Quote:
Originally Posted by SCOTI
It actually should be a standard & should be addressed early on if someone is really trying to improve braking ability. Similar thing is rear disc swaps. If the rear wheels lock up using drum brakes, rear disc brakes are just for the glamour show (on a street driven truck).
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I quit upgrading brakes and started upgrading tires after seeing how much better my '64 VW stopped just by changing to a tire that had more grip. It had 100% stock drums all the way around and the stock single circuit master cylinder. I had the typical 145/80-15" Firestone F560 tires up front that everyone has used since the 70's on a lowered Bug. Due to the hard compound it would easily lock and skid the front tires without doing much to slow the car down, and it was especially sketchy in the rain. I've seen a lot of VW people swap to discs because "the drums lock up too easily" yet they're running tires with decades old technology.
I swapped to a more modern summer/high performance 195/50-15 and the car would then pull .97g stopping and did so without locking up as easily- you could threshold brake much easier. At the time my mom had a '99 New Beetle with four wheel disc, 205/50-16 summer tires, and ABS that did .99g braking; basically identical performance between four wheel drum brakes that went into production in 1958 and four wheel disc brakes that went into production in 1998. I now have a '63 VW with discs up front and 195/50-15 tires and it doesn't stop the car any shorter than my drum brake '64 because the tire is still the limiting factor in stopping shorter.
Also relevant- dad had a '57 VW that had been upgraded to the later 58-64 style drums but it had reproduction Firestone bias ply tires. You had to plan stops 15 minutes in advance because the tires had such little grip.
On the Festiva, I put all season tires on it when I'm not autocrossing it and it feels almost unsafe because I know I'm missing out on the braking performance of the stickier track tires. I actually lightly hit a deer one night because I had all season tires on it, and I know I could've stopped shorter and avoided it had I still been on stickier track tires. Same brakes, different braking performance.