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Clydesdales/Athenas (200+ lb / 91+ kg) Looking to lose that spare tire? Ideal weight 200+? Frustrated being a large cyclist in a sport geared for the ultra-light? Learn about the bikes and parts that can take the abuse of a heavier cyclist, how to keep your body going while losing the weight, and get support from others who've been successful.

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Old 02-27-12, 02:02 PM   #1
The_DK
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Anyone else feel totally unstable on skinny tires?

My hybrid, I feel like I could ride over anything and it doesn't matter. Branches, railroad tracks, dirt, rocks, small cars. No problem. 700x35.

My Caad 10 5 on the other hand... scares the hell out of me going downhill at 30mph on just asphalt. 700x23

I hit a little gravel too and put me in a nasty wobble I was (thankfully) able to recover from. Seems like every little rock and pebble is out to kill me.

I never stand on this bike to pedal.

Now, I feel like I reach to far on the bike and need a somewhat shorter stem. - but doesn't a shorter stem make the front wheel -more- twitchy?
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Old 02-27-12, 02:33 PM   #2
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No, my road bikes all feel stable as hell. Even the twitchy ones.

Having said that, a CAAD 10 is a full on race-geometry bike and it's supposed to be "responsive" and to you, that may be uncomfortable. No road bike is going to enjoy gravel or sand, that's for sure. If the fit is wrong with the stem you have, I'd get it fixed. Stability won't be affected as much as your comfort.

Another suggestion you might want to consider is hawking your CAAD10 on ebay or CL and getting a frame that's set up more for "comfort" like a Giant Defy, Cannondale Synapse, Specialized Roubaix or one of those configurations. See if you can find a shop to let you test ride some and determine whether geometry is part of your issue.
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Old 02-27-12, 02:33 PM   #3
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I suspect it's normal for adults to feel leery of the skinny tires especially when used to looking at and riding 35c wide wheels.

You will get used to them and at the same time avoid (if you possibly can) gravel, sand, debris as they are not designed for that purpose. To put it another way, running out of pavement and hitting loose dirt, gravel or sand will likely not end well.

See if you can borrow a shorter stem from your LBS and try it out for a few days to see if it helps. I don't think changing out the stem will make it more twitchy, at least I have never found that to be the case?
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Old 02-27-12, 02:53 PM   #4
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My hybrid, I feel like I could ride over anything and it doesn't matter. Branches, railroad tracks, dirt, rocks, small cars. No problem. 700x35.

My Caad 10 5 on the other hand... scares the hell out of me going downhill at 30mph on just asphalt. 700x23

I hit a little gravel too and put me in a nasty wobble I was (thankfully) able to recover from. Seems like every little rock and pebble is out to kill me.

I never stand on this bike to pedal.

Now, I feel like I reach to far on the bike and need a somewhat shorter stem. - but doesn't a shorter stem make the front wheel -more- twitchy?
Skinny road bike tires have never been a favorite with me either. I much prefer fat tires like those on a Cruiser or MTB for comfort and safety.
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Old 02-27-12, 02:54 PM   #5
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I think my bike has 700c 28. I haven't felt nervous at all but I'm not a speed demon by any means. I think I hit 23-24 mph tops going down a small hill. I'm also a huge rider (390).

I have another set of tires and rims that i was going to try, those are 700c x 23 and I wonder how I will feel on those.
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Old 02-27-12, 03:12 PM   #6
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TrojanHorse is close to the mark. I purchased a bike with aggressive geometry and on the first real ride, I was going down a hill and when I hit about 33 mph, the front wheel started wobbling violently. A new experience, and figuring that I was going down for sure, I started looking at the road cut embankment thinking I would do less damage to my body if I went sideways into it. Thankfully, I was able to regain control and rode the brakes, keeping the bike at 25mph to the bottom of the hill. Funny thing is that at the bottom of the hill, you make a left turn and have a nice 7-mile run at about a 1-2% down grade with the wind pushing you. Not steep enough to freewheel, but you can get good speed with the wind assist. I was able to ride at plus/minus 35mph along that stretch and the bike exhibited no inclination to become unstable again.

