Also false. Both tiagra and 105 had/have triple chainring options. You can run as low as a 32T with a med. cage 105, according to spec. Some have reported that you can use a 34T low although it's not (officially) recommended by the factory.
Plenty of brands sell road bike models with a 50/39/30, with a 30T, and it's possible to swap this out for a 32 or even 34T low.
Originally Posted by
gsa103
That also requires running MTB components to get that low-range gearing. You can't get there with a standard road group. Its an option, but will add a lot to the cost of a new bike.