Long travel rear for a 100 series

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Timely post. I’m picking up parts for this using Dobinsons shocks/springs based on this setup. i think they’re here but don’t know their mud name.

was doing some math on the bump stop height. I don’t plan on moving shock mounts.

Can I still run the swaybar with TT extended Hd links? Any adverse on road handling effects?

View attachment 3600654

View attachment 3600655
Another member on here was looking at the MRA59-A685 shocks which are the 6" lift shocks for the 80 series. In talking with Burns it would seem that if you run the 6" shocks you wouldnt need to relocate the shock mount or run AHC spacers. I tried reaching out to the other member to see if he had ordered the 6" or the 4" but no response.
 
Another member on here was looking at the MRA59-A685 shocks which are the 6" lift shocks for the 80 series. In talking with Burns it would seem that if you run the 6" shocks you wouldnt need to relocate the shock mount or run AHC spacers. I tried reaching out to the other member to see if he had ordered the 6" or the 4" but no response.
Yes this is correct math if your shock mount relocate and/or ahc spacers are 2”. I am unsure the exact differences between the 4” shock travel and the 6” shock travel. I would get the exact measurements and do the math. 50mm is 2”. Just to make sure it’s not a 56mm difference or something.

You would just need to adjust your bump stops accordingly so as not to prematurely blow out your shocks.
 
Yes this is correct math if your shock mount relocate and/or ahc spacers are 2”. I am unsure the exact differences between the 4” shock travel and the 6” shock travel. I would get the exact measurements and do the math. 50mm is 2”. Just to make sure it’s not a 56mm difference or something.

You would just need to adjust your bump stops accordingly so as not to prematurely blow out your shocks.
Great point. I didnt notice but from the specs Ive seen the difference between those 2 shocks are 54mm so a tad over 2". What would that mean? That it would that much more droop and could potential cause some issues with lines? Probably best to stick with the 4" shocks and relocate the brackets I guess to be on the safe side.
 
Great point. I didnt notice but from the specs Ive seen the difference between those 2 shocks are 54mm so a tad over 2". What would that mean? That it would that much more droop and could potential cause some issues with lines? Probably best to stick with the 4" shocks and relocate the brackets I guess to be on the safe side.
The 4mm difference is less than 1/4”. it would basically be 1/4” more droop than I currently have with the 4” shocks and 2” chop. Just something to consider when you’re adjusting your bump stop height.

I wouldn’t think it would cause any issues with the abs lines.
 
One thing to consider, you can have all the downtravel you can muster, but it will be useless if your springs are not applying down pressure. (Hanging free)
Right. If I remember correctly those Dobinsons springs you run are very tall.
 
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@BurnsCrew do you remember changing the rear brake lines? Was there any interesting to modify or you were able to replace them normally. great deal as I need to replace mine anyways. FJ Cruiser/4Runner 20" Rear Extended Stainless Steel Brake Lines (Set of 2) - https://trail-gear.com/fj-cruiser-4runner-20-rear-extended-stainless-steel-brake-lines-set-of-2-lines.html
Yea. I believe these were the exact ones I used. It is a great deal vs slee. I have a 2005. I believe 1998/1999 models have different rear brake lines. (Just FYI)

As far as install, I think it was fairly straight forward. I do not think I really had to modify anything, but I did bend the axle side bracket on the rearward most line up some for some additional slack.

FWIW, the only time the brake line comes close to being taught is when on a lift and both rear tires are suspended. And it’s still slack enough with this set, and bending the bracket up a bit to pose no issues with my particular set up.
 
Yea. I believe these were the exact ones I used. It is a great deal vs slee. I have a 2005. I believe 1998/1999 models have different rear brake lines. (Just FYI)

As far as install, I think it was fairly straight forward. I do not think I really had to modify anything, but I did bend the axle side bracket on the rearward most line up some for some additional slack.

