Fifty Plus (50+) - down hill speed

Do any of you, with steel bikes, have any problems going down hill above 30mph. I've read on the touring forum, that some people were all over the road going down hill with steel bikes, or they started to go into a high speed wobble. I'm thinking it may be because of the way the bike is loaded, but I thought it may be a good question here, as we don't load up that much, when we ride.

I've had my nothing-fancy Schwinn steel fixed gear conversion up to 32mph on downhills. Only problem was spinning fast enough to keep up!

It may be the loading, plus the likelihood that touring bikes aren't built mainly for speed.

I think the limiting factors are design and build quality rather than the material. Generations of racers and fast recreational riders have been riding steel bikes down hill- and mountainsides just fine.

Steel bikes can be fine descenders, but I would never try to go fast downhill with a loaded touring bike. That's just crazy.

All of my road bikes are steel, IMHO are there any other kind worth riding??

Descending is not about the bike, its about the rider.

If you have the skill and the ability( and the nerve) then high speeds are exciting, although it can be a little scary at times. In the UK we have sheep and cattle grids which can add a frisson to a descent.

My tourer is steel too, and I ride with an BOB Ibex trailer, they has been up to 49 mph.

Have faith in the bike , brakes and your ability, and go for it.


50+ at 50+ mph,,what a rush!!!

george

I thought this forum meant that when I first joined :)

I have descended mountains on my Bridgestone at speeds up to around 50mph without wobbles. There are many things that can cause a bike to wobble. I don't think frame material is very high on the list. I would not expect a bike with any well designed, well aligned frame to develop a wobble at speed unless there were imbalanced loads or misaligned wheels on it.
I would be careful about taking some of the so called "expertise" often found on these forums. There is a natural tendency to take a very limited set of experiences and make broad generalizations and conclusions. Especially when you add the tendency to try to justify our own choices.

I have descended mountains on my Bridgestone at speeds up to around 50mph without wobbles. There are many things that can cause a bike to wobble. I don't think frame material is very high on the list. I would not expect a bike with any well designed, well aligned frame to develop a wobble at speed unless there were imbalanced loads or misaligned wheels on it.
I would be careful about taking some of the so called "expertise" often found on these forums. There is a natural tendency to take a very limited set of experiences and make broad generalizations and conclusions. Especially when you add the tendency to try to justify our own choices.

That's kind of what I was thinking. One, of my many motorcycles, would always get a high speed wobble at about 80 mph. If I kept going, at about 100 mph it would stop. None of my other bikes would do this and one day while sitting in the garage it dawned on me. I took the back case off of the 750 Honda and took it for a spin and it was gone. Anyhow there is a person that had a high speed wobble on a loaded touring bike and he wont ride steel anymore. I really think it would be hard to beat the ride of a steel bike, but I'll find out next week. Thanks guys.

My inability to go faster that 30 MPH has nothing to do with wobble but to do with my ability to envision what it would feel like to come off the bike at 50+ MPH. :eek:

Have to admit that I regularly reach 45 + on my bikes but they are aliminium. Now the Tandem is aluminium and offroad we reach quite high speeds over very rough ground. That Cannondale frame has no flex in it whatsoever but I would have thought that the rough ground would throw it about a bit but the Weight of the thing and the very long wheelbase does give it a lot of stability at speed. Now that Tandem has been loaded even further with Panniers and Top bag and the only reason the speed was kept down was the fear of blowouts with the extra weight.

If you get wobble, clamp the toptbe/seat with your legs. It will often smooth out.
I think on teh forum you were on they must have been talking about riding with loads.

My top speed downhill was on a Bianchi Squadra with Columbus SL frame. Hit 53 mph in Pomfret, CT.

I recently came to the conclusion that the faster I went downhill, the sooner I had to start climbing uphill again. Now I tend to use a downhill as a rest/recharge break so I have something "in the tank" for the next uphill.

If you get wobble, clamp the toptbe/seat with your legs. It will often smooth out. Yes, that is the best first-line emergency response to the problem.


I think on teh forum you were on they must have been talking about riding with loads. The high-speed wobble problem seems to be related to resonance, which is a function of load (rider and cargo) and frame stiffness. The resonance itself can be induced by out-of-balance or out-of-round wheels, headset bearing issues, a mis-dished rear wheel, or bad wheel bearings, but the speed at which a given bicycle will start to oscillate dangerously, or at least disconcertingly, varies with the other factors mentioned. When too many customers complained about resonance in early 25" Nishiki Competition frames, Kawamura re-engineered the frame, replacing one of the butted tubes in the main triangle with a straight gauge tube, which shifted the resonance enough to solve the problem for most riders.

