aerohorst

I'm asking myself two questions:
1) Is the effect of frame mounted front racks on steering really zero (if you take weight distribution out of the equation which is possible by loading an appropriate amount of weight on the rear rack)?
2) And are frame mounted or fork mounted front racks more prone to shimmy (aka speed wobble)?

Two observations:
1) Almost all of the front racks I found that attach directly to the head or down tube are on cargo bikes. One rare exception is this non cargo bike: Schindelhauer Gustav, search for "Schindelhauer Gustav VIII - Urban Bike 2018 - Walkaround" on YouTube (I can't post links here because my account doesn't have 10 posts).
You'll find many cargo bikes with front racks by doing a Google image search for: "front rack" cargo bike.
2) Pretty much all bicycle touring front racks are attached to the steering axis (most often to the fork, sometimes also to the front axle or the handlebars). Examples are ALL racks presented here: bikepacking com/gear/lightweight-front-racks-for-bikepacking/

My reasoning (favouring frame mounted front racks):
The reason for why touring bikes have front racks that steer with the handlebars/fork is probably because touring bikes (at least in the US) have drop bar handlebars and 28" wheels: the luggage would interfere with the drop bars because the rack doesn't turn with the handlebars. I don't use drop bars so this doesn't effect me. My rational is to put rather heavy (denser) items on the front rack in order to balance out the weight distribution of the bike given that most of the luggage weight is on the rear rack.
Front loads attached to the steering axis change the steering characteristics and increase the effect of wheel flop which is destabilizing. Steering axis mounted front racks might also probably make no-hands-riding harder (above a certain weight).
< rodfordbuilt co uk /1ukmkdfstaoc6p7d99zmkf092duxyy/2018/11/06/porteur-and-postie-racks > claims that wheel flop is greater with frame mounted front racks which doesn't make sense: wheel flop is the vertical distance the steering axis moves when handlebars are turned (for illustration see: bikeradar com /features/the-ultimate-guide-to-bike-geometry-and-handling/). The effect of wheel flop (a reinforcement of the steering movement) is increased when weight is attached to the steering axis so steering axis mounted front racks increase the effects of wheel flop while frame mounted front racks don't. I can just guess how he came to his conclusion: bikes, independently of the effect of wheel flop, with a forward weight distribution have slowed down steering because there is more weight over the front wheel while it turns. High trail, which goes along with high wheel flop, also slows down steering. His frame mounted front racks may have been loaded with higher weight. So he came to associate frame mounted front racks with wheel flop. The rodfordbuilt author probably confused the term "wheel flop" but maybe he has in fact picked up on some other negative steering related aspect associated with frame mounted front racks?

Anyone with experience with frame mounted front racks?

Does the weight on frame mounted front racks impact steering characteristics (ignoring overall weight distribution on the bike)?

Has anyone compared frame vs steering axis mounted front racks in terms of high speed shimmy (aka speed wobble) susceptibility?

Edit: People in the comments asked for my experience and the problem I'm trying to solve. That makes a lot of sense. So here is some context:
Application is touring on pavement (80%) and gravel roads (80s) with 15-20kg of luggage. Not a big load at all so any front rack would work. But the goal is to build a great handling bike not only a good enough handling bike hence this post. My goal is to replicate the ride feel of a gravel/endurance road bike I particularly like. To do that properly I have to keep the weight distribution of my loaded bike similar to the unloaded reference bike. I keep as much luggage as possible near the center of gravity (frame bag) which also decreases shimmy issues (see my post yesterday). The rest of the luggage I distribute on front and a rear racks so that the overall weight distribution is similar to the unloaded bike whose ride feel I like. I actually plan on getting a custom frame mounted front rack made (and a custom frame.) so this is not purely a theoretical discussion. My experience: I have toured for almost 20 years (deserts, pavement and everything in between) on various bikes including a bike with low rider panniers (plus rear panniers): With the fork mounted panniers I liked the planted feel and the ability to climb without loosing front wheel traction (bc of the good weight distribution). But no hands riding was terrible with the low riders :/ (probably because of wheel flop) and I ride like no hands riding to take the stress of my lower back.

Trakhak

If you search for it, you can probably find a Bicycling! magazine article from the 1980s where Jim Blackburn reported the results of tests of all of the most common rack configurations (not including frame-mounted front racks, which were unknown at the time, at least in the U.S.): rear panniers, front panniers placed high, low-rider front panniers, handlebar bags, top-of-rack front and rear bags, etc.

