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Old 12-30-2011, 04:26 PM   #1
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Default Some suspension advice

Hi guys, I am having a little trouble getting the suspension in my Losi 810 buggy set just right and would like your opinions.

Here's the prob: During the summer, I noticed that handling was good, however on the big jumps, the chassis would sometimes bottom out when landing flat on the track. Stock setup for the 810 is 30 wt oil, 4-hole pistons with 1mm holes, medium springs (the only springs available for the 810 are soft, medium and hard) and no rebound. They are 12mm shock bodies. One other thing to point out, I did notice that the buggy did bounce around a bit on a stretch of small bumps (kind of like a washboard section though not quite that aggressively bumpy). To keep the buggy from bottoming out, I decided to change the oil to 35 wt, still keeping 0 rebound. However, the pack seems almost too hard. There is virtually no give when I drop the buggy to the ground. And what concerns me even more is, when I fully extend the shocks and then lay the buggy back down on the ground gently, it doesn't settle down to proper ride height. The shocks stay extended. It seems like the 35 wt oil is just too thick to properly pass through the 1mm piston holes. The shocks will move down if I push them with my fingers though, or push down on the buggy with my hands.

I am torn between two options:
1. Drill the piston holes wider, maybe 1.2 or 1.3mm

2. Go back to 30 wt oil and use the hard springs

I am actually leaning more towards option 2, since the buggy already was a little too bouncy on the small bumps. Thoughts?
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Old 12-30-2011, 04:56 PM   #2
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Originally Posted by Zao18 View Post
Hi guys, I am having a little trouble getting the suspension in my Losi 810 buggy set just right and would like your opinions.

Here's the prob: During the summer, I noticed that handling was good, however on the big jumps, the chassis would sometimes bottom out when landing flat on the track. Stock setup for the 810 is 30 wt oil, 4-hole pistons with 1mm holes, medium springs (the only springs available for the 810 are soft, medium and hard) and no rebound. They are 12mm shock bodies. One other thing to point out, I did notice that the buggy did bounce around a bit on a stretch of small bumps (kind of like a washboard section though not quite that aggressively bumpy). To keep the buggy from bottoming out, I decided to change the oil to 35 wt, still keeping 0 rebound. However, the pack seems almost too hard. There is virtually no give when I drop the buggy to the ground. And what concerns me even more is, when I fully extend the shocks and then lay the buggy back down on the ground gently, it doesn't settle down to proper ride height. The shocks stay extended. It seems like the 35 wt oil is just too thick to properly pass through the 1mm piston holes. The shocks will move down if I push them with my fingers though, or push down on the buggy with my hands.

I am torn between two options:
1. Drill the piston holes wider, maybe 1.2 or 1.3mm

2. Go back to 30 wt oil and use the hard springs

I am actually leaning more towards option 2, since the buggy already was a little too bouncy on the small bumps. Thoughts?
light oil and heavy (stiff springs) will make it really hard to handle (atleast for me it does) it will bounce all over the place on a rough or hard track surface, better off would be stick with 35 and go to a softer spring with 50% rebound. this is just my opinion and what i would do.
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Old 12-30-2011, 05:11 PM   #3
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From what I have read about suspension setup, the heavier oil will make it even bouncier on the small bumps. To me, it also seems counterproductive to use a heavier oil and a lighter spring, since the lighter springs will not let the shock rebound back to ride height as well as the medium springs. And as for setting 50% rebound, I already have an issue with too much pack, so the rebound will make that worse. Just an FYI, I am not dismissing your advice, I am just talking it out. I need to discuss this with more of you guys if I am ever going to learn .

As of right now, this is how suspension setup works in my head....
1. Oil weight determines how the car handles in the small bumps.
2. Piston size determines pack and how well it soaks up big jumps.
3. Match springs to your oil weight so that you get a brisk rebound, without making it too rigid. I have read that you don't use a heavy spring with a light oil, or a light spring with a heavy oil....that you should match your spring to have a similar dampening to your oil.
4. Rebound can be used to add more pack to your shock setup without having to increase oil weight or change spring tension.

Hmmmm, you know what.....using my thoughts in #4, I could always go back to trying the 30 wt oil, and build the shocks with 50% rebound.

Once again, I definitely welcome more discussion, and please correct my theories if I am way off. I am trying really hard to read up more on suspension setup lately, and it's sometimes hard to work it in my head.
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Old 12-30-2011, 05:15 PM   #4
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Originally Posted by Zao18 View Post
From what I have read about suspension setup, the heavier oil will make it even bouncier on the small bumps. To me, it also seems counterproductive to use a heavier oil and a lighter spring, since the lighter springs will not let the shock rebound back to ride height as well as the medium springs. And as for setting 50% rebound, I already have an issue with too much pack, so the rebound will make that worse. Just an FYI, I am not dismissing your advice, I am just talking it out. I need to discuss this with more of you guys if I am ever going to learn .

As of right now, this is how suspension setup works in my head....
1. Oil weight determines how the car handles in the small bumps.
2. Piston size determines pack and how well it soaks up big jumps.
3. Match springs to your oil weight so that you get a brisk rebound, without making it too rigid. I have read that you don't use a heavy spring with a light oil, or a light spring with a heavy oil....that you should match your spring to have a similar dampening to your oil.
4. Rebound can be used to add more pack to your shock setup without having to increase oil weight or change spring tension.

Hmmmm, you know what.....using my thoughts in #4, I could always go back to trying the 30 wt oil, and build the shocks with 50% rebound.

