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-   -   CRT.5 Big Bore Shocks done easy & cheap (https://www.rc-monster.com/forum/showthread.php?t=11153)

entjoles 05.22.2008 08:01 PM
now i will have to do this.........


really looks great :yes:

lincpimp 05.22.2008 08:28 PM
I have all the parts to do this, and will have to give it a try!

Finnster 05.29.2008 11:07 AM
I like how this mod turned out. I was a bit skeptical at first, but seems like it fits really well.

I wonder if there is a business opportunity for Mike to make a new F shock tower to accomodate the GTR shocks, and provide a few mounting holes for adjustability. Perhaps a bit of work on the body mount as well. Considering its just a flat plate, it should be a piece of cake for him, and there are tons of .5 drivers that would go for the mod vs the very expensive DM-1 shocks.

GO-RIDE.com 05.29.2008 12:59 PM
Skeptical, how dare you sir. :mdr: I originally made a front shock tower that had mounting holes about 12mm above the original ones, but I did not like the way the body was lifted up. However, it would be nice to have a tower that had two or three holes inboard near the body post holes we are using for mounting the GTR shocks. I'd like to be able to get more up travel and reduce the amount of droop.

Finnster 06.03.2008 05:43 PM
I have the rear LXOne shocks installed in the back, but have not cut any coils. 30wt oil. Still waiting for the F springs to come in to finish it.

Ran it a bit in some rough sandy areas, and the back seems pretty good so far. It does sit a bit high, and I noticed it tended to roll on asphalt were it would hold or slide before. Its def got to come down a bit.

Otherwise I was looking at getting some lighter springs as well. My .5 has the OFNA Ex chassis and small 3S 2500 batts, and @ ~2000g+, may be lighter than some RCM ext chassis conv. Anyway...

I couldn't find a rate for the std yellow LX1 springs. So I tested it and came up with a value of 76 gF/mm (or 4.26lb/in, 0.75 N/mm (trx style).)


Spring rate converter FTW

I also found an HPI Spring that fits well. Now the package rates that as 71 gF/mm (3.96lb/in, 0.70N/mm) but I tested that as well and came up with 59 gF/mm (3.3lb/in, 0.58 N/mm.) IDK why I came up with such lower values than HPI did. My method was slightly crude, but was very reproducible.

Shouldn't matter too much, as I just wanted to get a relative rating to the other springs in that series for the Hellfire. The blue spring I used was softest, while the OFNA yellow spring seems closest to the HPI silver (soft) spring FWIW. The springs are long @ 80mm vs ~72mm for the OFNA's, but both need to be cut down anyway.

GO-Ride: How do you determine what length to cut the springs too? Why wouldn't you cut them short enough to use the stock shock mounting holes? LMK, as I don't want to trim any springs until I am sure on what I am doing. Thanks

Finnster 06.04.2008 11:21 AM
So I tested the CRT.5 springs using the same method as above. I used the rear grey springs as well as the blues.

Grey: 59 gF/mm
Blue: 63 gF/mm

The blue HPI hellfire springs are almost the same rate as the stock grey springs on the CRT.5. The yellow OFNA 1/8th springs are quite a bit tighter, and the blue crt.5s are in the middle.

I would guess the silver HPI hellfire springs are ~74gF/mm by my method, heaiver than the .5 blues, but still less than the yellow LX1 springs.

GO-RIDE.com 06.04.2008 01:00 PM
Quote:
Originally Posted by Finnster (Post 178988)
GO-Ride: How do you determine what length to cut the springs too? Why wouldn't you cut them short enough to use the stock shock mounting holes? LMK, as I don't want to trim any springs until I am sure on what I am doing. Thanks
Just from watching the car on the track it seemed that the yellows were pretty close in rate to what I wanted, but they were so long that I could not get the right ride height (bones level w/ 2.2 truck tires). So, I cut 1 coil off and tested them, the car still sat too high. I cut a second coil off and now the car needed a bit of preload to get bones level.

I don't have the crt.5 here with me, but if I remember right with the shocks mounted in the standard shock tower holes it was going to be very difficult to get the right ride height and the wheels would be very limited on up travel. From my experience with the car on the track mounting both the front and rear upper shock mounts inward gives the car good handling in the corners, lots of up travel for rough sections, and enough droop for big jumps.

