter stacks front and rear, plus I added "bypass plates" to the compression stacks---not something Fox ever did---to increase bleed because they didn't have enough and made the Scout terrifying to drive over washboard. The foxes are better now, but what I need to do is add bleed the proper way, by drilling more bleed holes in the pistons.




A truck with a 100" WB drives really weird on the street with this valving and requires the use of at least one sway-bar, but it does work very well out in the desert on washboard now, and also what I'd call "chop": corrugations bigger than washboard but small than true whoops. 100" WB with all leaves and limited travel, I can only expect so much.

Anyway, that's enough on this Fox tangent.

 

[Patrick Morris]

Bilstien bro! They don't recommend over a 120 stack on comp up the 12" and 80 for the 14's. Tiny shaft and short rod guide problems. Rebound to the ****ing moon though.

Darn, sorry just read this. Hadn't though about it before, but this makes sense. The Fox shafts are 5/8" (or bigger). No problem going with all .012s plus a rate plate on comp if you want.

 

[Patrick Morris]

Speaking of shafts, here is something I remembered. The shafts seem prone to rust. I've had to replace both my front shafts at one time or another. Maybe they got dings in chrome plating from rocks, can't say. But then rust would spread from its origin and creep under the plating. On one of the shafts the rust started up high and flaked up plating enough that it shredded the seal and began an oil leak on that shock. So I had to replace the shaft AND the seal on that side.

One of my rear shocks has a tiny spot of rust on it too, but it's down near the eye. Hasn't spread yet so I'm not worried about it.

Just something to be aware of.

 

[4runner666]

I'd like to revisit this before I get my truck out of the garage in a few months.

Singe cab Tacoma, 2RZ, w56, duals,
Diamond 8" housings.
37" tires.
Leafs front and rear
Approximately 4.5" up travel front with 2" " lift stock front springs ( they go negative)
5.5-6" Rear All pro springs (look like J59's)
Approximately 4000lbs

I have 7100 short bodies in the 255/70 valving. These come with a linear piston which makes them different than the 5xxx series shocks digressive piston. Yes I already own them, the short bodies help keep them under the bed.

Since most people that tune shocks speak in dia. and thickness I converted what I have.

Nut
.82 x .080 washer
.70 x .020
.86 x .020
1.10 x .018
1.26 x .018
1.47x .015
.70 x .006 bleed shim
PISTON
.70 x .004 bleed shim
1.47 x .008
1.26 x.010
1.10 x .012
.78 x .012
.70 x .020
.86 washer

I don't know 100% what I will need, but I want to have some shims on hand to play with before I get complacent and forget about it. I'd like to avoid the shocks needing a full rebuild when I go for a valving change.

Based on what I've read here, Race Dezert and other forums is that with Leaf Springs you need very little rebound and usually more free bleed.

To increase free bleed on a Bilstein you change the thickness of the small diameter shim next to the piston. The biggest size I've seen on the Bilstein chart is .2mm or .008". This shim does not cover the holes on the piston so has no other effect on the valving aside from spacing up the "cover" shim. no easy way to compare this so I will start with ordering .008" shims and see where i go from there.


To Reduce rebound I had a look at Bilstein's lightest rebound that uses free bleed which is "160", it is:

Nut
.82 x .080 Washer
.78 x .020
.86 x .020
1.10 x .012
1.26 x .012
1.47 x .010
.70 x .008 Bleed shim
PISTON

Seems like it would be much heavier still than the general recommendation of starting with a .008 stack on a Fox. Bilstein sells (has part numbers for) individual .008 shims so I was thinking of ordering a full .008 stack like that.

Compression seems close to the recommended base of running a full .012 stack on a fox but I'm down one shim and cant determine if that would create more or less valving. Just guessing I think it would be less. I may just leave this and adjust later, or order the required shims to make it a full .012 stack.

