XV-01 Very Slow Build

[Pylon80 3757]

To anyone wishing to upgrade their CVA's, the biggest improvement will come from using TRF machined pistons. Unlike the CVA ones, there is no leakage around the piston under normal conditions which makes the damping action so much more consistent and controllable. I use the 3-hole ones and never go above 400# oil.

The o-rings and shafts are very nice but still a very minimal performance upgrade compared to the black coated shafts and red o-rings that come with CVA's.

[skom25 2210]

I checked stock shafts and they seem to be quite nice. I was afraid that they used that harsh, black coat, but this seems to be fine.

If blue o-rings will be available, I will use them. If not, I will stay with stock or... buy aluminium shocks.

TRF are too expensive, but if "standard" version will be available...

[Pylon80 3757]

3 hours ago, skom25 said:

I checked stock shafts and they seem to be quite nice. I was afraid that they used that harsh, black coat, but this seems to be fine.

If blue o-rings will be available, I will use them. If not, I will stay with stock or... buy aluminium shocks.

TRF are too expensive, but if "standard" version will be available...

How about CC-01 aluminum shocks? Just a thought.

[skom25 2210]

They are fine for long damper version. At least this is information I have.

Today I realised that standard shocks do not have too much travel. I am bit surprised. It is probably less than on front suspension of average buggy.

[Pylon80 3757]

9 hours ago, skom25 said:

They are fine for long damper version. At least this is information I have.

Today I realised that standard shocks do not have too much travel. I am bit surprised. It is probably less than on front suspension of average buggy.

Oh that's right you are on the regular damper version. Yes it's using pretty short shocks but that doesn't matter, the suspension works extremely well.

[BuggyDad 5989]

3 hours ago, Pylon80 said:

Oh that's right you are on the regular damper version. Yes it's using pretty short shocks but that doesn't matter, the suspension works extremely well.

Yes, you'll find it very different to a buggy. The suspension is hugely active, it's a joy to watch, I think. I'm looking forward to putting mine back to rally spec sometime. 

[skom25 2210]

Hubs and shocks mounts ready:

Biggest difference between XV-01 and cheap models is e.g. bearings fitment. They sit tight and there is just minimal play on hub. 

Hint: I try to set Hexes on their final position even before I put wheels on. To do this, I use piece of plastic to not scratch Hex and regular M4 nut.

Hex screw has to be loose. Next you tighten nut ( not too much, just to compress parts) and then Hex screw. After that operation, you can be sure that Hex will not move when you install wheels. It is hard to compress parts together using fingers and at the same time tighten Hex screw.

Mounts on shocks towers:

I was limited by two screws lengths: M3x20 and M3x25

First one was bit too short with suggested setup, second one definitely too long.

I put chassis on flat surface and used different spacers to keep mounts geometry and have enough thread, to install ball nut. It is not perfect, but good enough. Angle between lower and upper ball nuts is minimal.

I really have to make turnbuckles, but I already feel pain in my fingers, even I have not started yet... I thought about Tamiya tool, but it is so expensive and it is almost like one attempt per model, that I really have doubts that I need it.

[BuggyDad 5989]

2 hours ago, skom25 said:

Hint: I try to set Hexes on their final position even before I put wheels on. To do this, I use piece of plastic to not scratch Hex and regular M4 nut.

Hex screw has to be loose. Next you tighten nut ( not too much, just to compress parts) and then Hex screw. After that operation, you can be sure that Hex will not move when you install wheels. It is hard to compress parts together using fingers and at the same time tighten Hex screw.

I like this idea. I do up the hex only tight enough that it's not loose on the axle, so it can still move along it under pressure, fit and remove wheel, then nip up. Ultimately though, the screw in the hex only needs to be tight enough that the hex won't come off with the wheel, I reckon. Your method is far better. 

2 hours ago, skom25 said:

I really have to make turnbuckles, but I already feel pain in my fingers, even I have not started yet... I thought about Tamiya tool, but it is so expensive and it is almost like one attempt per model, that I really have doubts that I need it.

It hasn't arrived yet but some time ago I ordered a similar tool off AliExpress. It was very cheap. I also at the time couldn't see the Tamiya one in stock. There are two different sizes, I think one for TCs and one for buggies (although I think my TCs and buggies have all the same size adjusters 🤷). Meantime I put the adjuster loosely in a drill chuck, hold a wrench on the turnbuckle and slowly drive it up. It works to save the fingers. Maybe someone could make a hybrid solution - tamiya tool machined down at the handle end to fit in a drill or even 1/4" hex for a driver. 