Shark413 06.09.2008 03:05 AM
This thread is fantastic. I love my brushless CRT.5 but the extra weight of the battery was really overworking the stock shocks and even with the heavy springs I was getting too much chassis slap. After seeing this thread I added Revo shocks in the front and Kyosho 1/8 front buggy shocks in the rear. The only difference was that I moved the body mounts to the outside shock mount holes. GO-RIDE.com, great idea.


http://i142.photobucket.com/albums/r...13/front-3.jpg
Revo shocks, Jato 1.6 springs 40wt oil

http://i142.photobucket.com/albums/r...3/03080003.jpg

http://i142.photobucket.com/albums/r...413/rear-1.jpg
Kyosho 1/8 scale buggy shocks, medium spring, 35wt oil

Finnster 06.09.2008 06:00 PM
I took the .5 to the track and was happy with the mods. I used pink jato springs in front, and cut down blue HPI springs listed above. 30wt oil all around.

RCM Mike also took a look at the mod and was impressed by it. Good job on the thumbs up from RCM! :great:

After some discussions w/ Mike, it was decided the oil could go down slightly in the F and up in the rear. I'm going to go for 27.5wt in F, and 35 in the R and go from there. I'll have to take a 2nd look at the yellow springs as well. Race weight is 1950g for my .5.

We had it to compare to a non modded .5 and the benefit of the mod was obvious. All in all I think I spent ~$35. Really I just bought the shocks and springs. I popped out the ball stud from the ofna stockers and popped it in the GTR ball end so it fit in the crt arm properly.

Arct1k 06.09.2008 06:14 PM
Yeah it worked pretty good! Humbug!

PS only because Ryan trashed me at the track... my setup was way off though - when I breaked I forward flipped which Mike helped fix... and then in the final I dropped to 2s and it wasn't enough...

3s was fun on the tripple though - Further / higher than the 1/8... Landing another issue...

PPS bought some revo shocks last night to try this mod...

Finnster 06.09.2008 10:35 PM
Quote:
Originally Posted by Arct1k (Post 180749)
Yeah it worked pretty good! Humbug!

PS only because Ryan trashed me at the track... my setup was way off though - when I breaked I forward flipped which Mike helped fix... and then in the final I dropped to 2s and it wasn't enough...

3s was fun on the tripple though - Further / higher than the 1/8... Landing another issue...

PPS bought some revo shocks last night to try this mod...
That's not what I meant you silly man. I just meant when we were dropping the trucks and bouncing the suspensions side by side. As far as the racing goes.. IDK. Mike's desc was pretty good: :wink:

Quote:
Ryan played it safe and cool on the track, while Arct1k/Chris was a bit wild early on, but settled down later in the day
You'd catch up then fly off that triple...lol...I thought you were trying to lawn dart the moon. I just tried to stay slow and steady and not wreck, esp as our class always had lazy marshals. I'm not practiced enough to go balls out around, and every time I started pushing too fast for my skill I'd wreck it and lose lots of time. I was happy to see how durable the trucks were. Other than that servo saver, I was surprised nothing broke on the little things. I'm always nervous about breaking stuff. (my old Emaxx reflexes I guess.) I did push and land the double perfectly at the end and was stoked. Mostly I wimped out and did singles. If I could get that down, and doubling the whoops, I'd be pretty happy. It was fairly easy on the Revo (when it was working) but I couldn't get the timing quite right on the .5.

Anyway... the shocks did seem to me much better than I had before. Much plusher and more confident w/o so much slapping. It was a pretty rough track and well worn by the 1/8th scalers, but the little truck just rolled over it.

lucias 07.16.2008 12:40 PM
has anyone tried the GTr shocks on the rear as well? or are they to short? I was about to roder mine and thought about rodering 4 to see if they would fit but I figured I would ask since you guys would already know...

Arct1k 07.16.2008 12:44 PM
I believe too short and not enough travel...

GO-RIDE.com 07.16.2008 01:26 PM
Yep, too short and not enough travel. I'm using Ofna LX One front shocks I bought on ebay for less than $20. They are the same parts as the 13mm shocks off the earlier Jammin CR/CRT. Very nice shocks.

