XRAY - Model racing cars

Hi everyone,

I'm having here to many problems with rear belt on T3 2012 with Gear diff.
Is this only my problem or anyone else is having the same problem?
Please, any tips?

I damaged a few as well.

Run the rear belt a bit tighter than you normally would.

When you tight it you have no problem anymore?

Here in our track.... I break 2 and other 5 drivers broke 3 or 4 each one!
Something is wrong.
Last year nobody had problem with their belts.

I think it's the extra force that the gear diff puts through the belt. A diff put less strain on the belt.

Since I tightened the belt a bit I have only broken one belt.

Skiddins

Anyone from XRAY could help us?
I will test tomorrow one more time.
Which motor you use?

13.5 and 10.5

We are using 10.5 motor with Supercharger software.
Let's see what happens.

I run with motor 10.5 since 2 months ago and I never broke the rear belt. But is true that the belt is too tight, I must to put in the middle hole for best tension of this.

Check that the screws of the spur are on the left (on motor side).

The geardiff has a slightly larger diameter than the balldiff. This leads to a higher belt-tenstion with the same setting as before. I also broke some belts last year, until I used less belt tension.

Of course the wear of the belts is higher than with a balldiff, because there is more load on it than before. But if your belt breaks after only 20 batteries, you have too much tension in it.

If it jumps over, making a clicking noise and the belt dies because of tooth-wear, your belt tension is too low,

Does this mean 38T with slightly bigger gap between the teeth (different pitch which also alters the ratio)? Or differently asked, is the T3 2012's front solid axle also bigger in its diameter than the previous versions (both show #305188 but we all know that world famous sentence "... are subjects to be changed without prior notice." )? Or is it a wanted built-in rear overdrive simply?

Hi,

I test middle set (tension position) to 2 steps looser.
I broke the belts on all steps.
I never tensioned the belt for test. I will do that!
Yesterday I use one step loosen and broke another rear belt!
I'm having too many problems with belts this year.

When you go full throttle out of slow corners with the geardiff, there is a huge load on the rear belt. And even more when the track is bumpy, because the wheels can slip and when they touch the ground again, there is a shock going through the drivetrain. With the balldiff there was an element which could relief this shock (balls slipping on the washers), but with the geardiff all torque has to go through the belt.

The difference in diameter is only very small, but you can measure it with a caliper gauge. I think this comes from tolerances.

If the belts break on all steps of the excentric holders, there is not much you can do except accelerate more smooth. Maybe you have a lot of wheel slip while accelerating out of corners. Then, if you accelerate more smooth, you will also get faster laptimes.

I have run a 5.5T and 5.0T for at long time with one belt.
Something is very wrong.
Check for sharp objects on the belt drives.

I only broke one when someone reared me and the side of the diff. broke and cut the belt.

I checked everything!
No objects at all. The bel simply brake.
I think I will use ball diff because 1 belt for day is to much.

I will test for more tension on it!
I just test middle no less tension.
Now, I will test middle for more tension.

Hi dude im having the same problem with braking rear belts two belts and not a full run off battery yet waiting for local hobbies store for more belts ..

im also using gear diff with 13.5 turn motor 84 spur and 32 pinion front all good ???

The HPI rear belt 66494 apparently also fits the T3

On the layshaft check the play on the 20tooth pulleys where the pin goes through the layshaft. Within the pulleys the slot for the pin can have excessive play. This can give a bigger jolt as you accelerate hard. If so just rotate the pulleys so the pin goes through the unused slot in the 20tooth pulleys.

Both slots on mine are heavily worn so changing my pulleys this week. There will still be slight play but try and get it as best as you can. I may try and make it a little tighter somehow. But less play will also help under braking.

Last year with ball diff I broke no belts at all!
So... I thinking about ball diff test.