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Help! Felt 29er sizing?

gibbonesquegibbonesque Posts: 5
edited September 2015 in MTB buying advice
I have just ordered a Felt 9 seventy online. I have never sat on a Felt. Haven't ridden a mountain bike in years. I ordered the Large (20"). I have tried a bunch of other 20" inch 29ers and they seem fine. But when I looked on the Felt website (after ordering :shock: ) I seem to come up as a medium. I've also read lots of forum posts from tall people (around my size) who say they don't ride a 20". I am at least 5'10 (and a half) I have at least a 34 (and a half) inseam. I have a positive ape index. Am more or less built like a gibbon. The next size down is 18", which I feel would be too small. The type of riding I'm likely to do is more distance than technical. I prefer a more upright position as have a neck/upper back injury that niggles from time to time. I am female but used to riding a gent's frame. I am nowhere near the bike store I ordered from, and there seem to be no Felt suppliers near me with Felt mtn bikes in stock. Should I stick with the 20" or opt for the 18"?


  • The RookieThe Rookie Posts: 27,748
    5'10" is under average height, suggesting you would want at most a medium, additionally longer than average legs means a shorter torso and that means you would want a shorter cockpit length to suite that torso length, I think you should have got a medium. The good news is that it comes as standard with a setback seatpost, changing to an inline will shorten the cockpit length by about the same as the difference between a medium and a large.
  • Thanks. The Terms and Conditions say I can change it if the size isn't right, and they have a 18" in stock. I figure my true frame size is actually 19.5. I'm just short of 5'11" and have exceptionally long arms and legs. Will get my local bike shop to set it up with an inline to try before I send it back!!
  • The RookieThe Rookie Posts: 27,748
    I'd be very surprised if a 19.5 is the right size with that length torso, longer legs means you need a shorter frame, and that comes with a smaller size. You have a massive adjustment on saddle height in the seatpost, but cockpit length has only a time range of adjustment.
  • I wouldn't stress unduly. I am 5 ' 9" with 33" inseam and long arms and ride a Large Giant Anthem. I am right at the bottom end of the large fit but it fits me better than being right at the top end of the medium fit. I have shortened the stem from the 80 mm stock to 65mm which I think is a better length for steering anyway.

    I have only just bought it and every shop told me I was a medium until I started testing the bikes out. Having long legs does mean a shorter torso but arm length can easily make that back up. :)
  • The RookieThe Rookie Posts: 27,748
    Look at a rider side on and you'll see the torso makes up a bigger proportion of the cockpit length and the arms, by about 2:1.
  • I have tried 19" and 20" bikes in other makes. I tend to want to lock out my arms (I'm probably about to be told that's incorrect, but that's how I ride) and I found there was too much bend at my elbows on the 19" frame. The lower body was ok, but the upper body just didn't feel right. That's why I had thought I needed a 20". When I use the various size calculators on the net, I always come out as a 20". Only the Felt website - and lots of personal feedback posts on forums tell me different. Hence confusion :? Thanks for your input, it is much appreciated.
  • It does come with a 100mm stem
  • RockmonkeySCRockmonkeySC Posts: 15,247
    Locking your arms straight is very bad. Elbows should always be bent partly to give a lot more control but also to stop you ruining your elbow joints.
    Do you ride a road bike? It sounds like you're trying to size a mountain bike like you would size a road bike.
    Our local shop Specialises in road bikes but sells a few mountain bikes, all the staff are roadies. You can spot beginners who have bought from there a mile away. Always on Trek 29ers which are too big, never been wrong yet!
  • Excuse my ignorance, HTH - but are you saying the 100mm stem will come into play in a useful way if I buy the Medium? My geometry was never great.

    And no, SC, you wouldn't catch me on a road bike!
  • Excuse my ignorance, HTH - but are you saying the 100mm stem will come into play in a useful way if I buy the Medium? My geometry was never great.

    And no, SC, you wouldn't catch me on a road bike!

    Hi gibbonesque. Sorry it wasnt very well explained it was meant more for Rockmonkey to see what his thoughts were.

    Generally a 100mm stem is pretty long these days for a mountain bike. 70 mm is more of an average size so you could shorten the reach by 30 mm by swapping the longer stem on the Large bike for a shorter one.

    As you have discovered sizing online is tricky. What Rockmonkey says is all the right stuff, he is spot on with what he is saying, however I know from my own sizing that for me despite all reccomendations mediums are not right for me because my arms are very long.

    Some people are outside the norm. Long legs = long arms then you are also saying you are Ape positive. My arm span is nearly 6' 2" and I am under 5' 10". ( Basically I should be out hunting Wooly mammoths )

    From what you have said and the fact you have a similar body shape to me I have a sneeking suspicion the medium is too small for you and a large with a shorter stem will be ok but obviously you will only know when it arrives.
  • The RookieThe Rookie Posts: 27,748
    If your arms are straight, how can you steer, one grip has to go further away from you....

    You could shorten the cockpit with a shorter stem and/or an inline seat post.
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