Wheels digging into side of car

[DuckOfAllTrades]

Preparing for districts, I decided to reprep my sons car. His car was fast, finished 4th overall, but I wasn’t happy with it and felt it should have been faster. He would lay down a fast time, then a slow time, then a fast time, etc.... he had the fastest time of the day. Inconsistency killed his chances for the win. Taking the wheels off the back, I discovered what I think is the answer. The back wheels had dug into the wood they had rubbed so much! Just a perfect circle indention if you know what I mean. This puzzles me. It is a DD4H body, so the back wheels are canted. I checked the gaps before I took the axles out, they were good. Any ideas what caused this? With canted wheels, it should rub much if at all, right? What would make it rub so hard it would indent the wood?

I should have use CA glue around the body where the wheels rubbed, but at the time didn’t know to. I’m planning on filling in the indentions, they are deep, and applying glue/graphite. Once I re prep, it should be much faster and consistent.

But anything else I should do to prevent rubbing? It’s a big concern of mine now with this car.

 

[ironband]

If the axles are canted and the alignment good, then I wouldn't expect such a rubbing to occur in racing.

However, spinning the wheels to work in graphite, test gaps, etc, can cause some graphite wear in the side of the car. And, if the stop section was rough, or the car got bounced around or had wiggles coming down the track, the bouncing motion could have caused what you are seeing.

How deep are the indentations? Do they look deeper than they are because of graphite transfer etc?

When you did a roll test on the car, did wheels migrate outward consistently forward and back?

If so, then the indentations are likely due to handling the car, spinning the wheels with the car upright, and possibly from fishtailing on the track or a rough stop. it's unlikely that they are rubbing as the car is running (excepting wiggles).

I don't usually treat the area around my rear axle holes with anything since they shouldn't be rubbing.

 

[DuckOfAllTrades]

If the axles are canted and the alignment good, then I wouldn't expect such a rubbing to occur in racing.

However, spinning the wheels to work in graphite, test gaps, etc, can cause some graphite wear in the side of the car. And, if the stop section was rough, or the car got bounced around or had wiggles coming down the track, the bouncing motion could have caused what you are seeing.

How deep are the indentations? Do they look deeper than they are because of graphite transfer etc?

When you did a roll test on the car, did wheels migrate outward consistently forward and back?

If so, then the indentations are likely due to handling the car, spinning the wheels with the car upright, and possibly from fishtailing on the track or a rough stop. it's unlikely that they are rubbing as the car is running (excepting wiggles).

I don't usually treat the area around my rear axle holes with anything since they shouldn't be rubbing.

That’s the crazy thing. On a roll test and on the tuning board, they did great. It’s second run was the fastest time all day! Then it slowed. Not sure what happened. Ran smooth all day, not a single wiggle.

I’m not sure how deep they are. I’d say 1/8 - 1/4 mm. They are healthy indentations like the wheels went to being a buzzsaw into the body.

 

[txchemist]

Did your wheels have the inner hub removed?

 

[Jimmy & his 2 Kids]

Sometimes it’s hard to see wiggles in real time and wiggles may have caused that though with not knowing or seeing how deep that’s just a guess. All my axles hole areas get CA then the smoothing treatment other than the NDFW. Always... unless I’m using washers which often aren’t allowed.

 

[DuckOfAllTrades]

Did your wheels have the inner hub removed?

They have a two step hub, have to be as close to stock as possible for our Pack.