Dobinsons IMS Struts and Shocks - Adjustable Height Monotubes - 2nd/3rd Gen Tacomas

The ride is night and day different. I went with the 600lb springs I believe. I got the chance to ride some service roads this weekend and couldn't be happier.

 

Update on resupply, front IMS have been sold out for a while now, but more are due mid-October. Don't have a delivery date for the rears yet, but they're in production.

 

I know a lot of Dobinsons coils are sold out right now, but there's a price increase next week, October 1st, on all coils!! Any orders placed until then, even if they're on backorder, will still get the current pricing.

Just a heads up!!

 

Well crap....looks like I'm late to the party.

I recently stumbled accross Dobinson, had never heard of them before. Any talking points as to how they compare to OME, Fox, Icon, etc...? I like the triple adjusters on the MRA shocks and have no idea why fox doesn't do rebound damping and OME only does one compression and one rebound for example. I'm also considering Fox from accutune since they do a custom valving for your vehicle's weight. I'd appreciate any thoughts. I have a FWC on my access cab TRD OR 4x4 with 5100s up front on stock coils and TSB springs in the rear with firestone airbags and the stock 4600s (tired 4600s).

 

Dobinsons has been around much longer than icon, fox and even OME. They're australian made and are of great quality. Their leaf springs don't squeak, front shocks have the most adjustability of any comparative market shock absorber and their pricing is extremely reasonable. Not to mention you can choose custom coil colors!

 

I appreciate the response, it is very helpful, but I have a few specific questions as well I suppose:

1. BP-51 and TRD pro (Fox) use internal bypass, Dobinson's doesn't. How do I know if I would benefit from the internal bypass over the "conventional" damper design? Accutune told me that internal bypass isn't great for daily driver due to ride height fluctuations from adding people and gear changing the way the shock behaves with different loads since the bypass is engaged based on the position of the shock which changes relative to loading in addition to terrain.

2. Fox and BP-51 use an aluminum body and Dobinsons uses a DOM Steel body...sounds strong but also rust prone. Do shock bodies wear out? Should I expect more rebuild cycles out of the Dobinson's? Will they rust before I get a chance to rebuild them? What about heat dissipation? Fox and BP claim to use aluminum for better heat dissipation

3. Damping adjustments....Dobinson's has all the adjustments...why don't the others? I just don't understand, Fox and King have all the racing cred and seem to do different things, but maybe they valve all of their shocks custom for the race and adjusters are for the weekend warriors. I know in motorcycles, rebound damping is considered less important but I'm not actually sure why.

4. Valving-I have a four wheel camper which weighs probably a little over 1000 lbs. Dobinsons and BP51s claim to handle extra loads via their adjustments. Accutune custom builds the shock to the customer specification (they request a load for each axle and design a valve stack to that). If you get adjusters they valve it in a way that you have more adjustability "headroom" Where do the Dobinsons and BP-51s max out as far as load? Would it be outright crazy to use something like a stock 5100 or nitrosport under a camper?

5. Travel-do any of the options restrict or increase travel in any way? And I guess along with that goes the discussion of bump stops and if they affect your bumpstops ability and/or require additional mods like limiting straps or bump extensions.

Ok, i think that about covers it...I realize these are difficult questions and many may not know the answers....that's why I'm asking. I also think it's good for discussion purposes, so I'm interested to hear your thoughts

 

I'll give some answers or opinions here for you. Hopefully some others will chime in with their Fox/BP experience too.

1. I think it depends on the type of driving you do ultimately. Bypass shocks are usually used in racing, but so are adjustable shocks. I think the idea behind the internal bypass is it gives multiple chambers for the oil to get out and go around the body of the inner bore for cooling, and then with the adjustment of the opening of those chambers (the bypass), it controls how the oil flows through. The same is done with oil going in or out of a reservoir, but it can also offer more adjustment at the reservoir I believe.

2. There's no way for the shock body to wear out unless the piston fails, then the shock is toast anyway. Seals or hoses are much more likely to blow before a piston failure I think. The Dobinsons are EDP coated, which is the best that can be done for steel. People that live in really bad climates would need to do exterior maintenance on them to keep the threads clean if they think they'll ever need to adjust the height again. Aluminum threaded bodies have their own sets of issues in salty climates. I've seen test results both ways between aluminum and steel and heat dissipation. I don't think it's worth worrying about, since they're only offered one way anyway, you have to go with the shocks you feel will suit you better. Any shock with an external resi will run cooler than one without due to all the extra oil and hose length with the resi.

