# Effects of towing another rider



## Sparticus (Dec 28, 1999)

A 73 y/o riding buddy recently got an ebike (Trek Rail, carbon frame) and really enjoys riding it. My GF enjoys this friend’s new ebike too because he got a tow rope and has begun pulling her up the hills (Oregon logging roads.) He attaches the tow rope to his ebike’s saddle rails.

Meanwhile I’m off the back climbing the old school way — via human power. Whatever.

Anyway this new situation led to a discussion about whether it’s good or bad to use an ebike to tow another rider.

Anyone aware of any research that provides evidence that towing another rider is bad for the bike? Or evidence that towing is not bad for it? Is the increased motor &/or frame stress inherent in towing beyond what the bike is designed for? Got any anecdotal towing stories?

Or are towing stresses expected and therefore factored into ebike design so there’s no potential damage to motor or frame?

Not seeking off-hand opinions — already have plenty of these. Thanks for educated insight, first hand experience or links to credible info.
=sParty


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## mtbbiker (Apr 8, 2004)

Each manufacturer has a rider weight limit. But if it were me, I’d only tow your own young kids. Towing an adult would definitely stress out the motor, due to slower speeds which adds more heat and sooner or later that person will cook their motor. Not to mention more wear and tear on all drivetrain parts. 


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## rangeriderdave (Aug 29, 2008)

I think it would make a difference if the GF is pedaling or not. And for how long of tow. If you think about as if a solo rider is riding up a 3% grade eco versus a 10% in turbo ,a lot of variables . From what I've read there is a 250# limit on a lot of motors ,pretty easy to go over that. I think that over heating the motor would be the biggest concern. With the load on the drive train next.


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## RickBullottaPA (Mar 4, 2015)

I don't see there being many issues with (reasonable) towing. The motor will only make so much power/torque. Towing another bike up a modest grade is no different than not towing anyone up a steeper grade. Obviously it'll chew up battery fast.


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## roughster (Dec 18, 2017)

The problem with towing is the "getting towed" person typically stops pedaling at all and a "true 100% tow" puts A LOT of tax on the motor and most likely exceeds its capability. This will eventually result in a burn out of the motor. Now if the person getting assisted by the pedal assisted bike actually pedals and contributes and just uses the tow as an extra assist? Probably not too bad. I would suggest using a tow rope that has elasticity to encourage the getting towed person to keep pedaling.


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## Sparticus (Dec 28, 1999)

It makes sense that towing puts additional stress on the motor. How much stress? Too much? Too many variables to know, but without question, more stress than when not towing. The increased amount of stress would obviously depend on terrain, grade and weight of the towed rider plus as pointed out previously, how much assistance or lack thereof the towed rider was providing through their own pedals.

What about stress applied to the dropper post and/or frame's seat cluster? Towing would generate backward force to the seatpost as opposed to the typical downward force of a rider sitting on the saddle. Is the frame up to this type of stress? The dropper post?

I searched online for any mention of towing within any Trek owner's manuals that I could find. Crickets. I did discover that all Trek "class 4" bikes (aka "all mountain" including bikes with more than 4" but less than 7" suspension travel) have a weight limit of 300 lbs, but found this matter addressed within a generic bike manual that goes out with all Trek bikes whether analog or ebike. I could find no mention of towing within Trek's separate "electric bicycle" manual, wherein Trek pretty much stuck to how to charge and care for an ebike's electrical components & battery; very little on applied usage of the ebike itself. Zero about towing.

Perhaps Trek simply wants to steer clear of the whole subject of towing. I wouldn't blame them. Towing unquestionably falls outside intended use. But it seems to me that if Trek couldn't quantify the risks of towing to ebike &/or rider, they'd say something -- somewhere -- to the effect of "Never tow another rider with your ebike." But... nuthin'.

Meanwhile I found many YouTube vids about how to tow plus more than one product (tow cables/cords/straps) available for sale for this very purpose, so it's obviously not an uncommon activity. Weird.
=sParty


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## mtbbiker (Apr 8, 2004)

Sparticus said:


> Meanwhile I found many YouTube vids about how to tow plus more than one product (tow cables/cords/straps) available for sale for this very purpose, so it's obviously not an uncommon activity. Weird.
> =sParty


I believe most of the kits are designed for towing your own kids. I personally don't think that would be an issue, but once you start trying to tow an adult, your bike is going to have issues. Unless it's just a quick push to get someone over the top of a steep climb. In So. Ca. at Sky Park, I've seen this several times, but always kids, not adults.


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## 127.0.0.1 (Nov 19, 2013)

I can see a tow strap failing and blinding the rear rider permanently, so there's that.


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## Slap Happy (Feb 3, 2004)

I got the Towwhee a couple years ago to help get my kids out deeper on family rides. It all started before I even had an e-bike. Towing, even a kid, under solely your own power can be a heck of a workout. Bringing the e-bike into the tow mix really opened up doors on being able to spend more time out, go further with the kiddos, etc. It's been fantastic.

At that time, I am reasonably sure Towwhee just had the one product. Now if you look at their site, they have adult, e-bike and moto specific products. Would clearly indicate more interest around this.

https://towwhee.com/ebike-motorcycle

I've been out on rides with mixed e and non-e riders, where the e's help the non-e's with towing. It's allowed old riding groups to stay connected in my experience, at least occasionally. I can see how it is more weight, and therefore more strain to some degree. Doesn't seem likely any of this has really been measured or clearly defined by the industry, but who knows.

E-bikes are happiest under lower gearing at high cadence. Assuming you are using lower gearing, and whoever is hanging off the back is contributing some effort, my gut is that it can't be all that detrimental. Battery sapping...sure. Motor killing? I don't think I would worry about that, but again - I don't think anyone truly knows.


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## RickBullottaPA (Mar 4, 2015)

So, you do understand that bike weight limits are primarily related to frame stresses and strength, not eBike motor power, right?

And all major drive systems include some form of overheat protection.

The biggest issue(s) with towing are simply battery usage and safety (having a strap on a bike and towing someone if you don't do it properly could end poorly).


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## Sparticus (Dec 28, 1999)

RickBullottaPA said:


> So, you do understand that bike weight limits are primarily related to frame stresses and strength, not eBike motor power, right?


Yes, this being one of the points I attempted to include within my posts above, but perhaps implied too tangentially.
=sParty


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## 89hawk (Nov 21, 2007)

I used my Meta Power to tow my son. He is about 100lbs. I keep it in ECO mode and he helps pedal. We average non e bike speeds or slower going up hills. Looking at the power meter I am 1/2 way on it. Battery still seems to last a long time.

On very steep hills we walk up them. They seem to real stress everything and it is hard to keep balance at a walking pace.


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