The 1960 Capo I rode in Los Angeles (full double-butted Reynolds 531) used to wobble badly on descents if I overloaded the Pletscher rack with textbooks. My 1959 Capo (evidently straight-gauge Reynolds 531, based on the seatpost diameter it takes), sometimes wobbled with a previous wheelset, but it has been well-behaved since it got new paint (yes, probably irrelevant), a different wheelset, and a headset rebuild.

FWIW, I've found that my Columbus steel bikes and my aluminum frame/carbon rear & forks bikes felt more stable than my Titanium LeMond. That is not to say that the TI was unstable or dangerous. Just had this "flexy" feel to it.

Don't forget geometry.........my sport touring Romulus is a far smoother, more stable and confidence inspiring fast descender than my twitchy criterium bike.

Do any of you, with steel bikes, have any problems going down hill above 30mph. I've read on the touring forum, that some people were all over the road going down hill with steel bikes, or they started to go into a high speed wobble. I'm thinking it may be because of the way the bike is loaded, but I thought it may be a good question here, as we don't load up that much, when we ride.

I was just out last week with a load of over 40 lbs in bags front and rear. No problem shooting down a hill at about 34 mph. I was a bit concerned about the brakes overheating, but that's a different post.

I don't think frame material has as much to do with high speed wobble as frame alignment, the wheels being true, how weight is distributed, etc. I'm wondering if what you saw wasn't just another type of steel bashing, which some folks feel a strong need to do.

Steel bikes can be fine descenders, but I would never try to go fast downhill with a loaded touring bike. That's just crazy.

I was touring down in the Hill Country and I exceeded 30 mph on some hills---the ones I climbed at about 4 mph.

I guess I'm crazy, but experienced no wobble or anything. Only problem I had was nearly running over a deer.

Frame material will effect resonance but it is not fair to say that steel or TI or Carbon etc is the ultimate difference. Tubing diameter, wall thickness and the geometry of the frame and fork all contribute to the ultimate point at which a bike will oscilate due to resonance.

I suspect as mentioned here that the loaded touring bike reference had to do with basically stable frames being loaded in such a manner as to bring the total into resonance.

Do any of you, with steel bikes, have any problems going down hill above 30mph. I've read on the touring forum, that some people were all over the road going down hill with steel bikes, or they started to go into a high speed wobble. I'm thinking it may be because of the way the bike is loaded, but I thought it may be a good question here, as we don't load up that much, when we ride.

I have a hill that's good for a solid 40mph close by. I've gone down it on no less than 4 different steel framed bikes without a wiggle. The idea that a steel frame is responsible is ridiculous, unless it was badly made or been damaged.

In my youth, I toured on a steel-framed Peugeot. It never wiggled either. More likely it is bad loading as you thought.

I tend to use a downhill as a rest/recharge break so I have something "in the tank" for the next uphill.
+1

Hit 42mph recently on two different hills on my 4130 long wheelbase recumbent. No instability.

I've not had any problems with the Coda going down hills at what feels like high speed to me. The fastest so far has been 42.8 and no wobbles. I do like the disc brakes when I'm going that fast on longish hills.

40+ on my Mercian and rock steady. I have experienced high speed wobble on other bikes and while not pleasant, its pretty easy to clamp the top tube with your knees, and gently apply the brakes an slow down till the wobble subsides.

...or they started to go into a high speed wobble. See this...

http://www.pro-am.com.au/speed_wobble_on_a_bicycle.htm

Don't forget geometry.........my sport touring Romulus is a far smoother, more stable and confidence inspiring fast descender than my twitchy criterium bike.
Bingo, we have a winner with this response.

Terrierman, do the disc brakes help you stop quicker, or is there some other reason you feel safer with them?

They are very positive and do not fade from heat on long downhills.

Amount and location of weight can contribute to a speed wobble. So can frame geometery, a poorly adjusted head set, poorly adjusted hub bearings, riding position, and some other stuff I'm sure I'm forgetting.

Frame material has nothing to do with it except, as one poster said, to the extent that that material combined with the right other factor or other factors sets up the harmonics just right for the particular rider at the particular time. But that can be true of any frame material, not just steel.

All your friend can conclude is that that particular bike in that particular condition carrying him and that particular load at that particular speed will go into a speed wobble. Hardly enough to swear off all steel frames.

