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Making sense of the ‘19 GT Sensor 29

43K views 233 replies 39 participants last post by  SergMTB  
#1 ·
The new Sensor has good value, good initial reviews and seems to fit in perfectly next to other exciting new short travel 29ers like the SBG Transition Smuggler. Except for one important geo figure: bb height. Even in the low geo setting the Sensor bb is about 17mm higher than the Smuggler. This might be a welcome change for some with really rocky climbs or tall people who need to run 175mm cranks. It’s also a golden opportunity for those who like to experiment with wheel sizes, specifically mixed wheels sizes: 29 front 27.5 rear. I have played around with the reverse mullet a bit and really really liked it. You get the incredible 29er stability and traction you need through the bars and front end, but the snappy, playful rear 27.5ers are know for.

I started this thread hoping to get some input from knowledgeable ppl on this idea and maybe to inspire some others to try it. Correct me if I’m wrong: the overall wheel diameter difference between 29 and 27.5 is 38mm when running the same tires. If you run a 27.5+ that number goes down a bit. So you’re looking at a 19mm drop in the rear axle height, which will net about 10mm drop in bb height and -1 degree slackening of the hta and sta. The seat can be slid forward to help counteract the slacker sta, making the tt length a bit shorter.

Reverse mullet GT Sensor geo changes:
64.5 hta
75 sta
346 bb height

Sounds like a pretty incredible trail bike to me. I’m in the market for a bike like this and just might pull the trigger when frame sets become available next month.
 
#96 · (Edited)
2019 GT Sensor Sport mods - 27.5 wheelset

Got my Sensor Sport about 6 weeks ago and I'm coming from a 2018 Stumpjumper. This all aluminum Sensor weighed in at almost 34 lbs. stock. My first three trail rides in the central Virginia Charlottesville area were just OK. Mostly rocky, hilly stuff with lots of switchbacks and plenty wet. The 29" hoops are OK, but not great for me - emphasis on the "me". I started my SENSOR PROJECT. Reba 140mm boost fork. Mercury X3 Enduro 27.5 Wheelset. Maxxis Rekon 2.6x 27.5 tires. Syncros 50mm stem with 35mm clamp holding a Easton Haven handlebar. XTR M980 175 crankset. Shimano M8000 XT brakes with 180mm rotors. New weight is 30 lbs. This bike now handles like a slot car on short, rocky turns and the 140mm of travel up front is perfect with the 27.5 wheels. The bike can be taken down to less than 30 lbs. but the current weight is fine and competitive with bikes in and above is price range. I had many of the components on hand from the Stumpy so I didn't have to shell out lots of dollars for the project. With a lifetime frame warranty, this bike has lots of pontential. And I'm still a fan of 27.5 wheels for the terraine I ride. The stock crank, wheels and fork are where the excessive weight was hiding. I'm currently using a Thompson seatpost, so if I change to a dropper I'll pick up some weight.
 
#97 ·
Mbr.co.uk has a review of the alloy sport up. Looks like they are doing a comparison with the Rift Zone and the Fluid. This is great because those are three of the bikes I'm considering. They gave the Sensor a 7 and the Rift Zone a 9. The Fluid review is not up yet. Maybe tomorrow.

They seemed to like a lot about the Sensor and even mentioned it has the best suspension of the three. It seems the one thing they don't like, or rather hated, was the high bottom bracket. They can't get over it. What does everyone here who has one think of the bottom bracket height? Is it as big of an issue as they say? Or are they making roo much of this?
 
#102 ·
So people on this bike, can I get a ride report? I'm looking for a playful, poppy ride that likes to change direction with the geo this bike has for aggressive days. Coming from the GG Smash, that bike was a straight line monster trucker. Before that, I had a Canfield Riot and that was the most fun bike I have ever had but there were other compromises. I am looking for a bike that likes to manual and bunny hop and rewards looking for jibs over just bombing. Any body with some insight and what they can compare this bike to?
 
#103 ·
I'm looking for the same exact thing. The new cf Riot is supposed to drop soon but the Sensor has been on my short list along with the Ripmo and SB130. So... the Smash wasn't very playful? That was on my list too! I'm guessing the Sensor would be similar based on the 4 bar suspension, high bottom bracket (relatively speaking), and long chainstays (again, relative to the Riot). I did get to ride the Ripmo and SB130 back to back and the SB130 is way more fun/poppy which I attribute to the lower BB and lower shock and fork travel. The shock travel was much smoother also than the Ripmo which I attribute to Yeti's Switch Infinity system and NO Igus bushings like the Ripmo uses. The cost is a joke tho - could get a complete Sensor for what the Yeti frame costs!!!

Have FUN!

