fooferdoggie
Well-Known Member
that would be easy to get on but can you imagine riding that 50 miles or climbing 20% grades on?
Minimizing Step-through Frame Flex
- Thread starter frostcrystal
- Start date
Handlebars
Well-Known Member
- Region
- Canada
The bike that flipped right over had no noticeable wobble. What it had a was a nice rear rack that extended back further than what I figure it should have had. All it took was going over a little sidewalk on-ramp on a hill slope. Actually flipped it another time before I fixed it, so I'm sure of what caused it.
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fooferdoggie
Well-Known Member
I would not want a front hub on a tandem the front slips too easily as it is. we have to be so careful on hard packed trails as is. we have done 3000 feet in 40 mile rides with lots of 15% or more grades.
PedalUma
Well-Known Member
- Region
- USA
I would say have your BF look into welding on twin mixtie top tube bars. These could on your bike extend from the seat stays to the steer tube, with a couple of cross members. The front of the rack could also have twin bars that connect to the seat tube at the seat stays. Most racks do.
frostcrystal
New Member
- Region
- USA
It was the front wheel that I lost control on. It was sort of swaying side to side like a speed wobble, or that swerving you get when you're going much too slow, except I was going at about 11mph. I managed to get home by really clamping down on it with stiff arms. It sounds as though my path forward is to attempt to balance out the load more toward the front somehow?
That said, I've definitely hauled some heavy loads on my regular (step-over, non-powered) bike with no issues, which was why I jumped to the conclusion that it was the step-through that was the problem with this bike.
It's a possibility. I'm usually quite good about making sure the tires are inflated, but I also don't usually inflate them to the fullest extent.
Thankfully I'm a girl so I can ride step-through bikes without worrying about my image, hahaha. They ARE nice and easy to mount, even if I'm more comfortable with the top tube.
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frostcrystal
New Member
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- USA
I've never seen those before! What is the advantage vs attaching directly to the seat tube? I think the issue that he mentioned with this bike is that there isn't much room above the battery on the steer tube to add a top tube; it's doable but it'll be tight.
It was also suggested to me elsewhere to add the stays to the rack. It currently attaches (weirdly enough) to the fender, but I think it's also welded directly to the frame at the bottom. I'll definitely look into it.
PedalUma
Well-Known Member
- Region
- USA
What appears to be the sway at the front is in fact caused by flex at the rear. Steering is caused by the rider fist leaning in the opposite direction of a turn. You are naturally compensating for the noodle effect causing what feels like steer wobbles up front. The front is not the cause. It is a symptom.
Another thing to note: Aluminum does not like to flex. Springs are not made of it. When it flexes it develops fatigue fractures.
Do Aluminum Bike Frames Wear Out? – Brainy Biker
brainybiker.com
Stefan Mikes
Well-Known Member
- Region
- Europe
- City
- Brwinów (PL)
Your e-bike is equipped with a hub-drive motor, adding to the rear weight. Additionally, your e-bike is designed for riding in the upright position. It just means the front is not loaded enough. I cannot find the cure for that but that's decidedly not the frame flex.
I found this picture taken when I bought this steel frame tandem on Wayfair in 2013 for <$250. Not overly heavy for a tandem - beautiful, comfortable and sturdy bike that I'd ride anywhere. It would be a great candidate for a hub motor assist.
indianajo
Well-Known Member
Rack welded to the fender is definite sleaze. A fender has no strength. When my MTB had rim brakes, the frame was wide enough at the top, I put clamps around the two struts. 2 1/2" apart. Then I ran 6" long 5/16"NC bolts to the frame of the baskets splayed out to the side. Angle brackets were bolted to the basket frame. Then I could tension the basket towards the front of the frame. It limited the sway, but not enough. The rack welded to the frame of my bodaboda is much more stable from side to side.
Solarcabin
Active Member
- Region
- USA
Retrospec Bike Rack Cross-Bar Top Tube Adjustable Adapter
Attachments
PedalUma
Well-Known Member
- Region
- USA
If not the frame, fine. Maybe not. This problem arises when the back wheel is out of true or there are loose spokes. Easy enough to check. On second thought I will put my money on it. Have BF flip the bike, feel the spoke tension and look for a broken spoke or lack of true.
frostcrystal
New Member
- Region
- USA
Tragically you'll lose money on that haha. I took the bike to a LBS shortly after buying to make sure everything was good (habit of mine from Goodwill bike sales). No loose spokes, both wheels in true. Was thrown a month or two after and it was one of the first things I checked after that.
EDIT: I have lied to you all, the bike rack is not welded on at the bottom. Bafflingly, the seat stays have bolts for rack brackets, but the rack itself doesn't, so I'm not sure how I would attach brackets to it. I guess I could take a drill to it.
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PedalUma
Well-Known Member
- Region
- USA
Or. something like VersaMounts could work, to support the rack but you would need large shims. Better than drilling.
I have an Ariel Rider C class, which is a step through. It has a built in (or on?) rear rack, to which I've added a top trunk and folding baskets on each side. The top trunk never carries much weight. I regularly load the folding baskets up with groceries which can be pretty heavy--beer, milk, etc. Often, the extra weight is all on one side, and I never notice any problem whatsoever from that. I have never noticed any sway or wobble that seemed to result from the step through configuration. In fact, there's not much movement at all in the frame. The battery is on the front of the seat tube, making the frame resemble one of Rad's bikes (don't know the model name). That puts the weight low and centered. Also has a mid motor. I do carry a bag on the handlebars, but it doesn't carry much weight. I have never had the front wheel threaten to lift, even though this is a very short wheelbase bike with an upright riding position (which I really like, as my wrists and hands used to get painfully numb after some distance).
I like the step through because on my former non-electric Trek diamond frame, swinging my leg over with the rear rack loaded was extremely awkward. Whenever a sassy kid says, "Hey boomer, how come ya riding a girl's bike?" I answer, "This ain't no girl's bike kid, this here's a STEP THROUGH! Besides, I'm too old to qualify as a boomer."
I like the step through because on my former non-electric Trek diamond frame, swinging my leg over with the rear rack loaded was extremely awkward. Whenever a sassy kid says, "Hey boomer, how come ya riding a girl's bike?" I answer, "This ain't no girl's bike kid, this here's a STEP THROUGH! Besides, I'm too old to qualify as a boomer."
My wife and I both pedal step-thrus (only mine is an ebike). To transport these on a platform rack, we needed to equip both bikes with that type of removable top tube. Worked great for our purposes, but I can't see it doing anything for frame stiffness, as it isn't attached solidly at either end.
My ebike is an Ariel Rider C class. I have a small trunk on the rear, and folding wire baskets as panniers. I use it often for grocery shopping, and have never noticed frame flex. I may not be loading cargo as heavy as you are carrying, though.
PedalUma
Well-Known Member
- Region
- USA
A frame adaptor is only for hanging a step through on a rack. They have nothing to do with the structural rigidity of a frame. I have only experienced a noodle-like twisting flex in a steel Mixite. If your frame has flex like this, use a different frame. This bike is nice. It feels like a Como. Note the lack of ugly wires. It is a mid-drive. I started with a Giant Momentum Vida frame. The ride is smooth. The red one had that wet noodle twisting flex. Part of the problem was the older style, heavy battery.