He found that one of the worst combinations for bike stability was that which was most common back then: rear panniers plus front handlebar bag. That combination brought out the worst tendencies in the steel bikes that he tested---in particular, the awkward "wallowing" that discouraged pedaling while out of the saddle.

On that topic, I'm pretty sure all the test bikes were steel. Since then, Cannondale aluminum touring bikes have generally been praised by the comparatively few riders who have toured on those bikes, which ride well because the torsional rigidity of the frames mitigates or eliminates that wallowing problem. (It's noteworthy that while American touring riders still seem to prefer steel bikes, a significant proportion of the European touring bikes on the market have aluminum frames, usually combined with an aluminum fork.)

The best of the tested combinations was the use of front low-rider panniers alone, with as little weight as possible added elsewhere. The test riders found that weight in low-rider panniers actually improved the way the bikes rode.

I can attest to the benign effect of low-rider panniers. My shopping bike, a 1995 Cannondale H300 hybrid with flat bars and a pair of panniers on low-rider front racks, is effortless to steer at anything above slow walking speed. The only time I notice the weight up front is starting from a dead stop, and even then only for the first pedal stroke.

I don't know whether the low-rider pannier/rack combination improves or degrades no-hands riding. Why would I care? The hands-on handling is perfect, which is all that matters.

Reddleman

I’ve ridden about a bit on a 20” wheeled folding bike with a combination of luggage setups, including a loaded front bag (10l Carradice bar bag) attached to the head tube of the frame and two 26l panniers on a rack at the rear. Frame mounted front racks and bags are commonly found on smaller wheeled bikes (Moultons for example have used them since the 1960s) and they don’t affect the handling, but there is the visual effect of the bag going straight ahead when steering left or right to get over to begin with.

Where I have noticed an issue before is when there is some flexing in a rear rack when under load, creating a wobble through the bike that is exaggerated by a frame mounted front bag and affecting the steering. This appears to be lessened through either reducing the weight at the front, or adjusting the rack and the location of weight in the rear panniers to reduce the flex at the rear. I suspect the latter is primarily due to the longer struts needed to connect the rack to the chain stay of a small wheeled bike, which would not be an issue with larger and more standard wheels.

staehpj1

Many decades ago I hauled massive loads With one of those heavy pre WW2 bikes with a small front wheel and provisions for various cargo boxes to be mounted on front. I am not sure what was originally on the one we had, but we had a big wooden box on it that we hauled news papers in. I'd say it was a beast handling wise, but it is hard to compare it to anything else since even the bare bike was probably as heavy as a lot of Trans America loaded bikes.

I have used fairly heavy handlebar bags frame mounted on a little rack instead of on the bars. They were a bit lower than when on the bars. I didn't notice any handling hit.

I have carried the large majority of the load in a pair of front panniers and found that while a bit different the handling was good. I liked that setup.

djb

I have ridden a frame mounted rack bike (a Brompton ) and as someone who has ridden fork mounted racked bikes for decades, I have to say that the difference was there, but for me certainly not a game changer.

as you noted, there are not many frame mounted rack bikes out there, pretty much for the reason of practicality , once its designed to be there, its always there, so less flexibility on how one uses a bike and what configuration it has.

while you are looking for a black and white answer, there really isnt one. Fork mounted racks and panniers and a given load can vary quite a lot in how they handle --- due to bike frame characteristics, rack position, rack quality, how much weight, how low the weight, uneven weight etc.

and then you get into one rider thinking that a bike handles terribly , while another just finds it fine and adapts, so do understand that this isnt a 1+1=2 sort of question and answer, and frankly you'll just have to get riding experience with a loaded bike to either see what you think, and or to get used to something that feels different to a regular bike or a bike that has a front load on a frame mounted rack or cargo system---of which you know there are not really many out there.

as for shimmy or speed wobbles, again there are a slew of factors that come into play with this, and load distribution and other mundane details can resolve this, but it completely depends on the bike, the rack, the load, the tires, you name it. Too many to make a blanket statement.

good question, but fork mounted rack systems work perfectly well, especially with a good setup.

staehpj1

One thing I'll hesitantly add is that shimmy and speed wobbles have a large rider component so a rider who has never had a problem with them is likely to not have them with a new setup. A rider who has had a problem with them on other setups is more likely to. Some riders I have known have complained of them on almost everysetup they have tried. Some have never experienced them at all even when seemingly doing everything that should cause them. Some have found subtle hints of them that they could manage to suppress.

