I've not owned both, but I did test ride a 900 Tiger Rally Pro and then later bought a very early 800 roadie (so early it was before the XRT/XCA model names). I got the 800 because it was so cheap and I was unsure what to get. So I bought the 800 last year intending to only keep it until I found the bike I wanted. But I've been so impressed with it that I may well keep it a lot longer.
900 GT - Basic road biased Tiger. Does
not have some of the extras like electronic suspension. Cast alloy wheels. Tubeles. This replaced the 800 XR.
900 GT Pro - Top model road biased Tiger with all the bells and whistles like electronic suspension. Cast alloy wheels. Tubeless. This replaced the 800 XRT.
900 Rallye - Basic off-road biased Tiger. I can't remember what it's missing compared to the Pro. Spoked alloy wheels but tubeless I think. This replaced the 800 XC (which was tubed).
900 Ralley Pro - Top model off-road biased Tiger. Has everything except electronic suspension only available on the GT Pro. Spoked alloy wheels but tubeless I think. This replaced the 800 XCT (which was tubed).
Very early 800's lacked ride by wire and ABS. They also have a single welded frame and older dash. Later 800's have ride by wire, ABS, a replaceable bolt on subframe and modern TFT dash. The XRT/XRC should be these later models so all good. Later 900's (2024 onwards) have more power, torque slighly lower down and the better TFT from the Tiger 1200. However the TFT takes about 20 seconds to power up which is a complaint many people make. The later 2024 900 also had a redesigned seat which is meant to be more comfortabvle (not that the early one is uncomfortable at all).
2010 - 2014: Early 800's (optional ABS, old dash, cable throttle)
2014 - 2019: Later 800's (ABS, new dash, ride by wire, replaceable bolt on subframe). Started using the XRT/XCT model names I think.
2019 - 2024: Early 900's
2024 - 2025: Later 900's (more power, newer dash)
Main Engine Differences Between 800 and 900
The 800 has a traditional triple cylinder engine. This is a very smooth engine with a very linear power curve. It is ideally suited to the road biased 800's such as the XRT. But some people commented on it not being as tractable offroad as the usual v-twin engines in competitors. To address that Triumph changed the crank (now referred to a T-Plane crank) and cylinder firing order. By firing slightly out of order it makes the rear wheel more tractable when offroad. But it is less smooth when on road. Triumph improved this a little with the later 900's (2024 onwards).
Seat Height
The Rallye/XCT is taller than the GT/XRT. Both the 800 and 900 have adjustable seat height. I am 5" 8" with about a 31" inseam. I could ride the 900 Rallye Pro by putting one foot down but could not flat foot it even with the lowest seat setting. I can just about flat foot the 800 roadie on the lowest seat setting and remember being able to do so with the 900 GT Pro when I sat on it. I would avoid the GT Low because I think the lower suspension affects the ride and resale value.
My Opinion - 800 vs 900
I have seen 900's for £8k to £9k and really good ones about £10k. So personally I think an £8k 800 is too close in price to the 900. If it's that close in price I would go for an early 900. But if you can get a much cheaper 800 then they are still teriffic bikes. So to me it makes sense either to get a cheaper 800 or a good 900, but not an 800 which is close in price to early 900's, otherwise future resale will be harder.
My Opinion - GT/XRT vs Rallye/XCT
What sort of riding will you be doing? I loved the look of the Rallye and XCT. But realistically I wouldn't be taking it off road. So the GT/XRT makes much more sense for me. The Rallye is meant to be an excellent offroad machine for someone who knows what they are doing. But I think there are better options out there for someone new to offroading (which I would be). If you're going to be doing a lot of offroading then get a much smaller, lighter bike. The GT/XRT is meant to be much better
on road than the Rallye/XCT.
I was genuinely surprised how good my 800 roadie is on the road, even with fairly chunky 70/30 tyres. I've never tried a bit of green laning on it and I doubt I would be great at it. But I expect it would get up a gravel road to a campsite just fine, for example. The GT/XRT will be just fine on changeable poor quality tarmac roads.
I'm not sure if any of that helped but hopefully some food for thought
