#1 problem is the tires on that car. You would be better off with Pit f103 rubber of some sort.

https://www.tqrcracing.com/shop/prod...no=1&o_pg_no=1

Finding tires to work is the problem. If you can find them, try Ride soft rears and hard fronts. Those are the only rubber F103 tires I was able to get any use of. These tires fit well on TRG F103 rims. The ride rims are softer than egg shells. In regards to the Ride tires, I have two sets that I hold onto like gold and hoping I find something else that works.
Also, if the rear of the car comes loose off power, try reducing the rear droop to 1mm or less. That should help some.

Thank you both for the advice.

I'm doing a "narrow chassis" conversion because.. well.. I can. But I'll come back to that.

I brought the car to the indoor track (at WCRC) and with a little sauce, and on black carpet, the car ran pretty well. With the tamiya tires on it. I've still not gooped the kingpins, and i'm running a Tamiya mini CVA shock in place of the standard spring to the rear pod. It's running two holes, and Tamiya yellow fluid in it.

I've been progressively trying to set my diff looser and looser. My brain is still stuck on touring car/off road buggy logic of making ball diffs as tight as can be.

When I worked up to going "fairly fast" on the carpet, the rear end started hopping. I don't know if that's the tires, or something I can solve with setup.

I have a light coating of diff grease on my damper pads. I've adjusted the damper pad preload spring from the 4mm to 6mm, and back to 2mm, with some, but difficult to quantify results on handling.

I feel like the problem may just be the big fluffy tires out back, they are acting a little bit like the old car stadium truck tires before foam inserts were a thing.

I bought Tamiya's modern F1 wheels, and tires, and body. I'm ordering parts to do the modern F1 front end... To see how the chassis handles as a modern F1 car.

I got some of those Shimazo tires ordered, and the parts to complete the narrow body chassis.

I'm excited to try both ways.

What is considered to be the more competitive kit? TRF102 or the F104 Pro II?

The Pro II is more basic and has a friction plate. Don't expect major changes. The TRF102 is the better kit.

Honestly, there are better options out there. Tamiya F1 cars aren't too great. (I do have a TRF102 for sale though.) ;)

Much to my disappointment, the F104 narrow front end, takes different screws than the F104w front end does. So.. I couldn't drive my car last night. AAAAand I found that the shimazo tires require foam rims, instead of the lipped rims. So that didn't happen either.

I like the round carcasses, and wide, full, foams. The foams that came from tamiya were.. only like 1/2 the width of the carcass, and less than 2/3 the height of the tire.

so... Here's a look at my converted F104w.

A Real Life Tinker Gnome: The f104w transformed. A f104 pro?

https://lh3.googleusercontent.com/-g...930_005442.jpg

And for refrence, here's what it started as:

https://lh3.googleusercontent.com/-r...903_205104.jpg

Here's the list of parts I needed to do the job:

The plastic parts - F Parts: 42289 TRF102 / F104
The kingpins - Stainless Shaft: 58431 - 3x33.4mm F104
Ball Connectors - 4mm Ball Connector: 44002 (Gold Color, 5pcs)
Ball Joints to match - 4mm Adjuster: 44002 - 6pcs
Metal Parts for the suspension - 5mm Aluminum Ball Nut - Blue 10pcs
E-clips to hold the Kingpins - E-Clip 2.5 x 6 x 0.4 - 10pcs RM01 / F103 / FGX
Front wheel bearings - 5 x 10 x 4 mm (4 pcs) - F104 Front Axle Bearing
Cap screws for the front suspension pivots - M3x6 Flathead Screw (4pcs)
TurnBuckles - 3x35mm(2pcs)
Bolts to hold the front end on - 30mm m4 flathead screws. (2pcs) and nuts M4 nut (2pcs)
Knuckles - Carbon Reinforced Uprights - F103 / F104 Tamiya (54154)
Screws - m3 x 10 (2pcs)

And I think that's it, not including the body and tires. This is really and updated list to the list a couple pages back.

I have a question. Im building the F1R3 chassis and dont understand the whole spacer thing on the front end. Is there a set amount in total there should be as in 5mm under the axle and 3mm on top for a total of 8mm? If not there is a lot of play up and down.

You need to use spacers under the steering knuckle to get rude height. There should be a set screw on the knuckle to lock it on the king pin.
Hopefully you can see it in the below photo

Yep. I see them on mine (I have the Tamiya adjustable knuckles). So I dont need to worry too much about the spacers on top to fill the gap?

Correct, though you can use the space to adjust droop if you want.

The tamiya alum knuckles need more shims than the stock tamiya plastic knuckles, they are thinner.

IIRC 1mm above and 1mm below or maybe .5 above and .5 below

Just got an F104 from a friend. I upgraded it with all the available hop ups to a pro/x1 and beyond, keeping it tcs legal. It is a beast...raced it for first time a week ago and was keeping up with the pack...while running the Reedy 25.5...everyone else was running 21.5s. What a car! They were all running the latest chassis from other manufacturers.

What advantage do you all see to adding the aluminum steering knuckles?...literally the only upgrade I have not done.

They can be run in either trailing or inline configuration and are even more durable than the stout plastic knuckles.