Finnster 07.16.2008 04:52 PM
There should be tons of F buggy shocks you can find to work. The LX1s are nice as they are alu caps and fully threaded. I wouldn't really mess w/ anything else unless you found something that would fit even better.

The setup really is nice. I hadn't driven the .5 in a few weeks as I have the MM now in my Hyper ST. Working on it again last night and you could drop it from quite a hieght w/o bottoming out. Very plush too tho.

lincpimp 08.03.2008 12:06 AM
Did this mod today, and realy like it. I used the plastic jato shocks on the front and the lx shocks with the yellow springs on the back. Question is, is there any reason not to cut the rear springs? It does sit a bit too high, and the shocks are too stiff. I do need to go with lighter oil, that is for sure. I will try removing 2 coils and see what that does.

What is the general preference for jato front springs? I have silver IIRC, and seem a bit soft. And what weight oil do the jato preassembled shocks come with? Traxxas just calls it silicone oil. Any guesses?

GO-RIDE, any chance of a pic of your rear shocks installed?

MetalMan 08.03.2008 12:28 AM
A bunch of us are using the pink Jato springs, and I think I have 40wt. oil in mine. Traxxas oil is about 35-40wt.

lincpimp 08.03.2008 01:48 AM
Quote:
Originally Posted by MetalMan (Post 197552)
A bunch of us are using the pink Jato springs, and I think I have 40wt. oil in mine. Traxxas oil is about 35-40wt.
I will give the pinks a try. The stock oil seems fine to me, but I am not the miost experienced in setting up suspension and shocks. I do not race so stock settings usually do fine for bashing...

GO-RIDE.com 08.04.2008 01:25 PM
Quote:
Originally Posted by lincpimp (Post 197543)
Did this mod today, and realy like it. I used the plastic jato shocks on the front and the lx shocks with the yellow springs on the back. Question is, is there any reason not to cut the rear springs? It does sit a bit too high, and the shocks are too stiff. I do need to go with lighter oil, that is for sure. I will try removing 2 coils and see what that does.

What is the general preference for jato front springs? I have silver IIRC, and seem a bit soft. And what weight oil do the jato preassembled shocks come with? Traxxas just calls it silicone oil. Any guesses?

GO-RIDE, any chance of a pic of your rear shocks installed?
I don't think I ever posted a pic of the rear shocks on mine, but remember someone else posting a pic that had them mounted the same way I did. I don't have my crt.5 handy, but I think I remember how I mounted them.

I believe I just used the stock crt.5 mounting hardware, but I put the upper mounts in the oval slots, on the shock tower, for running 2 body mounts. I only run 1 rear body mount so I had both of those slots open. This leans the shocks in quite a bit so you can still get the rear dogbones level for proper handling. I then mounted the shocks to the outer hole on the arms.

I've seen others mount them in the stock shock tower holes, but you end up with too high of ride height for racing. For bashing it's probably fine.

bustitup 11.14.2008 06:00 PM
would these work in the front?

http://cgi.ebay.com/ws/eBayISAPI.dll...m=110311279634

GO-RIDE.com 11.14.2008 06:30 PM
Those are the right shock bodies, but the springs and pistons will be too stiff for a crt.5. You need the Jato (1.4mm hole) pistons and Jato (pink 1.4) springs to work with the CRT.5.

bustitup 11.14.2008 08:15 PM
Quote:
Originally Posted by GO-RIDE.com (Post 232752)
Those are the right shock bodies, but the springs and pistons will be too stiff for a crt.5. You need the Jato (1.4mm hole) pistons and Jato (pink 1.4) springs to work with the CRT.5.
if I get the jato plastic ones at tower i wont need the 1.4 jatp pistions?...just the 1.4 pink springs

GO-RIDE.com 11.14.2008 09:16 PM
Quote:
Originally Posted by bustitup (Post 232777)
if I get the jato plastic ones at tower i wont need the 1.4 jatp pistions?...just the 1.4 pink springs
That is correct, but pistons are super cheap. Amain has a 6 pack of pistons (1.3, 1.4, 1.5) for $3, or you can drill out the Slayer/Revo pistons that come with the shocks.

magman 11.14.2008 09:35 PM
I did the mod to my crt.5....http://i271.photobucket.com/albums/j...jalbee/267.jpg

Thanks for the tip. The front suspension is perfect. I am still working on the rear to get it to my liking

GO-RIDE.com 11.14.2008 09:54 PM
Quote:
Originally Posted by magman (Post 232791)
I did the mod to my crt.5....http://i271.photobucket.com/albums/j...jalbee/267.jpg

Thanks for the tip. The front suspension is perfect. I am still working on the rear to get it to my liking
The new chassis looks awesome. I'll be getting one down the road to replace my original RCM .5 chassis.

