Pre-Runner Springs - lots of rear wheel travel

[piroman683]

Hey community, my name is Mike and I've been some what active here, mostly around suspension related topics. I've enjoyed jumping my truck since the day I got it and have been upgrading, testing, breaking, and upgrading again various components. With all the desert type riding I do with some occasional rocks I ended up going the route of having custom springs made. I have been testing and fine tuning things over the last 12 months (well 9 because I moved to Spain for 3).

Anyway, I am gearing up to launch a Kickstarter for these springs. I do not have final costs just yet, but a set of 4 will NOT exceed $750 including tax and shipping. I have a supplier lined up, I have jumped, crawled, whooped, and towed over 6k with these, so I've very close. I will include a ton of info on the kickstarter as to the design, methodology behind the design, target warranty, etc. The goal is to sell 50 pairs, stretch goal is 100 which allows for afull production run. Here are the current specs, but chould change by up to 1in and 10lbs.

Please note, the rears were a massive challenge. no current spring allows for more than about 13in of wheel travel. This is due to the multi-rate approach which limits compressability. Most lifts result in never using the last 2-3in of up travel on the shock which means you're missing out on wheel travel and flex!

Front: single rate at 160 lbs/in, free length 21 in, compressed 6.5, usable spring travel 14.5, estimated equavlent lift based on Rubicon is 2-3in, clears 37's no problem, and probably 39's with Nemisis fenders, tested with Fox 3.0's and 2.5 DSC (11.17in travel, have room for 12.17in travel)

Rear: (this was freaking a challenge) - single rate at 150 lbs/in, free length of 26in, compressed length just under 8in, total possible usable length is 18 inches, max I've been able to achieve with a lot of sway bar mods is 17.25 (rock jock standard JT kit limits you to 16in - no way around it). Tested with Fox 2.5 DSC's and Fox 3.0 External Bypass with resi coolers (actual kit is for raptor).

I have a short video of some small whoops at 65 with still more room to go faster:

There are other videos on my chanel of other tests. Also, here is the link to the 3.0 work I've been doing: https://www.jeepgladiatorforum.com/forum/threads/anyone-running-the-fox-3-0’s.41778/post-1188734

I leave for Sedona tomorrow for Christmas where I'll put all the details together, then the Salton Sea for more testing during New Years. Once the Kickstarter is ready I'll post it here.

Cheers,
Mike

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[JTDay]

Looking forward to more info. That's a massive amount of rear wheel travel.

 

[piroman683]

Looking forward to more info. That's a massive amount of rear wheel travel.

Oh man, trust me, I'm really excited for this!

 

[piroman683]

here is the link to my website that I am building. I'll be linking the kickstarter to this and capture all the testing I have done and have been doing. I'm getting excited for this!

https://fundamentalmotorsports.com/

 

[thekbad]

I’m in.

 

[Huhnowwhat]

Have you looked at ADS's website? They have JT-specific 3-tube external bypasses available. Thoughts?

 

[piroman683]

Have you looked at ADS's website? They have JT-specific 3-tube external bypasses available. Thoughts?

The shocks they make are only 2.5in diameter, I'm running 3.0 external bypasses on the rear right now. The rear ADS's have a compressed length of 18.37in and a stroke of just above 11in. The problem with that is no JT will ever tuck more than 18.8in of compressed shock length, so in this case you have un-used stroke. The 3.0's i'm running at this moment compress to 18.9in and it takes a big G-out to get those things compressed all the way. You also have to cut your exhause and replace the track bar in the rear with the Rock Krawler Pro-X upgrade, and cut out the stock bump stops and install the fox ones with them tucked up as high as possible. oh, and you DO NOT need to use bump stop pads on the rear axle either. BFG 37's have plenty of clearance at full bump with about 2.5in of space left.

The other issue with compressing even to 18.8in is that most springs will result in you only compressing to about 19.75-20.5 due to the spring coil height beacuse of the number of coil windings when making a multi-rate spring.

 

[piroman683]

Now this doesnt mean the ADS shocks are not worth purchasing, it depends on what your end goal is, how you drive your rig, and so on. I am happy to seem them and Bilstein making bypasses for the JT even if they are only 2.5in diameter shocks.

What is not clear to me for ADS is the shaft material, if the bodies are 4130, types of seals and wear bands used to make their shocks. The price is a little better than a Fox or King 2.5in bypass, but I've seen a lot of other shock manufacturers use lower grade steel for the shafts that result in plating issues in the long run. ADS does not specify a lot of the materials so it is hard to tell.

Additionally, Fox 2.5's are aluminum single piece bodies which reduces a lot of weight. Even Fox's internal bypass shocks weigh less than a comparable regulay bypass shock.

 

[Huhnowwhat]

The shocks they make are only 2.5in diameter, I'm running 3.0 external bypasses on the rear right now. The rear ADS's have a compressed length of 18.37in and a stroke of just above 11in. The problem with that is no JT will ever tuck more than 18.8in of compressed shock length, so in this case you have un-used stroke. The 3.0's i'm running at this moment compress to 18.9in and it takes a big G-out to get those things compressed all the way. You also have to cut your exhause and replace the track bar in the rear with the Rock Krawler Pro-X upgrade, and cut out the stock bump stops and install the fox ones with them tucked up as high as possible. oh, and you DO NOT need to use bump stop pads on the rear axle either. BFG 37's have plenty of clearance at full bump with about 2.5in of space left.