[skom25 2210]

7 minutes ago, BuggyDad said:

I like this idea. I do up the hex only tight enough that it's not loose on the axle, so it can still move along it under pressure, fit and remove wheel, then nip up. Ultimately though, the screw in the hex only needs to be tight enough that the hex won't come off with the wheel, I reckon. Your method is far better. 

It hasn't arrived yet but some time ago I ordered a similar tool off AliExpress. It was very cheap. I also at the time couldn't see the Tamiya one in stock. There are two different sizes, I think one for TCs and one for buggies (although I think my TCs and buggies have all the same size adjusters 🤷). Meantime I put the adjuster loosely in a drill chuck, hold a wrench on the turnbuckle and slowly drive it up. It works to save the fingers. Maybe someone could make a hybrid solution - tamiya tool machined down at the handle end to fit in a drill or even 1/4" hex for a driver. 

Thank you!

So, there are two different tools for different adjusters? I was sure, that tool is compatible with both, but it was just my idea without any confirmation in facts.

[BuggyDad 5989]

20 minutes ago, skom25 said:

Thank you!

So, there are two different tools for different adjusters? I was sure, that tool is compatible with both, but it was just my idea without any confirmation in facts.

I think Tamiya does two different sized tools. My AliExpress one didn't give a size option but it was cheap so I didn't properly research the sizing thing and just went for that.

[skom25 2210]

Turnbuckles? Nah, 30 minutes of work...

3 hours later.

I had to use three spares, because I had feeling that I threaded them bit on angle. I was not sure, so just made new. I am still not sure if they are perfectly straight, but I really do not want try again.

It really feels like big quality jump over my DT-03 and TT-02B.

Today was my birthday party and I got soldering iron as an gift. I want to learn how to solder ( I know basics and I am able to do simple jobs).

Unfortunately grip is bit hot, so I need to solder quickly....

[skom25 2210]

Have I said 3 hours? 1 hour more today 

As you can see, turnbuckles on rear are on absolute limit. I set them as in manual. I do not suspect that I will need more negative camber, so maybe it will not be an issue.

Unfortunately, when I installed them and tried to set correct length, I scratched one of them. I had one spare, so prepared new one and this time, set both of them with fingers.

As you can see, I used blue 2 mm spacer between hub and arm. Stock part is plastic and 1.8 mm. There is less slope with 2 mm, but still around 0.1/ 0.2 mm of free movement. I thought for a moment to remove all slope, but I am not sure if it is good idea. I think that if I remove all movement, parts start to wear much faster.

I forgot to mention, that I cleaned cups and driveshafts with soap to remove all dirt. To protect metal, I used tiny amount of WD40 on cosmetic pad and then clean cloth to remove excess.

There is one thing I do not understand:

On rear cup there is one urethane bushing in diff cup and half on hub axle. On front there is one on diff cup and 3mm o-ring on hub axle.

Why? Is there really any reason to use o-ring instead of urethane bushing?

[Grumpy pants 5511]

It is really coming along well. 

[Pylon80 3757]

On 12/10/2023 at 2:39 AM, skom25 said:

Why? Is there really any reason to use o-ring instead of urethane bushing?

Nope, no valid reason. You can do it all with urethane bushings. Just make sure the total thickness is not causing the suspension to bind, especially left to right differences.

[skom25 2210]

Belt tensioner.

I did not like stock version, so made my own. I do not have plan to use that small cover. I prefer to keep an eye on belt tension.

I tried to be as minimalistic as possible. I used 0.3 mm shims instead of 0.2 mm, just to have bit more space.

To have correct position, there is 1 mm spacer between nut and chassis. On outside, I used 0.5 mm washer and nut from kit.

Because I really like to care about small details, I sanded end of screw to have flat surface...

[skom25 2210]

Belt cover and wheel arches installed.

As you can see, I used aluminium bolts for wheel arches. 

I also bought countersunk aluminium screws, but they are really bad. After first contact with key, I already saw some deformation od edges. You can say, that it is only visual issues. Well, I believe that almost all people buy them only to make model pretty...

Belt cover is a different story. Part from kit had like a "bubble" deformation on one side. It was fine, but I was bit afraid that it can touch belt. Yesterday I bought new sprue. This time there was no bubble, but cover looked more like banana... After installation it seems to be fine. At beginning I heard some rubbing, but then I moved cover from side to side and I do not hear any strange noises anymore ( I checked many, many times even with cover pressed a bit, to simulate movement during run...)

Antenna mount is on central position, to keep balance on chassis center. LOL.

I also ordered Pre Cut stickers, but I will write more about this during body build.

