Granny Gear makes front tire kiss sky- Mtbr.com
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  1. #1

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    Granny Gear makes front tire kiss sky

    When climbing uphill today on my 14 inch Sonix vl120 I used my granny gear and every time I pumped the cranks while sitting the front tire shot straight up like it was shot out of a cannon. The first time it caught me by surprise and I landed on my left knee scraping it up. Bike didn't get a scratch just the side of pedal. Thereafter I had to stand while going uphill, while evryone else sat on their bikes going up.
    Is the fact that mine is a 14 inch frame with shorter wheelbase the culprit, I guess I just can't use the granny gear unless on the flats but the middle gear is much better suited for that. Anyone else have this issue as My old X6 and K2 never had these issues going up the same hill in the past

  2. #2
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    Quote Originally Posted by Orangecrush
    When climbing uphill today on my 14 inch Sonix vl120 I used my granny gear and every time I pumped the cranks while sitting the front tire shot straight up like it was shot out of a cannon. The first time it caught me by surprise and I landed on my left knee scraping it up. Bike didn't get a scratch just the side of pedal. Thereafter I had to stand while going uphill, while evryone else sat on their bikes going up.
    Is the fact that mine is a 14 inch frame with shorter wheelbase the culprit, I guess I just can't use the granny gear unless on the flats but the middle gear is much better suited for that. Anyone else have this issue as My old X6 and K2 never had these issues going up the same hill in the past
    Yeah, I had the same problem and I was quite frustrated when I first rode my Sonix this spring. The fix for me was easy though. I slid my seat forward and no more wheelies while climbing steep stuff. In fact, I was pleasantly surprised by how well the bike climbed after that. The other thing you should check is the pressure in your rear shock, i.e, the SAG. As has been mentioned here a million times, keep the sag at 10 millimeters.

  3. #3
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    Also...Get zero offset seat post. Remove the spacers from the steer tube. Get a straight handle bar instead of the raised one. Remove the stem and install is so it points down instead of up. This will move your center of gravity (CG) more on the front wheel.

    Smaller your frame is more straight up your position is on any bike and you CG is more back. Realize that the handlebars are pretty much in the same height whether you ride a 14" or 21" frame but your seat hight from ground would wary a lot depending on the frame size.

  4. #4
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    OC, how tall are you? The 14" size is really small...designed for riders who are about 5' tall or less. You might be on the wrong size bike with too much seatpost showing. This would increase your effective TT length quite a bit and put you too far over the back wheel, causing your front end to become too light.

    Like Furrydogs said, it could also be bike set-up. The Virtual Link bikes are really finicky about sag...you have to go with no more than 10mm on the Sonix or it just gets too "squatty" in the rear end, which will make your front end become too light. If you need help setting the sag on your bike, let me know and I'll walk you through it. It's not hard; shouldn't take you much more than 5 minutes.

  5. #5

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    Thanks for the responses, getting used to a new bike has its moments, had it not been so hot I would of worn my lizard skins shin pads but didn't. Ouch!

    Downhill, I looked at the 14" and 16" both on clearance. The only difference seemed to be weight, theySun and Ski weighed both bikes and the 16 was 1.7 pounds heavier. Stand over height was about the same, wheelbase was probably an inch shorter, so I went with the lighter bike. I am 5'8" 175 pounds. The 14 inch bike feels good to me. It is almost too responsive at times (the VLS system). Going over a bridge with a 6-8 inch drop at the end I pulled up on the front tire in middle gear and pumped the cranks and wow the front tire was way up there, not uncontrollable but up there...The X6 I had was a beast and was impossible for me to do a wheelie on flat land period, my K2 is not much easier.

    I quess the pedal responsiveness of the VLS system and a lighter Sonix (10 pounds lighter) in comparison to my old heavy and sluggish X6 is just something I need to get used to like driving an under powered vehicle that is a dog when you hit the gas compared to a Corvette or other high performance vehicle, punching the gas on the vette will move you out a lot faster than the clunker you were used to.

    Going up hills the VLS is proving so efficient that a granny gear is over kill and going to get me killed. I'm learning. One thing is for sure, I rode more aggressively and faster on the trails today because of the Sonix, it's race ready I just need to get used to it and understand my limits on it. By the way, the sag on shocks seems right at about 3/8's of an inch but I did notice the seat is out over the back tire a bit more, maybe I'll fool with the seat and try to position it more forward. I measured the seat to the steering column at 16 inches and 1/8 of an inch...is that too roomy of a cockpit?

  6. #6
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    Oh boy. No wonder you are popping wheelies. I hate to be the bearer of bad news, but you really should be on at least a 16" or even an 18". I am 5'7" with a 31.5" inseam, and I am in between the 16" and 18" sizes. I opt to ride the 18" since I've always prefered a bigger bike with a longer TT.

    Right now, the problem that you have is since you are having to put the saddle height up so far, you are increasing your effective TT length. When this length is increased, it's putting your center or gravity too far over the back wheel which makes the front end really light.

    All isn't lost, though. If you feel comfortable on the 14", just make sure you keep enough air pressure in your rear shock so you avoid the rear end getting overly soft and further compounding the issue. You can also follow some of the tips Ozvena gave about switching to flat bars and possibly going with a zero offset post. A zero rise stem might also help.

    Just being wary that your front end is going to be lighter than it should will help you be prepared on steep climbs. You'll either get off and walk (hey, we all do it from time to time!) or you'll adjust your riding position so that your weight is more on the nose of your saddle when you climb the steeps.

    Let us know how it goes!

  7. #7
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    Ride it and make sure you can stand it. If you are not 100% happy with the fit sell the bike ASAP while it has low miles and 0 scratches (here, craigslist, ebay etc) and get a properly fitted frame.

  8. #8
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    Wow, 14". I am only 5'5" and am riding a 16".

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