3. Good question. Ask the other brands. It's "easy" to have DSC adjusters on the resi, but very tricky for the rebound adjustment design that Dobinsons has on the MRA struts and shocks.

4. If you're comparing a $100 shock to a $500 one, you've got a lot more reading to do!! Since you're running 5100's already, you can see how they feel when you add the weight, but I wouldn't expect them to last for a long time under a heavy constant load. At a minimum, a twin tube shock would be what I'd suggest with a camper. The structural design of them is just a lot stronger. I've sold lots of them, check out the FWC thread too. Dobinsons don't max out on load, the vehicle shouldn't be put past GVM anyway.

5. Dobinsons increases travel to the maximum ability without having to change brake lines or any other components. They can be used with stock bump stops, but with a camper, you may be running airbags anyway that would remove the bump stops. Upgraded bumps are recommended when carrying heavy loads. I recommend these if you won't be running airbags: https://exitoffroad.com/product/timbren-abstrfk-active-off-road-rear-tacoma-bumpstops-kit/

 

Awesome post and lots of good information!

 

1. Agreed and maybe this is in the weeds for a non-racer, it just seems like ARB is not a race company and Fox is. Fox offers internal bypass on the TRD pro but not in their standard lineup of aftermarket shocks. ARB puts internal bypass in an "overland" shock....not really sure why. Maybe it's more about heat over extended periods of time on corrugations rather than shock performance? Just seems odd

2. The seals will polish the internal diameter over time, but I agree that this will likely outlast any vehicle assuming no significant impacts.

3. Ok fair, but does Dobinson's (or ARB) make a case for why I need the rebound adjustability or is it really just for the highly discriminatory driver to really fine tune things or is it more piece of mind, knowing you can if you want. From what I hear most people find the settings they like and leave it there. In the case of trucks with campers they find settings for the configurations of their vehicles and not the terrain they're going out into (I admit I have very limited experience here)

4. I've done a lot of reading and over on WTW have gotten the advice that "most people over here (on the WTW) will just run 5100s or nitrochargers and not bother with fancy reservoir shocks" Which sounds risky to me and a potential complete waste of money out of the box if they can't dampen the weight. Or maybe they'll just wear out sooner, which is a lesson I would possibly be willing learn. A set of those costs about the same as a rebuild cycle on the reservoir shocks if you send them out I think.

5. I am running airbags already. The ride is supported and feels pretty safe on the road, but off road is a whole different story. My 2nd gen weighed in at 5800lbs (full gas, half propane, empty water tank). Initially I was dissappointed and scared (considered boxing the frame) but now having read some more threads, people are driving around 7000lb Tacomas! So I'm at least more assured that the weight can be managed on the truck even though it will be heavier than GVWR. I probably won't drive my truck without the camper more than an hour or two (and that would be rare) so I'm not super worried about the ride when unloaded but I do want it to be driveable still and would like to be able to still flex it unloaded on some of the harder local trails. Are these impossible goals? Do you have a recommended setup for me? I'm wondering if medium duty springs would be better since I have the airbags already or if I should consider the heavy duty and suffer more when the truck is unloaded. How the heck do the high payload hilux, landrovers and even F-350s handle the unloaded driving configuration?

PS: thanks for the response, I think this is a great topic to discuss. I'm trying to keep it mostly generic, but I also need to find the right fit for my truck ;P

 

That's right, most people set it to how they like it then leave it, but they also had the chance to set it how they like. I adjust my MRA's whenever I load up or go offroad, leaving it soft on the road for unloaded daily driving. Also, when I hit I-70 this summer, that crappy road had me adjust the low speed compression again so that it wouldn't be so bad with all the expansion joints and rough surface in eastern Colorado.

Yes, twin tube and monotube shocks are "throw away" designs, but at ~$100 each piece, it's no big deal to change them out if they do wear out. A shock rebuild is $150-200 depending who does it, per shock, so that's something to keep in mind, plus shipping both ways.

