Seriously (not subjectively)... Do suspension forks improve safety on Urban ebikes?

[Ken M]

I asked this a while back and got mostly subjective feedback that if more comfortable then safety is improved as well but I think that is pure speculation. I understand that active suspensions improve comfort levels on rough surfaces but I do not think they make an urban / commuting ebike safer (let's just stick with speeds up to 28mph / 45kph).

If an ebike is equipped with tires say 2" or wider so they provide a significant shock absorption function as well as improved handling then I would like to know if there is an objective data that indicates that a suspension fork improves safety? I know the marketing people will throw out all kinds of subjective claims but I want to know because I think forks are mainly put on urban ebikes for their added maintenance costs down the road. Even the comfort element is ??? given that some stems are available with shock dampening functions and carbon forks certainly absorb some vibrations.

I've just been told is not safe to ride an ebike at 28mph on the street without a supsension fork and I think that is just the vocal opinions of a minority that think they know it all.

 

[bikeman242]

Really the only way to answer this is for you to ride down a bumpy city road with a rigid frame at 28mph and ask yourself if this is safe.

Personally, I love the comfort of full suspension on my eBike, and think it is a major safety advantage.

 

[Nova Haibike]

I would like to know if there is an objective data that indicates that a suspension fork improves safety?

The short answer is no, at least not that I have ever seen. If there is data out there, any improvement would likely be very dependent on the quality and adjustability of the fork, and also the tuning of the fork by the user.

Really cheap forks are worse than rigid ones. Same for poorly maintained forks.

 

[Stefan Mikes]

the marketing people

You seem to have answered your question yourself Look to Trek Allant+ 9.9s, a premium (carbon fibre) Class 3 e-bike: it is a rigid for e-bike on 2.4" tyres. U.S. Specialized Turbo Como is a rigid fork e-bike on 2.3" tyres. The first version of Specialized Turbo Vado 5.0 was equipped with the rigid fork. Only later, the marketing people at Specialized must have enforced applying the suspension fork for Vado. (Besides, the Euro Turbo Comos have the sus fork, too).

As you said, the 2+ inch tyres provide a lot of shock absorption capabilities. So, the suspension fork is solely for the ride comfort (and skinnier tyres can be used) but it doesn't seem to provide any extra ride safety capability.

Really the only way to answer this is for you to ride down a bumpy city road with a rigid frame at 28mph and ask yourself if this is safe.

"Been there, done that". Owning three very different e-bikes (each of them capable of high speed) gives a lot of experience.

Really cheap forks are worse than rigid ones. Same for poorly maintained forks.

I agree. My "traditional e-bike" was equipped with Suntour Nex shock. After I bought my rigid-fork Vado with 2" tyres, I was impressed how smoother Vado felt on the same bumpy segment of the street I live at. Then the Suntour fork broke. I replaced it with Rock Shox Paragon Gold RL, and now both e-bikes behave similarly to each other, the only difference being my Lovelec is equipped with 1.6" tyres, and Vado rides on 2" ones.

 

[theemartymac]

At this point in bike development, I would say it certainly CAN improve safety, but that does not mean it DOES improve safety. As mentioned, lots of variables. As an 'ex' downhill mountain biker, you absolutely gain significant safety at speed with GOOD front suspension. I.e. air over hydraulic with damping. My old Norco VPS with a Marzochi shock absorbs curbs like they are mere sidewalk cracks, and my control and braking ability is exceptional at motorcycle speeds. I commonly exceeded 80kph downhill in very good control, regardless of variability of terrain. Flats are greatly reduced, and the wheel deforms much less ensuring your steering input remains true, your brakes perform as intended with less heat build up, and your bars are damped to the point that you can maintain fine motor skills and modulate your braking properly.

Now my low-mid range Ebikes with lower end spring shocks are certainly not capable of that, and while they absorb a single unexpected bump like a pothole reasonably well, they don't help that much on washboard, loose gravel, or variable terrain. There is not enough damping and they have no way to manage heat. You quickly lose fine motor control on the bars, and you end up just trying to hang-on as opposed to staying ahead of the problem. Where they do seem to help is by reducing persistent vibration in my hands, but that is comfort more than safety.

So if you want to improve your safety and ride high speed, a high quality front shock can certainly do the job. There are no modern street motorcycles without front suspension for a reason. But the mere presence of a 'shock' does not guarantee any safety improvement. And if you are a casual cruiser, you probably will not see any improvement other than a small comfort gain, at the cost of significant weight.

 

[Stefan Mikes]

Wise words, @theemartymac! Yet let me tell you an anecdote.

I had a pleasant, long and fast downhill ride last Summer, nothing extreme but the terrain was pretty rough. When I stopped at the foot of the hill, I discovered both my shock and damper had been inadvertently locked out! It was the 2.6" downhill tyres run at pretty low pressure that did the job. No wonder some MTBers ride hard-tail e-bikes

Of course I unlocked the suspension for the next day's ride that was even faster and far more difficult!

 

[Dallant]

Just to throw a wrench...with only experiential ”data”. How much pressure you have in your tires is probably more critical to safety and comfort than the average shock fork is. My Allant+7 has a low-end Mobie25 spring front fork but I ride my SCHWALBE G-One 2.75 x 2.25 at the high end - 45psi generally. I certainly feel in better control and thus safer with the higher pressure on pavement. The fork is mostly there, IMHO, to help absorb shock to my bum right shoulder.

 

[Stefan Mikes]

2.25" is a lot, Dallant...

 

[AHicks]

My vote - more about comfort than safety. If you want to ride with rigid forks because the springs or hydraulic types don't make your bike "safer", you should go for it.

I also think you're going to find "data" that will back up the "with" or "without" call darn skinny.

