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Old 07-07-2011, 09:02 PM   #706
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Hi, just completed my rx8 n ready to run it...

But noticed that there's an option to use 28T or 29T side pulley..

Can someone pls enlighten me as to how does these pulley affect the drivetrain and
driving characteristics..

Many thanks in advance... Cheers
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Old 07-08-2011, 07:51 AM   #707
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Last edited by motojon; 07-08-2011 at 11:03 AM. Reason: read the ratio chart
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Old 07-08-2011, 10:05 AM   #708
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it changes the final drive train ratio....i think 1.513 with the 29t and 1.32 with the 28t.....the larger the number the higher the torque lower the number the more top end u have
I think you wrong man.....

The 28 and 29 side pulleys got something to do with over drive ratio between front tires rotation against rear tires rotation per single revolution.

Must check with overdrive table ratio and look for front and rear tires diameter.

In general, 29t is slower rotation per revolution than 28t.

In other words, if you plan to use 28t side pulley, you should use thinner front tires diameter.
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Old 07-08-2011, 10:37 AM   #709
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The pulley changes the overdrive, or the split needed in tire sizes.

The bigger pulley reduces the mechanical overdrive in the front, and the smaller pulley will increase the mechanical overdrive in the front.

The reason I say mechanical, is simply that it's changing the axle rotation front to back, but depending on the split (size of tire front to rear), the actual overdrive on the ground can be altered, which is also the reason for the pulley changes..

There is a NT1 table on the teamxray website that explains it relative to the NT1, but the idea is fairly general "NT1 Quick Reference Table"..

The example I would provide "purely hypothetical", since I dont' have a roll-out calculator handy is this..

"example only, I don't have the actual numbers"... If you use the 29t pulley, mechanically you will have a 2% overdrive, or the front axles turn 2% more rotation than the back axle. If you use a 7mm split front tire being 7mm smaller than the rear tire, the 2% split will remain as 2% overdrive.

Now, if you increased your split to an 8mm or 9mm difference, you can actually reduce the amount of overdrive regardless of pulley, because the rear tire being larger will rollout further than the smaller front tires, or vice a versus, if you reduce the split to a 6mm or 5mm, the overdrive grows from the mechanical 2% and is increased based on tire split.

It's the same for the smaller pulley, which simply adds more mechanical overdrive, but the tire split can increase or negate the affect.

The biggest reason I choose between the two, is sidebite... If the car feels right at 2% overdrive, but I want to rebalance the car for a little more rear sidebite, it's possible to do so by changing pulley's, going to the smaller pulley will increase the mechanical overdrive, but by going to a larger split, I keep my 2% overdrive, while increasing the sidewall of the rear tire encouraging more sidebite.
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Old 07-08-2011, 02:33 PM   #710
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Hello racers

I'm currently running the 10th scale but probably I will pass to the 1/8 soon so I'm looking for a good car.

I should choose between the RX8 and the Serpent 966.

I'm taking some info here and there on these 2 cars and more people on the track said me that the RX8 still needs more steering and has some problems with pulleys and so.

Problems with steering seems to be delete with the new +1 steering blocks (and a little work with the dremel on those parts to have more mechanical turn)

..but...how is with the transmission? At the Worlds in Miami some pulleys weared out by the stress... something has changed?

Thanks to all
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Old 07-08-2011, 04:51 PM   #711
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The pulleys are fine on mine. Only the clutch cause the problem, I'm using Serpent shoe, works perfect, but u have to do some facbrication like using Mugen spring seat.
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Old 07-08-2011, 07:45 PM   #712
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Quote:
Originally Posted by Darint View Post
The pulley changes the overdrive, or the split needed in tire sizes.

The bigger pulley reduces the mechanical overdrive in the front, and the smaller pulley will increase the mechanical overdrive in the front.

The reason I say mechanical, is simply that it's changing the axle rotation front to back, but depending on the split (size of tire front to rear), the actual overdrive on the ground can be altered, which is also the reason for the pulley changes..

There is a NT1 table on the teamxray website that explains it relative to the NT1, but the idea is fairly general "NT1 Quick Reference Table"..

The example I would provide "purely hypothetical", since I dont' have a roll-out calculator handy is this..

"example only, I don't have the actual numbers"... If you use the 29t pulley, mechanically you will have a 2% overdrive, or the front axles turn 2% more rotation than the back axle. If you use a 7mm split front tire being 7mm smaller than the rear tire, the 2% split will remain as 2% overdrive.

