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  1. #1
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    Does more travel always equal less pedal efficiency?

    So I was pretty much set on buying a Jamis Dakar XCT 650 this year, but more 650bs just keep popping up and they're pretty freaking sweet. Not that I've had a chance to check one out in person, but I love to Norco Sight Killer B, Rocky Mountain's Altitude, and the Santa Cruz Bronson. However those are all 5.5" - 6" travel bikes versus the Jamis is a 5" travel bike. I'd say 80 -90% of my riding I don't need 6" of travel (realistically I probably don't need the 5" either).

    So I guess my question is, would I be stupid for buying a 6" travel bike? Would I lose pedaling power compared to the Jamis?

  2. #2
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    Longer travel brings more weight, given the same frame material and similar design. More weight for more strength to endure the bigger hits longer travel is designed to handle.

    Suspension design, and to a much lesser degree, shock design, is what makes pedaling efficient.

    For example, from my test ride experience, the Turner DHR downhill bike with DW-Link suspension having 8 or 9 inch travel pedals as efficiently without pedaling bob like the best pedaling 3 or 4 inch travel XC bikes. But the DHR frame is more than double the frame weight for enduring very big hits, and the long wheelbase and slack angles are better for more than double the downhill speeds than possible to handle well on a short travel XC bike.

    Consider your riding interests. How fast and how rough you like to ride, and look for bikes with suspension travel to match the fastest speeds and most difficult technical situations you want to ride. Then narrow the search to the best pedaling suspension designs or shocks that pedal well for the travel you want.

  3. #3
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    [QUOTE=Shagen7;10288684]So I was pretty much set on buying a Jamis Dakar XCT 650 this year, but more 650bs just keep popping up and they're pretty freaking sweet. Not that I've had a chance to check one out in person, but I love to Norco Sight Killer B, Rocky Mountain's Altitude, and the Santa Cruz Bronson. However those are all 5.5" - 6" travel bikes versus the Jamis is a 5" travel bike. I'd say 80 -90% of my riding I don't need 6" of travel (realistically I probably don't need the 5" either).

    Suspension design plays a strong role in pedaling efficiency. With that said most modern shock's will curb "pedal bob" when switched on. Personally, I find geometry makes a large impact on a bikes climbing ability. More travel more sag makes a bike harder to climb.

  4. #4
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    Another thing that has an effect on most designs (if there's chain growth during compression) is chainring size. A smaller chainring gives the chain a stronger pull, which resists chain growth, and when the chain resists growth it resists compression of the suspension. The downside of a small chainring is that pedal feedback is increased, so when the chain is tight and the suspension is compressed by force, the cranks will spin backwards (unless the rear tire slips first). With a large chainring it's inversed: more pedal bob when mashing, less pedal feedback when the suspension is compressed.

    Note that overall gear ratio doesn't matter, so the gear ratio could be equivalent (24/12 has more pedal bob than 48/24), but the phenomena only depends on chainring size.

  5. #5
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    No, suspension design plays the biggest role in efficiency.

    The problem with adding travel is that there's more travel. Let's say you every time you pedal, while standing, you use 1/4 of the travel. On a 4" bike, that's an inch of travel. On a 6" travel bike, that's 1.5" of travel. That travel is basically energy that could be propelling you forward, but is instead going into the shock and getting converted into heat.

    This is complicated by suspension designs. Some will actually amplify suspension movement via pedal forces. Those designs are **** and should be avoided. Others counteract suspension movement via pedal forces/chain torque. Good ones balance those forces perfectly (100% anti squat), bad ones cause extension past sag/neutrality. Even then, some extension past sag can be good, in particular for climbing in the small ring.

  6. #6
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    Thanks guys! Seems like I'd be best off with the Jamis considering the terrain I'll be riding the majority of the time.

    I need to do my research on suspension designs, and I'm guessing there is more then one opinion on each design........

  7. #7
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    My thoughts on suspension a well executed design regardless type of suspension will work great... People say dw link, maestro or vpp is the best I rode a trek with abp full floater design and loved it my current ride is art which is a version of fsr haven't tested yet due to weather and it hasn't arrived yet, but my point without getting to far off track a single pivot done well can be just as enjoyable as any other design. Check out bikeradar article on suspension it could take you week of reading and research but then without real long field test its still just someone's opinion and from what I've seen its a sensitive issue lol . Oh and something else you may not of considered is maintenances of some suspension designs require more care and money to maintain.

  8. #8
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    Quote Originally Posted by Shagen7 View Post
    ... I'd say 80 -90% of my riding I don't need 6" of travel (realistically I probably don't need the 5" either).

    So I guess my question is, would I be stupid for buying a 6" travel bike? Would I lose pedaling power compared to the Jamis?
    I would not use the word stupid, but you will be dragging around a lot more bike than you need. That means probably more weight and upfront cost. Money is money and dragging weight around could be major pain every ride. It depends on what you want from the bike.
    Joe
    2003 KHS Alite 4000 26" Hardtail - XC, All mountain, blah blah blah.. I just ride.

  9. #9
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    I rode a 2012 Dakar for a year and really liked the bike. Mine had a Rock Shox Monarch with no lock out or Pro Pedal feature. While the bike. Climbed well, I was wishing for that feature. Then I broke the frame. That's one reason I bought a Scott Genius 720. Much burlier frame. The Scott has more travel than the Jamis but also has TwinLock which is pretty much the same as Fox's CTD. I love the feature. Before riding 650 bikes I was all about carbon XC bikes (Trek Top Fuel) with super efficient climbing. The combo of larger wheels and the TwinLock gives for a great ride. Not sure if the Jamis model you are looking at has ProPedal or similar but you can always upgrade. BTW, Jamis did come through with a new frame so they are all good in my book. Hope you are looking at a 2013. They look beefier. Enjoy!

  10. #10
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    Thanks again for the info guys. I did read up on suspension design over at bikeradar, very helpful.

    I am looking at the 2013 and yes frames are beefier and stiffer then last years. It comes with the Rock Shocks 3 positions rear shock (Pro Model).

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