Select the coils and leaf springs based on the added constant weight, so if the camper is pretty much always on there, then you'd choose the springs to match that weight (L59-112-R in this case), so that the airbags aren't being relied upon so much. Also, if an airbag fails remotely, the springs will still hold it up just fine probably without needing to limp home, as opposed to using stock spring, having an airbag fail, and a bunch of weight in the bed. Leaf springs are also progressive, so if the weight isn't on the bed, then the lower leaves don't get engaged and it will still ride fine.

Yours is a 2006 access cab long bed, right?

 

yes 2006 access cab 4x4 TRD off-road with rear locker. I think rocksliders would be my only planned mod beyond suspension, but could consider an aluminum winch bumper in the front at some point.

With the camper on I'm at 2520lbs on the front axle and 3340lbs on the rear (water tank empty)

 

Ok. Definitely the 112 rear springs. Fronts will depend on what the added weight ends up being up there, if you decide to get that bumper, etc.

 

I don't know what the stock front axle curb weight is, but I know I'm currently only 235 lbs shy of the GAWR. As is, you think I'm ok with stock coils?

 

I don't know either, I only go by additional weight over stock.

Stock coils if you want no lift. What are your hub to fender measurements front and rear right now?

 

Front (Bilstein 5100s at highest setting with stock coils)
Driver: 23" Passenger:22.5" (reverse taco lean?) Could be not quite level maybe

Rear (TSB springs w/firestone airbags)
Driver 22 1/4" (airbag is low though) Passenger: 23 1/4" (airbag at 60 psi)

 

Front is 2.5" to 3" of lift. Not sure why you're leaning the other way

Rear is pretty close to stock height, stock is usually about 22" hub to fender.

 

That sounds about right. I may need to drive the truck around the block and park it somewhere different and remeasure to see if I really have reverse taco-lean. I thought on the front I should've had 1.75-2.5" I didn't think a 5100 could get you to the full 3" without a spacer. That said...if they level out after a drive and a flatter parking spot, would you recommend keeping stock coils and going with the 112 spring in the rear? Can you tell me how many leaves are on the 112s and how horrendous the ride might be unloaded?

Regarding the shocks question. I thought I had done enough reading on shock design/technology, but after a chat with Mainline Overland, I felt a little like I was back to square one. I thought I had concluded that for the rear I needed adjustable damping and that was leading me obviously to the MRA, but they said I'd still have a good ride and capable damping with the twin tube "disposable" shocks. I'm not super critical of the ride quality in general (barely noticed a difference with 5100s up front so I didn't bother changing the rears), but right now the ride quality I think is extremely subpar (due to soft stock springs, firm airbags and old shocks). I'm not looking to haul ass and be an idiot with a 1000lb camper in my bed but i want to feel like the truck is well planted, safe and capable. I'd be interested in your take on this.

 

If you don't want to change out the front coils, you can leave it as is since you have a lot of lift already.

7 leaves. They're designed to have that amount of weight on them for them to ride properly. I've had people tell me they rode fine when empty and others tell my they rode really firm. Not only will they be firm unloaded, but the lift height will go up without the weight on them.
You can jump into the other Dobinsons 2nd Gen thread and pose the question in there if anyone else is running those springs when empty to get their feedback. https://www.tacomaworld.com/threads/dobinsons-2nd-gen-tacoma-suspension-options.458013/

MLO has built a lot of trucks with Dobinsons twin tube shocks with great results. A buddy of mine worked for them and his Tacoma got at least 45k miles on it over 2 years and his twin tubes did well for him. It's true, a "throw away" shock can be replaced many times over compared to the cost of a set of adjustable shocks with resi's. It all depends what driving you'll be doing. For varying terrain, adjustable shocks to change with the terrain are awesome, and especially with varying load rates in the back, being able to soften or firm it up you'll see is invaluable.

Problem #1 though is you don't have adequate springs to support the weight. That's the first step.

 

Agreed on the springs i think. I was hoping the airbags would be the support the springs needed and that shocks might tame their behavior a bit, but the more i think about it, beefier leaves will "tame" the airbags' behavior by mostly avoiding them and using them as bump pillows instead.

I'll check in on that other thread.

Any update on availability?

 

Of what parts?

The only Tacoma parts not in stock right now are front 302/314 coils and 221 struts. The IMS's are due next week, coils and struts in mid-November.