Oh, and a big +1 on clamping your knees on the top tube as soon as you feel a wobble start.

See this...

http://www.pro-am.com.au/speed_wobble_on_a_bicycle.htm

Good article. I knew about clamping the knees around the top tube but had never heard that standing would help stop the wobble.

I've never experienced this problem but did have a scary moment on a recent ride while descending a hill. I was doing around 37 mph when a strong cross wind hit me and it felt like the bike was skipping across the road. Whoa! I started hitting the brakes and slowed it down:eek:

As you know I bike a lot. Over 10,000 miles/year. Going downhill over 30 MPH scares the hell out of me. I do it but with great concern. Around here we get little practice at high speed downhill biking.

On cross country I had to learn it fast but never got comfortable. I do not look at the type of bike (steel or whatever). I think it is experience and practice over and over again until your reptile brain makes automatic adjustments.

Oh, and a big +1 on clamping your knees on the top tube as soon as you feel a wobble start.

An advantage of the good ol' level top tube design. It is much easier to find the top tube with your knees.

That's kind of what I was thinking. One, of my many motorcycles, would always get a high speed wobble at about 80 mph. If I kept going, at about 100 mph it would stop. None of my other bikes would do this and one day while sitting in the garage it dawned on me. I took the back case off of the 750 Honda and took it for a spin and it was gone. Anyhow there is a person that had a high speed wobble on a loaded touring bike and he wont ride steel anymore. I really think it would be hard to beat the ride of a steel bike, but I'll find out next week. Thanks guys.

Correction, the wobble would start at 100 and then slowing down to 80 it would stop, thanks.

When the wobble starts at 40+ grabbing the top tube with the knees helps keep me on the bike by compensating for the suddenly slippery saddle.

I ride an old steel Trek hybrid and regularly make over 40 mph on some of the steeper downhills with no wobble. Most hills around here are fairly short, so I don't maintian that speed for long.

The steel issue is commpletely bogus, like a lot of other supposed problems with steel frames, from excess weight to their alleged propensity to rust. Every frame material has tradeoffs, but my steel Atlantis, Rambouillet and even my 20+ year-old steel Trek-based singlespeed are as solid and stable as bikes can be. Both the Atlantis and the Rambo have been over 50mph and scared the crap out of me, but they were dead stable.

I am a mechanical engineer by education and experience. Going down from Mingus Mountain on so-so quality roads, heavy traffic, curves and all this on 23 mm rubber tires at 120 PSI?
That scares the hell out of me.
And some of you worry about steel vs CF vs AL vs Ti frames?
Some of these race light tires are so thin that anything can perforate them. So it comes down to luck.

53.5 MPH on my Seven ID8 Ti. for 17 miles of downhill from Lake Sabrina above Bishop, California down to Bishop. Top tube clamped between my knees, hands light in the drops. Got some cable friction burn on my knees from brake cable movement. Specialized Armidillo tires at 125 lbs.
I used to wobble but now I know what to do.

My Raleigh Record has had a wobble problem from day 1, which would happen while descending the Niagara Escarpement on my way home from school. Not a tremendously huge hill but large and steep enough to get up to a fairly decent speed. It doesn't track very well when riding no-hands either, the fork is probably out of alignment. I've since moved to Queens and now my regular ride is a steel Centurion Trac which I've gotten over 30mph on the Velodrome in Kissena Park. It is quite a smooth ride.

The wobble is a lot scarier when you're on a motorcycle.

I've never experienced any uncontrolled shaking on my current steel Ritchey BreakAway or it's predecessor, an all aluminum Giant TCR2. The speed would have been 35 to 37 mph...

I ride steel. I took a bad fall 3 years ago - partial shoulder dislocation. When I got on the bike a few weeks later and did a club ride I noticed a wobbel on the first descent. I did not know what it it was. Had the bike checked - no problems with it - thought it was just me getting nervous. This came and went over the next couple of years. Thought it was me, thought it was the bike, could never isolate it. A few months back I spoke with the local bike guru - single man LBS. Been in the biz since Comte Mede de Sivrac made his first wooden bike. He told me of a study done by Schwinn (In his words "When they WERE a bike company") that linked it to the position of weight on the seat tube. He suggested moving the seat up and loading the bars more. Since I did this I have had no more problems - I have hit 45 on a steep down hill. I also think some of my issues were being tense in the shoulders from the crash. I have noticed the bike does track better with the seat about 1 cm forward. I also noticed that the seat had gotten loose and slipped back to the end of the rails. It all made sense at that point.

