Fioroni Tractive IV diffs exposed

[Ryu James]

some of you have asked me about my Fioroni Tractive diffs and how i like them so i thought i would post what i have found out. when i first put the Tractive diffs on my buggy i just pulled out the stock ones and put the Fioroni ones in. before i put the fioroni diffs in though i disassembled them to put on the acer racing ceramic bearings. so i was able to see the entire assembly of the Fioroni diffs

it wasnt til now while building my truggy that i have taken apart the losi stock diffs and here is what i noticed. they are exactly the same as the Fioroni diffs. the only difference is that the Fioroni diffs come packed with GREASE, not oil. the grease is equivalent to 300k diff oil or higher essentially giving you full lock up. and of course the fioroni diffs look much nicer but that is it. inside they are part for part identical but surprisingly the fioroni diffs are heavier by about 10grams, due to the alum casing i am sure. and let me just tell you, at the track, my buggy cannot turn worth a shit cuz of those fioroni diffs packed with grease. so i am going to have to change that out.

anyway, save yourself $750 (for front, center, and rear diff) on packing grease and stick with your stock diffs.

just thought i would post this cuz i have been asked by several and i am sure many have wondered when shopping around, "what does that fioroni diff do? must do something awesome for $250." well, thats what i thought and....well you get my point.

aside from the diffs the other parts from them have been great!

anyone interested in some $150 fioroni diffs?

[JERRY2KONE]

Hey there James thanks for the update and great insight on the Fioroni diffs. I was wandering the same thing when I saw them thinking that they must really be something for that kind of money. I was actually going to try a set on my next project, but now the cat is out of the bag so to speak. That is what we are all on here for. Sharing our experiences and info on products that all of us may or may not be interested in purchasing. Sorry for your loss $$$ and at the very least your loss has saved several other people on RCM $$$ for the same curiosity. At least they look good when you open them up huh?? Maby if you put some lower grease or oil in them and try again they will handle better for you. Good luck with selling them.

[brushlessboy16]

so your telling us that the losi has Torsen diffs????? wow

Dont think that would be good for a center diff in BL anyways, power goes to the wheels with the most traction... that just spells wheelies.. not so good on the track when you are trying to get from point a to point b as fast as possible.

[Sammus]

Wow losi diffs use traction ramps? I think this is losi's secret tech exposed...they should be worth much more...

For anyone who wants to know the actual difference: fioroni tractive is a clutch type torque sensing diff that uses special traction ramps (a heap of different ramp angles are available for different tuning) which activate a kind of clutch between the spider gears and the drive shaft (the internal gears rest on an angled cutout, so as the diff unloads the pinions climb the ramps and locks the diff more and more)

The ofna style torsen diffs are geared torque sensing diffs, which use a weird worm gear drive setup. The disadvatage is that both driveshafts need to be loaded for it to work properly - if one wheel lifts the diff just unloads.

An advantage of uing torque sensing diffs over speed sensing (ie the viscous diff we're all used to) is that there is n to no power loss in a torsen diff (unlike a viscous), and they last a lot longer.

Originally Posted by brushlessboy16

power goes to the wheels with the most traction... that just spells wheelies.. not so good on the track when you are trying to get from point a to point b as fast as possible.

That is not right. Torsen diffs 'sense' when there is a torque load on an axle and increase the coupling of the driveshafts to keep a certain maximum torque difference between the wheels, you still get the inside wheel spinning at higher rpm.. If you bind one wheel of a viscous diff and go wot, your other wheel will spin fast. With torsen I think this (potentially, depending on the setup) is impossible, it will lock once the difference is big enough (its all relative to the torque on the axles, which i think will only let the ratio of loaded and unloaded wheel rpm be so much). I think torsen diffs often only are limited slip under throttle, and open off throttle - something you cant acheive with a viscous diff.

Ryu James: Perhaps you didnt reassmble them properly after taking them apart before using them?

Here is the exploded view of the Tractive diff: you can see it is very different to a standard diff

http://www.twf8.ws/new/tech/options/...e_IV_mugen.pdf

edit: just d/l the losi 8ight manual to look at its diff. They are the normal sealed oil kind.

