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Pylon80

Spool!

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5 minutes ago, Superluminal said:

Shame its hidden as its a nice looking bit of kit

It gives you an excuse to do maintenance on the car though 🙂

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53 minutes ago, toyolien said:

You'll also need new shorter universal shafts too.

d3.jpg

 

I think you would be able to use it with normal swing shafts on a type S though, arms are about 1.5mm wider than standard TT-02 if I recall.

I have had similar length issues with the older TT-02 oil filled gear diff. Had a set of Eagle Racing 38mm swing shafts knocking around and I was able to use that to make Frankenstein Universals!

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Yikes… I have these on order for my TTs. On the RR I have dcjs which were a bit of work to make fit. I’m not aware of DCJs under 39 mm… maybe they will release them for XV02

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16 minutes ago, Raman36 said:

Yikes… I have these on order for my TTs. On the RR I have dcjs which were a bit of work to make fit. I’m not aware of DCJs under 39 mm… maybe they will release them for XV02

That's right, the M chassis ones are 33 and then there's nothing until 39. There is always the trick of using a slim bearing that buys you 1mm extra margin. Not sure if that will be enough.

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If running a spool it’s worth every penny :)

Although on a stock TT02 I think putty in the std diff makes it handle better. Just a little bit of give protects the drive train and helps it into the apex.  Also no chatter with universals.

 

 

 

 

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Somebody could explain me, please, the need of a spool in the front end?

Thanks

Max

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On 9/28/2022 at 8:51 PM, Pylon80 said:

I think you would be able to use it with normal swing shafts on a type S though, arms are about 1.5mm wider than standard TT-02 if I recall.

I have had similar length issues with the older TT-02 oil filled gear diff. Had a set of Eagle Racing 38mm swing shafts knocking around and I was able to use that to make Frankenstein Universals!

So, just following the logic through....

When installing the spool on a 'standard' TT02, recommendation from Tamiya is to use shorter 37mm universal shafts instead of 'standard' 39mm shafts

When considering the Type S, the manual (published long before the spool was released) recommends the XV-01 front assembly, which has a 42mm shaft

So to use the spool in the Type S would need a shorter shaft, so the 'standard' 39mm shaft or XV-02 rear assembly?

Is that right?

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58 minutes ago, kontemax said:

Somebody could explain me, please, the need of a spool in the front end?

Thanks

Max

Touring Cars will need a very stiff front diff or even a spool at the front to prevent the inside wheel from spinning ("diffing out"). This happens when power is applied while the car is still leaning into a corner, offloading the inside wheel. The opposite wheel just stops providing any traction. Some 1:1 scale cars have Torsen diffs which provide full differential action: they can't spin a wheel on one side. We RC hobbyist do not have access to miniature Torsens :) We use "open diffs". So the simple solution is, as often, a compromise: we slow down the diff or even replacing it with a spool. That makes the tires slip a little in any turn, but at least you avoid one wheel spinning while the opposite wheel stops. This is really required for racing and generally speaking when using higher power and when the track has the grip required to allow leaning aggressively into the corners. You don't need that for parking lot fun but you need it on any but the most novice classes at the track.

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2 minutes ago, Juhunio said:

So, just following the logic through....

When installing the spool on a 'standard' TT02, recommendation from Tamiya is to use shorter 37mm universal shafts instead of 'standard' 39mm shafts

When considering the Type S, the manual (published long before the spool was released) recommends the XV-01 front assembly, which has a 42mm shaft

So to use the spool in the Type S would need a shorter shaft, so the 'standard' 39mm shaft or XV-02 rear assembly?

Is that right?

The part just came out so I doubt many people have tried it on a TT-02 type S. On the Tamiya picture, the 37mm shaft, on a standard TT-02, looks awfully close to binding... From my own measurements the Type S was 1.5mm wider per side. That might not leave enough clearance with 39's.

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On 10/3/2022 at 11:02 PM, Pylon80 said:

Touring Cars will need a very stiff front diff or even a spool at the front to prevent the inside wheel from spinning ("diffing out"). This happens when power is applied while the car is still leaning into a corner, offloading the inside wheel. The opposite wheel just stops providing any traction. Some 1:1 scale cars have Torsen diffs which provide full differential action: they can't spin a wheel on one side. We RC hobbyist do not have access to miniature Torsens :) We use "open diffs". So the simple solution is, as often, a compromise: we slow down the diff or even replacing it with a spool. That makes the tires slip a little in any turn, but at least you avoid one wheel spinning while the opposite wheel stops. This is really required for racing and generally speaking when using higher power and when the track has the grip required to allow leaning aggressively into the corners. You don't need that for parking lot fun but you need it on any but the most novice classes at the track.

I suppose you are speaking about 4WD touring models, right?
I remember we used the front one way and, eventually, the rear spool.

Max

 

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How does a spool compare to a diff locker (e.g. Tamiya TT-02 Diff Lock Block 54649)? They appear to fulfil the same function but, seeing as both exist, it seems likely there is a subtle difference.

My guess is that the spool is simpler, with fewer moving parts, so is more reliable, has less slop, and less rotating mass to accelerate.

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26 minutes ago, wilysloth said:

How does a spool compare to a diff locker (e.g. Tamiya TT-02 Diff Lock Block 54649)? They appear to fulfil the same function but, seeing as both exist, it seems likely there is a subtle difference.

My guess is that the spool is simpler, with fewer moving parts, so is more reliable, has less slop, and less rotating mass to accelerate.

Agree. The diff locking block allows you to lock and unlock the stock diff quickly without changing anything else on the car (out drives, drive axles etc) but it does have some slop. Also, if you are using the large diameter drive axles it is your only option (short of dropping epoxy glue inside the diff 😅). The spool on the other end is from the XV-02 and would replace an oil-filled gear diff since they come as standard. When used on the TT-02 it will be a much fancier part than the diff locking block, similar to what high end TC cars would use. Probably lighter and certainly with much less slop (or no slop at all) as you mentioned.

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