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Old 11-01-2005, 05:15 AM   #1741
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Quote:
Originally Posted by backplate
Hi all, does anyone came across this problem, the front hubs vibrates and jerks alot when the car is at half or full steering and throttle is at half squeeze or more... the steering travel is perfectly fine and the bearing is good too. please advise me on this.. by the way, i'm using spool in the front. my friends who are using the same set up do not have this prob.

Hi, Yes all touring cars suffer from this. It is a problem with the CVD not being a proper constant velocity joint. Essentially through the rotation of the CVD at an angle, the wheel is accelerating and decellerating through one revolution. The more steering is applied, the greater the velocity differential -the more vibration.

All cars will suffer from this to a greater or lesser extent, and the vibration is more noticable with a spool (although it happens on all transmission types). There is no way to eliminate this with the current configuration of Hubs and CVDS. Our CVD does reduce this, but you can reduce this on your std ones, by making sure that they are absolutely clean and oiled up before the race.

I have had cars (PRO4) which at times vibrated like mad, then after cleaning and reassembling it reduced.

Hope this helps.
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Old 11-01-2005, 03:34 PM   #1742
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Hotbodies website now has cyclone Hara set-up posted..

http://www.hotbodiesonline.net/set_ups.html

still better to download from the HPI Japan site...
the HB site has the handwritten set-up and not the typed clean
pages from the HPI japan site.
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Old 11-01-2005, 11:38 PM   #1743
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gearing question
i am racing mod and want to use a 9x2. just wondering what everyone is gearing their cars at? also if you could give me an idea where i should start at for gearing.
i am using an epic shock 9x2. i changed the spur over to 48 pitch and using an 81 tooth spur.
thanks for any help
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Old 11-02-2005, 01:28 AM   #1744
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I installed TIR's (http://www.titaniumracing.com/product.asp?prodnum=321).

It also comes with some nice aluminum strengthenning covers that are placed on the derlin outdrives.

I haven't raced with it yet but I made some modifications.

1. I replaced the stock HB aluminum black dogbones with TAMIYA's steel 42mm dogbones

2. I then found out that the small shaft of the dogbone is smaller in diameter than that of the stock HB dogbone and it could damage the spool's derlin outdrive (or even if it was stainless steel, because the contact area is too small and it would cut like a knife!)
Thus I took some XRAY Drive Shaft Replacement Pastic Caps 3mm #305240
http://www.teamxray.com/teamxray/pro...166&kategoria=

and placed them on the TAMIYA dogbones.
Because the Xray plastic caps were a little thicker than the gap of TIR's derlin outdrive, I carefully removed some material from the outdrive in order to fit without jamming/binding.
Now it runs very nicely, and smooth. Of course only track testing will confirm if everything is OK, so this weekend I will find out..
The result is shown in the below pictures.
Attached Thumbnails
Hot Bodies Cyclone-img_2869b.jpg   Hot Bodies Cyclone-img_2868b.jpg   Hot Bodies Cyclone-img_2874b.jpg   Hot Bodies Cyclone-img_2859b.jpg   Hot Bodies Cyclone-img_2867b.jpg  


Last edited by John Doucakis; 11-02-2005 at 06:51 AM.
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Old 11-02-2005, 06:31 AM   #1745
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Quote:
Originally Posted by John Doucakis
I installed TIR's (http://www.titaniumracing.com/product.asp?prodnum=321).

It also comes with some nice aluminum strengthenning covers that are places on the derlin outdrives.

I haven't raced with it yet but I made some modifications.

1. I replaced the stock HB aluminum black dogbones with TAMIYA's steel 42mm dogbones

2. I then found out that the small shaft of the dogbone is smaller in diameter than that of the stock HB dogbone and it could damage the spool's derlin outdrive (or even if it was stainless steel, because the contact area is too small and it would cut like a knife!)
Thus I took some XRAY Drive Shaft Replacement Pastic Caps 3mm #305240
http://www.teamxray.com/teamxray/pro...166&kategoria=

and placed them on the TAMIYA dogbones.
Because the Xray plastic caps were a little thicker than the gap of TIR's derlin outdrive, I carefully removed some material from the outdrive in order to fit without jamming/binding.
Now it runs very nicely, and smooth. Of course only track testing will confirm if everything is OK, so this weekend I will find out..
The result is shown in the below pictures.
fyi shcumachers blades are thinner than xrays
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Old 11-02-2005, 07:09 AM   #1746
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Thanks.

