While it is most likely related to disturbing your rear ABS sensor, if sorting that doesn't fix your problem, you may need to consider your front tire size!!
Please bear with me while I explain a little. Firstly, the 'nanny' relies on the sensors on each wheel telling it that the wheels are turning at the same speed, so if you've changed your rear wheel & the size difference (rolling dia/circumference) between front vs rear is now much more than about 20mm different to what it was/what the nanny expects it to be, you might need to do something (like change air pressure in the tires or fit similarly 'over-sized' tires up front) so that the front vs rear tire speeds match better or at least get within the limits the nanny can handle - it seems that the closer the speeds are to being within an acceptable difference, the faster you can travel before the nanny gets upset....
Generally, fitting a 215/60 on the rear instead of the OE 225/50 shouldn't be much of an issue to the nanny or anything else, but the generic or nominal tire sizes on their sidewalls don't always tell the full story, so whatever brand tire you've fitted might actually be pushing the increase limit just a little, especially if you are running a fairly high tire pressure (say, anything over 30 psi!!) Add to that the fact that the front wheels are only ground driven, so if they are getting a little worn & low in their tread depth, and maybe you are running a fairly low pressure in them (say, anything below about 18 psi) you could be pushing the rolling dia/circumference difference into the realm of 'too much' for the nanny!!
So like I said earlier, if sorting the ABS sensor position doesn't resolve your problems, you might hafta look at finding out
exactly what the rolling dia of your new tire is & compare it to the specs on the OE crap rather than going by a generic size comparison chart. Even if they seem pretty close, consider the state of wear/tread depth on your front tires & check your tire pressures all around. Many tire fitters use 40 plus psi to 'seat the bead' when fitting a new tire, & that might be OK
IF they remember to drop it back down to a safe road pressure, but they often don't!! And as I've experienced myself, running the rear tire pressure too high by as little as 4psi in your new rear tire is quite enough to upset the nanny when you still have fairly worn OE front tires or they are running a 'lower than spec' pressure!!
Dropping my new rear tire pressure by 2psi (to 26 psi from 28 psi) & upping the fronts (from 18 psi to 22 psi) pushed my 'upset the nanny' front/rear speed variance high enough so I didn't get any 'limp modes' for any of my usual 'daily driving' speeds, but it wasn't until I fitted new front tires that were about the same % larger than the OE size as the rear increase was that I resolved it entirely!! Good thing my front tires were almost worn out I guess; altho while putting an after market tire on the rear improved things a lot, fitting them on the front as well as the rear improved the ride & handling, traction etc
sooo much more that if I bought a brand new Spyder right now, it wouldn't get off the showroom floor before I tossed the Kenda crap & ordered some real tires!! :thumbup:
I do hope your issue is just the ABS sensor positioning, but if it's not, I hope the info above can help. Good Luck.