A pilot friend calls them PIOs or pilot induced occillations. I am convinced that pilot induced occilations are a real thing when it comes to bike shimmy or speed wobbles and often a factor or even the main cause. Because of this I never tell someone a given setup should be okay or not unless I know the rider well and even then I'd temper any advice wit an "it depends on the rider".

tcs

Any weight on the front of the bike will accentuate wheel flop. Physics. Geometry. If the weight is on the steering axis, it 1) increases the moment of inertia of the steering axis, slowing the steering response and countering the accentuated wheel flop, and 2) puts the increased weight into the rider's hands and makes it directly controllable.

tcs

Shimmy.

A hidden feature of a good touring bike is a stouter top tube and beefier seatstays. This increases the frame's resistance to twisting [due to having masses (touring dunnage) attached front and rear].


I owned a bike decades ago that was built so light (how light was it?) it would sag down as you mounted it. It was common for the front and rear wheels to take two independent, oscillating paths through corners. Oh, what jolly fun.

djb

here's a question for you.
Have you toured before, have you used front panniers? Have you had handling problems that are giving you concerns?

why don't we start with that?

tcs

Actually, racks mounted on the steering axis are darn near universal, irrespective of handlebar type.

1964 Schwinn Varsity Tourist



In 60 years of cycling, I've learned to keep an open mind, but be leery of 'everybody is wrong' theories.

randallr

+1 to this - front low-riders are excellent for stability during touring in my experience, both on a 1973 Raleigh Grand Sport and on a 1993 Klein Adept (super stiff).

Yan 

You're worried about nothing. A lowrider front rack (Tubus Tara or similar) is very easy to ride with and you will get used to it within a few minutes.

cyccommute 

One of the things I immediately noticed when I got a Cannondale touring bike and compared the loaded riding to my old steel touring bike was the ability to climb out of saddle with a load. It’s not something that I could ever do…in essentially 20 years of use…on my steel touring bike. The steel bike wasn’t really prone to shimmy but it was a little sensitive to balance on the front load.

I do off-road bike packing and have to say that all of the problems that Blackburn and Berto detailed in that article are common in bikepacking bags. I suffer through using them but they are not optimal for handling nor stability. I end up going over the bars more often with a touring load on a mountain bike than I ever do on an unloaded mountain bike. The load is just too high for good stability.

I’ve toured with a light load in low rider panniers (on-road) as well as a similar load on the rear. The front load is far easier to ride with.

79pmooney

I've only ridden handlebar bag with rear load and LowRider panniers and varying loads in back. The former until about 1980 when I put LowRiders on my Peter Mooney. That was a revelation and I've never even considered doing anything else. I very quickly figured out the heavy stuff needed to be in the front panniers and if there was nothing else, leave the rears at home.

But - heavily loaded LowRider panniers 1) put a big load on the front rim when you hit say a pothole edge. Blown and damaged tires and dented rims happen unless tires are big enough with enough air and everything is strong enough. 2) I haven't studied this systematically but my experience suggests that flexy forks especially forks with a lot of rake do poorly with the heavy panniers. I farmers market with one of those skinny forked Raleigh Competitions. Loaded it is a flexible mess. Haven't noticed speed issues but accelerating while turning hard (say to head up a steep hill) is interesting! By contrast, my much stiffer Mooney with it's much straighter and stiffer fork (and about 2 degrees steeper head tube) behaves beautifully with any amount of weight in those panniers.

Other comments re: handling - in marginal road conditions, loaded LowRiders are wonderful. Angled railroad tracks and snow; a huge help. For my commute to campus in Ann Arbor from nearly the highest point in town. I used to carry extra books just for the steering stability. Allowed my to push my weight back over the rear tire when otherwise I'd be weaving around and skidding and ultimately walking. RR tracks - loaded LowRiders = lower heart rate spikes when you cross the angled ones.