Once again, I definitely welcome more discussion, and please correct my theories if I am way off. I am trying really hard to read up more on suspension setup lately, and it's sometimes hard to work it in my head.
i will be watching also, have been racing for 5 years and learn something new every day! that was just what i would do so maybe might learn somthing myself here! good question and hope the good guys post up...lol
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Old 12-30-2011, 07:31 PM   #5
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http://jq-products.com/the-news/43-t.../160-the-guide

Read the section on shock setup, there is some really great advice in there.
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Old 12-30-2011, 08:14 PM   #6
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Ah thanks Slider30250. I have read that guide before, but you posting it made me read over the shock section again. The piston section was particularly enlightening. Turns out that piston hole size can have a big affect on handling in the small bumps, not just on pack during the landing on big jumps. And that definitely makes sense, looking back at how my suspension won't settle down at all when I just gently lay the buggy on the ground. The piston holes are too small to let the oil easily pass through the holes. Right now, I am seriously thinking that I will try the 35 wt oil and drill my piston holes larger.
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Old 12-31-2011, 07:48 AM   #7
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Quote:
Originally Posted by Zao18 View Post
Ah thanks Slider30250. I have read that guide before, but you posting it made me read over the shock section again. The piston section was particularly enlightening. Turns out that piston hole size can have a big affect on handling in the small bumps, not just on pack during the landing on big jumps. And that definitely makes sense, looking back at how my suspension won't settle down at all when I just gently lay the buggy on the ground. The piston holes are too small to let the oil easily pass through the holes. Right now, I am seriously thinking that I will try the 35 wt oil and drill my piston holes larger.
Your welcome, one thing to point out, your suspension not settling to ride height is normal when you just gently set the buggy down. Drop your buggy from about 12 in high onto your setup table to get the suspension to settle properly.
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Old 12-31-2011, 08:35 AM   #8
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No, I mean it doesn't move AT ALL. The shocks stay fully extended if I just gently lay down the car. And if I drop the car from 12 inches off the ground, the suspension still barely moves. The pack is definitely far too hard. I don't think 4 holes @ 1mm is cutting it. There is no give in the suspension.

Compare this to my D8T kit I just recently built. I have 40 wt oil with 6-hole 1.2mm pistons. Even if I just gently lay down the kit, there is still some give in the shocks and it settles down a bit. It also behaves properly when I drop it down to properly assess ride height.

At this point, I am thoroughly convinced that I need to modify my pistons to soften the dampening a bit, if I stick with the 35 wt oil. But I think what I might try first is going back to 30 wt oil and adding some rebound.
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Last edited by Zao18; 12-31-2011 at 08:54 AM.
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Old 12-31-2011, 09:15 AM   #9
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No, I mean it doesn't move AT ALL. The shocks stay fully extended if I just gently lay down the car. And if I drop the car from 12 inches off the ground, the suspension still barely moves. The pack is definitely far too hard. I don't think 4 holes @ 1mm is cutting it. There is no give in the suspension.

Compare this to my D8T kit I just recently built. I have 40 wt oil with 6-hole 1.2mm pistons. Even if I just gently lay down the kit, there is still some give in the shocks and it settles down a bit. It also behaves properly when I drop it down to properly assess ride height.

At this point, I am thoroughly convinced that I need to modify my pistons to soften the dampening a bit, if I stick with the 35 wt oil. But I think what I might try first is going back to 30 wt oil and adding some rebound.
Before you make any changes just double check your suspension without the shocks attached and make sure that the arms move free. What you just described actually sounds like binding. It's always a good idea to look for stuff like that first before you do anything else, hopefully everything works out for you and your buggy drives the way you want.
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Old 12-31-2011, 09:23 AM   #10
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I am pretty sure that they moved freely before I mounted the shocks, but I think I will double check, just in case. Like you said, better to be sure of that before messing around with anything else.
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Old 12-31-2011, 10:38 AM   #11
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To me it sounds like you have air in your shocks do you bleed correctly are you sure you have no rebound without your shock springs attached if no then you have too much pack
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Old 12-31-2011, 12:26 PM   #12
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Pretty sure I have no air in my shocks. I bled them correctly and when I squeeze the shocks with my fingers, the dampening feels consistent through the whole travel of the shock. If there were air, you actually feel the shock suddenly easier to move. At this point, I am almost dead certain that I have too much pack. I don't think that a 4-hole 1mm piston is cutting it for 35 wt oil. I think I need to either step back to 30 wt oil and combat the bottoming out with some rebound added, or if I want to stick with 35 wt oil, I need to drill my piston holes bigger. I mean, look at the buggies/truggies that normally use 35 wt oil. They have 6-hole pistons, starting at 1.2mm size. The 4-hole, 1.0mm pistons in my shocks must just be producing excessive pack.
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Old 01-19-2012, 10:53 AM   #13
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I recently read The Guide. And from what I understand you can actually make these shocks work in two stages. You have 4 hole pistons at 1mm. Drill 2 of those to start with at say 1.3mm. This way in my thinking you get low speed and high speed damping while sticking with 35wt. The 1mm holes would still allow the pack for the big jumps, while the 1.3mm holes would allow for low speed bump compliance. Just a thought from what I took from it.
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Old 01-19-2012, 11:13 AM   #14
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You need to drop the car to make it settle into ride height. The tires are closer to each other with the arms in a lower position. If you put it on the table, there's too much resistance on the tires and the car won't go any lower. Just drop it from about 7inches.

If the track is bumpy and the chassis bottoms out on the bumps, use a heigher rideheight and build the shocks with more rebound.
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