Tried riding several more times and even though there was no "death wobble", the bike felt unstable on descents. On flats, it is fantastic ... very responsive. You only have to think about moving, and the bike takes off like a jack rabbit. I finally stripped the bike and moved the Dura-Ace components to a new frame, putting the offending frame in the spare bedroom to languish. The new bike is just as fast, based on GPS tracks, even though it doesn't feel like it is. The new bike feels very stable also.

Fast forward six months and I built up that "racing" frame with Ultegra components. Same problem. No wobble, but gives a very unstable feeling on descents. Even tried 25mm tires, which helped stability on my other bike. Those made it feel a little bit more stable, but still unsettling on descents. It's sad too because that bike really likes to climb. Only problem is that I have to get back down the hill after climbing it.

It's sitting in the bedroom again, sans wheels. I asked a LBS guy about it and he speculated that it is a bike best suited for guys who don't weigh as much as I do. I'm at 207 right now and am working on getting to my ideal, (in my mind), of 185 by mid-summer. I'll try the bike again when I loose a few.

p.s. For me anyway, stem length has no effect on responsiveness/twitchiness. I had a pro fit on the bike too. It may be my "riding style", or my weight, or the bike's geometry, or who knows what.
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Old 02-27-12, 03:24 PM   #7
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fwiw, I did consider the synapse, (and similar felt) but 61cm wasn't big enough for me. The Caad10 had a 63 so, there I went.

I'm not riding IN sand or gravel, just the road garbage on the side of the road, or what comes up on the MUPs.

Now I know why all the roadies ride to the left of the bike lane, I think.
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Old 02-27-12, 03:44 PM   #8
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Even on my road bike, I have wider tires. I run gatroskins on both mtn bike commuter and road bike.
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Old 02-27-12, 03:50 PM   #9
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I had a bike with a replacement front fork. It had little trail to it at all and was quite twitchy. You couldn't ride it no handed. It had road tires, but that wasn't why it was twitchy.
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Old 02-27-12, 04:03 PM   #10
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See if you can borrow a shorter stem from your LBS and try it out for a few days to see if it helps. I don't think changing out the stem will make it more twitchy, at least I have never found that to be the case?
I think the worry is that with a shorter stem small changes in the angle of the bars will result in a larger movement of the front wheel. FWIW, I haven't found that a 10-20mm change in stem length makes much of a difference in the way steering feels.
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Old 02-27-12, 04:24 PM   #11
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Took me a while to find it but this article may shed some light on your shimmy problem. I didn't realize your frame was as large as it is but check out the article and see what you think:

http://velonews.competitor.com/2010/...-poorly_121162

Lennard Zinn is quite well known for his unorthodox opinions on large frame design.
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Old 02-27-12, 05:45 PM   #12
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I'm the exact opposite I guess. Put me on 23's/25's and racing down GMR's switch backs are no biggie at 30 mph. Put me on an MTB with fat knobbie tires and it sucks. Low pressure, wide area seems to shift side to side, they are not meant for road riding. Narrow track road tires are like riding on rails.



I did shorten the stem on my Cannondale. Took about 2 rides before I forgot I made the swap. No problems on fast 40+ downhills. But as far as race bikes, I think geo and model has much to do with stability on downhills. My Lemond Chambery was great on the downhill. This new Madone is not quite as stable. Both race bikes but the Lemond was more relaxed.
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Old 02-27-12, 05:56 PM   #13
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I think Trojanhorse pretty much hit the nail on the head. A Caad 10 is a bike that many racers love to use as it is light, fast, stiff, and very responsive. It isn't horribly expensive, so if it gets crashed, it's less expensive to replace than some of the others. What racers see as being responsive, more casual riders might view as "twitchy". Something with a more relaxed geometry might be just the thing.
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Old 02-27-12, 07:12 PM   #14
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What racers see as being responsive, more casual riders might view as "twitchy". Something with a more relaxed geometry might be just the thing.
Don't know how long the OP has been riding his bike, but I know that when I got back on my race bike after a 10-year lay-off I thought it was almost too twitchy to ride! A couple of weeks in the saddle, however, and I got used to the "responsive" handling again. That said, my bike felt equally stable (or unstable) regardless of speed. Not clear to me if the OP is just having problems at high-speed or if the bike is generally unstable...
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Old 02-27-12, 08:11 PM   #15
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Did you take the bike to the bike shop to make sure everything is tightened properly in the steering? Did you get fitted properly on the bike? I mean really fitted by someone who knew what he/she was doing and not someone who just looked at you and said "looks great." You didn't say what your current stem length was? Unless you go too short, I've had better handling with shorter stems than longer ones. I ride a full race geometry bike and have been 70+mph on it with no problems at all. You do want to make sure you have a relaxed grip of the bars. A death grip can cause the shimmies.
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Old 02-27-12, 08:28 PM   #16
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I think if I were going 70 on my bike I'd have a death grip on everything that could grip anything, and maybe a few other things too.