Just my observations after about 45,000 miles with LowRiders

Trakhak

The OP has undoubtedly been talked out of frame-mounted front racks by this point, given all the testimony in favor of mounting panniers on low-rider fork racks.

aerohorst

Thanks for the hint at the magazine and the summary of the test results.
I guess what you describe as "wallowing" is also referred to as shimmy which is more likely to occur under high loads, a flexible frame and if there is lots of weight at either end if the bike. There is an animation in here: www cyclingtips com/2020/07/bicycle-speed-wobbles-how-they-start-and-how-to-stop-them/ (under "How the bike actually moves") which illustrates how a pronounced rear/front loading accentuates shimmy. Sotge theory squares with these observations. But these test results don't make a distinction between frame mounted and steering axles mounted front loads.

saddlesores

is this all hypothetical, interesting, a fun topic to consider?
or are you seriously considering going with a frame-mount front rack for touring?
have you any experience carrying a load for extended distances with either type of rack?
what volume/weight do you need to transport, how far, under what conditions?

saddlesores

links to animations are nice, but what is your end goal?
do you have a specific problem with front-end load you're trying to resolve?
you mention bikes/racks you've found or seen on the internet, stuff you've read, things people have said, but no mention of your experience.

Trakhak

"Shimmy" refers to a more or less uncontrollable ongoing oscillation in a bike's frame and can render a bike dangerous to ride. Bikes loaded with touring gear are apparently no more or less susceptible to such oscillation than unloaded bikes.

"Wallowing" is very different. It occurs when a loaded touring bike is less than ideally torsionally rigid, with the result that pedaling while riding out of the saddle causes the wheels to follow two different tracks. Not usually unsafe, just annoying enough to discourage out-of-the-saddle riding.

There seems to be no one frame characteristic that would enable a rider to predict whether a given bike will be prone to shimmy. On the other hand, wallowing generally correlates with combinations of lighter-weight steel frames (with smaller-diameter frame tubes) and (poorly distributed) heavier loads.

Note that many people who have posted in this thread have reported very good experiences with panniers mounted on low-rider front racks, with some of us even preferring the way that setup makes the bike ride compared to the unloaded bike. But no one has offered any data on frame-mounted front racks, likely because they're nonexistent on touring bikes (as opposed to cargo bikes).

In fact, I've never seen or heard of a frame-mounted front rack, other than on a Workman or other cargo bike, and I've been obsessed with high-end racing and touring bikes since the mid-'60s. Since bikes with panniers on low-rider racks ride, if anything, better than unloaded bikes, what would be the point of going to the trouble and expense of coming up with a custom installation of such a rack, only to end up with a bike that, at best, handles no better than an unloaded bike, if not worse?

GhostRider62

I've toured with 30 pounds to 100 pounds on steel, aluminum, magnesium, and carbon. 20 inch wheels, 650B, and 700 C. Blackburn low riders, rear racks, backpacking bags, handlebar bags, tailfin bags, etc. The frame is a big deal. The Klein aluminum and Zinn Magnesium handle loads best and the only two I would trust at very high speeds. Low on the front fork is always my first choice for weight. Behind me and narrow for aerodynamics. Everything else is a compromise based on experience and preference. Like naturally the bottles of wine belong in the front lowrider bags but you have to consider the loss in case one crashes; therefore, they go in the very back pocket of the rear pannier for safety although such weight distribution is not ideal. Appropriate tradeoffs require experience off the internet.

aerohorst

Wheel flop is the vertical distance of the head tube (or any other part of the steering axis) when the wheel is pointing straight forward vs when the wheel is turned. The bikeradar article in my OP has a picture illustrating this. No weight on the front wheel, no matter how it is attached, changes this amount of vertical travel. The difference between frame mounted and steering axis mounted front racks is that...
1) ...when the wheel is turned any weight attached to the steering axis amplifies (originally I wrote "accentuates" which doesn't make sense, kindly pointed out by GhostRider62 ) this wheel movement because the head tube "falls" down into the turn. So when there is weight on the steering axis this fall (aka flop) is more pronounced. So wheel flop itself with a steering axis mounted front rack has not increased because the geometry has not changed (wheel flop is a function of head tube angel and trail) but it was enhanced. Some reference outside the bicycle world to the definition of wheel flop: fxsolver com/browse/formulas/Wheel+flop
2)... both the frame mounted and the steering axis mounted front rack push the weight distribution forward (center of gravity of the bike/rider/luggage system moves forward). This slows down the steering because there is more weight in the front wheel, which increases stability. But if you add frame bags and panniers the weight distribution shifts rearwards again which negates this effect.

So the question remains: where is the effect on steering of a frame mounted front rack asides from weight distribution effects?

