The 75/50 is a long travel, full-power eMTB, and that's pretty much exactly how it feels on the trail – there's no hiding the extra mass, especially on slower speed, tighter trails. However, it carries its weight well, and isn't a cumbersome, wallowy bike – even at 30% sag the suspension is very supportive, giving it a more efficient feel than its geometry numbers and travel amount might suggest.
Straightlining up steep, techy climbs was where the 75/50 really excelled. One of my favorite test laps includes a rocky, rooty moto trail that I still haven't managed to clean without dabbing, but I did get closer than I ever have while on the 75/50. The trail is full of long, extended steep sections where maintaining an even power output is the key to forward progress.
Cleaning tricky climbs on an eMTB isn't simply a matter of picking the most powerful mode and hanging on – that technique is a recipe for looping our or spinning the rear wheel in vain. On the 75/50 I could quickly switch between modes to keep the WTB Judge rear tire digging into the ground as I worked my way upwards, balancing the power output to match the trail angle and surface conditions.
The 75/50's 77-degree effective seat angle is fairly steep, although I do think it could go even steeper without any negative repercussions. On an eMTB you end up remaining seated for a longer portion of a climb compared to a regular bike, which makes being able to find the right weight balance between the front and rear wheels even more crucial.
I've come to prefer mixed-wheels for most eMTB applications, but it'd be interesting to try the 75/50 with the rear triangle that's used for the 29” version (and option Crestline will be offering in the future) – I have a feeling the longer chainstays would give the bike even more stability while climbing and descending.Race Mode
Along with providing 400% assistance, the main talking point with the Bosch Race motor is the additional overrun. Basically, the bike continues forward a little longer under its own power once you stop pedaling compared to the standard Performance CX motor.
It takes some time to get used to that additional shove of power, and it's certainly not a feature that's usable in all situations - if you're riding a technical, exposed trail it's not going to be the mode to choose. I enjoyed it the most when going into a flat corner, where the extra power can be turned into a higher exit speed. It's also a handy feature for getting over downed logs – you can take a half pedal stroke and then sort of lunge / push to get over the obstacle.
Realistically, I don't think it's all that necessary for the vast majority of riders, but it also doesn't hurt to have it – remember, the extra assistance and overrun are only present in that one mode out of four.