TRF502X, things to improve

[Chris]

Dear all,

When building the TRF 502X I have found some things that Tamiya or an aftermarket company could improve:

- the shock tower attachment on the front upper gearbox cover does have a wrong angle. This should be the same angle as the front kick-up. The result is binding of the front shocks when mounted according the manual. It can be solved by use of a double shock tower, but the shocks won't be square with the lower arms. The TRF 511 doesn't have this problem.

-The slots in the diff joints are too large, in this way dust can easily enter the "sealed" gearbox. To prevent this i used a piece of heat shrink to cover the slots. (only covering the slot that's inside the gearbox)

Some minor things:

-Where is the angled steering system from the TRF 511? I for the best steering characteristics the steering system should be parallel to the steering uprights, like was done on the TRF 511 and 501X.

-The rear shocks are not reversible like on the TRF 511. Shocks can only mounted on the front side of the suspension arms. BTW: I didn't like driving the rear mounted option on the TRF 511.

-The gear box housings are not fully sealed like on the TRF 201. A sealing edge is missing. The gearboxes are very stiff and secured with 6 screws, so hopefully there is no need for sealing edges.

-accessing the motor screws is not easy, an improved motor mount like on the B44.1 should be nice.

- a double slipper clutch, I like this option very much on the TRF 511

So hopefully tamiya releases soon an updated front gear box cover and improved diff joints.

[AndrewCaunt]

The front steering has to be turned round 180 degrees so that the car steers better you have to dremel gear box housing.It makes akaman same as 511.

[Chris]

Originally Posted by AndrewCaunt

The front steering has to be turned round 180 degrees so that the car steers better you have to dremel gear box housing.It makes akaman same as 511.

True, but you can also use 6 mm spacers to achive the same geometry

[Bomberpilot]

Hi to all,

...and its got some bumb steer ( neagtive ) in the last few bits of inboard travel on the front, which " opens " the outside steering angle. Still have no idea to shim that, because of not enough place...

After driving 501 ( orig and AC GTO ) and 511, i am a bit dissapointed:
- the front whishbones start to wobble after 6 Packs inddor
- still no parts availible here


Greetings from Switzerland
Maurice

[fastinfastout]

seems like 502x was released too early

[Bomberpilot]

it seems like Tamiya has lowerd the quality to Schuey, durango and co, if the official price of the 502 would be the same as the others, i would say okay, but for more money i want more quality...like Fiat vs. Porsche...

We will see...

[Chris]

Originally Posted by fastinfastout

seems like 502x was released too early

I disagree, it's a great car. But there is room for improvement!

[discostu]

Originally Posted by Chris

Dear all,

When building the TRF 502X I have found some design mistakes:

- the shock tower attachment on the front upper gearbox cover does have a wrong angle. This should be the same angle as the front kick-up. The result is binding of the front shocks when mounted according the manual. It can be solved by use of a double shock tower, but the shocks won't be square with the lower arms. The TRF 511 doesn't have this problem.

-The slots in the diff joints are too large, in this way dust can easily enter the "sealed" gearbox. To prevent this i used a piece of heat shrink to cover the slots. (only covering the slot that's inside the gearbox)

Some minor things:

-Where is the angled steering system from the TRF 511? I for the best steering characteristics the steering system should be parallel to the steering uprights, like was done on the TRF 511 and 501X.

-The rear shocks are not reversible like on the TRF 511. Shocks can only mounted on the front side of the suspension arms. BTW: I didn't like driving the rear mounted option on the TRF 511.

-The gear box housings are not fully sealed like on the TRF 201. A sealing edge is missing. The gearboxes are very stiff and secured with 6 screws, so hopefully there is no need for sealing edges.

-accessing the motor screws is not easy, an improved motor mount like on the B44.1 should be nice.

- a double slipper clutch, I like this option very much on the TRF 511

So hopefully tamiya releases soon an updated front gear box cover and improved diff joints.

This is your post

agree with point one 2mm spacer longer bolt job done

point 2

no more than any car with similar design (B44 D4)

point 3

not possible as gear box in the way

point 4

no where does it say this can be done!

Point 5

Again no more than cars of similar design (B44 D4)

Point 6

Not a problem if kit supplied allen key used

Point 7

Both the 511 and 502 have the same type of slipper clutch

like i said it sounds like you dont like this car.

stu

[Chris]

Originally Posted by discostu

This is your post

agree with point one 2mm spacer longer bolt job done

point 2

no more than any car with similar design (B44 D4)

point 3

not possible as gear box in the way

point 4

no where does it say this can be done!

Point 5

Again no more than cars of similar design (B44 D4)

Point 6

Not a problem if kit supplied allen key used

Point 7

Both the 511 and 502 have the same type of slipper clutch

like i said it sounds like you dont like this car.

stu

point 1; Stupid solution, shocks are not perpendicular to the suspension arms which gives bad performance!

point 2; Have a good look at the B44.1 the slots are outside the housing.

point 3; Have a good look at the DB02.

point 4; Still not possible to mount shocks at the rear side of the suspension arm and as mentioned before i don't think there is any need for it.

point 5; After testing it is proven that no dust will get inside the gearboxes, a sealing edge is not essential.

point 6; It's easier with a B44.1 motormount!

point 7; Obviously you don't have a clue what a double slipper clutch is and what is does.

Some other improvement points:
-the inner camber link mounts are too high
-the front gearbox cover should be reinforced

Why do you think i don't like this car? I love it! But if you read my posts in this topic welll, i wrote that there is room for improvement.