For rear shocks I've found that 1.5 pistons are key for good handling the bumps. I use 30 or 35 wt Losi oil with them.

bustitup 11.14.2008 10:00 PM
well in that case I will get the revo/slayer shocks ...i kind of like the aluminum bodies..... thaks man very helpfull

magman 11.14.2008 10:30 PM
I believe that my springs are too stiff..I tried oils from 20 to 50w with out desired results. I was thinking of drilling out the holes in the pistons a little bigger to allow more oil to flow better.

bustitup 11.14.2008 10:57 PM
what tires and wheels are those?
Quote:
Originally Posted by GO-RIDE.com (Post 160041)
http://www.go-ride.com/72.3.195.221/...m/DSCN5203.jpg

If you've spent any time driving the crt.5 hard you know the front shocks are way over leveraged and even with thick oil and single hole pistons they bottom out much too easy. I've seen a number of guys who have gone to the Ofna DM1 front shocks, but they have some draw backs too. 1. They are expensive $100+ if you have to piece them together. 2. They don't have as much stroke as the stock shocks, so you lose some travel.

So, after taking some careful measurements and doing a bit of research I found the Revo/Jato shocks fit the front of the crt.5 very well if you mount them in the body mount holes. This gives them a very RC8 look. I've only had a chance to test drive them a few minutes, but so far they are very good. With the old shocks when I dropped my car from 6 - 8" the chassis would slap firmly. With the new shocks I can drop it from 15+" and only the back will slap. Yet, I still get perfect sag/ride height.

Here's what I used:
1. $27 - Pair of revo/jato shocks (includes pistons & oil)
2. $5 - Ofna shock stand offs (ofna 36610) (4pc, only need 2)
3. $5 - Jato 1.4 shock springs
4. $2 - (2) 3mm x 35mm button head srews
5. $2 - (2) ofna 6mm ball (ofna 30403) (comes in a pack of 6 for $5)
Misc: a few random washers, (2) 3mm locknuts

Here’s what I did:
The shocks come pre-built, but not filled with oil.
1. Disassemble the shock per included instructions to remove both the installed piston (revo) and the blue bottom out bumper. The installed piston is for the heavy revo and the bottom out bumper is way to stiff to compress with a crt.5. If you don't want to disassemble you can easily cut the blue bumper off and the piston is replaceable through the top of the shock.
2. Reassemble the shocks with the Jato (grey) #14 piston, 30 wt oil, and Jato 1.4 spring. The 30 wt oil seems great for bashing, but I might try 25 wt for a slippery track. If you are running a heavy battery you may want the 1.6 spring.
3. Removed the flanged ball from the lower shock eyelet. Replace it with the ofna 6mm non-flanged ball (or similar item).
4. Drill a hole all the way through each of the plastic front body mounts. I used a drill bit a little smaller than the existing hole and drilled that hole all the way though the plastic.
5. Assemble the upper shock mount as follows: (35mm screw, washer, shock, washer, ofna stand off).
6. Thread the screw all the way through body mount and add a washer and lock nut to the back. After first testing this I added a 2mm shock spacer between the washer and stand off to further get the shock away from the shock tower so the preload adjuster will freely spin.
7. Mount the lower shock eyelet in the outside hole.
8. Set your ride height
9. Admire your work with a cold beverage
10. Get your bash-on

Top view of the mounting setup.
http://www.go-ride.com/72.3.195.221/...m/DSCN5204.jpg

Back view of the mounting setup.
http://www.go-ride.com/72.3.195.221/...m/DSCN5205.jpg

Full droop brings the shock to full length. You have to use internal shock spacers if you don't want full droop.
http://www.go-ride.com/72.3.195.221/...m/DSCN5206.jpg

Even with 2.2 truck tires the wheels will come off the ground about 5mm with the front of the chassis on the ground.
http://www.go-ride.com/72.3.195.221/...m/DSCN5207.jpg

Let me know what you think.

