450 LBS, to much resistance?

So far I have tried 3 Zwift rides. 2 free rides and one Fit to Fun Workout. The resistance during the free rides feels SIGNIFICANTLY greater than when I ride outside. During the free rides my avg speed at 0% grade was about 1/3 what it is outside at the same cadence and gear(as reported by my Garmin 830). The two free rides that I completed took more than double the time a similar route would have taken IRL. Being extremely new to indoor riding my first assumption is that the resistance algorithm is way off due to my high weight. How can i adjust this to make it closer to IRL conditions? The resistance was so far off I had to stop multiple times, something I never do IRL. My primary goal for Zwift is to have a fun way to ride when the weather is bad. I have been riding outdoors for about 3 years.

Example rides:
IRL - 4.4 mile loop with 233 elevation, takes me about 30 minutes to complete.
Zwift - Volcano Circuit 3.4 mile 102’ elevation, STRUGGLED for 44 minutes to complete the route.
Zwift - Mech Isle Loop 2.5 mile 127’ elevation, struggled for 49 minutes to complete the route.

450lb rider
6’6" tall
40yr old
Cannondale Quick CX2
TruTrainer rollers
Garmin 830 with sensors
Ipad Air running on home WiFi
Two fans for simulated breeze

It would be interesting to see if reducing your weight and height in Zwift, say 220 lbs 6 ft tall brings it closer to reality

450 lbs? If that’s your stat then I say go get it done! If that’s not your actual stat why opt for that setting?

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Are these the TruTrainer Smartload rollers or one of the other models that is not controllable? I have not used any of those products but if you have a controllable trainer, lowering the Trainer Difficulty setting in Zwift will make it produce less resistance on the hills. The calibration of the rollers will also be important and that’s something you can discuss with TruTrainer if the reported speed/power seems off in their app. It’s possible (even likely) that they never tested their product with a rider of your weight. If you’re using a speed sensor with non-controllable rollers then you can increase the reported wheel size to make it estimate greater power and go faster in the game.

Edit: one other thought… if you are using the stock tires or other multi-surface tires, you may have better luck with a smooth tire designed for road rising.

I am going to give that a try on my next free ride. Curious if anyone else has tried that.

Yes, that is my actual weight.


Yes I am using the SmartLoad model. I specifically wanted a controllable trainer that could provide resistance as close to IRL as possible. I tried adjusting the Trainer Difficulty in the middle of last nights ride, and only noticed a small change.

I plan on emailing TruTrainer to get their perspective. They were very responsive when i emailed them about the weight capacity of the rollers. Hopefully they can provide some insight.

Ahh i forgot to mention the tires. I use “smooth” tires 700c x38 Schwalbe marathon plus tires.

The Marathon Plus is a heavy, draggy, thick tyre so I’m not surprised it feels like a slog. However, if that’s what you are used to riding outside too then your comparison is still valid. I suspect that the power/weight calculations in both the rollers and in Zwift are struggling to simulate IRL riding due to your being at the upper end (or even way off) their models.

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The Trainer Difficulty setting makes hills flatter, but it doesn’t make flat roads flatter: it only reduces resistance on climbs and increases resistance on descents. Set it to 0 and see how it behaves on a climb. It will be just like a flat road on all terrain.

I agree with Colin that the Marathon Plus is not really a road tire. One option for you might be the 700x32 Continental Home Trainer tire, or the 700x37 Continental Contact Speed. You probably only need to use a smooth tire on the rear wheel. Tire choice and pressure would be another good question for the trainer manufacturer.

I don’t think that this represents TD properly. It certainly does not make a climb just like a flat road because your speed will still be the same as if you’re on the climb - it’s only the resistance that changes, as if you’ve got some super-low gears.


It won’t correct a trainer that is under-reporting power but if the hills are causing you to grind along at 30 rpm and burning up your legs, it will help with that.

Unfortunately we don’t know if the trainer is inaccurate or if the Zwift physics model is struggling to do the right thing based on the rider’s size. It would be interesting to see comparison power data between the rollers and a direct drive smart trainer (a test ride at a bike shop or on a friend’s trainer would help) or a second power meter. It might also be interesting to compare speed in Zwift with speed in one of the alternative cycling apps.


I shied away buying a direct drive smart trainer due to their low weight limits. I’d hate for it to collapse during a ride. I have thought about buying a power meter for the bike, but wanted to reach out to the community for input on this issue before spending the money and risking damaging a component.

After experiencing the issues discussed I decided to hammer down on one of the inclines to see how everything responded. I was able to get into the highest gear, but the MPH only went to about 3.5, my estimate is that similar IRL conditions would have put me at about 6 MPH. While hammering down the Smartload roller also sounded like it was really struggling create enough drag.

I emailed TruTrainers and hope they have some insight. Would really like the rides to be much closer to IRL conditions.

OK, you’ve lost me. Surely pedalling down any sort of incline IRL will have you well above 6 mph? Freewheeling will get you that fast!

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I think the ‘hammering down’ is the verb, but up an incline. That’s how I read it. Like ‘put the hammer down’.

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That is the speed going UP the incline. I can hit over 40mph going down some of the hills around me.


What’s your speed like on level ground and how many Watts (not W/kg) are you seeing on the screen?

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I’m far from being the local technical person, but I looked at your two saved rides and the watts are correct for the w/kg, which tells me the systems is converting your watts of record correctly. (One of these is on a 0% flat) This conversion is used by the system to establish mph. If you feel the wattage you’re putting out does not, in the Zwift system, equate with your IRL experience then I’d suspect there is something haywire with how your system is picking up your power output. I’d recommend you take this discussion to your local bike shop and ask their advice. Bike shop staff will be, in my experience, glad to help you out.

Forgot to check this on last night’s ride. Will try again on the next ride.

I will stop by and see what they have to say.

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