You can also approach this question more visually: you can think of the frame mounted front rack as a very heavy head tube. Will that have a effect on steering characteristics besides the weight distribution?

aerohorst

Application is touring on pavement (80%) and gravel roads (80s) with 15-20kg of luggage. Not a big load at all but the goal is to build a great handling bike not only a good enough handling bike.

My goal is to replicate the ride feel of a gravel/endurance road bike I particularly like. To do that properly I have to keep the weight distribution of my loaded bike similar to the reference bike. I keep as much luggage as possible near the center of gravity (frame bag) which also decreases shimmy issues (see my post yesterday). The rest of the luggage I distribute on a front and a rear racks so that the overall weight distribution is similar to the unloaded bike whose ride feel I like.

I actually plan on getting a custom frame mounted front rack made (and a custom frame.) But nerding out on the theory is also a lot of fun for me.

My experience: I have toured for almost 20 years (deserts, pavement and everything in between) on various bikes including a bike with low rider panniers (plus rear panniers): With the fork mounted panniers I liked the planted feel and the ability to climb without loosing front wheel traction (bc of the good weight distribution). But no hands riding was terrible with the low riders :/ (probably because of wheel flop) and I ride like no hands riding to take the stress of my lower back.

staehpj1

If that is your goal I have a suggestion. Consider ultralight touring or at the very least lighter touring. The lighter the load the less it affects the ride feel. With ultralight backpacking gear I have found I can tour with as little as 9 pounds of gear, but carrying a bit more still has most of the benefits of ultralight packing. I did the southern tier with 14 pounds of gear and the light load was a joy. The camping was enjoyable. I also did other tours with light loads including an on/off road MTB tour with 11 pounds of gear (33 pounds including the bike). You don't need to go that light to see substantial benefit. As I went lighter and lighter I found somewhere around 20 pounds of gear was a point where the bike started to really feel much more unladen. Even at the low end the weight range you mentioned the bike isn't going to feel anything like your unladen " gravel/endurance road bike" regardless or the rack or bag system.

What makes the bike not feel like your unladen bike isn't the low rider racks. Properly designed and set up racks are likely not going to be improved on by frame mounted racks. You may see improvement with bikepacking style frane mounted bag and a reduced load, but with the load you suggest it is going to ride like a tank regardless of the baggage style with the best most likely being traditional low riders with panniers.

If packing lighter than 15-20 kg isn't an option then you are in a very "normal" range and are likely best off using the "normal" setup. There is a reason that it evolved the way it did and is still the most popular for that style of touring.

As far as the frame mounted option over the low riders. I suspect they are a solution searching for a problem to solve.

Tourist in MSN

I agree that shimmy is an oscillation or resonance, but I find that a loaded touring bike is more susceptible to the problem of shimmy.

I had a touring bike that handled great when unladen but had a bad shimmy with a load. Speed where the shimmy developed varied with weight of load and exact placement of the weight, generally the shimmy occurred at between 17 and 21 mph.

I eventually gave up on that bike, put the frame in the metal recycle bin. Several people told me I could have gotten good money for the frame, but I did not want someone to build it up and get injured, so I just took the loss on the frame. Put the wheels on a rando bike frame, put the fork on a titanium frame.

A frame builder told me how the welder on the bottom bracket shell had their heat settings all wrong on the welding machine, thus the bottom bracket shell was warped from that and that probably caused the entire frame to be too weak. Surly refused to honor the warranty, they said it was normal for a frame builder to have to rethread warped bottom bracket shells, they mailed me a pair of Surly socks and a Surly flask for my troubles.

I have had a very slight resonance on my heavy touring bike when heavily loaded at about 14 mph, but it was very slight and if I loosened my grip on the handlebars it would go away completely. It was so slight that you normally would not notice it, other than on a long boring day on a bike tour when you start to notice everything because you are so bored.

I have not pedaled out of the saddle for over a decade, my knees can't take the stress of trying to power up a hill by standing on the pedals. My descriptions of shimmy are in the saddle.

saddlesores

shouldn't it be a fairly simple thing to construct your own? frame-mount baskets are available as options from multiple e-bike manufacturers. you may have to macguyver a modification to the mount, but start with an available rack.

https://ebikegeneration.com/products...ke-rack-basket
https://www.amsterdam-bicycle.com/sh...um-front-rack/