I hit 40 all the time but 70 ... phew!
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Old 02-27-12, 08:50 PM   #17
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I don't think there's a stem made that can affect twitchiness anywhere close to how much it's affected by fork trail.
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Old 02-27-12, 09:46 PM   #18
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That's a very interesting article.

I'm getting a fit done tomorrow... I have the seat/pedals perfect, but I just can't get the handlebars right on my own.

It has a: Cannondale C3, 31.8mm, 6 deg. I think that is 120mm.

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Old 02-27-12, 10:21 PM   #19
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I don't think there's a stem made that can affect twitchiness anywhere close to how much it's affected by fork trail.
I don't think there is an argument there but it really makes no sense to think about spending several hundred bucks on an aftermarket fork without really knowing how it will affect the bikes handling. The bike was designed to handle properly with the fork it has on there. It'd be just as easy to make the handling worse.
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Old 02-27-12, 11:19 PM   #20
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For me, drop bars are why I can't ride a road bike at speed. 50mph on a mountain bike (with 26x2.1" knobbies) was fine. 40mph on a Specialized Allez Triple with 23c Michelin Krylion carbon tires, and everything adjusted and in tune was scary. Switch to a Sirrus with flat bars and 28c tires, and I can still ride faster but I feel much more comfortable at speed. Whipping 90 degrees onto a side street is also much easier for me on the Sirrus, it just hugs the road, while the Allez felt very skiddish under me in comparison. I attribute it to flat bars. I also won't use bar ends at speed or for sharp cornering, hands have to be on the flats.
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Old 02-28-12, 12:55 AM   #21
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I think my Hybrid handles much more surefooted with the 26C's I put on in place of the 35C's.
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Old 02-28-12, 01:11 AM   #22
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OK, Allez is the aluminum version of a Tarmac... same "responsive" geometry we're talking about here - the Tarmac is specialized's full zoot race bike. No wonder it feels more flighty!

I guess I'm the opposite - when I'm on a hill > 30 mph descending, I'm in the drops 100% of the time. Better grasp of the brakes, if necessary, and I really do think it's more secure & stable regardless of the bike.
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Old 02-28-12, 03:06 AM   #23
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I don't think there is an argument there but it really makes no sense to think about spending several hundred bucks on an aftermarket fork without really knowing how it will affect the bikes handling. The bike was designed to handle properly with the fork it has on there. It'd be just as easy to make the handling worse.
The CAAD 10 is designed to handle like a race bike with the OEM fork. Handling impacts of fork geometry changes are fairly well understood.

If you want more stability, a fork with more trail is one way to make it happen...
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Old 02-28-12, 07:11 AM   #24
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I don't think there is an argument there but it really makes no sense to think about spending several hundred bucks on an aftermarket fork without really knowing how it will affect the bikes handling. The bike was designed to handle properly with the fork it has on there. It'd be just as easy to make the handling worse.
Oh, no, I would never suggest that anyone new to road riding should expend the effort and cash to swap forks. My point was just that fork trail (in concert with the head tube angle) is probably the main factor, and changing stems will have an almost unnoticable effect on the problem.

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Old 02-28-12, 07:17 AM   #25
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All very interesting. I have about 100 miles on the bike. It's very intermittent though, because it keeps having mechanical problems. Maybe I'll get it back this week and put another 100 miles on it and see where I'm at.

I wonder if I should flip my stem? I never feel quite right on the hoods. Even though I'm pretty bent over, it makes me feel really high on the bike. - drops way more comfortable.
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