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Thread: BMC Trailfox

  1. #1
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    BMC Trailfox

    I've read some good discussions about the 2007 BMC trailfox that is on sale at Jenson USA.

    I'm probably gonna get one, but I was looking for input from owners about a few subjects that haven't come up in the forum.

    Maximum disc size? will the frame accept my 7" maguras?

    Maximum wheel/ tire size? I have outlaws (28mm) and prefer 2.25 or 2.3 tires. Will they fit?

    Head angle. I know there is a lot of info on the head angle. 71 is listed, but for what for length? I plan on using the maximum travel (140mm) so I'm curious how slack that will be.

    Stand over height? I'm 5'11" with a 32" inseam. I plan on getting 19". Agree?

    Thanks for input!

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    I have had my 2007 Trailfox for about a year now. its a great bike, but the headtube angle 71 is a little steep for a trail bike. (in my opinion). I have a 21" frame with a 34 inseam and it fits good. I am running 185 avid rotors on the frame. Tires are 2.3 Toro's that fit fine.

  3. #3
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    I think the Pike would accompany this bike perfectly. At 140 I would guess the HA would be around 69.5-70 as the Pike has a long A-C length. I have a Tora on there at 130mm and I'm comfortable with it, but I definitely wouldn't mind another 1/2 degree slacker for descents...

  4. #4
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    BMC are pretty sweet bikes. Not a lot of them in the States, but the one's I've seen have ridden really well.

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    Quote Originally Posted by atomfranco
    Maximum wheel/ tire size? I have outlaws (28mm) and prefer 2.25 or 2.3 tires. Will they fit?
    I have WTB Velociraptor 2.1s on my 2007 Trailfox and there's still lots of clearance. I would think a 2.3 would work as long as it's really 2.3.

    Head angle. I know there is a lot of info on the head angle. 71 is listed, but for what for length? I plan on using the maximum travel (140mm) so I'm curious how slack that will be.
    I want to say it's 71-degrees using a fork with 110mm of travel, which is the minimum that BMC recommends, but I can't find where I read that. You might talk to Jenson. I had a couple of questions before purchasing the frame and they answered them pretty quickly. I've got a 130mm fork and wish that the head angle was a bit more slack...

    Stand over height? I'm 5'11" with a 32" inseam. I plan on getting 19". Agree?
    I'm 5'9" with a 32" inseam and I bought the 17". It's the right size for me. I've got 1-2" of clearance with the 2.1" tires. That's straddling the frame as close to the saddle as I can get. Sounds like your torso is longer than mine, so 19" is probably the right size for you though standover might be getting tight with the larger tires you prefer. Again, I'd give JensonUSA a call and see what they say. I was originally going to order the 19", but they talked me out of it... and it was the right call for me.

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    Thanks to all the advice.

    I'm going to call Jenson and BMC and see if they have more geometry figures.

    The fork I plan to use is a Marzocchi 2006 Z1 SL that adjusts from 130 to 150 mm. I know that BMC maxes the fork travel at 140, but I don't imagine 145 is going to break the frame. Probably that will slacken the head tube a bit more and make the frame a more comfortable trail bike...

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    Quote Originally Posted by atomfranco
    The fork I plan to use is a Marzocchi 2006 Z1 SL that adjusts from 130 to 150 mm. I know that BMC maxes the fork travel at 140, but I don't imagine 145 is going to break the frame. Probably that will slacken the head tube a bit more and make the frame a more comfortable trail bike...
    There's some rule of thumb for this, which I've already forgotten. I think it's something like: adding 1 inch of fork travel slackens the head angle by 1 degree? Or something like that.

    FYI, several guys in the AM Forum have reported good results using one of these to slacken the head angle. One guy said that with a 130mm fork and the headset externalizer the HTA goes from 71-degrees to just below 70. Not a huge improvement, but it's something...

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    interesting news.

    I talked to a Jenson rep who told me that the listed head angle of 71 is taken from the engineering specs and is not a real world measurement with a fork mounted. Strange!

    I'm still waiting to hear from BMC...

