Terrain Tamer parabolics installed (4 Viewers)

[White Stripe]

Do the parabolic springs still use stock sized 40 series bushings?

 

[TemboTusk]

Jonathan, ( @Jonathan Hanson ) look forward to the full article about the parabolic springs in your Exploring Overland tech section!
As someone mentioned, we have been hearing about parabolic springs for 20 years, but getting a hold of them was near impossible.

 

[Jonathan Hanson]

Do the parabolic springs still use stock sized 40 series bushings?

I think so; they're 25mm.

 

[White Stripe]

I think so; they're 25mm.

That's too bad. Fj40 bushing stock size is too small. Some aftermarket springs come with larger eyes. Probably fine for light offroad though.

 

[jim land]

That's too bad. Fj40 bushing stock size is too small. Some aftermarket springs come with larger eyes. Probably fine for light offroad though.

Maybe they have 81-84 big bushing and early small model, just like OME

 

[duncanrm]

HJ47 Heavy Duty TT Parabolics out now.. the ride is superb!

Top (standard)
Bottom (HD)..

 

[Jonathan Hanson]

That's too bad. Fj40 bushing stock size is too small. Some aftermarket springs come with larger eyes. Probably fine for light offroad though.

Hmm . . . my stock-size bushings on the stock springs performed quite well for 80,000 miles before I swapped suspension. But maybe I was only doing "light" off road.

 

[Jonathan Hanson]

The entire Terrain Tamer review is here.

 

[cstav86]

The entire Terrain Tamer review is here.

Your writeups are first class, thank you for your knowledge and sharing it with the community!

 

[White Stripe]

Hmm . . . my stock-size bushings on the stock springs performed quite well for 80,000 miles before I swapped suspension. But maybe I was only doing "light" off road.

I've always gone through stock sized bushings pretty quickly. Springs with larger bushings seem to get longer bushing life for me.

 

[Jonathan Hanson]

Your writeups are first class, thank you for your knowledge and sharing it with the community!

Thanks very much for saying so.

 

[Jonathan Hanson]

I've always gone through stock sized bushings pretty quickly. Springs with larger bushings seem to get longer bushing life for me.

I've found the material makes more difference. Terrain Tamer is using a synthetic elastomer they claim dampens vibration like rubber but lasts like polyurethane. But even polyurethane isn't perfect.

 

[iliketrucks]

Jonathan, I appreciate the quality review you did on these! Do you have some more shots of your rig? I'd like to see the stance of it on level ground. The 235/85r16s with this lift sounds like a very good looking and functional all around combo, though I wish I could find some load range C tires in that size.

One thing I wonder is why OEMs aren't using parabolics? (to my knowledge). There must be some sort of drawback, hopefully only cost.

I also wonder how these do on the road. It's not uncommon for me to hit 65 mph with a fully loaded rig for hundreds of miles at a time. Stability is important!

 

[White Stripe]

I've found the material makes more difference. Terrain Tamer is using a synthetic elastomer they claim dampens vibration like rubber but lasts like polyurethane. But even polyurethane isn't perfect.
View attachment 3809702

I've found the material makes more difference. Terrain Tamer is using a synthetic elastomer they claim dampens vibration like rubber but lasts like polyurethane. But even polyurethane isn't perfect.
View attachment 3809702

I've used a couple different bushing materials. The fj40 and fj55 bushing od diameter is very small and the shoulder is very small in diameter too. The fj60 model and late fj40 models went to a larger bushing I suspect because it was an improvement.

 

[duncanrm]

I've found the material makes more difference. Terrain Tamer is using a synthetic elastomer

They are interesting bushings! I am very keen to see how mine fair in the coming year.. I noted the install instructions suggest they are greased at install and are good for their service life after that - I'm rather skeptical and plan to regrease regularly - choice of grease still not clear, any thoughts?

 

[Grayscale]

I'll entertain the possibility that the Terrain Tamer springs have some amount of twist. So, with the stock set of leafs, the bushings had to make up for any difference in angle between the axle and the shackle and rigid pins. But, it almost looks like Johnathan Hanson's 40 is actually twisting the leaf-packs themselves at full droop?

That is more flex / articulation than anything I've seen, aside from SOA rigs.

 

[Jonathan Hanson]

Jonathan, I appreciate the quality review you did on these! Do you have some more shots of your rig? I'd like to see the stance of it on level ground. The 235/85r16s with this lift sounds like a very good looking and functional all around combo, though I wish I could find some load range C tires in that size.

One thing I wonder is why OEMs aren't using parabolics? (to my knowledge). There must be some sort of drawback, hopefully only cost.

I also wonder how these do on the road. It's not uncommon for me to hit 65 mph with a fully loaded rig for hundreds of miles at a time. Stability is important!

Here is a quick driveway shot of it. I'm sure it's cost that prevents OEMs from installing parabolics. As far as stability, there's no doubt the parabolics roll more than standard leaf springs; it could hardly be otherwise! I think shock control will be the determining factor there. On mine I feel fine on the highway so far. I might experiment with the adjustments on the Konis, but they feel good where they are. I'll also install the TT shocks after a while, to see how they perform by comparison. Shocks for parabolic springs need to be valved a bit firmer to compensate for the lack of interleaf friction. PS I'm with you on wishing someone would make a 235/85x16 tire in load range C. E is a bit overkill on a 40.

 

[Augustiron]

I would crack the piggy bank for these in a 4"

 

[jayp2]

Last time I looked at the parabolics the cost was quite steep due to shipping

If the shipping wasnt exorbitant due to weight/dimensions and overseas shipping from AU it would be more attractive and affordable.

For the money you're well into custom Alcan spring packs based on actual weight of your rig front/rear etc with lift of your preference with or without orbit eye option

 

[Flatlanderfj40]

@orangefj45 just sent a kit to KS and @50peaks for Sunflower. Can follow his build and upcoming adventures Here