1/ Yeah, but ABS on '10 on Roadsters can only accept a small margin of change in front tyre size before it affects ABS sensors which use a stated ratio between front and rear rotations to calculate when it is required to operate. i.e. the change in wheel speed between front and rear that the ABS programming interprets to determine if wheels are rotating at same speed. If they are not, one is slower than the other indicating imminent lockup so the brake pulses or releases and re-engages within microseconds to prevent wheel lockup.
Go too small a diameter/rolling circumference at the front and ABS stops working altogether
. I think some informed posters in other threads have said over 3% difference can potentially affect ABS operation.
2/ If you increase the rear axle height by 0.5" with a 1" overall diameter increase with an Exedra Max 55 profile rear this will reduce the amount you can decrease the front overall diameter to stay within a 3% F/R difference to maintain ABS functionality.
3/ Roadsters and later Tourings only affected by this ABS issue, but also the Roadsters have less ground clearance than Std anyway as pegs and peg rails lower. This means too big an increase in rear axle height or decrease in front axle height will give quicker turn in and cornering response etc at the risk of grounding heavily when cranked over in a curve. Remember any undulations, potholes or bumps mid corner will compress suspension and make what would be OK on a smooth regular road surface suddenly a major ground contact that could unload contact or tires and cause a crash.
4/ Similar effects on rake and fork dynamics may occur with lowering or raising rear suspension height. Stock rear shock length is 12.5" but Progressive for example has 11" - 13" lengths available in 0.5" increments for Rockets.
I already run an Exedra Max 240/55 profile 16" rear and 13" rear Progressive 444 to get an overall 1" height increase at rear. With stock Avon Cobra 150/70/17 front fitted I have already quickened steering response by increasing fork rake angle while maintaining ABS function. May be possible to go to 140/17 front but any more would risk ABS function.