On tire truing...

[Mitch58]

Just a short note here;

I have a Hudy tire truer which I think is fantastic, it does an incredible job making the cars super smooth. Any way yesterday I happened to have several cars sitting on the track that I had set up with H&R 18K motors for new racers and IROC racing all very smooth and fairly quick.

Out of shear boredom I took them to the bench and put them on my test block and ran them over some fine wet wet/dry sand paper.

Every car gained 3-6 tenths. So now these smooth easy to drive cars that an experienced racer could dip into the high 6s are capable of hitting 6.3

[Pappy]

What kind of rubber? Several things could have caused this. Room temperature and humidity make a difference.

[Mitch58]

These were NSR Supergrips. We used to do this at a club track before we had any truers. This is the first time I've combined the two. My track is in a finished basement so the temp is always the same, being the Pacific NW the humidity can change a bit.
We used to race on a club track in a garage when most of us used urethanes. In the winter we ran Paul Gage XPGs but in the summer we had to switch to PGs as the softer compound had too much grip.

[SpeedyNH]

yep. my problem is that the Hudy axle, for standard 3/32 commercial wheels, is not a nice tight fit in a lot of modern 32nd car wheels, so they're not a concentric cut. sponge tires on commercial tracks, no problem, used it for years all they way up through GT-12, G7 and Eurosport.
but for e.g. Slot.It compatible types and such, where down to a thou is critical? i can only do a only a rough cut. heck, i know guys who use 1500-grit on a sheet of glass using the car to get 'em right.

[RichD]

I have the same issue with the Hudy axle. I have considered having a custom one made or possibly turning down the spare 1/8th inch axle. The axle should be centerless ground, rather than machined.
When Shoreline Model Raceways hosted a proxy race for cars with rubber tires last year one of the cars that was a top runner in the earlier races had very little grip. When I examined the tires I found that they had become glazed, but none of the other cars had that problem.

[Gascarnut]

I did this to make a Slot.it compatible shaft:

I took a 55mm long Slot.it axle, and using some red Loctite, I attached a 40mm length of 3/32" ID brass tubing to one end. Once the Loctite had set, I clamped the axle in my lathe and machined off about 3 mm of the brass tube completely at the end of the axle. Then I clamped the axle in the lathe with the 15mm of original axle in the chuck and the 3mm in a bushing held in the tailstock. This kept the axle straight and supported as well as I could. Then I machined the remaining brass tube down to 3mm diameter, which is what the Hudy shafts are. With small cuts and a sharp tool it goes quite easily, and my final sizing was done with some 600 waterpaper.

Then I slid a 3/32" ID aluminum collar onto the axle end, and that gave me a Slot.it size shaft that fits the Hudy bearings.

The other way would be to grind down a 3mm shaft, but I think that with home equipment it will be difficult to maintain the size and accuracy needed.

[Mitch58]

Interesting, I've nevr had an issue with my axle. Did yours get shipped with something metric like 2mm by mistake? I even ordered an extra one and it is a perfect fit also.

[Redlynr]

I think they are talking about just a small amount of play, like you get when you put a slot.it wheel on an NSR axle. Small, but noticeable slop.

[Gascarnut]

Yes, there's a small bit significant difference between Slot.it's version of a 3/32" axle and everyone else's. The Slot.it axles are very slightly bigger. So, any Slot.it wheels or others designed for their axles are loose on a regular Hudy shaft. Also, when grinding the tires on Slot.it front wheels, the wheels don't grip the stock Hudy shaft tight enough to grind properly.

[Area 51 Raceway NC]

I use dry wall paper for truing my tires. The larger gaps do not clog up like the regular sand paper

[Nonfractal]

For me, commercial tyre truers are good for tearing off diameter and getting the tyres to be about the right shape.
As a final step, skimming on the axle (in the car) finishes everything off perfectly.

Alan W