CRT.5 Big Bore Shocks done easy & cheap

[GO-RIDE.com]

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.


Back view of the mounting setup.


Full droop brings the shock to full length. You have to use internal shock spacers if you don't want full droop.


Even with 2.2 truck tires the wheels will come off the ground about 5mm with the front of the chassis on the ground.


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.

[Hickoryhead]

Slick setup!!! Nice Job.

[supralover72]

Really great idea dude. Will they fit in the rear on the tower or are they too short?

Thanks.

[GO-RIDE.com]

Originally Posted by Hickoryhead

Slick setup!!! Nice Job.

I can't believe no one else has done this. They fit perfectly on the front if you use the body mount holes.

[GO-RIDE.com]

Originally Posted by supralover72

Really great idea dude. Will they fit in the rear on the tower or are they too short?

Thanks.

I don't think they will have enough stroke for the rear of the car. The Revo's have about 22mm of shock stroke and the back crt.5 shocks have about 30mm. I still think the front CR/CRT shocks are the best for the back, but I haven't tried them yet. I didn't think they would be worth it without good front shocks.

[supralover72]

Ah thanks. I guess it's just best to stick with 1/8th scale front's for the rear then. Thanks.

[MetalMan]

Originally Posted by GO-RIDE.com

I can't believe no one else has done this. They fit perfectly on the front if you use the body mount holes.

I was getting there . Except I am starting out with Jato shocks filled with the Traxxas oil (~35wt), and have purchased several Jato spring sets so I can find the ideal spring for my CRT.5.

Jammin X1CR front shocks do fit pretty much perfectly on the rear of the .5. Mine are set up with a good oil, but the soft springs I have on them right now seem a bit stiff. Once I mount the Jato shocks like you did I can dial in the suspension.

Nice work!

[GO-RIDE.com]

I had a chance to run my crt.5 at the indoor track on Friday. It was awesome with the Revo front shocks. I even liked the stock rear shocks set up with the white springs. It handled just as good as the best setup with the stock shocks, accept now it skims across the whoops straight instead of kicking, and it lands the triple super smooth. It also seems to jump better and more consistently. There were a few times when I was the only car on the track and a number of guys were just watching it run. They were pretty impressed.

My next step is to get Big Bores for the rear so I can run lighter damping, but still have more control. I like the rear white springs, but I have them over damped so they can keep up with the big bore fronts on the big jump landings. With a little lighter damping I'd get more rear traction in the turns.

MetalMan, what rear springs have you tried? Are you able to get the right sag (bones level)?

[MetalMan]

I had a XTM front 1/8 spring set laying around, and used the blue set:
http://www.hobbypeople.net/gallery/149354.asp
Without any preload the rear sits higher than I would like. The springs might just need to be cut down, but I haven't gotten enough driving time in to determine whether or not they are too stiff.

[GO-RIDE.com]

If you are at zero preload and the bones are higher than level, I'd say those springs are just too stiff. Cuting them down will make them a bit softer from removing the looped end of the spring, but the rate of spring gets stiffer the less coils it has. I checked that link and it looks like those blue 58mm springs are the softest that XTM offers. I guess we'll have to find a different mfg.

[jnev]

I am about to finish building my CRT.5 and I haven't even drove it yet, but I have put 70weight oil in the front shocks, and it feels like they have 20 weight oil in them.

So I will definitely try this mod. Can you tell me for sure though whether the Revo shocks will fit the back as well or could be made to fit? I know you said it may not have enough stroke, but could you do me a huge favor and check to see if it can fit for sure.

If you can do this, I'd really appreciate it.

Originally Posted by jnev

I am about to finish building my CRT.5 and I haven't even drove it yet, but I have put 70weight oil in the front shocks, and it feels like they have 20 weight oil in them.

So I will definitely try this mod. Can you tell me for sure though whether the Revo shocks will fit the back as well or could be made to fit? I know you said it may not have enough stroke, but could you do me a huge favor and check to see if it can fit for sure.

If you can do this, I'd really appreciate it.

I just did this mod to my crt.5ext.( I am running 30wt oil and the green springs with #13 pistons, I feel like it could have used the #14 pistons though for a little bit faster movement) It works really well from just bashing it so far(lots of jumping on grass). I have not had a chance to get to the track yet though. I am running ofna buggy front shocks on the rear of my crt.5 too. The revo shocks are too short for the rear though, not enough stroke.

I really need to get pics of my crt.5 up here! For the last couple of months I've been swamped with homework and band practice though.

Bye

[GO-RIDE.com]

Cemetary Gates,

What springs are you running on the ofna front buggy shocks?

On the front with the Jato pink 1.4 springs I'm pretty much have max preload, which really isn't much because the Revo shocks are not threaded very far. I was thinking of going up to the 1.6 springs. How are the green 1.1 springs setting up?

One other thing I noticed is that if you tighten the bottom cap tight on the revo shocks it creates a lot of drag btwn the shock shaft and seal. I'm thinking of puting a small oring or thin nylon washer btwn the cap and shock body so the cap stays tight but doesn't over preload the seal.

[miniGranis]

This is probably a "I should have guessed" kind of question, and I have tried to google it but I havent found anything usefull.
Here we go: When you guys refer to piston #13 or #14 where do I find the pistons ?
How many different ones are there, I have only found references to #1-3 at buytraxxas.com

[GO-RIDE.com]

Originally Posted by miniGranis

This is probably a "I should have guessed" kind of question, and I have tried to google it but I havent found anything usefull.
Here we go: When you guys refer to piston #13 or #14 where do I find the pistons ?
How many different ones are there, I have only found references to #1-3 at buytraxxas.com

5 sets of pistons came with my Revo shock kit. There were 3 for the Revo (black) labeled 1, 2, 3. There were 2 for the Jato (grey) labeled 1.3, 1.4, and refer to the size of the holes in mm. I started with the 1.3mm holes and they felt over damped. I'm now using the 1.4mm holes with 30wt and they are pretty good.