[discostu]

Originally Posted by Chris

point 1; Stupid solution, shocks are not perpendicular to the suspension arms which gives bad performance!

point 2; Have a good look at the B44.1 the slots are outside the housing.

point 3; Have a good look at the DB02.

point 4; Still not possible to mount shocks at the rear side of the suspension arm and as mentioned before i don't think there is any need for it.

point 5; After testing it is proven that no dust will get inside the gearboxes, a sealing edge is not essential.

point 6; It's easier with a B44.1 motormount!

point 7; Obviously you don't have a clue what a double slipper clutch is and what is does.

Some other improvement points:
-the inner camber link mounts are too high
-the front gearbox cover should be reinforced

Why do you think i don't like this car? I love it! But if you read my posts in this topic welll, i wrote that there is room for improvement.

clearly i havent got a clue i do appologise

one thing can you please explain to me what the difference between the 511 slipper and the 502 slipper.

also can you show me a picture of the lower gearbox detail of the db02 to see how they have achived the clearnce for the angled steering rack.

camber link to high not if your racing on high grip
gearbox cover pssibly differnt matterial possibly the db02 gearbox top (softer plastic) not carbon composit

yes the b44 mount is easier but the 502 doesn't have that, thats why they supplied the correct tool for the job

as for mounting the shocks on the rear im confused tamiya do not say you can do this so so why are you surprised you cant!

the tower could be slightly angled agreed but the reason you have a ball at the top and bottom of the shock is so it can sit at its own angle to a point if tamiya had suplied the longer bolt and 2mm spacer not a problem.

the reason i think you dont like this car is you have posted nothing but negatives towards it.

stu

[kidcongo]

The 502X is a great performer and very durable......has some quirks like anything. I feel some people have a "hate-on" for it because they have so much invested in their 511's and don't want the future to wipe that slate clean. No one likes it when the model they have spare parts, driving comfort, and maintenance know-how for gets deleted, but time waits for no one. I'm sure the 502X will be history soon enough.

RE the slipper assembly: I cannot see how heat from the motor could be conducted through the tiny ball of the slipper assembly bearings and be heating it up significantly. I have pots from my stove that have metal handles welded right to the pot. The metal handles never get hot because they are only tack-welded in three small spots. You need surface area to conduct heat, and I don't see it happening through the bearings (which only truly have contact in a microscopic edge of the inner balls). The slipper is essentially thermally insulated from the motor. I am glad Tamiya included an aluminum motor mount as that works like a heatsink for the motor and keeps temps in check.

My slipper and diffs are silky and I have no problems with settings drifting during a race. I am thinking of upgrading to ceramic balls, but that is after about a year of running the car.

Try tightening your diff a bit so you dont get flat spots on the balls.

[DaveG28]

Point 3: there's room. Not sure what angle can be achieved but I think with the right design enough. It isn't easy to see but look carefully here and you can see the db02 is angled. It has also pushed the steering rods into a much more 511 position:

http://kentech.blogs.se/2012/01/26/m...ures-12529054/

Bad news is I cannot think of an easy way of achieving this on a 502, you need a 511 style steering base I think to create the angle off a carbon chassis, if the db02 has the angle though maybe the next TRF will again.

From Lee Martins setups from Euro's looks like he was getting around the outer wheel lock issue by cutting into the castor block to allow more inner lock.

Re double slipper: I love it! It creates a system where the rear belt can slip Independant of the front belt, and I think this really helps it when landing off jumps on high grip tracks. Unfortunately, you can't set it independantly, you only have one nut, but it will slip independantly.

Doesn't Kyosho have something on their 4wd?

[Chris]

Originally Posted by kidcongo

RE the slipper assembly: I cannot see how heat from the motor could be conducted through the tiny ball of the slipper assembly bearings and be heating it up significantly.

You don't use metal shielded bearings?

Originally Posted by kidcongo

Try tightening your diff a bit so you dont get flat spots on the balls.

I do not get flat spots on the balls. Fact is that the slipper gets very hot in my TRF502X, with the same motor it remain cool in the TRF511 with the same motor. I will try a different brand of motor next race. And teflon shielded bearings

[Chris]

After testing the TRF502X upgrade kit i can say the car is now really a top level 4WD off-roader.

Will the TRF511 with upgrade set be as fast as the upgraded TRF502X?

Still hoping for a (soon) release of gear diffs for the TRF502X and a more angled shock tower attachment.

Originally Posted by Chris

- the shock tower attachment on the front upper gearbox cover does have a wrong angle. This should be the same angle as the front kick-up. The result is binding of the front shocks when mounted according the manual. It can be solved by use of a double shock tower, but the shocks won't be square with the lower arms. The TRF 511 doesn't have this problem.

-The slots in the diff joints are too large, in this way dust can easily enter the "sealed" gearbox. To prevent this i used a piece of heat shrink to cover the slots. (only covering the slot that's inside the gearbox)

[kidcongo]

My first niight out with the 502X upgrade chassis I took 1st in one of the heats, and 3rd in the A-Main, which for me was quite a step-up. Not sure if it was the improvements to the 502X chassis or just luck, but the car seemed much more connected and responsive with the upgrade set. I found I was thinking at lots less about driving the car, and doing better as a result.

[Aussie Top Force]

I agree with others, the upgrade set works a treat!

However, here is something that needs improving. the rear sway bat mounts are too exposed and easily moved as the screws don't tighten well.

This one was ripped out by another vehicle rear ending the 502X.

I've PM's Fredrik to see if he can find a solution

[taomo]

Originally Posted by Aussie Top Force

I agree with others, the upgrade set works a treat!

However, here is something that needs improving. the rear sway bat mounts are too exposed and easily moved as the screws don't tighten well.

This one was ripped out by another vehicle rear ending the 502X.

I've PM's Fredrik to see if he can find a solution

I'm also interested in a solution to this problem.
The upgrade set works fine for me too but, with the new rear shock tower, the wing touch the rear tires in fast corners

Regards

[Chris]

Gear diffs for the TRF502X?