So I would be looking at:

Nut
.82 x .080 washer
.70 x .020
.86 x .008
1.10 x .008
1.26 x .008
1.47x .008
.70 x .008 bleed shim
PISTON
.70 x .008 bleed shim
1.47 x .008 maybe .012
1.26 x.010 maybe .012
1.10 x .012
.78 x .012
.70 x .020
.86 washer

Some Questions for the experts.

1. Will a piston have much affect on the valving at lower shaft speed since the sims are controlling the "orifice size" until they are blown open? my assumption is no not until the shims have opened far enough that the piston becomes the orifice.

2. Bilstein's stacks seem to increase in thickness as they get further from the piston. What will the do vs a stack of equal thickness shims?

3. How mush difference does the thickness of the washer under the washer make, as it is acting as the pivot point and does not flex itself?

4. Anything I'm missing that makes comparing Bilstein to a Fox valving different?

 

[bdkw1]

I'd like to revisit this before I get my truck out of the garage in a few months.

Singe cab Tacoma, 2RZ, w56, duals,
Diamond 8" housings.
37" tires.
Leafs front and rear
Approximately 4.5" up travel front with 2" " lift stock front springs ( they go negative)
5.5-6" Rear All pro springs (look like J59's)
Approximately 4000lbs

I have 7100 short bodies in the 255/70 valving. These come with a linear piston which makes them different than the 5xxx series shocks digressive piston. Yes I already own them, the short bodies help keep them under the bed.

Since most people that tune shocks speak in dia. and thickness I converted what I have.

Nut
.82 x .080 washer
.70 x .020
.86 x .020
1.10 x .018
1.26 x .018
1.47x .015
.70 x .006 bleed shim
PISTON
.70 x .004 bleed shim
1.47 x .008
1.26 x.010
1.10 x .012
.78 x .012
.70 x .020
.86 washer

I don't know 100% what I will need, but I want to have some shims on hand to play with before I get complacent and forget about it. I'd like to avoid the shocks needing a full rebuild when I go for a valving change.

Based on what I've read here, Race Dezert and other forums is that with Leaf Springs you need very little rebound and usually more free bleed.

To increase free bleed on a Bilstein you change the thickness of the small diameter shim next to the piston. The biggest size I've seen on the Bilstein chart is .2mm or .008". This shim does not cover the holes on the piston so has no other effect on the valving aside from spacing up the "cover" shim. no easy way to compare this so I will start with ordering .008" shims and see where i go from there.


To Reduce rebound I had a look at Bilstein's lightest rebound that uses free bleed which is "160", it is:

Nut
.82 x .080 Washer
.78 x .020
.86 x .020
1.10 x .012
1.26 x .012
1.47 x .010
.70 x .008 Bleed shim
PISTON

Seems like it would be much heavier still than the general recommendation of starting with a .008 stack on a Fox. Bilstein sells (has part numbers for) individual .008 shims so I was thinking of ordering a full .008 stack like that.

Compression seems close to the recommended base of running a full .012 stack on a fox but I'm down one shim and cant determine if that would create more or less valving. Just guessing I think it would be less. I may just leave this and adjust later, or order the required shims to make it a full .012 stack.

So I would be looking at:

Nut
.82 x .080 washer
.70 x .020
.86 x .008
1.10 x .008
1.26 x .008
1.47x .008
.70 x .008 bleed shim
PISTON
.70 x .008 bleed shim
1.47 x .008 maybe .012
1.26 x.010 maybe .012
1.10 x .012
.78 x .012
.70 x .020
.86 washer

Some Questions for the experts.

1. Will a piston have much affect on the valving at lower shaft speed since the sims are controlling the "orifice size" until they are blown open? my assumption is no not until the shims have opened far enough that the piston becomes the orifice.

2. Bilstein's stacks seem to increase in thickness as they get further from the piston. What will the do vs a stack of equal thickness shims?

3. How mush difference does the thickness of the washer under the washer make, as it is acting as the pivot point and does not flex itself?