I do plan on getting the Jammin X1 CR front shocks for the back of the CRT.5, but the front shocks are the ones that need the help the most. After dialing in the front Revo shocks I rebuilt my stock rear shocks with white springs, single hole pistons, and 40 wt. oil. They can just about handle as much compression load as the big bore fronts, but they rebound a bit slow for ultimate handling. A set of 13mm rears would be great if I can find a set of long springs that are soft enough for the light crt.5.

bustitup 11.23.2008 04:10 PM
wow...finished the front shock mod with the aluminum revo/slayer shocks for 14 bucks....drilled out the pistons with 1.5 and the truck lands so much better its amazing

what should I do to the rear now ?...keep my stock rear and change springs to what?

rschoi_75 11.23.2008 07:33 PM
Yeah, this mod is well worth the time and effort. For the rear you should hook up some 1/8 buggy front shocks. Pretty much any will work. Just swoop in on a cheap auction on ebay and get the corresponding mounts for them. I'm using some ofna ultra lx front shocks that I got for $8 + shipping.

GO-RIDE.com 11.23.2008 10:51 PM
Quote:
Originally Posted by bustitup (Post 232829)
what tires and wheels are those?
Those were some cheap pre-mounted GRP tires and wheels from towerhobbies. The knobs started peeling off pretty quick and the molded foams are too stiff even for the heavy crt.5 I would only recommend them for bashing, but the road tire version are good for parking lot fun.

jnev 11.24.2008 12:10 AM
bustitup - I am using the same shocks as rschoi is...
http://cgi.ebay.com/NEW-OFNA-Front-S...QQcmdZViewItem
Three minutes left in the auction. There are many similar shocks on ebay though that would work just as good.

bustitup 12.01.2008 02:24 PM
Quote:
Originally Posted by jnev (Post 235487)
bustitup - I am using the same shocks as rschoi is...
http://cgi.ebay.com/NEW-OFNA-Front-S...QQcmdZViewItem
Three minutes left in the auction. There are many similar shocks on ebay though that would work just as good.

I ended up getting these for about $18 shipped....springs should be ok?

http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA:IT&ih=001

GO-RIDE.com 12.01.2008 05:48 PM
Quote:
Originally Posted by bustitup (Post 237813)
I ended up getting these for about $18 shipped....springs should be ok?

http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA:IT&ih=001
Those are the same ones I use on my "Monstered" e-crt.5. The yellow springs work great. I cut 2 coils off of each spring so I could get the ride height I wanted, but the overall spring rate is very good.

The stock pistons are 1.4mm holes, but I like 1.5mm hole pistons with 35 - 40wt oil if you drive at a track. If you are just bashing then the 1.4mm pistons with 20 - 25 wt oil.

rat 12.11.2008 09:04 AM
guys..what an awsum thred good work..

bustitup 01.14.2009 03:58 PM
I have a complete set of brand new shocks front and rear to do this mod that have allready been modded
pm me for details and price

http://www.rgcbuilders.net/springs.jpg

Jason 06.26.2009 11:56 PM
here my shock setup it wont work better then the stock shock for me .. when I run over bump the rear end goes up in the air and sometime flip and it REALLY dont do jump fine...

front shock is electric revo aluminium body and titanium shaft white soft spring with piston black 2 holes and AE 35WTS SHOCK OIL.

rear shock is front jammin X1-CRT shocks with white soft spring + white 2 holes piston and AE 50WT SHOCK OIL.


http://img146.imageshack.us/img146/4706/photo001svk.jpg

http://img146.imageshack.us/img146/4239/photo002a.jpg

http://img35.imageshack.us/img35/7760/photo004xla.jpg

Jason 06.28.2009 09:21 PM
:neutral:

rhinopole 10.15.2009 05:45 PM
Does anyone know if these will fit?

http://cgi.ebay.com/NEW-2-4GHZ-REVO-...item1c0ca515d6

Thanks.

magman 10.15.2009 06:07 PM
yes they will


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