Now, if you increased your split to an 8mm or 9mm difference, you can actually reduce the amount of overdrive regardless of pulley, because the rear tire being larger will rollout further than the smaller front tires, or vice a versus, if you reduce the split to a 6mm or 5mm, the overdrive grows from the mechanical 2% and is increased based on tire split.

It's the same for the smaller pulley, which simply adds more mechanical overdrive, but the tire split can increase or negate the affect.

The biggest reason I choose between the two, is sidebite... If the car feels right at 2% overdrive, but I want to rebalance the car for a little more rear sidebite, it's possible to do so by changing pulley's, going to the smaller pulley will increase the mechanical
overdrive, but by going to a larger split, I keep my 2% overdrive, while increasing the sidewall of the rear tire encouraging more sidebite.
Wow.. That's quite a techincal theory.. Thanks for the reply.

If possible, hope someone can explain it in a very simple layman term.. Hahaha
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Old 07-08-2011, 07:46 PM   #713
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Old 07-08-2011, 08:27 PM   #714
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Quote:
Originally Posted by nitro_fanatic View Post
Wow.. That's quite a techincal theory.. Thanks for the reply.

If possible, hope someone can explain it in a very simple layman term.. Hahaha
Simpel, with the smaller pulley you have more on power steer which can help a lot on small tracks with tiny corners.
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Old 07-08-2011, 09:10 PM   #715
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Great info guys!! So whats that optional +1&-1 steering block do?will the +1 give more steering??
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Old 07-09-2011, 10:45 PM   #716
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Quote:
Originally Posted by Roelof View Post
Simpel, with the smaller pulley you have more on power steer which can help a lot on small tracks with tiny corners.
Thks Roelof. That's easy to understand.

So with 28T pulley, any problem if I use with a tyre split of 7mm? Thks
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Old 07-10-2011, 04:14 AM   #717
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Originally Posted by beebone View Post
The pulleys are fine on mine. Only the clutch cause the problem, I'm using Serpent shoe, works perfect, but u have to do some facbrication like using Mugen spring seat.

or just use the serpent cup that fits shoe,thats what i did..now i have to figure what to do as my 1 gallon jp eagle 9 might be gone, due to a tight wristpin????? looking to see if i can get it regrooved on one side, or miracle falls from the sky, even desoto didnt get back to me if they even had a p/s/r set, and thats not good!! but for the other guy crossed between serpent and rx8, hands down get the RX8 best 1/8 i ever driven!!
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Old 07-11-2011, 07:20 AM   #718
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Picked up my new RX-8 this past Monday from Brent Gottfried and promptly went to work throwing the car together. I got a base set up from Ralph Burch and headed out friday for the Racine, WI Midwest series race with the paint still wet on the new car. It didn't take much work and the car was working very well. I was able to get the car qaulified 2nd but it was better and better every run. So far I'd say it fits me better than my Mugen MRX-5 and I can't wait to get some more stick time with it.


My car on the left and Vector03Cobra's Mugen

Jeff TQ'd and won but we had a great race for the main! In the end he edged me out by 2 sec at the end of the 30 min race.

Thanks for the support from http://www.rcamerica.com/ and Brent Gottfried!!
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Old 07-11-2011, 07:36 AM   #719
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Originally Posted by nitro_fanatic View Post
Thks Roelof. That's easy to understand.

So with 28T pulley, any problem if I use with a tyre split of 7mm? Thks
The only problem you can face is going into a corner offthrottle. The tire split will cause friction between front and rear and mostly the rear will become more loose.

You just have to give it a try to see what it does. As mentioned the smaller pulley is most of the time the better choice on very small tracks with tight corners.
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Old 07-11-2011, 09:07 AM   #720
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Originally Posted by Dasmopar View Post
Picked up my new RX-8 this past Monday from Brent Gottfried and promptly went to work throwing the car together. I got a base set up from Ralph Burch and headed out friday for the Racine, WI Midwest series race with the paint still wet on the new car. It didn't take much work and the car was working very well. I was able to get the car qaulified 2nd but it was better and better every run. So far I'd say it fits me better than my Mugen MRX-5 and I can't wait to get some more stick time with it.


My car on the left and Vector03Cobra's Mugen

Jeff TQ'd and won but we had a great race for the main! In the end he edged me out by 2 sec at the end of the 30 min race.

Thanks for the support from http://www.rcamerica.com/ and Brent Gottfried!!
Looking forward to getting mine. Hope it shows up sooner rather then later.
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