4. Anything I'm missing that makes comparing Bilstein to a Fox valving different?

1, no.
2, the damping curve is more progressive as velocity goes up.
3, are you talking about the clamp shim? It's diameter will effect the damping curve pretty equally. Thickness only effects high speed. If your running a real light stack you will need a thicker clamp shom or 2 to keep the top out washer from turning into a rate plate.
4, drill bleed holes versus bleed shim. Way better. Drill them .089 so that they can be tapped 4-40 if you need to close them.

 

[4runner666]

1, no.
2, the damping curve is more progressive as velocity goes up.
3, are you talking about the clamp shim? It's diameter will effect the damping curve pretty equally. Thickness only effects high speed. If your running a real light stack you will need a thicker clamp shom or 2 to keep the top out washer from turning into a rate plate.
4, drill bleed holes versus bleed shim. Way better. Drill them .089 so that they can be tapped 4-40 if you need to close them.

Thanks for the explination.

2. It seems a progressive valving would be somewhat undesirable on compression and maybe desirable on rebound.

3. Yes the clamp shim. Good info. So running a full stack of .008’s on rebound I should keep the existing .020 clamp shim and potentially add more thickness.

4. What makes bleed holes better than a bleed shim? A more direct flow path? More industry understanding since most big brands use this method?
The bleed shim option seems much more tuneable. (And it’s less work right now lol)
I had watched some videos where someone mentioned shims can “stick to the piston” and roughing them up helps prevent it. With a bleed shim this would not be an issue although I probably would never know the difference.

If I were to drill them it looks like I have the space. I had a look at the fox piston and I could mimic that. 3 holes? (Not my pic)

 

[bdkw1]

Thanks for the explination.

2. It seems a progressive valving would be somewhat undesirable on compression and maybe desirable on rebound.

3. Yes the clamp shim. Good info. So running a full stack of .008’s on rebound I should keep the existing .020 clamp shim and potentially add more thickness.

4. What makes bleed holes better than a bleed shim? A more direct flow path? More industry understanding since most big brands use this method?
The bleed shim option seems much more tuneable. (And it’s less work right now lol)
I had watched some videos where someone mentioned shims can “stick to the piston” and roughing them up helps prevent it. With a bleed shim this would not be an issue although I probably would never know the difference.

If I were to drill them it looks like I have the space. I had a look at the fox piston and I could mimic that. 3 holes? (Not my pic)

2, no. Progressive is velocity sensitive, great on comp. Rebound, doesn't matter nearly as much.

3, rebound, agian, don't matter much. The extra space only matters if there's a top out washer like comp. Even with that large washer you won't see enough velocity on reb for the shims to hit it and create a knee in the curve.

4, the only bleed shims I've dealt with were OEM stuff for bikes. I've never had a selection to choose from. But being a machinist, I've got lots of ****ing drill bits. I'm also not sure what the changes in the bleed shim diameter and thickness would do proportionally. Also not aware of anybody doing it that way in performance tuning off road. So your kinda on your own with that

 

[4runner666]

2, no. Progressive is velocity sensitive, great on comp. Rebound, doesn't matter nearly as much.

3, rebound, agian, don't matter much. The extra space only matters if there's a top out washer like comp. Even with that large washer you won't see enough velocity on reb for the shims to hit it and create a knee in the curve.

4, the only bleed shims I've dealt with were OEM stuff for bikes. I've never had a selection to choose from. But being a machinist, I've got lots of ****ing drill bits. I'm also not sure what the changes in the bleed shim diameter and thickness would do proportionally. Also not aware of anybody doing it that way in performance tuning off road. So your kinda on your own with that

Great, thanks for the help!

I do have a drill press but I’m far from a machinist. I will give it a go with bleed shims as they can be ordered and if I can’t figure that out or feel more bleed is needed I will drill some holes. When the piston is out I’ll do some math to figure out the surface area difference between 3 bleed holes@ .089 and the bleed shim. It should be the area of the rectangle created by taking the circumference of the piston holes vs the distance to the “face shim”. Maybe I won’t, maybe I’ll just chuck em in there lol.

I won’t update this thread for a few months now but I’ll return with my findings. I will test the stock valving and then the changes so I can report on the difference.