FWIW, the only time the brake line comes close to being taught is when on a lift and both rear tires are suspended. And it’s still slack enough with this set, and bending the bracket up a bit to pose no issues with my particular set up.
Thanks so much. This is a fun project for me as I am getting some longer shocks soon and after doing the brake line replacement I can weld/make the rest of the mods needed to run the longer rear setup. Yipeeee
 
@BurnsCrew

Got some specs from CrikyMike with Dobinson. I went with the A685 shocks, they are only 40mm longer extended but 20mm longer compressed. Is that going to be an issue or should I Just get the 4" shocks? It seems like the 4" ones are more tested/proved to be compatible setup

MRA59-A687 - Rear 4" Shocks - 670mm extended, 410mm compressed
MRA59-A685 - Rear 6" Shocks - 710mm extended, 430mm compressed
 
So if you wanna space down your bumpstops, run the 6” shock. That 30 mm would be about 1.15” space down needed. My 35s rubbed the inner fender wells on the back with stock sized bumps and spacing them down helped eliminate this.

Which is why I ultimately ran the 4” shock with the axle side mount chop.
1) more clearance for rocks
2) clears inner fender with bump-stop drop (have to with axle mount chop)
3) maximizing the droop without damaging abs lines or e brake cable or the rear end link binding.

🍻
 
@Lazarus556 Just FYI, different manufacturers measure using different methods....

Screenshot 2024-04-09 at 11.22.20 AM.png
 
@Lazarus556 Just FYI, different manufacturers measure using different methods....

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Good point, and why it’s important to know the same brands 100 series shock lengths vs same brands 80 series shock lengths. (100 series designed shock would be your safe callapsed length) Once you figure that out then draw your conclusions on collapsed and extended length differences from there.

Based on this photo, I have no idea why anyone would measure a shock like fox does. 🤷‍♂️ It makes the most sense to measure from mounting surface to mounting surface like OEM designs or king.
 
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Well, I can see that changing bushings types would yield a different measurement. Plus when crank down on the stem nut, the bushings compress. On the plus side, if you measure as does FOX, there's leeway so you won't kill the shock on compression..... even when the bushing wears down and maybe even crumbles.

I guess if one is really serious about their suspension, they aren't using shocks with stems anyway. 😉
 
Well, I can see that changing bushings types would yield a different measurement. Plus when crank down on the stem nut, the bushings compress. On the plus side, if you measure as does FOX, there's leeway so you won't kill the shock on compression..... even when the bushing wears down and maybe even crumbles.
I think I understand what you’re saying. Yes the bushing that goes between mounting surface to mounting surface will compress when tightening down but it’s also designed to that way.

I also guess I can understand the fox argument as it’s a non compressible surface. Still, I’d rather adjust bumpstops accordingly like Toyota does to be the limiting factor of my uptravel and protect the shock that way. You could always space it down an extra 1/4” if you want a little extra peace of mind. 🍻
 
Regardless of published specs on compressed length I’m just gonna throw on a shaft bump and then either add or subtract shims from my bumps to make sure I’m using the entire stroke 👍
 
Regardless of published specs on compressed length I’m just gonna throw on a shaft bump and then either add or subtract shims from my bumps to make sure I’m using the entire shaft bump
Regardless of published specs on compressed length I’m just gonna throw on a shaft bump and then either add or subtract shims from my bumps to make sure I’m using the entire stroke 👍
Does a shaft bump just keep shock from bottoming out?
 
Usually the shaft bump is just extra insurance because the shock mounts are not usually enough to support the weight/impact.

I'm not for one way of measure or another. Just letting others know there is a difference.
 
Does a shaft bump just keep shock from bottoming out?
Yes. It’s just a little safety margin.
Not much on my Kings but it’s better than nothing.
Here’s a photo of mine before I moved the shock mounts to get more compression. You can see how the shaft is dirty from not being completely used
IMG_5790.jpeg
 

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