  9. #9
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    I take it he means the 71 degrees is not static because different forks have different axle-crown lengths. For example, my RS Tora at 130mm has an a-c length of 509mm, about the same as the Fox Talas that goes to 140mm. I've never bothered to try and measure it myself, but by eye, I'm guessing my Trailfox is closer to 70 degrees at 130mm. Looks about as raked out and handles about the same as my Specialized Hardrock did at 100mm which had a listing of 70 degrees.

  10. #10
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    word.

    My marzocchi has an a-c length of 518.5 to 538.5 mm. I think that will actually slack the frame quite a bit.

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    I'm assuming that the Trailfox Jenson sells is still backed up by BMC's warranty even though it's a closeout frame no longer stocked in the distribution channel? Good company to deal with. I have one of their tri bikes.

    They're dumping the Shiver frames too, Sweet frame, but I had to think twice since technically it's a womens frame. I just had visions of hitting the trail and hearing "Why are you riding a girls bike?? " LOL

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    I've tried to reply to this thread twice now and my damn browser keeps messing up, lol.

    I think that the 110mm fork and 71 degree head angle theory is accurate. I have a Marzocchi 55R 140mm fork which has a pretty tall ATC length, and it rakes the frame out a little more than some of the others I've seen. Probably sub-69 degrees. I haven't had any problems going downhill on this bike, even on the really steep parts as long as I get my weight pretty far back. I'm actually planning on hitting up one of my local ski resorts this summer on this bike. I'm that comfortable going fast downhill on it. I'll probably jack up my fork the extra 20mm and look into hydraulic brakes first though. The geometry does make for a sweet trailbike though, and it performs its job very well.

    You should be able to fit your 7 inch rotors on this bike, as there is a guy running 203mm rotors no problem (though it's wayy overkill). 160mm is really all you need for a trail bike anyways though.

    For tire size, I'm running 2.35's and still have plenty of clearance, and they are on a pretty wide rim.

    I already told you in a PM, but for other prospective buyers: My biggest peeve with this frame right now is the super long chainstays. I'm not sure how much this affects your ability to bunny hop or even get front wheel off the ground, but I'm having trouble bunny hopping very high. Trying to get the front end up very high takes a lot of effort as well, which makes getting over logs a bit rough. I think if I were to do it all over again, I'd probably get something with shorter chainstays and a steeper head angle, but a very similar wheel base to this bike. I'll probably replace it next season with a Heckler to be honest.

  13. #13
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    It's 1 degree for every 10mm of travel, but that doesn't take into account different ATC lengths of different fork manufacturers. Though I don't know how much this varies from fork to fork.

  14. #14
    low speed, high drag
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    I think the rule of thumb is 1in.=+/-1 degree, so roughly 20mm.
    As for the long stays, I'm not really noticing them. Bike feels plenty "flickable" and I think the stability of long wheelbase is partially why I haven't noticed the steep HA so much, or so I think. I have limited experience with FS bikes, but bunny hopping always seems to take more effort in general than it does on a hardtail. Not sure how you feel about clipless pedals but that definitely helps crank the bike up.
    I'm content with this bike right now, especially for the price. Down the road I wouldn't mind splurging on a Marin Wolf Ridge for the rough stuff. The new SC Chameleon looks really sweet too and almost makes me want to go back to a hardtail. The new trailfox looks great too, but it's way out of my price range.
    Too many cool bikes to choose from these days. I just wish I had the budget for all these toys...

  15. #15
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    I am also looking at this frame; I am gonna use it for XC! is it a good match with a 110 mm fork for XC.

    Br
    Lars

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    That short of a fork will give it a very steep head angle. But, for XC, that's probably what your looking for. These bikes can be built up very, very light if you choose to do so. Even race worthy.

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    Can the head angle be compared with my C'dale Taurine with headshock ?

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    After starting this thread and receiving endless good advice from all you BMC riders, I ended up not buying the frame...I needed something a little less XC and a little cheaper. Thanks again!

  19. #19
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    Which bike did you buy?

  20. #20
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    I think the headangle at 110mm is like 71 or 70 degrees, so you can compare that to the taurine.

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