thecoloradokid
Well-Known Member
- Joined
- Jun 17, 2020
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- Location
- Colorado
- Vehicles
- '22 Taycan CT4s + 2023 Rivian R1T
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- #1
I thought I would share some data of my drive from Denver to Tucson over the past week and a half. I wanted to understand the efficiency impact of the Porsche roof rack on the drive and the efficiency impact of the roof rack with a road bike on top of the vehicle. I broke the drive into four legs - one leg with just the roof rack, one with the roof rack and the bike mounted on top of the car, and I then did the return legs with the roof rack and bike removed and tucked away inside the car. As reference, I have a 4s, am running 20 inch Pirelli winter tires currently, and the temps were in the low to mid-20's early in the morning and then rose to the low to mid-60's by the afternoon.
First leg of the drive from Denver to Socorro, NM with just the Porsche roof rack mounted on the car. Temps were very cold in the early morning, but gradually rose to the mid-60's by arrival. There is some elevation gain, but more elevetion loss after Santa Fe. Pardon the dusty car!
Leg two of the drive was from Socorro, NM to Tucson, AZ. This leg I had the bike mounted on the Porsche roof rack. Temps were in the mid-30's when I left and in the high 60's by the time I arrived. there was a little bit of a headwind as well. That all being said, you can see th pretty big jump in kWh impact with a 20lbs road bike on top of the car.
Car with bike mounted with a Thule bike carrier to the top the car.
While in Tucson, I removed the roof rack for the return drive. I broke up the drive exactly as the trip out, so I could have as similar driving routes as possible. The picture above shows the Drive from Tucson to Socorro, NM with no roof rack, nor bike on top of the car. There was a slight tailwind, but not more than a 5mph. You can see the efficiency improvement without the roof rack or bike compared to the 45.2 kWh/per 100 hit on the way out. 20% difference in efficiency is pretty sizable.
Here is the longer return leg from Socorro, NM to back to Denver, CO. There was a slight headwind once I got to Colorado, and there is some good elevation gain throughout the drive as well. But, you can still see a noticeable kWh/per 100 efficiency difference in driving efficiency from the first picture's details when I was driving with just the roof rack fixed to the top of the car - the roof rack alone is a 10% hit in efficiency at highway speeds.
I think we all know that altering the aerodynamics of the Taycan will hurt battery efficiency, I just wanted to know what the impact would be with just the roof rack, and then a bike on top of the car. Not an exactly a "rocket scientist" comparison, but close enough to know that the just roof rack can cause up to a 10% reduction in efficiency at highway speeds, and the impact is almost a 20% reduction in efficiency with a 20lbs road bike on top of the car at highway speeds.
Moral of the story here is that if you drive long distance and at speed with the rack and/or a bike ensure that you either keep the speed reduced and under control, or ensure there are many places to charge along your route. If your are driving 20 miles down to a local park, then no need to worry. One final thought, I would imagine that carrying a cargo box on top of a Taycan will be at least a 30% hit to efficiency at highway speeds.
If you are keeping score on the Electrify America charging network, I used 18 chargers during this trip, and every single one worked. There were a couple of times I needed to change chargers, but every location was able to provide a successful charge for me to continue my trip. I even thing I may have broken a record at one, but I will post a different thread.
If anyone has any questions about car handling, or efficiency with the roof rack, please let me know. I was trying to identify efficiency for all global users, since I know we sometimes tend to get caught up in regional silos.
Cheers
First leg of the drive from Denver to Socorro, NM with just the Porsche roof rack mounted on the car. Temps were very cold in the early morning, but gradually rose to the mid-60's by arrival. There is some elevation gain, but more elevetion loss after Santa Fe. Pardon the dusty car!
Leg two of the drive was from Socorro, NM to Tucson, AZ. This leg I had the bike mounted on the Porsche roof rack. Temps were in the mid-30's when I left and in the high 60's by the time I arrived. there was a little bit of a headwind as well. That all being said, you can see th pretty big jump in kWh impact with a 20lbs road bike on top of the car.
Car with bike mounted with a Thule bike carrier to the top the car.
While in Tucson, I removed the roof rack for the return drive. I broke up the drive exactly as the trip out, so I could have as similar driving routes as possible. The picture above shows the Drive from Tucson to Socorro, NM with no roof rack, nor bike on top of the car. There was a slight tailwind, but not more than a 5mph. You can see the efficiency improvement without the roof rack or bike compared to the 45.2 kWh/per 100 hit on the way out. 20% difference in efficiency is pretty sizable.
Here is the longer return leg from Socorro, NM to back to Denver, CO. There was a slight headwind once I got to Colorado, and there is some good elevation gain throughout the drive as well. But, you can still see a noticeable kWh/per 100 efficiency difference in driving efficiency from the first picture's details when I was driving with just the roof rack fixed to the top of the car - the roof rack alone is a 10% hit in efficiency at highway speeds.
I think we all know that altering the aerodynamics of the Taycan will hurt battery efficiency, I just wanted to know what the impact would be with just the roof rack, and then a bike on top of the car. Not an exactly a "rocket scientist" comparison, but close enough to know that the just roof rack can cause up to a 10% reduction in efficiency at highway speeds, and the impact is almost a 20% reduction in efficiency with a 20lbs road bike on top of the car at highway speeds.
Moral of the story here is that if you drive long distance and at speed with the rack and/or a bike ensure that you either keep the speed reduced and under control, or ensure there are many places to charge along your route. If your are driving 20 miles down to a local park, then no need to worry. One final thought, I would imagine that carrying a cargo box on top of a Taycan will be at least a 30% hit to efficiency at highway speeds.
If you are keeping score on the Electrify America charging network, I used 18 chargers during this trip, and every single one worked. There were a couple of times I needed to change chargers, but every location was able to provide a successful charge for me to continue my trip. I even thing I may have broken a record at one, but I will post a different thread.
If anyone has any questions about car handling, or efficiency with the roof rack, please let me know. I was trying to identify efficiency for all global users, since I know we sometimes tend to get caught up in regional silos.
Cheers
