losi999

My Hyper 7 PBS is bottoming out on some of the larger jumps at the track. Should I just change the springs, I have heard a couple people say that the blue Kyosho springs work well. I guess I could also change the shock oil. Any advice? Which should I do first and what weight oil should I use if it's changed?

thanks

dagass

If you're bottoming out, you'll want to change the oil before you make any other changes. Oil controls compression and the springs control the rebound. One thing to consider is that on the bigger jumps, buggies are going to bottom out no mater what you do. Thats just the nature of the beast. That being said, a good neutral setup on the PBS is Kyosho blue springs with 35wt in the front and 30wt in the back. Shock mounting positions are per the manual.

Also, look at what the other guys at the track are running. Are they bottoming out too? If not, don't be afraid to ask them what wt oil they are using and what springs they have. More often than not, the guys at the track will be happy to point you in the right direction.

scale only 4 me

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Dagass
Dittos

studysession

Get some pics / vids of those jumps - Not today but this weekend I am posting pics of Dagass's Hyper 7 doing some jumps on my website. Lynx the great is also sending me some videos to post online as well.

nitroman88

My Feedback: (5)

unless it slamming down really hard i wouldnt worry about it. but if your really concerned abotu it just put some heavier wieght oil in the shocks.

losi999

do you guys know what weight oil is included in the Hyper 7 from the factory?

dagass

The stock oil is pretty light. I seem to recall reading somewhere that it is in the neighborhood of 25wt.

studysession

Dagass - what shock oil and diff grease weights do you run?

dagass

Study,

I'm running Associated 35wt up front with 30wt in the rear and 5mm spacers all the way around. My diffs are filled with Ofna Silicone and they are 3K, 3K, 1K going front to back. Originally, I was setup with 5K, 7K, 1K per the Ofna manual but found that combination to be less than perfect on a tight, technical track. My low speed steering was not the best and I would push really hard coming out of the turns.

I actually learned a pretty important lesson during this last diff teardown. If you plan to fill your diffs with silicone fluid, be sure to tear apart the diffs first and clean our ALL the grease that was put in there by Ofna. I made the mistake of not doing that and over time, my diff fluid mixed with the grease and I ended up with "silly putty" in my diffs (see pic below). I tested my freshly rebuilt front diff (filled with 3K) against my rear diff (which had 1K and the factory grease) and found that the rear felt like it had 5K in it. The picture shows my front after it was cleaned and refilled with 3K silicone and my rear which had yet to be cleaned. The difference is plain to see. One looks like it is filled with water while the other looks like it's filled with mud.

studysession

The thicker the diff grease can give like a locked diff effect in away.

That looks like it gelled up or something in those pics.

Jitters

My Feedback: (28)

dagass, thanks for the info too!! I love it when you get the straight stuff and not speculation. My PBS had the same problem and I totally forgot about changing shock oil. Like not seeing the forest for the trees... or something like that. I tend to make things more complex than they are.

crazzyguydj

my buggy never bottoms out. i have a hyper 7 pro with an os .21 VZ B and i run tamiya 700 silicone damper oil in back and 600 in front. not sure what those weights are though. also i have the pulrple shocks in there which makes them even harder.