j240z

Thanks, Bivens. I'm on it!

haywyre

I was told to try using the 16 pulley and the 18 pulley from the MRX-3 what will this do? will you have to have less of a differance in size in the tires
HAYWYRE

Bivens

First....you may be able to do this with the 16/19 belt (I think it's a 363mm long belt ???)...but.....


WITH THE STOCK MTX-3 DRIVE PULLEYS:

19:24 and 16:32

OR....1.26315 (side ratio) and (0.500 front belt ratio)

FOR A TOTAL RATIO OF: 2.526:1

(the rear achieves this with a 19 tooth and 48 tooth pulley system = 2.526 ratio also)

WITH THE 16/19 CONVERSION:

the front drive is

16:19 and 16:32

OR.....1.1875 (side ratio) and 0.500 (front belt ratio)

FOR A TOTAL RATIO OF: 2.375:1

and...... 2.526/2.375 = 106.357% or 6.357% overdriven


IF you could use a 16:18 side ratio....(1.125)...then the overall total front ratio would be 2.25:1

and...... 2.526/2.375 = 112.26% or 12.26% overdriven.....(with the 16:18)

This would require a split of approximately 7mm (63mm Rears and 56mm fronts) to get back to a non-overdriven condition......you'd be trying to run on new tires in the rear and riding on the rims in the front........any questions?

(I think a 16:20 would be fun to try....anybody know where to find a 20T pulley and a 364mm belt? )

sbmon

16/19 conversion
The main thing I will once again mention to people contemplating this conversion is that if you stagger the tire diameter as suggested to properly run this conversion you must also not forget to make an adjustment to your front droop accordingly. If your tire diameter is 4mm smaller up front you will be jacking down on the springs to get your ride height back to where it needs to be and then you will be effectively losing the droop you started with, so for a 4mm smaller front tire you would have to add about 2mm of front droop to keep the droop up front relative to the rear. While this conversion may work (I still haven't felt the need to try it, the car handles so good stock why screw with it imo) for some , I don't think it's worth the hassel (and if this simple conversion is all that then why didn't Mugen design the car with it ). And heres another thing for the people who have been running this conversion for a while I have a question. If you run the conversion and start a 30 minute race with say 63mm tires in the back and 60 mm tires in the front , lets say you have 3 mm of tire wear during the 30 minute race . Now what are the diameters of your front and rear tires? Is this really even tire wear? I think I will stick to trueing.

Varuth

What is KY? Is it good?

Taylor-Racing

sbmon,

Absolutely. If the standard pulley configuration works for you, that's great. Plenty of people run it standard and love it.

For us, we're used to the Kyosho EVO which comes standard with overdrive, so are familiar with that. But it's not too uncommon - 1/8th cars run overdrive all the time.

Certainly you would need to alter the droop but this would be done after setting the ride height anyway, and indeed when ever you change your ride height irrispective of the pulleys you run.

If you look at the tyre wear issue, what's actually happening is that the front tyres are now wearing faster than when they were the same size as the rears. Why? Because there is less rubber area/circumference in a front 60mm tyre than a rear 64mm tyre and it's turning faster as well. The result is even wear - more or less.
The benefit for a 30 minute race is that the overdrive pulleys will reduce the difference in wear rate between the front and rear tyres and thus, the change in handling that invariably goes with it.

Anyway, as I say, if the standard pulleys work for you, it's all good.

Bivens

OK, stick to truing.....I will say that there is less truing if you run the conversion.....That's a fact.....I normally can run a set of tires from a starting point of 63mm rear (and 59.5mm front) all the way down to 59 and 56 with a change in OD-ratio from a starting point of about 0.99 to 1.01.......without truing the fronts. Much less truing and more consistent......and yes....you must still pay attention to ride-height and droop...but you should be doing that anyway.....

Because obviously......many people think it's too complicated....just my opinion.....Personally, I'd like even more options....like the 1/8 scale cars have....Maybe on the MTX-4....

Is running for 5 minutes...then truing....then running 5 more....then truing....then 5 more....then truing.....then running the main and having to compromise the OD ratio by anticipating the split to change desirable for you?? At the end of my 30-minute main...I may have wear that gets me a 1mm change in the split....compared to a 2-3mm change in the split without the conversion. (This can be a bigger problem on low-traction abrasive tracks with fast tire wear than on permanent circuits with lots of grip and low wear.)

I agree.....well said...

jscamry

iTrader: (5)

hey all I have seen people w/ a carbon fiber strip connecting the body posts, does anyone know where i can find this item?

thanks Jason

kreidel

iTrader: (2)

What if someone discovered a setup that would enable us to run a harder rear tire but retain that rear traction? Speak up if anyone has one!!!!

Bivens

MTX-3 Overdrive Chart can be found here......

GIF Image Format

Microsoft Excel format (*.xls)

(thanks to 3hobby.com for hosting it......nice site)

jscamry

iTrader: (5)

hey all, I was wondering if anyone has tried to use a 710 front one-way diff in an mtx-3.

thanks Jason

Tag

iTrader: (31)

how far do you guys run your foam tires down to ? i usually run all the way down to about 55mm (rear)before i notice any handling change .. i have seen people run until there's no more foam on the tires...

Taylor-Racing

Oh, you know OZDC then?

Bivens

I'd like the ability to quickly change from a one-way to a spool.....or to have the "adjustable" diff's they've got......any ideas?

Profoxcg

iTrader: (2)

Can you run a spool in the front of a mugen? who makes it?

thanks !