Pulled the trigger on suspension upgrade

[Jono.ful]

The issue with 2.5 rears per the Radflo owner (I talked to him over the phone) is that you are not supposed to run a bigger shaft rear than in the front (the 6112s have a small shaft for a big shock). I wanted his 2.5 Radflo rears w/o reservoirs. He did not make any money off that advice plus seemed like a true enthusiast so I guess he is right.

Huh? Why would different diameter shock shafts front and rear make any difference at all?

 

[MAST4R]

Huh? Why would different diameter shock shafts front and rear make any difference at all?

It has been a while. I remember him saying that the rear would feel like it is pushing the front and he said that's not a good feel at all.

It is possible this only happens in higher speed applications close to his racing heart but I did not want to risk it since he was categorical about it.

I know someone posted they do run Radflo 2.5 rear with 6112 and feel fine so I guess it would also depend on how much the driver is in sync with the machine.

I would like to give it a try, but it is a steep price if it does not work out.

 

[Jetboy]

Thanks, yes, the Icons do great at preventing bottoming out. Had not had any since installing them; bottomed out too often when stock.

The issue with 2.5 rears per the Radflo owner (I talked to him over the phone) is that you are not supposed to run a bigger shaft rear than in the front (the 6112s have a small shaft for a big shock). I wanted his 2.5 Radflo rears w/o reservoirs. He did not make any money off that advice plus seemed like a true enthusiast so I guess he is right.

I might next try the Billstein 1.5" rear spring at 186lb rate. The 1" Eibach I have is 204 or so.

The Icon 2.0 is 8 7/8 shaft length and the body is 13" before it dm decreases at the top.

The ride is fine, I am just looking for optimization. When it felt a bit much was last month: we drove from near Big Water up Croton Rd-Left Hand Collet intersection--Smoky Mountain back south as a loop in not much time. Croton is slow in places but fun. Smoky mountain is fast at the ends but very annoying in the middle, neither fast, nor slow, lots of embedded rock.

It's perfectly fine to run a larger rear shock than front. But it's usually the best way to spend your $ to put the larger shocks up front. It just needs to dampen the right way. What you usually don't want is rear suspension that's significantly better than the front to the point that you lose control with the front end first. So for example if you're pushing the limit and you're going around a corner - you want the rear end to slide out first - you don't want the front to push through the corner or lose control while the rear end stays planted. But beyond that type of issue - there's really no way to do everything well with passive suspension. You just can't optimize for desert racing, mid speed, and slow speed off road. All of those things would use a different shock valving to have the best ride and performance. And you can't do those things and also make it ride great on the highway - unless you start using more active suspension systems like the newer generations of electronic shocks or complex systems like Lexus/Toyota AHC system.

One way to get a really nice ride for the rear passengers would be a bypass shock. The rear TRD Pro shocks are probably really nice for this. They should be. If you wanted the best setup for medium speed rear comfort, those would be great. If you wanted to go crazy you could buy a set of Bilstein 8100 rears. They're probably the best bolt on rear shock on the market and you can tune for exactly how you want it to ride. But they're $$$. Sometimes they go on really big sale discounts on Ebay, but I've never been paying attention when they do. Otherwise I'd have bought a set.

It would be really great if there were some way to have a test drive with 10 different suspension options and compare them all back to back. Otherwise for the most part we're really all just guessing at subjective feelings.

Also FWIW I think you're meaning piston diameter, not shaft diameter. Usually in shocks the shaft is a reference to the solid rod that pushes the piston. The size of the actual shaft isn't all that relevant to dampening - it has some effect on pressures internally due to the volume of the shaft and also has effect on durability, but dampening is mostly driven by the valving and the piston size. Larger pistons allow for more valving precision because as the piston gets larger you have more room to do more things with the piston and the valve stacks.

They can also hold more oil, but that's rarely an issue for the 4Runner. Even over extended distance at high speeds on very rough washboard, I can never get them hot enough to be an issue.

