Putting more weight on the front

[Sunder]

This is going to be a strange question, but I am using this time In social distancing to improving my eBike for when things get back to normal.

My problem is that my bike has way too much weight on the back and not enough weight on the front. I've never been a pro rider, but my eBike handles very differently from any other bike I ride and feels less stable.

Everything is on the rear at the moment. Motor, battery, controller, even the pannier for my change of clothes and the battery charger.

I dont necessarily need to make the bike lighter, but reallocate the weight distribution. I have a few thoughts, but wonder if anyone has any others:

1. Get a front suspension fork with disc brakes. My commute has a few pot holes, and not having to slow down as much to avoid them wouldn't be too bad anyway.

2. Move the controller to the centre triangle. It's a phaserunner so weighs almost nothing anyway, but every bit counts?

3. Front panniers? I've heard bad things about them for handling though, interferring with cornering and more suited for low speed touring bikes than high speed hybrid/commuter bikes.

4. A heavy aero front wheel? Would be odd to only have aero front rather than both though.

5. Straight ballast at the front? Seems a bit silly, but if it makes my handling better, why not?

Any ideas would be appreciated. Thanks.

 

[goatman]

front suspension takes the road vibration out of the bars for me, my throttle hand doesn't get cramped on a long ride like a stiff fork.

 

[amberwolf]

1. Get a front suspension fork with disc brakes. My commute has a few pot holes, and not having to slow down as much to avoid them wouldn't be too bad anyway.

If they're really potholes, and not just rough patches in the surface, it's likely to take a serious amount of suspension travel to make any real difference. You might also need larger air-volume tires, kept at higher pressure, to prevent rim damage.

2. Move the controller to the centre triangle. It's a phaserunner so weighs almost nothing anyway, but every bit counts?

I wouldn't bother, unless moving the battery there, too.

3. Front panniers? I've heard bad things about them for handling though, interferring with cornering and more suited for low speed touring bikes than high speed hybrid/commuter bikes.

If you were going to move cargo to the front, I'd do it by adding a support to the frame itself, that effectively extends your toptube forward beyond the headtube, and mount the cargo carrier to that. Then it doesn't affect steering directly, as you dont' have to move it with the bars/wheel.

This can be done a number of ways, some of which require welding to your frame, but you can simply clamp long pipes to the sides of the toptube along it's length, and then mount the cargo carier to them. If it's all bolted or welded together other than the clamping to the frame, then it'll be pretty strong. (2x4's work, too, but are a bit less visually pleasing ).

That said, front panniers can be fine, as long as they don't stick out to the sides very far, and their mass (and that of whatever is in them) is centered on the line thru your steering tube down to the road. This way the mass is nearest to the circle being turned, and does not take as much energy to change direction, and doesn't affect your steering as much.

If you ahve a suspension fork, then unless it's an inverted fork, you prety much have to mount them on the lowers, which makes them and cargo all unsprung mass, and can disable or lessen the effect of the suspension, or be harder on your wheel in situations the suspension would otherwise have helped it.

4. A heavy aero front wheel? Would be odd to only have aero front rather than both though.

The aero wheels I've seen are lighter than regular ones, and weaker, as they use less (and thinner) spokes, except for the ones that use super-deep-crosssection rims, which might be as heavy or maybe heavier (still weaker).

But I wouldn't want to add weight to a bike just to balance it.

 

[Sunder]

No, mostly they are large cracks, raised slabs from expansion, and some resurfaced areas where the top surface erodes away from the bottom, causing holes maybe 1-2" deep? One wouldn't take me off the bike, but they aren't comfortable, and force me to slow down

Maybe I am being unrealistic about this, but on the good sections iof road, I am doing low 40s. On the bad section, mid 20s. If it's not because I am slowing down to minimise impact, it's because I am xlowing down to avoid the bigger ones altogether.

I am now leaning towards the shocks + disc brakes method. That should add another kilo to a kilo and a half to the front while giving other improvements.

The other one I thought about was going from a heavy DNP 7 speed to a lighter single speed. I am almost always in gear 6 ir 7 anyway, so I czn use the front chain ring to change ratios. That might save half a kilo at the rear.

 

[john61ct]

Personally I don't like the USA penchant for making what are really utility bikes based on the design of sport bikes.

The European design model resonates better with me, and I see no difference between a utility shopper, call it cargo, and a commuter use case.

A nice big strong basket up front, and / or pannier is the way to balance the weight of a rear rack / pannier.

And the battery pack is to me the obvious thing to put up there.

Making it a larger Ah capacity than strictly necessary has many strong and interrelated benefits, both higher power availability and lower C-rate stress, huge longevity benefits reducing avg DoD%

Another candidate is of course a front motor, but that opens a different can of worms.

 

[MadRhino]

You have the worst case of weight distribution right now. You know it, and you have experienced how bad it does handle.

When you build with rear hub motor, the battery goes on the front. On the down tube is fine, in the triangle is good if you need a lot. Sub 10 lbs can be very good on the front of the head tube under the handlebar (never on the, or in the front of the handlebar). Top tube bag is good at high speed ( weight low for slow handling, weight high for fast handling).