 

[rich c]

A lot of rigid gravel bikes out there. You can’t get a lot rougher than gravel.

 

[CodyDog]

I have both and don't care for a suspension fork for riding good roads. Most entry/lower end bike use a cheep mechanical fork which adds a lot of weight to the bike.

 

[Akrotiri]

I asked this a while back and got mostly subjective feedback that if more comfortable then safety is improved as well but I think that is pure speculation. I understand that active suspensions improve comfort levels on rough surfaces but I do not think they make an urban / commuting ebike safer (let's just stick with speeds up to 28mph / 45kph).

If an ebike is equipped with tires say 2" or wider so they provide a significant shock absorption function as well as improved handling then I would like to know if there is an objective data that indicates that a suspension fork improves safety? I know the marketing people will throw out all kinds of subjective claims but I want to know because I think forks are mainly put on urban ebikes for their added maintenance costs down the road. Even the comfort element is ??? given that some stems are available with shock dampening functions and carbon forks certainly absorb some vibrations.

I've just been told is not safe to ride an ebike at 28mph on the street without a supsension fork and I think that is just the vocal opinions of a minority that think they know it all.

I would say that high-end suspensions are helpful and increase safety (control of the bike) on s-pedelecs. On e-bikes that top out at 15mph I think suspension is overkill. On the flip side my allant 8s s-pedelec has a solid fork and it’s top speed is 28mph. I don’t ride at 28mph on a bumpy city road just the way I wouldn’t drive 80mph on a city side street in my jeep which would also be very unsafe. Rider conditions matter.

That being said there is a new breed of e-bikes like the trek powerfly FS and another by BULLS that are designed to be commuters and off road machines as well. So what one needs to look at is what the e-bike is designed for. Many unscrupulous e-bike companies slap on cheap front suspensions that barely work, increase chances of break down and maintenance but already have 4.8 inch tires, makes no sense imo. A fat tire bike makes a lousy commuter unless you live in Alaska or Norway and a cheap front suspension does nothing to increase safety, just merely adds weight , slight comfort and decreases reliability.

 

[antboy]

For urban bikes, I'd say probably not a lot safer in most situations, as @theemartymac said... There was one situation where I was glad to have it in the city, though.

Just past sunset, on a route I'm familiar with, I hit what felt like a curb at just about 18mph. The (cheap spring) front suspension on my 20" fat folder pretty much bottomed out and it rattled my teeth. I suspect that if I was on my rigid fork OHM Cruise, I probably would have eaten pavement, and even worse, damaged the bike. It's the closest I came to biffing it on a bike in the better part of a decade.

Turns out that the road was chewed up by construction in a way that was not obvious (and wasn't there two days earlier). Lots of construction in the area, and really crappy lighting near the Toronto port lands.

It was somewhat humbling, as I'm generally big on situational awareness, and get annoyed with idiots not paying attention. After I was rattled, I went back to take a look, and it was hard to see even when looking for it. It was also fixed in a one-week timeframe.

All that being said, 99.9% of the time, I prefer my rigid fork in the city, as I prefer how the Shockstop stem takes care of the FAR more common average bumps and road chatter, better than front suspension.

 

[rdowns]

2.25" is a lot, Dallant...

I think those tires really contribute a lot to the stable feeling of the Allant+ 7

 

[Roxlimn]

Depends on the tires, rider, and surfacing. Presuming that you ride at 45 kph on absolutely flat pancake asphalt, I'd say suspension only brings comfort from vibration fatigue. If it is at all possible for you to come across a 4 inch deep pothole at 45 kph suddenly and without warning, I'm going to say the suspension will probably prevent a crash if it is any good. Data on the safety properties of suspension has mainly been carried out on motorized vehicles. Poor or poorly tuned suspension may not affect handling at all. But good suspension should allow you superior traction on bad terrain and better handling because it absorbs shock that may wrench the wheel to either side or out of your grasp entirely.

 

[RandallS]

However you keep your tires on the surface, whether that be only your arms and legs (bio shocks or levers) or augmented with some suspension or a particular set of tires and pressures, is a good thing. For most of us, it's a combination of all the above.

No contact to the rolling surface means no braking or steering and therefore unsafe. Does a front fork help or hinder? As long as it's consistent and setup correctly for your weight, I'd think that even a poorer fork can help with some of the absorption and therefore help keep your front tire where it should be.

I am sure there are products out there that are less than optimal, but my last two bikes have had reasonable parts. Previous to that, my rigid MTB required me to be the shock absorber. It was not an issue, but I was pretty fit and my "levers" could do it almost all day in rough terrain. Not anymore...

My $0.02

 

[Stefan Mikes]

What I do like about the FS Randall is your legs/feet are part of the sprung mass, too Just saying.

 

[Mr. Coffee]

My cynical view is that there is unlikely to be hard data on the relative safety of suspension forks, if only because such hard data would likely keep bike manufacturers from selling stuff that customers don't need.

Yes, most street motorcycles have a suspension, but you need to keep in mind that there is a huge difference in the forces involved at 28mph and 56mph, and the added mass of the motorcycle doesn't help much either.

For myself, I suspect that most of the time I'd be a much happier rider with a nice springy steel front fork than with a suspension fork.

 

[Johnny]

At 28mph a well tuned suspension DOES improve safety significantly, it will keep your tires in contact with the ground.

The reason why some so called speed ebikes not having suspension is cutting the costs, they assume that those bikes will be ridden on well maintained roads without cracks, pot holes.

 

[Johnny]

A lot of rigid gravel bikes out there. You can’t get a lot rougher than gravel.

You can get a lot rougher than gravel (roads on the east coast). Those gravel bikes are not ridden at 28mph, they are ridden mostly around 10-14mph, makes a huge difference...