[brushlessboy16]

i know how they work(torsens), and in my post i stated that for center differential work, it would do that. because it reduces power to the wheels with the least traction.

those are not torsens.
They are very similar to the diffs in the new xray buggies and truggies.

[Ryu James]

Originally Posted by Sammus

Wow losi diffs use traction ramps? I think this is losi's secret tech exposed...they should be worth much more...

For anyone who wants to know the actual difference: fioroni tractive is a clutch type torque sensing diff that uses special traction ramps (a heap of different ramp angles are available for different tuning) which activate a kind of clutch between the spider gears and the drive shaft (the internal gears rest on an angled cutout, so as the diff unloads the pinions climb the ramps and locks the diff more and more)

The ofna style torsen diffs are geared torque sensing diffs, which use a weird worm gear drive setup. The disadvatage is that both driveshafts need to be loaded for it to work properly - if one wheel lifts the diff just unloads.

An advantage of uing torque sensing diffs over speed sensing (ie the viscous diff we're all used to) is that there is n to no power loss in a torsen diff (unlike a viscous), and they last a lot longer.


That is not right. Torsen diffs 'sense' when there is a torque load on an axle and increase the coupling of the driveshafts to keep a certain maximum torque difference between the wheels, you still get the inside wheel spinning at higher rpm.. If you bind one wheel of a viscous diff and go wot, your other wheel will spin fast. With torsen I think this (potentially, depending on the setup) is impossible, it will lock once the difference is big enough (its all relative to the torque on the axles, which i think will only let the ratio of loaded and unloaded wheel rpm be so much). I think torsen diffs often only are limited slip under throttle, and open off throttle - something you cant acheive with a viscous diff.

Ryu James: Perhaps you didnt reassmble them properly after taking them apart before using them?

Here is the exploded view of the Tractive diff: you can see it is very different to a standard diff

http://www.twf8.ws/new/tech/options/...e_IV_mugen.pdf

edit: just d/l the losi 8ight manual to look at its diff. They are the normal sealed oil kind.

thanks for the clarification Sammus. its not that i reassembled them wrong, i was just saying they look exactly the same as the losi diffs. maybe i am not seeing the difference. i am glad i am wrong though. makes not feel so bad about spending $750 on diffs but i have yet to drive a stock losi so i dont know what kind of performance advantage the fioroni diffs might be giving me. so are there different components to the Fioroni diffs or just the ramp angle on that one part makes the difference? maybe tonight i will tear down the center diff of both the fioroni and the losi and take some pics to post.

ok, so i am an idiot. maybe when i spend some time in a setup without the upgrades i can truly apprciate the fioroni diffs that i have. as for my turn in, i obviously need to adjust my suspension/sway bar to achieve desired results. that is another topic i could use some help with. anyway, here is a great article on the Fioroni diffs and what they do.


"Fioroni's Tractive IV torque reactive differentials are the most advanced differentials ever made for 1/8th off road vehicles and can be effectively used on buggies, truggies, oval cars, and rally (IGT) cars. An innovator in high end upgrade parts for radio control models, Fioroni's Tractive IV differentials are the fourth installment of 'torque sensing' differentials, following the international title winning Japan, Hyper, and Storm Traction differentials.

Tractive IV differentials are a type of limited slip/torque sensing differentials. They operate much the same as full scale Salisbury differentials, but on a smaller scale, and perhaps arguably in more severe conditions. The locking is enabled by internal ramps which act like a wedge, with the throttle and brake torque being applied to it. The rate of lock is in direct reaction and in direct proportion to the torque input- the more torque, the harder it locks. The angles of the ramps can be changed with optional parts to achieve various handling characteristics.

Compared to an 'open' or standard bevel gear differential commonly found in off road buggies and trucks, Fioroni's differentials work quite differently, both on and off throttle. While an open differential sends power to the tire(s) with the least amount of resistance (think front inside truggy tire ballooning coming out of a corner), the Tractive IV differentials balance the power output more evenly. Instead of thickening differential fluids or changing suspension settings to compensate for the loss of power, which often results in an equally negative effect elsewhere on the track, you can send more power to the wheels without a drastic change in overall handling. By adding lock, the wheel with the least resistance is less likely to spin, which means more power is being put down, resulting in faster acceleration.