[NM Frontier 13]

Chassis is coming out great! Just the right amount of blue!

[Honza 1169]

On 12/10/2023 at 10:39 AM, skom25 said:

Why? Is there really any reason to use o-ring instead of urethane bushing?

Yes, O-ring keeps the dog bone end in the center of the cup, while urethane bushing allows for some movement. Diff cups are generally a bit longer to allow for that movement.

[Pylon80 3757]

On 12/8/2023 at 10:58 PM, skom25 said:

Hint: I try to set Hexes on their final position even before I put wheels on. To do this, I use piece of plastic to not scratch Hex and regular M4 nut.

You can simply install a wheel and spin it. If it spins freely and you can't perceive any lateral play, you are done.

[Pylon80 3757]

4 hours ago, Honza said:

Yes, O-ring keeps the dog bone end in the center of the cup, while urethane bushing allows for some movement. Diff cups are generally a bit longer to allow for that movement.

You have a point! The o-ring helps at least one end of the dogbone center. O-rings don't allow for nearly enough change in width so Tamiya probably called for a urethane bushing on the other end. On many kits, they put urethane bushings on both ends. I have been doing this but I will probably try a black o-ring at the next re-build since I started using dogbones again recently (as opposed to universals) 

[Pylon80 3757]

20 hours ago, skom25 said:

I did not like stock version, so made my own.

I love that kind of modification, that is awesome.

[skom25 2210]

Me: Mom, can we buy TRF shocks?

Mom: No, we have TRF shocks at home

TRF Shocks at home...

Well...

Today I cleaned and prepared all parts. Plan is to build them tommorrow. 

Two pistons are from TT-02B aluminium shocks set, other two bought seperately as TRF. All have three holes, but for some reason in TRF holes are smaller.

I did quick test with TRF shafts. I had old shocks with red o-rings, so I just put both shafts to cleaned shocks and check movement. I have not found any issues with gold shafts and red o-rings.

[Pylon80 3757]

1 hour ago, skom25 said:

Me: Mom, can we buy TRF shocks?

Mom: No, we have TRF shocks at home

TRF Shocks at home...

Well...

Today I cleaned and prepared all parts. Plan is to build them tommorrow. 

Two pistons are from TT-02B aluminium shocks set, other two bought seperately as TRF. All have three holes, but for some reason in TRF holes are smaller.

I did quick test with TRF shafts. I had old shocks with red o-rings, so I just put both shafts to cleaned shocks and check movement. I have not found any issues with gold shafts and red o-rings.

It going to be ok as long as you identify which shocks have the small holes and which have the bigger holes - hole diameter makes a huge difference.

I am not the expert on buggy dampers  but I believe the large holes are critical and allows the damper to behave differently on small bumps and large jumps? Something about how the damping will drastically increase if you try to move the piston too quickly (large jump). If you want them all the same you can't make the holes smaller but you can re-drill the smaller holes. You will need a precision drill bit set for this. It's only money!

I know you hate building shocks so good luck.

Not meant as bad omen but I bought 2 sets of CVA to get one good set, since each set had 1 bad damper in it... The bad damper was due to a molding problem on the shock body which would cause it to draw air (bubbles) no matter how hard I tried to avoid it.  I have never heard anyone else on TC report this issue, but the fact that it happened twice tells me that I am not (completely) crazy. Only one damper per each set of 4 behaved this way. A shame, as the 3 other ones were perfect. If that happens to you it's not your fault... keep calm and order more

 

[skom25 2210]

23 minutes ago, Pylon80 said:

It going to be ok as long as you identify which shocks have the small holes and which have the bigger holes - hole diameter makes a huge difference.

I am not the expert on buggy dampers  but I believe the large holes are critical and allows the damper to behave differently on small bumps and large jumps? Something about how the damping will drastically increase if you try to move the piston too quickly (large jump). If you want them all the same you can't make the holes smaller but you can re-drill the smaller holes. You will need a precision drill bit set for this. It's only money!

I know you hate building shocks so good luck.

Not meant as bad omen but I bought 2 sets of CVA to get one good set, since each set had 1 bad damper in it... The bad damper was due to a molding problem on the shock body which would cause it to draw air (bubbles) no matter how hard I tried to avoid it.  I have never heard anyone else on TC report this issue, but the fact that it happened twice tells me that I am not (completely) crazy. Only one damper per each set of 4 behaved this way. A shame, as the 3 other ones were perfect. If that happens to you it's not your fault... keep calm and order more

 

I am not surprised. I mentioned two or three times some kind of defects in this build.

I built four or five sets without issues and I hope it will not change this time

 

[alvinlwh 7251]

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