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XC900 Carbon Mountain Bike 29"

Sale price: $2,499.00 Regular price:

Give it your all with the XC 900 mountain bike with rigid carbon frame. Get to the finish line faster with the ROCKSHOX REBA RL 100 mm frame, MAVIC Crossmax wheels and SRAM GX EAGLE 1X12 drivetrain.

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Sale price: $2,499.00 Regular price:

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San Francisco, 735 Market St. Options

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Model: 8663744

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A photo of the XC900 Carbon Mountain Bike 29" in use

XC900 Carbon Mountain Bike 29" | Cross Country Racing

Give it your all with the XC 900 mountain bike with rigid carbon frame. Get to the finish line faster with the ROCKSHOX REBA RL 100 mm frame, MAVIC Crossmax wheels and SRAM GX EAGLE 1X12 drivetrain.


12-speed SRAM GX Eagle, Tubeless Ready wheels


Give it your all: full carbon frame and seat post (frame: 2.4 lbs in M)

Shock absorption

Overcome obstacles with the Rockshox Reba RL 100 mm self-locking fork.

Braking power

Enjoy powerful SRAM Level T dual-piston brakes with 160 mm discs.

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XC900 Carbon Mountain Bike 29 

XC900 Carbon Mountain Bike 29 

XC900 Carbon Mountain Bike 29 

XC900 Carbon Mountain Bike 29 

XC900 Carbon Mountain Bike 29 

XC900 Carbon Mountain Bike 29 

XC900 Carbon Mountain Bike 29 

XC900 Carbon Mountain Bike 29 

XC900 Carbon Mountain Bike 29 

XC900 Carbon Mountain Bike 29

Product Customer Reviews

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XC900 Carbon Mountain Bike 29
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Great bike & great value.

Great frame, super smooth & fast ride, really pleased.

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Great Bike !! Best bang for the bucks out there.

Bought this after riding a 13Kg hardtail for a year. I wanted something livelier and faster up the hills. I'm about 179 cm and went for a medium as I have quite short legs and prefer smaller frames. The bike fit is ok for me but the seatpost is about 6 mm over the max extension ( 350mm post ) so see how that works out. I ride with a seat height of 71.5cm from BB to top of saddle so be aware. I set the bike up tubeless after fitting a pair of 2.25 Vittoria Barzo tyres which are exactly the same width as the original 2.15 hutchinsons. Plenty of clearance for mud. The hutchinson tyres are very much dry hardpack and won't handle a muddy wet UK winter. This added about 200g of tyre but removed 450g of inner tube ! so a good gain after all. The bike rolls well, grips well over any sort of terrain and comes in at 10.3kg w/o pedals in that setup. I'm impressed by the accurate, neutral, and responsive handling. It instills confidence on the flatter trails I've been riding during lockdown and is significantly faster than my old bike, knocking 20 minutes off my 3 a1/2 hour loops I've been doing. The finish is good. It looks better in the flesh than the pics and the gears and brakes are great. Huge leap forward from the canti brakes and 26" wheels I started riding on 30+ yrs ago ! Best MTB I've owned. Spend another £500 on Hunt race wheels with the hutchinson tyres on losing 600g, and I'd be tempted to go racing !!........Hmmmm that day has gone I think. Can't wait to get it into the dales and some real riding.

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Good, but not perfect

Has gone up a bit since I bought it, but still represents good value for the components you are getting. The frame is light and well finished, but the seat angle is a bit too slack. You are sat well back and the offset seat post doesn't help (though it may be possible to invert it). An inline post and long saddle rails have helped, but it needs to be steepened up a degree or so. Awkward internal gear cable too, really no need when the brake hose is external anyway. If you are after a fast, relatively light xc bike that has good components, and don't mind the geometry, then it will be a good buy.

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A brilliant value, super fast XC hardtail!

I've become a bit of a Decathlon fanboy of late, having now purchased 3 bikes from them. The first that I bought was this, the Rockrider XC 900 and this is what I think of it... I really do like this bike. A lot. I come from more of a roadie background and wanted to re-live the MTB days of my youth and whilst looking around for a suitable bike, I kept coming back to the XC 900. If you're a brand-snob then this won't be for you. Most people will know that a 'Rockrider' is from Decathlon, but if you don't care about that then you simply can't beat this spec for the money. The full carbon frame is stunning. The paint is deep and looks far better in the flesh than in the pictures. The hi-viz accents work really nicely against the red-fade colours. Nice. The SRAM GX groupset is fantastic, offering slick and reliable shifting. Most bikes at this pricepoint will have a SX or NX groupset, so kudos to Decathlon for the GX components. The Rockshox Reba RL is plush and just sits there quitely doing its job wih ease. Overall the riding experience is very positive. It's fast, light and handles beautifully. It flies up hills and comes down them with the same panache! It's only my own skill and fitness that holds this bike back. It really is the XC racer it's claimed to be. So what's not to like... I personally didn't get on with the gripshift style remote lockout lever. My left hand naturally tried to avoid it when gripping the bars, meaning I was trying to hold onto a very small section of the bar and that didn't inspire confidence. I replaced this with a cheap switch-style lockout lever and replaced the grips, so problem solved. This was personal preference thing though, the standard lockout lever worked fine. I added a longer stem as I felt the 70mm stem was too short. I replaced it with a 110mm one. I have a strong roadie background though and am very used to riding in a 'stretched out' position. Again, not something 'wrong' with the XC900, but a personal setup choice. The front wheel arrived out of true, which was a shame but no deal-breaker. They are also fairly heavy things the Mavic's, but there have to be some compromises at this price! I'm replacing them with a set of Hunt XC race wheels to instantly save 0.5kg The standard Hutchinson Skeleton tyres are properly race-focused, lightweight and have minimal tread. That's great if where you live is constantly dry and hard-packed, but they really struggled on my local wet, muddy technical XC loop. I've replaced them with the Hutchinson Taipan's which are a much better all-round tyre. Converting to tubless was easy enough as valves were supplied with the bike and tape already fitted in the wheels, although I had to re-seal the valve hole so that it was completely air tight as air was leaking out of there to begin with. So other than a few very minor points, the over-riding feeling is that this bike is superb value for money! You really can't go wrong! Go Decathlon!!

