Generally speaking, how many miles per week on the bike does it take to pull off 5:30 IM bike split? and still be able to run 
Is there one of those ‘rules’ like no less than X miles per week or you’re screwed??
Thanks!!
mark
Probably no hard rule, but if I had to place a lower limit on it I would say 200 MPW. That should be enough if you can handle it week in and week out over lots of weeks. IOW- not just ramping up for a month or so.
Definitely no such rule. Also, do you mean peak week or off weeks in the winter. IM “racing” is all about consistency over many months to years.
I’ve been sub 5:30 and my peak weeks are around 300 miles with a few 350-400 mile “training camp” bike focus weeks, off weeks as little as 75. With peak bike weeks, I’m then not running very much either (at least I can’t - I’m sure some still can).
There’s more than one way to skin a cat.
In the 6 months prior to my last IM I averaged 206km/129mi per week…min week 50km, max 415km (3 weeks out).
The result was a 4:49 ride on a fair course (just over 1000m climbing) in very hot conditions.
So no, despite what we’re told on Slowtwitch, there’s no such thing as a minimum mileage “rule”.
Just another data point. I have done it (sub-5:30 with good run) multiple times on a steady diet of 200-225 miles with a couple weeks a tad over that.
IMHO, it’s important to be consistent week after week. For instance, I usually don’t ride more than 4:00-4:30 for my long bike rides (even if I have occasionally gone further than that).
Good luck.