On older software (which you MAY still have on a ONE), you had the option to add or remove items from the status bar display, and the more you added, the smaller each one got, so they could all fit.
Similarly, if you turned off everything except one item, it got bigger to fill the available space
Have a look in the "preferences/ menu for "status bar preferences". If it's there, it MIGHT have that feature.
Unfortunately, in their wisdom, TomTom eventually removed that way to customise your device (along with a lot of other useful stuff!)
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TT used to allow the use of third-party "add-on" programs, and one that would probably do what you want is "Tripmaster" (from
here).
But all of these extra programs were make ages ago when TomTom were much more helpful with ways to modify or add to the core-program.
Now most of them won't work with recent software, so you'd have to revert back to quite old software and that's not always easy or even possible.
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To be honest, I think it might be a lot easier to keep the TomTom for navigation only and to use something else for your big speed display.
This topic on another forum has some suggestions including an iPhone app.
If you Google "Big speed display on GPS" you'll probably find some more.