As the others have written, I don't think material is the main culprit of high speed shimmy. Sometimes it's caused by a mechanical problem, i.e. loose headset, wheel bearing, out of true/round wheel, etc, and sometimes it's because the frame is a little bit flexy. In either case, if a vibration starts and just happens to be at the harmonic of the bike, then you've got a problem. To fix a shimmy, do something to dampen the oscillation - clamping the frame with your legs is the immediately available solution if it's your first time. I wonder if filling the top tube with insulation foam would help prevent a recurrence?

I've been lucky and never had a bike that shimmied. Both my recumbents have been over 50 mph; one is steel and one is aluminum.

Check this:

Study by Calfee... (http://www.calfeedesign.com/forksymmetry.htm)

I have only ridden steel bikes. I did alot of touring in the 80's with my Specialized Expedition. Fully loaded I never experienced a wobble. I now ride a 2002 Lemond Zurich and that bike is steady as a rock! I hit 53 miles on hour (descending towards Crowley Lake in Mammoth) on it once before backing down. The bike was fine. I scared myself!

Here's me going downhill with a bit of a wobble:

http://www.youtube.com/watch?v=Nv87Rt_7JiI

Don't worry, a little road rash is all.

I've heard crosswinds can trigger the problem even on a stiff frame and heavier wheelset. Human reaction to the sudden change triggers you to stiffen up and then that increases the risk of having the problem begin.

30 plus years with steel bikes and never had any wobble--it is usually due to a headset where the races are not parallel, loose or pitted with a groove or bump--I reach fairly regularly 45 plus mph and maximum was 50 mph--with a good bike it is very fun and safe!

Check this:

Study by Calfee... (http://www.calfeedesign.com/forksymmetry.htm)

Excellent article.........thanks.

Here's me going downhill with a bit of a wobble:

http://www.youtube.com/watch?v=Nv87Rt_7JiI

Don't worry, a little road rash is all.

Ow.....Ouch....ow, ow, ow..............ow.

Here's me going downhill with a bit of a wobble:


Hmmm ... I must have missed that mountain range during all of my trips to Florida.

I've had both of my recumbents over 50 mph, and both tracked perfectly at that speed. One is steel and one is aluminum.

Both my 'bents have disc brakes - the steel 'standard' recumbent has a rear disc and the aluminum lowracer has dual discs. Disc brakes are more powerful than Vees or dual-pivot, which means stopping with less effort. The other advantages are braking in rain, and no rim wear. I used to wear out rims about every 2-3 years.

...The high-speed wobble problem seems to be related to resonance, which is a function of load (rider and cargo) and frame stiffness. The resonance itself can be induced by out-of-balance or out-of-round wheels, headset bearing issues, a mis-dished rear wheel, or bad wheel bearings, but the speed at which a given bicycle will start to oscillate dangerously, or at least disconcertingly, varies with the other factors mentioned...

+1.

All (real) structures have resonances. These resonances are related to the materials they are made from and the weight distribution (related to the geometry) on the structure. Even for a simple bicycle it can be hard to intuitively determine all the possible modes in which it can vibrate. Bear in mind that things can change as you consume food and water, shift your position or stand, and these change the weight distribution and structural loading during the ride. The fluids being carried are also sloshing around with their own frequency so there are many coupled oscillators complicating the whole thing (with beat frequencies which cause the oscillation to appear to randomly fade in and out).

The other factor is the forcing function...The oscillating force that "pumps" the bicycle into oscillation. If the forcing function has a frequency close to a resonance frequency of the bike, then you could be in trouble. So many different things can stimulate a resonance: It can be an out-of-balance wheel spinning at just the right frequency (most obvious and common), sprinting with the bicycle going side-to-side like a pendulum, a sudden cross wind hitting at just the right angle.

I have sometimes had problems with wobble during loaded touring. Go down one hill and there is a slight wobble. At the bottom, eat a candy bar from the handlebar bag and gulp from a water bottle. Next downhill, no wobble.

It is complicated. But if you do experience the common wobble due to wheel imbalance, it may be possible to (here are some examples) balance it out by moving sensor magnets or wheel reflectors to the opposite side of the tube stem, change the weight distribution during packing (easy to do on in a touring situation), use wheels that are stiffer or less subject to side-wind loading, change to stiffer racks.