Big Rock Big Rock Right Wheel Issue

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matflat

Active Member
Messages
71
Reaction score
75
Location
South Africa
Arrma RC's
  1. BigRock 4x4
  2. Typhon 3s
Hello Arrma Forum Members,

I am a new poster and just took ownership of a Typhon 3S and a Big Rock 3S. The first week of owning them was awesome. However, the shop that sold them to me is unhelpful, so I am turning to you all to ask for some guidance and help. It is very difficult to get parts in the country (despite the shop being the main importer), so would really appreciate some guidance before I order parts from overseas.

The issue with the Big Rock is in the attached video. My son has a pretty fast, but rather parallel crash into the side of a kerb. He was only using 50% power driving forwards then he veered too far to the right of the road, hits the brakes, and as the road was a little slippy, the car went sideways into the kerb. It looked like a straight hit if that makes sense in that we thought the two right wheels hit at the same time, and that he may have been lucky. But we now know that something is up. And before I order parts that are tricky to come by in South Africa, I was hoping that fellow Arrma enthusiasts could tell me what to actually look for to diagnose where the issue sits.

I have added a video to this post so that you can see what I am describing. The short story is that every time he drives the car pulls to the right. No amount of correction helps at all. Viewed from the top, the right front wheel does look slightly out based on the left-hand side wheel.

I don't know what to check. Should I check the hub - or how do I check it to see if this is damaged? Should I just pony up and get some replacement wheel axles, hubs, turnbuckles, rod ends? I am not sure where to start.

Really hope someone can help me out. And if there is anyone from South Africa that has knowledge of parts shops that can help that would be really appreciated. I love these cars, and me and my kid are like unhappy dogs because we can't go blast around the park :)

Thanks,
Mat.

 
Take it apart. Go to the Arrma website and look at the exploded view. Lots of videos online. Get to know the rig. Not much can go wrong. Wrenching is simply a part of rc driving. After a few times you won't even need the plan. If money is no issue you might consider getting another Typhon for spare parts. And then order the parts to get the spare car into driving condition again. You also might consider using Typhon Nr. 2 to convert the Big Rock to 17mm hexes. Makes it easier to get tires and to have same tires on both cars. I would not want to wait every time for spare parts to arrive.

Close these holes to prevent sand and dust destroying the motor.

Holes1.jpg


Holes2.jpg


Is the wheel rim cracked?

Or axle AR310784 bent?

 
Last edited:
Take it apart. Go to the Arrma website and look at the exploded view. Lots of videos online. Get to know the rig. Not much can go wrong. Wrenching is simply a part of rc driving. After a few times you won't even need the plan. If money is no issue you might consider getting another Typhon for spare parts. And then order the parts to get the spare car into driving condition again. You also might consider using Typhon Nr. 2 to convert the Big Rock to 17mm hexes. Makes it easier to get tires and to have same tires on both cars. I would not want to wait every time for spare parts to arrive.

Close these holes to prevent sand and dust destroying the motor.

View attachment 256845

View attachment 256843

Is the wheel rim cracked?

Or axle AR310784 bent?

Many thanks for the suggestions. Going to start the tear down now and report back. Great point on closing those holes.
May have cracked the bearing hub, trashed a bearing, bent the steering tie rod… Take it apart and inspect all the parts.
Will do. Going to start the tear down now and then report back :)
 
Ok so I tore down the wheel section, removed the wheel nut, removed the end rods, removed the hub etc, the wheel rim isn't cracked. Inspected all of that and there wasn't anything clearly obvious. Gave the pieces a wipe down and couldn't anything that had cracked. All of the pieces seemed alright. I compared it to the left-hand side and it was the same.

As I was doing this and handling the pieces, the right slider front driveshaft sleeve slipped off (ar310780), which was a good thing. I then noticed that the piece it was attached to AR330469, the steering rack, houses the Arrma wheel stub axle (piece AR3107814 that RC-Dude mentioned), and if you look closely at the video, it does look like it is slightly bent. It isn't very pronounced, but the effect when compounded through the other components to the wheel would look like it is the culprit.