The other issue with compressing even to 18.8in is that most springs will result in you only compressing to about 19.75-20.5 due to the spring coil height beacuse of the number of coil windings when making a multi-rate spring.

Thanks for all that info. Your timing with the springs is uncanny, as we have a Mojave and use it primarily to go fast in the desert, with a little rock crawling sprinkled in.

We do go on long road/off-road trips but do not heavily load our rig, speed and handling are our primary concerns.

I've been toying with the idea of putting Fox 2.5's 4-tube bypasses on the front. I know there will be cutting and welding required but I can do all that. In your opinion, with your front springs, would a 12" travel Fox fit?

Lastly, what generation of Raptor shocks are you running in the rear?

 

[piroman683]

For the fronts I'd just stick with the Fox 2.5 DSC's, if you really want the bypass capability go with the3.0 internal bypass in the front. You already have bump stops up there and the 2.5 external bypass is more of a pain in the ass to fit vs. the 3.0 IBP's.

You also need to look at the ext. and collapsed length of those fox 2.5 external bypasses vs the 3.0IPB's. The 2.5 external have a thread on cap so that shifts all of your usable travel down more vs. the 3.0's. Also, I'm not using the supplied lower shock mounting hardware which you should be able to get away with, but always double cycle your suspension once installed.

Here's the rear shocks I'm using, you will need different spacers which you can by from Kartek:
https://www.ridefox.com/product.php...rd&model=F-150+Raptor&year=2017&position=Rear

I have a whole thread on the rears and their fitmet: https://www.jeepgladiatorforum.com/...nning-the-fox-3-0’s.41778/page-6#post-1188734

 

[Huhnowwhat]

For the fronts I'd just stick with the Fox 2.5 DSC's, if you really want the bypass capability go with the3.0 internal bypass in the front. You already have bump stops up there and the 2.5 external bypass is more of a pain in the ass to fit vs. the 3.0 IBP's.

You also need to look at the ext. and collapsed length of those fox 2.5 external bypasses vs the 3.0IPB's. The 2.5 external have a thread on cap so that shifts all of your usable travel down more vs. the 3.0's. Also, I'm not using the supplied lower shock mounting hardware which you should be able to get away with, but always double cycle your suspension once installed.

Here's the rear shocks I'm using, you will need different spacers which you can by from Kartek:
https://www.ridefox.com/product.php...rd&model=F-150+Raptor&year=2017&position=Rear

I have a whole thread on the rears and their fitmet: https://www.jeepgladiatorforum.com/forum/threads/anyone-running-the-fox-3-0’s.41778/page-6#post-1188734

Fantastic! Thanks for answering those questions. I'll be looking out for your springs to purchase.

 

[piroman683]

Fantastic! Thanks for answering those questions. I'll be looking out for your springs to purchase.

Np, the final phase of testing will happen at the and of April when I run my truck in the NORRA 1000 Mexican rally. It's a 6 day rally over 1200 miles off road. I'm limited to only 60 mph in the class I'm competing in because it doesn't require a roll cage.

 

[piroman683]

Quick update, I just finished towing a 5700 lbs trailer to the Salton Sea and back over New Years. The springs handled great, and I had no major issues. With a tongue weight of 570 lbs + 315 lbs of tools and gear in the bed the truck responded well on the highway.

I ran another 30 mile loop for high speed testing while out there nd had a mix of trails ranging from very rocky 30mph stuff to terrible wash board at 30 mph to rollers at 65mph, and some short small whoops at about 45mph.

I had hoped to finish getting the Kickstarter ready, but I needed some more documentation on a few things. I'm nearing the final stages and am expecting to launch it by January 8th.

I'll be doing some professional filming in Barstow the weekend of Jan 13th and 14th. I am not sure which day yet, but am hoping to do it on Saturday morning around Sunrise. The results of that will be shared here and the kickstarter updates.

Here's a few photos of the truck and trailer set up.

 

[Huhnowwhat]

Curious, what is your front up-travel, I'm assuming around 5"?

 

[piroman683]

Curious, what is your front up-travel, I'm assuming around 5"?

I didnt measure the uptravel in the front when I had the trailer attached, but I did just measure it now (empty, nothing in truck bed) and with the Fox 3.0's I have 6.5in of up travel (to the shocks bump pad, -082 part number).

I am not using the supplied shock extensions that come with the fox 3.0's. If I did I'd have only 4in of uptravel. I tested with the shock extensions and it rode like shit, so I pulled them off and have not had any issues with my configuration. The extensions push the lower end of the shock eyelet outboard by about 1/8th of an inch, and I am guessing that was to ensure no rub between the body and the frame during max flex.

When I was running the 2.5 DSC's in the front I had about 6in of uptravel. (-051 part number). If you run the -052 part number with these springs you will have closer to 5in of up travel, but 2 more inches of droop. The -052's are 1in longer in compressed length so it shifts your bump down by 1in, and assuming same ride height because you're only changing shocks you'd have about 5in of uptravel left, but you gain a lot of droop.

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