G MAN
 
#104 ·
I'm not holding my breath on any new Riot after conversations I've had. I think the Riot nailed the playful but it is a combination of elements in my experience. I have found the Evil Following to be similarly playful and it has longer stays and the Riot was higher bb. Smash was as far from playful as any bike I have ever ridden. I'm glad I tried it but honestly, did not care for it (not new carbon one but previous AL). Horst link can be configured so many ways so there is no reason to expect others to have same attribute as Smash just cause it shares expired patent. I think leverage curve and proper fit (reach/top tube and bar width/height) have a lot to contribute to this feeling.
Sensor has relatively short stays for 29er. No where near the Riot but nothing is and bb height is adjustable to let me play with that. I've also read it stiff has hell, something Smash was also but Riot definitely wasn't, so another plus for it. That and its Price make it worth trying out.
To that effect, I just ordered an Expert and will give it a go. The pricing makes it silly to not at least try out as I got complete for less than MSRP for the Offering frame I am also looking at trying out. I am recovering from a busted wrist though, so will be another month or so before I can report back.
 
#105 ·
Anybody have one of these and put a water bottle on it?

I'm trying to figure out how this is supposed to work with the cable guides. Obviously you can just bolt the cage over the cable guides, but the guides have a counter sink for the bolt head and I'm not to keen on just tightening my plastic cage over these holes.
 
#106 ·
At first I mounted the cage right on the frame so it would sit in the groove tube for max clearance. But there was so much clearance I decided to just mount it on top of the cable guides using socket head machine screws to prevent any cage to frame rubbing. The cage is secure and the bolts have stayed tight.
 
#109 ·
I’ve been scanning this thread, and I’m the owner of a 2019 Sensor alloy Sport.
A few things come to mind. Order longer water bottle cage bolts from Amazon or EBay made of titanium. Cheap, light and effective. Mercury wheelset (around 1800 gms. versus 2200+) and they’re 27.5. So it’s like an alloy Force short travel. The frame works well with either wheel size but I love the handling of the 27.5. SLX crank, and looking at a Reba fork. All in all you can get it to less than 30 lbs.
 
#110 ·
So this is really cool: Martin Maes, one of the fastest ews guys around is running mixed wheel sizes on his GT this year. If you recall that's why I started this thread and bought a Sensor. It's so prime for a 27.5 rear wheel it's almost like it was designed for it. Perhaps, knowing the number one GT rider is running the mullet on his Force, they were designed for it!



Unfortunately I never got to try the mixed wheel sizes cause I've been trying to sell the bike. I did however get a good California spring ride on to check out the wild flower bloom.

Image
 
#114 ·
I have a few rides in now on my Sensor Elite. First thing I noticed is that its a big, stiff, burly frame. My rig is right around 34.5 pounds with a Fox 36 and carbon wheels so its no light weight at all. The second thing is that the rear end is not plush at all! Hardly any low speed absorption. But what is more annoying is the wonky shock size. Its darn near impossible to find a shock size in trunnion 180x50. There are no coil trunnion shocks in that size at all!!! The most logical thing is find a 185 coil and have Avalanche do their magic.
Its a fast bike that feels better going fast. The taller bb hasnt been an issue for me yet.
 
#118 · (Edited)
I know my expert is 185mm. There are several trunnion coils in 185x52.5 and 185x55. The one Craig recommends is the Marzocchi Bomber CR and it come is those sizes. So does the RS deluxe which has similar design plus a climb switch. I'm going with an avy tuned Bomber for my YT Decoy.

The Deluxe R is a terrible shock. It's got no midvalve and the main piston is way over damped so it doesn't blow through the travel with big riders. I feel like the Deluxe RT3 makes this bike a pretty plush and supportive ride for only having 130mm out back.
 
#123 ·
Thanks! Its a fantastic bar and the price makes it even better. I have no reason to get the 35mm stuff. There is Nothing wrong with it but the old stuff is good enough for me. I went from a 120mm suspension bike with the 36 on that so when I switched it over I thought I should put it at 140 for something different. I do need to lower the lowers to see why its so harsh, so when I do that Ill probably put it to 130mm.
 
#124 ·
Currently own and ride a 2018 YT Capra 27AL. I love the bike and it works for most of my riding, but have plans to do some long distance trail rides this year which I think will be a bit much on the 170mm Capra.
The Sensor has caught my eye as it's geo is not that far off the capra, it has 29er wheels which appeals and if I get the Alloy Sport model it leaves me enough to buy a 150mm dropper, bars and tyres straight away. Then in future I can look to upgrade wheels and forks.
So just wondering what owners make of the Sensor, and specifically the alloy sport. Is it a good all day trail bike?