What do you think - is this a potential answer?

Your help in working this out has been phenomenal.

Cheers,
Mat.

 
Looks like it's the stub axle. Carefully hammer it straight again and install again . Check the bearings if they got a hit.
 
Ok so I tore down the wheel section, removed the wheel nut, removed the end rods, removed the hub etc, the wheel rim isn't cracked. Inspected all of that and there wasn't anything clearly obvious. Gave the pieces a wipe down and couldn't anything that had cracked. All of the pieces seemed alright. I compared it to the left-hand side and it was the same.

As I was doing this and handling the pieces, the right slider front driveshaft sleeve slipped off (ar310780), which was a good thing. I then noticed that the piece it was attached to AR330469, the steering rack, houses the Arrma wheel stub axle (piece AR3107814 that RC-Dude mentioned), and if you look closely at the video, it does look like it is slightly bent. It isn't very pronounced, but the effect when compounded through the other components to the wheel would look like it is the culprit.

What do you think - is this a potential answer?

Your help in working this out has been phenomenal.

Cheers,
Mat.

There’s a screw holding the stub axle in that tends to come loose. Run a 2mm driver up the shaft and loosen it, remove the stub axle, squeeze a drop of locktite into the screw hole on the axle then reinstall it and tighten down well. Do this to all the drive shafts at the wheel. Also make sure they are tight at the diff. I usually don’t locktite the connection at the diff just make sure it’s tight.

Maybe it’ll straighten out afterwards. Either way it’s a good idea to do so the wheels don’t fly off. It’s one of the first things I do on any new 3s car and axle I install. If my description doesn’t make sense, let me know and I’ll post some pictures later.
 
Looks like it's the stub axle. Carefully hammer it straight again and install again . Check the bearings if they got a hit.
Thanks RC-Dude. I’ll give it a go. Fortunately I managed to find two sets cheap in country as well so I preferred them for what will become an ever growing library of spare parts 👍🏻
Thanks RC-Dude. I’ll give it a go. Fortunately I managed to find two sets cheap in country as well so I preferred them for what will become an ever growing library of spare parts 👍🏻
Also the words hammer and careful aren’t in my vocabulary so I’ll see how that goes 😂
There’s a screw holding the stub axle in that tends to come loose. Run a 2mm driver up the shaft and loosen it, remove the stub axle, squeeze a drop of locktite into the screw hole on the axle then reinstall it and tighten down well. Do this to all the drive shafts at the wheel. Also make sure they are tight at the diff. I usually don’t locktite the connection at the diff just make sure it’s tight.

Maybe it’ll straighten out afterwards. Either way it’s a good idea to do so the wheels don’t fly off. It’s one of the first things I do on any new 3s car and axle I install. If my description doesn’t make sense, let me know and I’ll post some pictures later.
Hi Velodromed. Thanks for the info. If you have pictures that would be super helpful. I think I’ve got rookie syndrome as I’m a bit peeved that the shop doesn’t have spares and that on my Typhon the big plastic rotor is completely shredded and apparently it’s my fault, but the Big Rock is fine. I know it says RTR on the pack, but this site has been eye opening about what to do to actually set it up properly. All this help is really appreciated.
 
Do you mean the spur gear? The main gear that the motor pinion turns…
Yes I meant that. Still noobing on this 😂 the Typhons is shredded. I did a load of searching and thought I’d check the slipper clutch. So I took out the motor, took out the spur gear tightened it as it was really loose (there was no drive at all), then loosened it a bit so it want so tight. I then went on a video call and the whole thing literally blew up. It sheared the bolt and made such a loud bang everyone on the video call heard and saw the fall out. You learn something new every day.
 
