Using a trunk bike rack for heavy e-bike?

[05silgto]

Okay, my girlfriend recently bought a 3 bike trunk rack online, don't remember the brand or model. It's rated to hold 35 lbs per bike. My bike is a electric fat bike I converted and weighs about 70lb. Her bike is just an ordinary small cheap mountain bike, so we should be close to the weight limit. Now, I can't detach my battery because of the way I mounted it but I did place it in an ideal location at the lowest center part of the frame. I don't plan on relying on just the rack's rubber straps and I plan on using my own straps as a backup.
Anyway, I'm very technical and I have plenty of experience transporting dirtbikes on a hitch mounted twin dirtbike rack but that isn't an option in this case.
I was thinking of mounting my bike closest to the car and then her's. Strapping the front wheel to the bike frame to reduce movement and possibly taking some straps I use for dirtbikes and connecting one end to the bikes frame and the other end to a metal clip within the trunk as a added failsafe. Also like I mentioned before, I'll use something to reinforce the rack's rubber straps which hold the bike, I have some steel zip ties I was considering which is rated for 250lbs. We won't be transporting the bikes far, 30min. At the most, it's just a way she can enjoy biking with nearby family members.
Probably gonna get a lot of negative feedback on this but thoughts/suggestions? Anyone do anything similar?

 

[Hillhater]

What car ?..hatch, sedan , wagon , ?
What Ebike. (Hub or mid drive ) ?
For years i carried a heavy, mid drive, Ebike around in a regular sedan boot (trunk ?),.. simply bt removing the QR wheels and seat post and carefully loading .
A hatch would be easier , but an SUV is current choice with 2 bikes inside for security.
Oh, and i switched to a backpack battery system to make everything easier and lighter and to improve bike handling..!

 

[05silgto]

Sedan, saab 9-3 to be specific. Rear hub mounted motor.
The bike is a motobecane boris the brut fat bike. Removing the wheels would be more trouble than its worth with the hydraulic brake lines, and everything else. Even with that though, fitting the bike in a sedan would be pretty difficult. It's a large frame, for 6 to 6'3 riders.

 

[Balmorhea]

I have messed up a couple of cars with trunk racks. I wouldn't bother with them again.

Best remedy is to ditch the car. They suck and they make those who use them suck.

 

[LeftieBiker]

Unless you can make a semi-permanent mount for the trunk, with actual bolts and screws, forget the idea. Those strap-on racks are far too flimsy.

 

[Hillhater]

Have a tow hitch fitted and use a hitch mount rack..
OR rework your battery mount to make the bike lighter.
I have used those strap mounted racks to carry 3 adult bikes for long trips ( holidays) , with no problems
Just make sure the mounting straps are plenty tight !

 

[05silgto]

I have messed up a couple of cars with trunk racks. I wouldn't bother with them again.

Best remedy is to ditch the car. They suck and they make those who use them suck.

We don't really give a crap about the car, it's a crap car and we are just waiting for it to break down before she buys a midsize suv. I'm more worried about the bike falling off on the highway or something.
https://www.walmart.com/ip/Allen-Sp...MIkcnr7P2J7QIVqf_jBx0KzwBMEAQYASABEgICw_D_BwE Here is the exact bike rack.

 

[The fingers]

Have a bike trunk rack that I would not use for ebike. Trailer hitch receiver mounted one would be better. :wink:

 

[05silgto]

Have a tow hitch fitted and use a hitch mount rack..
OR rework your battery mount to make the bike lighter.
I have used those strap mounted racks to carry 3 adult bikes for long trips ( holidays) , with no problems
Just make sure the mounting straps are plenty tight !

https://ibb.co/SKPfzky
Here is a recent picture of my bike, ignore the crap on the tire, just got back from a ride. I made my own 72v battery pack and made a battery box out of rectangular pvc. I siliconed the battery inside the box to hold it in place and to help absorb vibrations. The main thing holding the box are 2 frame bolts near the bottom of the frame. After screwing in the bolts I cut a portion of the pvc and sealed it shut. So reworking a battery mount would be pretty involved and I like my current battery mount, might look like crap, but its great for weight distribution.
However, you got me thinking, I could probably fit my girlfriends bike inside the car by removing the front wheel, it would save more weight instead of removing the battery.