XT Route Mileage calculations compared to TT and Zumo 595

[Min]

Hi have an XT and noted that the calculation of travelling to a point is strange, so what have Garmin done to the software to turn a 10 mile trip into a 32 mile, take me through towns up and down hill when the Zumo 595 and 590 plus TT take me the route direct +/- 2 mile.

All are set for the fastest route without any other diversions, but the XT is strange that reversing the same route its always wanting to head for motorways or dual carriage ways adding 22 miles to a 10mile trip plus adding 30 minutes travelling time

I like the GPS but this calculation setup is a pain, it didn't happen on the 550 or 660 so what has happened? (Motorway Madness seeing?) Is anybody else noticing this problem as I have seen a comment of it liking motorways if a planned trip miscalculates.
The route I use is well known to me and knowing I have only 14-15 mile to get home and its telling me it added 15 more down dual carriageways and town that I know will be blocked with traffic, its not the fastest route. Fun when you run 3 GPS plus the low level Garmin in the car....

Any answers or thoughts (reminder they are all set the same)

Min G0JMS

[jfheath]

Welcome to the forums !

This issue has been lodged with Garmin Tech Support for while by a few of us. So far no software upgrade has addressed the issue.
The more people that raise it, the bigger chance there is that Garmin will do something about it. (I hope).

You have to be determined though. No matter what you say in your first email of phone conversation, they will direct you to help pages that contain information about one or two words that you have mentioned. At this stage they will ignore any argument or discussion. They are making sure that you haven't missed anything obvious. "Have you turned it on ?" I'm being flippant, but you get the idea,

They will then move you on to someone that suggests more practical things - like use more shaping points for the satnav to follow the route that you want. And maybe select avoidances to help shape the route.
But you have to stick to the notion that 'faster time' should mean 'faster time'. Back it up with examples where there are no road works, no traffic issues etc. And it helps if you can say honestly that you have cleared your riding profile and have installed the latest software and maps, and that you have no avoidances set.
All of these things detract from the message, but they have to ask them as they are common genuine reasons for the satnav doing something unpredictable.

But the bottom line is just that - you expect that if you ask the satnav to take the fastest route that it doesn't interpret that to mean take a massive detour in order to get to a faster road.

It's a big expectation to get them to fix it. This seems to be a fundamental software strategy - perhaps to minimise calculation time comparing different routes to using an algorithm that finds the fastest road in the vacinity and head to that. I don't know. Yet they already have software that works quite well from the 590. (The 595 has its own issues which appear to have been carried forward to the XT).

But I keep wondering if this really is such a big issue. I often travel on roads that are old main roads and are relatively fast and traffic free. Eg to get from Yorkshire up to Scotland. The A6 runs parallel to the M6 for most of its length and is a dleightful road to ride. The B7076 is the old trunk road into Scotland from Carlisle and runs parallel to the M74. Yet if I plot a route to Scotland, I have to keep putting shaping points to prevent the Zumo from taking me onto the nearby motorway. So I could just use the same tactic for faster roads - but whereas motorways are very clearly identified on a map, which roads Garmin decides is faster than another road is less easy to work out.

My 2 year guarantee runs out in April. I'm wondering if this unit really is not fit for purpose, ditching it and reinstalling my 590. If it is, should I have spotted it in less time than the 2 years that I have owned it ?

I could use Avoid Motorways - on the XT - but there isn't an equivalent of that in Basecamp. Interstates, Major Highways, State Highways do not translate well into UK road types. Interstates often means a motorway, but not always.

[Min]

Thanks for the reply and glad I'm not the only one that sees the issue, I have used Basecamp for many years and plan routes for trip on the bikes using the A7076 last year, did a ride while staying in Carlisle up to Moffatt and back down to Carlisle, before doing the Lakes in a day. https://youtu.be/r3n6XD58gK4

I do use MRA (even Tyre) but much prefer BC for planning and with care they work well and found that TT worked better last year when there was so many road closures (repairs but nobody working) but I have put lots of routing in and Garmin XT got confused, great when leading https://youtu.be/GjLhgoEoSck having to prod the GPS.

I hope they sort out their algorithm for the routing which will make it a muck better GPS, shame it hasn't the tyre pressure app like the 590 and 595.

Fingers crossed that it's resolved.

Min G0JMS

[jfheath]

The XT has some saving graces.

It will follow a track - which doesn't recalculate, but doesn't give instructions. Its actually better than it sounds.
It will convert a track to a 'trip' - which does give turn by turn directions and which will direct yo to the closest point to get back to the magenta line if you deviate.
Like the 590, will allow a track and route to be shown on the same screen

More info on the above is in section 6 here: app.php/ZXT-P45