Yes I meant that. Still noobing on this 😂 the Typhons is shredded. I did a load of searching and thought I’d check the slipper clutch. So I took out the motor, took out the spur gear tightened it as it was really loose (there was no drive at all), then loosened it a bit so it want so tight. I then went on a video call and the whole thing literally blew up. It sheared the bolt and made such a loud bang everyone on the video call heard and saw the fall out. You learn something new every day.
I’m having trouble picturing what you mean. I have five, 3/4S cars and never had anything like that happen. Can you describe a little bit more? Which bolt sheared off? Did you have it running on a stand while you were on your video call?
 
I’m having trouble picturing what you mean. I have five, 3/4S cars and never had anything like that happen. Can you describe a little bit more? Which bolt sheared off? Did you have it running on a stand while you were on your video call?
It was the bolt in the slipper clutch assembly. It’s part of the kit number ARA311033. That bolt popped out. I must have tightened it too much. I don’t have a stand yet unfortunately. That’s the next piece I need. The videos are if the Big Rock not the Typhon. I know what went wrong with the Typhon I just need to get the part as you’ll see in the below images.

3ED55054-DFC2-442E-88B3-6A3549434DA2.png


F88462C7-5D44-4EE0-B2EF-A534C96F00EC.png
 
Hello Arrma Forum Members,

I am a new poster and just took ownership of a Typhon 3S and a Big Rock 3S. The first week of owning them was awesome. However, the shop that sold them to me is unhelpful, so I am turning to you all to ask for some guidance and help. It is very difficult to get parts in the country (despite the shop being the main importer), so would really appreciate some guidance before I order parts from overseas.

The issue with the Big Rock is in the attached video. My son has a pretty fast, but rather parallel crash into the side of a kerb. He was only using 50% power driving forwards then he veered too far to the right of the road, hits the brakes, and as the road was a little slippy, the car went sideways into the kerb. It looked like a straight hit if that makes sense in that we thought the two right wheels hit at the same time, and that he may have been lucky. But we now know that something is up. And before I order parts that are tricky to come by in South Africa, I was hoping that fellow Arrma enthusiasts could tell me what to actually look for to diagnose where the issue sits.

I have added a video to this post so that you can see what I am describing. The short story is that every time he drives the car pulls to the right. No amount of correction helps at all. Viewed from the top, the right front wheel does look slightly out based on the left-hand side wheel.

I don't know what to check. Should I check the hub - or how do I check it to see if this is damaged? Should I just pony up and get some replacement wheel axles, hubs, turnbuckles, rod ends? I am not sure where to start.

Really hope someone can help me out. And if there is anyone from South Africa that has knowledge of parts shops that can help that would be really appreciated. I love these cars, and me and my kid are like unhappy dogs because we can't go blast around the park :)

Thanks,
Mat.

Hey I'm new to the RC world i have same issue with rear left tire on my big rock 3s. Thanks for all the help here i know what to look for
 
Hey I'm new to the RC world i have same issue with rear left tire on my big rock 3s. Thanks for all the help here i know what to look for
Hey @Michael b - the issue was so small in the end. But the compounded effect was huge. Once we got the part and replaced it the Big Rock goes :) I'll post some more updates on the various user mistakes I have made in the hope others can learn as well. On Sunday I drove my Typhon stright into a flag pole on a golf course. It hit the flag pole so hard it actually came out of the hole. Broke a steering block, luckily nothing else. You'll love the Big Rock, it is amazing.
 
Hey @Michael b - the issue was so small in the end. But the compounded effect was huge. Once we got the part and replaced it the Big Rock goes :) I'll post some more updates on the various user mistakes I have made in the hope others can learn as well. On Sunday I drove my Typhon stright into a flag pole on a golf course. It hit the flag pole so hard it actually came out of the hole. Broke a steering block, luckily nothing else. You'll love the Big Rock, it is amazing.
Ya my mistake on this accident driving on the street at 100% the car did about 15 cartwheels after that I didn't notice it until I was driving it though some think mud.
I asked Santa for some upgrades that I thought I'd need thanks for responding
 
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