 

[MAST4R]

Also FWIW I think you're meaning piston diameter, not shaft diameter. Usually in shocks the shaft is a reference to the solid rod that pushes the piston. The size of the actual shaft isn't all that relevant to dampening - it has some effect on pressures internally due to the volume of the shaft and also has effect on durability, but dampening is mostly driven by the valving and the piston size. Larger pistons allow for more valving precision because as the piston gets larger you have more room to do more things with the piston and the valve stacks.

.

Thanks, yes, I am probably asking too much hence may just try to soften the springs a little.

I am talking shafts/rods indeed. Not the piston.

The owner of Radflo was very clear about the shaft/rod dm discrepancy between 6112 and his shocks and the effect of running larger shaft/rod in the rear vs the front.

For the rest, the 6112 are softly valved hence the need for me to run 650lb front springs. I fear that having a monster rear shock would indeed be an issue.

Therefore, I may try to get the Bilstein rear springs. I have better uses for money than spending thousands on a vehicle suspension considering mine does the job really well most of the time. However, if we come to a point where they do go on a big sale down the road or I can grab a reasonably priced second hand system, I would be interested to try.

 

[Jetboy]

Thanks, yes, I am probably asking too much hence may just try to soften the springs a little.

I am talking shafts/rods indeed. Not the piston.

The owner of Radflo was very clear about the shaft/rod dm discrepancy between 6112 and his shocks and the effect of running larger shaft/rod in the rear vs the front.

For the rest, the 6112 are softly valved hence the need for me to run 650lb front springs. I fear that having a monster rear shock would indeed be an issue.

Therefore, I may try to get the Bilstein rear springs. I have better uses for money than spending thousands on a vehicle suspension considering mine does the job really well most of the time. However, if we come to a point where they do go on a big sale down the road or I can grab a reasonably priced second hand system, I would be interested to try.

The shaft size really has no bearing on suspension performance as long as it's big enough not to flex or collapse. I'm not sure where that person came up with that idea. If you used a 14mm shaft vs a 20mm shaft on the same shock - there's effectively no difference in shock behavior.

The bigger rear shocks typically are softer in dampening than smaller ones. I think that's the paradox - you usually have to go up to bigger more expensive shocks for a softer ride. It seems like most buyers want really firm aftermarket shock valving. And at least for me - and it sounds like you too - that's not what we're looking for at all. I like the soft OEM rear shocks better than the fox 2.0 until I load up the 4Runner with a bunch of weight or I want to go fast in the desert. And most of the time I'm not doing either of those things.

 

[MAST4R]

The shaft size really has no bearing on suspension performance as long as it's big enough not to flex or collapse. I'm not sure where that person came up with that idea. If you used a 14mm shaft vs a 20mm shaft on the same shock - there's effectively no difference in shock behavior.

The bigger rear shocks typically are softer in dampening than smaller ones. I think that's the paradox - you usually have to go up to bigger more expensive shocks for a softer ride. It seems like most buyers want really firm aftermarket shock valving. And at least for me - and it sounds like you too - that's not what we're looking for at all. I like the soft OEM rear shocks better than the fox 2.0 until I load up the 4Runner with a bunch of weight or I want to go fast in the desert. And most of the time I'm not doing either of those things.

Good point. But he is the owner of Radflo, not a random guy who answers the phone. If he does not know, who would?

It is possible that what he thinks about is a narrow case of racing applications. That would be common for an expert in a given area.

 

[LandCruiser]

Good point. But he is the owner of Radflo, not a random guy who answers the phone. If he does not know, who would?

It is possible that what he thinks about is a narrow case of racing applications. That would be common for an expert in a given area.

People who want to sell you something will say all sorts of things.

 

[MAST4R]

People who want to sell you something will say all sorts of things.

Actually, he talked me out of buying them so the opposite would be true here.

 

[Jetboy]

Good point. But he is the owner of Radflo, not a random guy who answers the phone. If he does not know, who would?

It is possible that what he thinks about is a narrow case of racing applications. That would be common for an expert in a given area.

That's kinda why I'm guessing he was meaning shock piston size, not the shaft size. The suspension will function based on the spring rate and dampening (and other stuff like geometry, etc). As far as the shock's contribution - the dampening is all that it does. Dampening isn't effected in a meaningful way by shaft diameter. There's just no mechanism that exists physically for the shaft diameter to change suspension behavior other than some small effect of pressure and weight differences. Even in racing situations.

