Are these the Losi ball cups Hupo Hönigl was using on his 501X: http://www.losipartshouse.com/servle...ty-Ball/Detail ?
Do they fit the stock turnbuckles of the car?

yes and yes - just remember Hupo was running yokomo ball studs, I think Hotbodies would work also though.

When i use a Losi ball cups.
Do they fit the ball studs of the car?

Unfortunately no.

You will need Schumacher, Yokomo, or HPI Ball studs.

Are these the correct HPI ball studs??

4,3x10,3mm PRO4

Thanks

HPI Ball studs can i use a Ball studs for D4?

thank you

I am using the d4 studs, though I'm using d4 cups as well.. but the losi cups should fit though I've not tried.

Hi Jimmy,
I'm thinking of following your example and buying myself the HPI Heavy Duty Ball Cups and the ball studs for the D4. Does it require any modification to my TRF501x parts? Thanks in advance.

no, the only thing I noticed though was the ball cup on the inside hole on the rear camber link - the HB ball cups will slightly rub on the chassis, it's only slight though so you can either sand them down or leave it.. I left it.

Other than that, I think it's all good. I won my first regional today with the HB stuff on. I am using B4 turnbuckles but the kit ones will do the same job.

Thanks Jimmy!
And congratulations on your win :D
Oh yeah. And thanks for this awesome website.
It was your articles that made me get the 501x as well as the nosram matrix evo 2007.

Im running the grey Schumacher ball cups but I also use the Schumacher ball studs too.I wasnt happy with the original tie rods so I opted for some tungsten items aswell.Never had anything come off yet.

The Kyosho ball cups are a direct fit. They feel very free, but I've been racing with them for 3 weeks and haven't had one come off yet.

Since i started this thread the buggers havent popped off since :D how ironic is that ....