marco I found that rotating the magnets by a few mm sorts out the different speed problem. If you look at the mounts you see that the magnet retainers can be put in 3 different slots in the casing (all beside each other). They come with the retainers in one of the side slots. Putting them in the middle one seems to sort it but its a bit fiddly to do.

I have happily run a bosch 400 on a 16:1 ratio with a small car speedo (http://www.howesmodels.co.uk/RadioControl/viewProduct.php?ProdID=1605http://www.howesmodels.co.uk/RadioCo...hp?ProdID=1605). I ran a computer fan over the speedo and it got warm but nothing too bad. I wouldnt advise running without some additional cooling.