But there is a big difference in piston or body diameter in performance potential. That's why I think it must have been a miscommunication of some type where he was trying to say large diameter cylinder and said shaft instead. Or he was referencing shaft size as a representation of the shock size overall. Something like a rule of thumb that shocks that have 18mm shafts are going to also be bigger and more capable than shocks that typically have a 12mm shaft. So he might have been using the shaft diameter as a shorthand way of meaning something else.

If not - he's probably wrong on the physics of suspension. There's just not any other way around it. The shaft size doesn't really matter (within the normal range of shaft to body ratios). But assuming he's pretty knowledgeable - he probably meant something else.

 

[MAST4R]

That's kinda why I'm guessing he was meaning shock piston size, not the shaft size. The suspension will function based on the spring rate and dampening (and other stuff like geometry, etc). As far as the shock's contribution - the dampening is all that it does. Dampening isn't effected in a meaningful way by shaft diameter. There's just no mechanism that exists physically for the shaft diameter to change suspension behavior other than some small effect of pressure and weight differences. Even in racing situations.

But there is a big difference in piston or body diameter in performance potential. That's why I think it must have been a miscommunication of some type where he was trying to say large diameter cylinder and said shaft instead. Or he was referencing shaft size as a representation of the shock size overall. Something like a rule of thumb that shocks that have 18mm shafts are going to also be bigger and more capable than shocks that typically have a 12mm shaft. So he might have been using the shaft diameter as a shorthand way of meaning something else.

If not - he's probably wrong on the physics of suspension. There's just not any other way around it. The shaft size doesn't really matter (within the normal range of shaft to body ratios). But assuming he's pretty knowledgeable - he probably meant something else.

I was surprised, too, which is why I doubled checked he was talking shaft/rod sizes and not shock dm.

Otherwise, the Radflo 2.5 with no resi are pretty well priced at under 700 for the pair. But I am a big fan of max match between parts. And so wary of mis-matches.

Even if the shaft is okay that still creates a mismatch between front (stronger spring, softer shock) and rear (softer spring, stronger shock).

Bilstein are correct at marketing the 6112 as an adventure, not a performance shock. That's what it is. It can do everything for a long time with no unnecessary maintenance. With 650lb springs, it can go as fast as I care to go. But despite the 2.65 body it is not a powerful shock by any means. I guess resilient would be a better way to describe it. Or a great value proposition at the right price which is how I got it.

Anyway, I will give the B12 Bilstein rear spring a try. The ride is fine under most conditions anyway.

It is just that I want to see if I can do a little better. That's the fun part, no?

 

[Jetboy]

I think the 6112 is a pretty good all around shock. My beef with Bilstein is WTF didn't they thread the body instead of the snap rings? That one change would have probably doubled the sales volume. It was the main reason I didn't buy them. Price is fair. Performance is pretty good. But the lack of adjustment was a deal breaker for me. And the cost would be almost nothing to do it. I don't understand Bilstein's logic.

I don't think the rear springs will make much difference. But it won't hurt to try it. They're primary task is to hold the weight up. The rest is done by the shocks. For off road performance you'll usually want the softest spring rate you can use and then dampen with shocks to maximize tire contact and body stability. Softer springs will provide more uniform weight distribution over uneven terrain and less body movement over obstacles at higher speeds, but end up with more body roll on off camber stuff in some situations. And of course softer springs don't work well for adding more weight or for highway use. It's all a bit of a balancing act unless you get super fancy with electronics that change behavior in different conditions.

 

[SpeedyKevin]

Good point. But he is the owner of Radflo, not a random guy who answers the phone. If he does not know, who would?

It is possible that what he thinks about is a narrow case of racing applications. That would be common for an expert in a given area.

He's literally just 2 minutes down the street from me (Glen). I'm eating lunch at the Panda express by Radflo lol

 

[LandCruiser]

Actually, he talked me out of buying them so the opposite would be true here.

I misunderstood what you were saying, sorry.

Regardless, I researched the hell out of my second lift and that never came up as a pro or a con with the discussions I had with suspension gurus.