Off throttle, the Tractive IV differential will act somewhat like an ABS system (Anti Lock Brakes). Your car will be more stable under braking and if you choose, you can increase the rear brake bias, often shortening brake distance. With today's improved suspension geometry and constantly improving tires, these differentials can be used effectively to lower your lap times. Another direct result is longer tire life. The less your tires spin, the longer they will last.

Fioroni's Tractive IV differentials are a powerful tuning option, not a savior to a poorly assembled and incorrectly setup vehicle. It is recommended to use the front differential first, followed by both the center and rear. By using all 3 there will be a noticeable change to the handling of the car as well as an obvious decrease in tire wear. The differentials can be used on a variety of surfaces from loose dirt to clean pavement. Make sure to try them in practice first and make chassis adjustments as needed before using them in racing conditions.

The standard ramp angles are 120 for Front differentials, 80 for center differentials, and 40 for rear differentials. Optional 60 and 100 degree ramps are available for your tuning pleasure. For optimum performance, it is recommended to clean and re-grease the differential after each weekend of racing, with a maximum of 3 races in between cleaning and re-greasing. Although not necessary, it is suggested to re-install the internal components in the exact position, and allow a short break-in time for new or freshly rebuilt differentials. Do not use any grease or oil except for the one included with your differential and available as a spare part (TRC-020). The differentials can be fully rebuilt and a full line of spare parts is available. You can further complement your car's drivetrain with Fioroni LIC range of lightweight axles, hubs, and gears, available for most popular racing buggies and truggies.

Fioroni Tractive IV differentials, like all Fioroni product, are designed and made in Italy using only the highest quality materials and process. Beware of knockoff 'torsen' differentials. They often work poorly and are made of sub par materials. Fioroni Option Team parts are tested and used by IFMAR World Championship winning drivers. Tractive IV differentials are available for the following cars and their compatibles: Associated RC8, GS Cl-1, Kyosho 777, Losi 8, Mugen MBX5R, and XRAY 808 (available June 2008)."

[lincpimp]

Some pics would be nice.

I would like to see a scaled down version of the detroit true trac diff for rc. It uses a scelection of worm gears (simple description) that will transfer torque to the higher traction wheel.

I am not sure how well they will work compared to a full size car, as the power to weight ratio is so different on an rc.

[Sammus]

pimp: that is how the ofna torsen diffs are designed, they have an exploded pic in a manual on their website (im pretty sure it's what your talking about)

brushless boy: the fioroni diff is a kind of torsen diff just not the worm gear type that ofna call torsen, and theyre nothing like the diffs in the new xray xb808 at least (well, according to the exploded view in the manual which shows a standard oil diff, i dont own one to pull apart here though)

[lincpimp]

Originally Posted by Sammus

pimp: that is how the ofna torsen diffs are designed, they have an exploded pic in a manual on their website (im pretty sure it's what your talking about)

Heres a pic I found, looks alot like the true trac. Interesting, I may have to try one of these...

http://www.ofna.com/images/opt-10596-big.jpg

Where did you find the exploded pic or manual? EDIT, found it!

[phatmonk]

I just so happened to have had a Traactive Fioroni IV Center diff for my Losi 8t and it wasnt at all the same as the Losi 8 diffs.Infact it would consistantly would cause the front end tires to balloon also a real waist of money IMO.I switched back to the stock Losi center diff.The insides of the Fioroni diff is allmost identical to the X-Ray active diff.Someone got ripped off if they were the same as the stock Losi diff.Also you have to regrease them after each use.A real pain in the rear

[phatmonk]

This is a pic of the Xray active diff.Its the very simular to the Fioroni Tractive IV.

[brushlessboy16]

Originally Posted by brushlessboy16

i know how they work(torsens), and in my post i stated that for center differential work, it would do that. because it reduces power to the wheels with the least traction.

those are not torsens.
They are very similar to the diffs in the new xray buggies and truggies.

I would love to run a torsen on my truggy, balloons front tires like crazy

[BL_RV0]

Originally Posted by brushlessboy16

I would love to run a torsen on my truggy, balloons front tires like crazy

You LIKE that?

[phatmonk]

Yea it wont help with the front tire ballooning

[BL_RV0]

I beat you.