Xc900 29er

Brilliant bike -perfect build quality excellent brakes smooth group set rides like a dream can’t fault this bike 10/10

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Pure XC bike Specifications, weight everything are Amazing Note:In site you mentioned that front 160mm disc rotor and 180mm on rear But in my bike both where 160mm rotor, due to this issue - (braking efficiency) is not enough. So, kindly give me a solution

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It's a super lightweight pure XC bike. Riding it for since 3 months now and it's no doubt amazing.

Excellent for people who are professionals

I got it from the store. Best product service and everything was smooth. I take my bike for regular off-roading and this Bike never disappoints. Happy after buying this bike.

Hi Nikhil,

That's a nice bike you're got yourself, and I'm glad you're enjoying it!

Please don't forget to bring it in to your nearest store for a free 6-month service so the bike stays in pristine condition.

Happy trails,

Celková spokojenost

Na kole mám najeto kolem 500 km. S kolem se tedy teprve seznamuji. Předtím jsem měl kolo Rafal 960 (26"), což byl v podstatě vývojový předchůdce. Musím říct, že se toho změnilo opravdu hodně, kolo je opravdu hodně tvrdé, dobře ovladatelné a přesné. Brzdy jsou dostačující. Měřím 182 cm a velikost L je pro mě ideální. Jediné co se chystám vyměnit jsou řídítka, mám objednaná karbonová. Kolo doporučuji všem ambiciózním hobby jezdcům.

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Super poměr cena výkon

S kolem jsem spokojený, perfektně mi sedlo (velikost L na mou výšku 176cm). Kolo jsem si nechal doručit na prodejnu, kde mi ho rovnou seřídili. Vše funguje, jak má. Drobnou vadou na kráse je vedení lanka z venčí, ale to se dá za tu cenu zkousnout. Co však vidím jako velký problém, kterým jsem však počítal před koupí z dostupných komentářů a při zkoušení, je zamykání vidlice Coboloc, které zasahuje výrazně do gripu. Grip je kratší a jelikož je mechanizmus v průměru širší asi o 6mm než samotný grip, tak pak při jízdě tlačí do ruky (a to nemám nijak velkou dlaň), zvlášť u takto širokých řidítek. Zkoušel jsem zda si na to zvyknu, alespoň v rukavicích, ale nakonec jsem objednal Rock shox One lock na levou stranu s ovládáním dole, k tomu nové gripy. Teď si konečně mohu jízdu užívat, jak bych si představoval.

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Kolo XC900

Za mě mohu pouze doporučit - zatím najeto sice pouze cca 100Km, ale oproti starému kolu je to opravdu pecka, na nic z nedostatků ostatních hodnocení jsem zatim nepřišel -brzdy v pohodě -Odpružení po doladění na moji váhu super - duše jsem demontoval - a jak zde bylo psáno, tak žádný tmel mi z pláště také nestříká - řazení přesné - pravda zámek vidlice bych asi řešil jinak, ale prohodil jsem s brzdovou páčkou, a pohoda

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Super kolo za tuto cenu! Výbava i design velmi dobré provedení. Kolo jsem pořídil v Decathlonu v Třebíči a ještě rovnou na prodejně přehodil přední vidlici za pevnou karbonovou a následně vyměnil pláště a duše za rychlejší a lehčí provedení. Ohledně seřízení kola mi pomohl technik Ondra, kterému patří velký dík! Super odvedená práce! S tímto drobným tuningem se hmotnost kola dostala lehce pod 9,5kg. V tuto chvíli ideální závodní stroj na polní i lesní cesty. Kolo je velmi dobře obratné a pod sebou o něm ani nevíte. I vlastnosti karbonového rámu, jsou příjemné. Řekl bych že velmi dobrá investice! Však v této výbavě za kolo od jiných značek, dáte v podstatě jednou tolik. Jen možná bych příště volil větší rám, měřím 172cm a u rámu M jsem se sedlovkou nadoraz. Celkově tedy spokojenost a ještě jednou poděkování celému týmu Decathlon Třebíč!

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Supr za supr cenu.

Supr za supr cenu.

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XC 900

Perfektní hardtail za super prachy! A to se nebavím o tom, že kvalitní servis je v Dekáči za hubičku. Dávám 10 z deseti!

Super hardtrail

Skvela 29 za rozumnou cenu Před koupi jsem si kolo vyzkoušela a poradne mi sedlo, vyměnila jsem si jen riditka za karbonova, sedlo a xtr pedaly, doporucuji.

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Additional Product Information


Bike frame : 100.0% Carbon fibre


5 years on the frame, 2 years on the parts



Superior quality. Unbeatable prices.

For 40 years, Decathlon has delivered the best value in the retail sports industry by offering high-quality, sustainable and cost-effective products.

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