Geometry next: handling is a matter of geometry just as well as weight distribution. That is how replacing your fork might give an advantage, setting a slightly longer wheel base, more trail, slacker steer angle. Then, setting your cockpit to place your saddle and handlebar on the same plane, proper handlebar width, is the way to place your own weight in balance with the bike.

Bike handling is a science, and a habit. Once you have experienced proper handling, you never want to go back and will do all that need to be done to set every new bike that you will ride.

 

[Sunder]

You have the worst case of weight distribution right now. You know it, and you have experienced how bad it does handle.

100%. It's not terrible, but it is worse than any other eBike I have built, I suspect at least in part because I am using lighter components all around, so the extra weight throws off the ratios, even if total weight is lighter.

When you build with rear hub motor, the battery goes on the front. On the down tube is fine, in the triangle is good if you need a lot. Sub 10 lbs can be very good on the front of the head tube under the handlebar (never on the, or in the front of the handlebar). Top tube bag is good at high speed ( weight low for slow handling, weight high for fast handling).

Some good ideas there, but I am thinking of going one further. I think (Haven't taken exact measurements yet) I can break my pack down and rebuild it so that it can fit on the downtube. Just need to figure out how I can 3D print a mount that's solid, yet easily removable. A top tube bag may be easier, though less rigid and centre of gravity higher.

I had a handlebar bag before, I agree, not really practical significant weights during high speed riding. Might be okay for a casual potter around.

Geometry next: handling is a matter of geometry just as well as weight distribution. That is how replacing your fork might give an advantage, setting a slightly longer wheel base, more trail, slacker steer angle. Then, setting your cockpit to place your saddle and handlebar on the same plane, proper handlebar width, is the way to place your own weight in balance with the bike.

You lost me here. I just bought a Rockshock Paragon Gold RL. It seemed to get some really good reviews for a commuter/cyclocross bike, only 50mm travel. Hope I haven't limited my options yet, but... How does changing shock increase your wheel base? Wouldn't you either have to change your head tube, or frame for that?

Now that we're talking about wheelbase though. I do wonder if the way I pack will make a significant difference. If I put more of the heavy stuff in front of rear axle, and fill the light clothes behind the rear axle... It's only shifting weight by 20-30cm at most, but I've read weight between the two axles make less of a difference to handling, than things in front of and behind them... How much is another question entirely.

 

[MadRhino]

The theorical line your own center of gravity is determining what weight of the bike is on the front or on the rear. The farther it is from this line, the more it does transfer balance, of course.

We can change the steer angle with offset cups in the headset (see Cane Creek Angle Set), but different forks are made with different effective angle and trail. Some forks are slack design, some other steep, some about neutral.

Ideal is variable geometry settings in the frame, that are usually a combination of 3 or 4 setting points on the dropout mounts, an eccentric BB, snd a variable headset. Fine tuning that is making the perfect geometry for the purpose, and rider measurements.

Batteries can be modular. I use 3 battery bags: one compact that is made to fit in front of the head tube, one down tube, one top tube. All together they are about 2.25 kw/h. I can ride shorter range with lower battery capacity, keeping the bags that are best for the type of ride.

 

[dogman dan]

Might look into handlebar mounting the battery. But pretty bad handling can be tolerated for just street riding.

Frame bag? carry your heavier stuff there, meaning tool kits, water you may carry, etc. Put only light stuff like your rain gear in the panniers.

You might look at front hub motor. I put my best commuters together with front motors. It allowed me better gearing in back, but also helped with weight balance for street. Dirt is why I abandoned front hubs, I wanted my street bikes to run better on a dirt road.

 

[Sunder]

Might look into handlebar mounting the battery. But pretty bad handling can be tolerated for just street riding.

Frame bag? carry your heavier stuff there, meaning tool kits, water you may carry, etc. Put only light stuff like your rain gear in the panniers.

You might look at front hub motor. I put my best commuters together with front motors. It allowed me better gearing in back, but also helped with weight balance for street. Dirt is why I abandoned front hubs, I wanted my street bikes to run better on a dirt road.

I was slipping with a front wheel on lower power than I'm currently running

Frame bag was an option. Handlebar bags ruled out because I also found it changed handling last time I tried it.

But thanks for the suggestions. I'll probably try the heavier forks first, then lightening the rear gears (Only use 2 of the 7 speeds, so might try just 1) then maybe moving the the controllers and the way I pack the battery into the panniers.

 

[MadRhino]

To put batteries on the front without affecting the steering handling, the center of the battery weight must be on a line drawn from the front of the stem to the front wheel axle. So you need a long stem, and a battery bag/case close enough to the head tube as to place it UNDER the handlebar. If the balance point of the battery weight is in front of the line between handlebar and axle, steering will require extra force from the rider, and will tend to oversteer once started to move.

You know you got it right when you can coast and steer the bike hands off, with your own weight transfer alone. Depending of the fork angle, trail, and weight, the battery weight that can be mounted on the front does vary, but I have found that +- 10 lbs is a good average.

Never add weight for a reason of balance. Transfer weight, mod geometry, adjust your own weight placement.

Every bit of weight that we add on a bike must serve a purpose: better suspension, better braking, better power, longer range, etc...
Saving weight can be expansive if you want to retain the bike’s qualities. Lighter, quality components are expansive. Before starting the cost escalade, first try not to add any useless weight.