Using a bike in Gate Crasher seems to work fine if you avoid high-speed crashes which take a lot of health. Due to better acceleration and top-speed compared to cars you usually find around there it's probably faster.

I tried to compare just the driving routes (without any luring cops) and it seemed using the usual car (with a top speed of about 95) compared to the bike you get during Candy (with a top speed of about 110) may be around 20 seconds difference. My driving probably wasn't the best though, so it's hard to tell.

The question is where to get the bike from though. If you do Gate Crasher after Candy, you have to wait for the drug to wear off before the mission starts, which takes about 25 seconds. Now otherwise during that time you would also have to find a faster car then you would already have (either when you reset and didn't get a good car at the safehouse or when you did Slink or something before that), which of course depends on how fast you find one, but it should usually be faster than 25 seconds.

So let's say waiting for the drug to wear off is 15 seconds slower than finding a good car, then it's possible to save some time using the bike. Of course it increases the chance of loosing time due to falling off, but using a car seemed to have a higher chance of having to switch to another one due to shotgun damage.

Another possibility would be to find a random bike spawn and using that for the mission, or using a car if you can't find one, but of course that is even less clear as to how much time it actually would save.

Overall, I'm not sure at this time whether it's a better strat or not, but it's worth a try.