 

[Jono.ful]

I was surprised, too, which is why I doubled checked he was talking shaft/rod sizes and not shock dm.

Otherwise, the Radflo 2.5 with no resi are pretty well priced at under 700 for the pair. But I am a big fan of max match between parts. And so wary of mis-matches.

Even if the shaft is okay that still creates a mismatch between front (stronger spring, softer shock) and rear (softer spring, stronger shock).

Bilstein are correct at marketing the 6112 as an adventure, not a performance shock. That's what it is. It can do everything for a long time with no unnecessary maintenance. With 650lb springs, it can go as fast as I care to go. But despite the 2.65 body it is not a powerful shock by any means. I guess resilient would be a better way to describe it. Or a great value proposition at the right price which is how I got it.

Anyway, I will give the B12 Bilstein rear spring a try. The ride is fine under most conditions anyway.

It is just that I want to see if I can do a little better. That's the fun part, no?

Who did you talk to at Radflo? Glenn, or the south African guy?

Dollars to doughnuts whoever it was intended to say piston rather than shaft. As others have said, the shaft has no impact on dampening, but the piston size absolutely does.

If you're that hard up for a set, I'm going to be pulling my Radflo ET 2.5" single tube coilovers and LT remote resi rears off in mid February. They'll have about 90k miles on them, but they just had new seals and fluid in July. Should be good more or less indefinitely provided you rebuild them every 30k or so.

Dm me if you're interested, we'll chat.

 

[MAST4R]

I don't think the rear springs will make much difference. But it won't hurt to try it. They're primary task is to hold the weight up. The rest is done by the shocks. For off road performance you'll usually want the softest spring rate you can use and then dampen with shocks to maximize tire contact and body stability. Softer springs will provide more uniform weight distribution over uneven terrain and less body movement over obstacles at higher speeds, but end up with more body roll on off camber stuff in some situations. And of course softer springs don't work well for adding more weight or for highway use. It's all a bit of a balancing act unless you get super fancy with electronics that change behavior in different conditions.

Thanks for those comments, valuable input. The springs are 186 vs 203-204 so it may not be worth the hassle.

He's literally just 2 minutes down the street from me (Glen). I'm eating lunch at the Panda express by Radflo lol

This is crazy, Glen, yes. Maybe you can ask him over some honey walnut shrimp!

Seriously, though, if you have a chance to ask, please do:guitar3:

Let's see if he tells you the same thing he told me

 

[SpeedyKevin]

Who did you talk to at Radflo? Glenn, or the south African guy?

Dollars to doughnuts whoever it was intended to say piston rather than shaft. As others have said, the shaft has no impact on dampening, but the piston size absolutely does.

If you're that hard up for a set, I'm going to be pulling my Radflo ET 2.5" single tube coilovers and LT remote resi rears off in mid February. They'll have about 90k miles on them, but they just had new seals and fluid in July. Should be good more or less indefinitely provided you rebuild them every 30k or so.

Dm me if you're interested, we'll chat.

What are you replacing it with??

 

[Jono.ful]

What are you replacing it with??

Custom length 2.5" remote resi Elkas front and rear. Eventually I plan to add a hydro bump stop to the rear as well.

 

[SpeedyKevin]

Custom length 2.5" remote resi Elkas front and rear. Eventually I plan to add a hydro bump stop to the rear as well.

Excellent choice! Can take it to the PMs but curious to what you're doing for the rears.

 

[Jono.ful]

Excellent choice! Can take it to the PMs but curious to what you're doing for the rears.

Same 2.5" remote Elkas with compression clickers, but they're doing a custom length for me to accommodate my LT springs (metaltech 104/300 lb/in) and adjustable 4 link setup.

 

[SpeedyKevin]

Same 2.5" remote Elkas with compression clickers, but they're doing a custom length for me to accommodate my LT springs (metaltech 104/300 lb/in) and adjustable 4 link setup.

Alright, last off topic post I promise. Planning out a rear LT eventually and curious to what everyone else is doing. You going with a 2 or 3 inch bump stop extension? One fella I was talking to spoke highly of the 2in (27.5 extended) versus the 3in as it would bottom out less frequently. Thoughts?