Friend of mine tried that but the holes for the dogbone pin on the Schumacher blades are too small.
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Old 11-02-2005, 07:28 AM   #1747
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Sweet car, where did you get the new Hara V2 motor from?
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Old 11-02-2005, 07:30 AM   #1748
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Quote:
Originally Posted by Skill
Sweet car, where did you get the new Hara V2 motor from?
From Oscar Jansen
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Old 11-02-2005, 01:58 PM   #1749
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Quote:
Originally Posted by tir
Hi, Yes all touring cars suffer from this. It is a problem with the CVD not being a proper constant velocity joint. Essentially through the rotation of the CVD at an angle, the wheel is accelerating and decellerating through one revolution. The more steering is applied, the greater the velocity differential -the more vibration.

All cars will suffer from this to a greater or lesser extent, and the vibration is more noticable with a spool (although it happens on all transmission types). There is no way to eliminate this with the current configuration of Hubs and CVDS. Our CVD does reduce this, but you can reduce this on your std ones, by making sure that they are absolutely clean and oiled up before the race.

I have had cars (PRO4) which at times vibrated like mad, then after cleaning and reassembling it reduced.

Hope this helps.
can you explain how the wheel is made to accel and deccel throughout a single revolution?
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Old 11-02-2005, 02:55 PM   #1750
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Quote:
Originally Posted by floodo1
can you explain how the wheel is made to accel and deccel throughout a single revolution?
The chatter comes from the fact that no R/C cars use true CVD's (Constant Velocity Drive). MIP and TiR CVD are actually just fancy rebuild-able UJ's (Universal Joints). The are no problems when the wheels are straight. However, as the wheels turn the UJ causes the axle to accelerate up to 7 deg ahead of the dog bone for 180 deg then decelerate 7 degrees behind the dog bone for the remaining 180. This 360deg cycle of acceleration and deceleration of the axle causes the chattering. Note that the car will not chatter with the wheels and tires off the car. The inertia of the rotating wheel resisting the axles acceleration and deceleration causes the chattering.

As the the drive system wears with use the chattering gradually gets better them pretty much disappears. The tiny amount of play that develops in a CVD with use allows the system to because less sensitive to and eventually can absorb the inherent oscillation.

This is why all the new guys have a problem with this but not the guys with older cars.

The chatter is only noticeable with spools. Diffs and one ways can absorb the oscillation.

All sedans chatter. The JRXS is the first car with a sort-of real CVD. It uses a very old articulating joint design to function as a CVD. It works and is very clever. Their ads say patent pending but I doubt they will be able to patent it as it has been around since the 1800's.

Others are working on real CVD's but the problem is that the materials available do not allow us to make true CVD's within the space and weight limitations required by our cars with acceptable durability....for now.

Some manufactures have figured out how to greatly reduce the chatter in their cars....and some have not
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Old 11-02-2005, 02:58 PM   #1751
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Adrian..
thanks for the explanation on the chatter...
Now I see why my pro4 chatters alot with a spool... I took the car apart trying to figure it out..and found nothing wrong...
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Old 11-02-2005, 03:07 PM   #1752
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Quote:
Originally Posted by rc-zombies
Adrian..
thanks for the explanation on the chatter...
Now I see why my pro4 chatters alot with a spool... I took the car apart trying to figure it out..and found nothing wrong...
The Pro 4 is a funny case. It is pretty much an improved copy of the TC3 but HPI missed a few things. Associated sedans have a pretty loose dog bone drive pin to diff output cup slot tolerances. I think AE did this on purpose to reduce chatter. On the Pro 4 HPI tightened this tolerance up because they though it was better (they didn't know any better) and spools were not that popular at the time. Hence the Pro4 chatter....and unfortunately Cyclone chatter too.
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Old 11-02-2005, 03:11 PM   #1753
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so to reduce the chatter I need to widen the pin slot on the spool...and also install the RDX or Xray pin plastic pin blades...?
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Old 11-02-2005, 03:19 PM   #1754
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I had a Yokomo CGM and had the same problem with the spool. It just sounds terrible. Didn't really see any performance issues as a result of it. I just seem to like driving with the spool so the noise is something I can ignore.
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Old 11-02-2005, 09:43 PM   #1755
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Have anyone tried the setup sheets for asphalt on their cars? Which one seem to work best for stock racing?
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