Does drivetrain matter?

Hello everyone,

I am somewhat new to Zwift and cycling. I use a Cannondale Topstone 4 gravel bike on a Wahoo Kickr smart trainer. I was wondering if using a gravel bike with a 1x drive train vs something like a roadbike with a 2x drivetrain has any negative effects in Zwift racing? My understanding is with a 2x drivetrain in outdoor cycling would allow me to go into a bigger gear and go faster. I am curious if my gravel bike on the trainer would be any different vs a road bike in Zwift?

Thanks!

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Hi Phil

Welcome to the forum.

On the trainer you will have the same issues as you have outside, if you spin out outside when riding with with people on road bikes you will see the same in Zwift.

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how many teeth on the chain ring? I’m guessing it is in the 40’s where most road specific bikes are 52 or so.

It depends on how big the gear is in relation to the power you can put out in a sprint. Looks like your high gear is 40x11 which will be large enough for some people but definitely not all. If you spin out the high gear then you either need bigger gearing or you need to do something like pairing via the QZ app (qzfitness.com) to get virtual gears that will increase the trainer’s resistance. Or spin faster. :grinning:

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microSHIFT, 11-48, 10-speed is what I have

Ok so my undestanding would be if I had something with more teeth that would prevent me from spinning out?

microSHIFT, 11-48, 10-speed is what I have

I think I topped out in a sprint in the 1200’s. Not sure yet if I had more in the tank or if that was due to my gears. Thanks for sharing the link. I will check that out now.

11 teeth is the highest gear available in back, so the question is whether you can (or need to) increase the size of the front chainring. It also matters if you intend to ride the bike outdoors and if the larger gearing would be appropriate for your outdoor rides.

When you reached 1200W what was your cadence and could you have pedaled faster? That’s a pretty big sprint for a relatively small gear but if you are happy doing really high cadence sprints then maybe it’s fine. If you ever need to do 1200W at lower cadence then you may need a bigger chainring or use QZ to increase the trainer’s resistance.

I don’t think I could have pedalled much faster. I am not sure how high my cadence got. I know it was over 110 momentarily possibly higher and I seemed to be pedalling as fast as I could. I am trying to see if I can look that up.

As far as outdoor rides I have not taken it outside yet. With summer approaching here I might ride it a little outside but I do ride an older mountain bike outdoors for now. This might just become my trainer bike.

The QZ seems really interesting. I am reading about it now. Thank you for all of your insight. I have been reading a lot of stuff online but kind of reached the point of information overload for now. I never realized there was so much to learn about cycling.

If you were pedaling as fast as you could in the sprint and you were in the highest available gear, I would want a bigger gear to find out if I could do more power. Once you reach your maximum cadence, you don’t really know how much more power you could have done. And if your fitness improves then you would for sure need a bigger gear, or do something to get more resistance from the trainer like using QZ virtual gears.

If it helps, I’m using a MTB with 44 tooth front chain ring. I race Category B and so far have not run out of gears. I have trainer difficulty set at about 30%.

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Thanks Steve,

I haven’t tried adjusting the trainer difficulty yet. I will try that. For now I really need to get my weight down if I have any dreams of ever getting to Category B. Also need to get my fitness way up. Currently at 117.9 KG which is no fun especially when climbing.

Trainer Difficulty scales gradients, so the effect of increasing it is that you get more resistance on climbs, less resistance on descents, and no change on flat roads because scaling 0% always results in zero. In a flat sprint it won’t help you get more resistance from the trainer. On an uphill sprint it will help. On a downhill sprint raising Trainer Difficulty will make you spin out that gear even faster.

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exactly that.

If you have short gearing on your gravel bike suited to climbing, lowering the trainer ‘difficulty’ will mean less gear changes (and less power drop from shifting) as you effectively ‘flatten’ the course and narrow the range of gear ratios required.

However, the price you pay for this is you don’t ‘feel’ the gradient change and might not respond quickly enough to short attacks on rollers and bumps. From experience I think most people racing have set TD to below 30% as they don’t often respond on short rolling gradients making the bumps excellent places to put the power down.

I’ve learned the best setup for my 3x9 XC Mtb is 30%. I use the smallest 4 or 5 cogs on the rear cassette and I’m always in the largest chainring. This means no cross-chaining and smooth pedalling.

At 30% I still ‘feel’ +3% gradients, prompting me to put out more power. I can choose to do this through increased cadence in an easier gear or more usually holding the current gear and increasing torque.

The added benefit is that for downhill sprints I am also less likely to spin out. The majority of my sprints are geared at 44 x 12 with a peak cadence of ~115rpm I’ve hit 1000 watts. (I still have 44 x 11 if I choose)

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Since you have Wahoo KICKR, you can increase the ‘Wheel Circumference’ setting for the trainer in the Wahoo app to increase the base level resistance in the KICKR when using a Bluetooth connection (I have not tried this when using ANT+ for control, so it may work then too).

I put this setting at ~2.400m when I am using my gravel bike (1x42t with an 11-28 cassette) on the trainer. This keeps me from spinning out in sprints during Zwift races. This combined with a slightly lower Trainer Difficulty setting than normal in Zwift keeps things pretty consistent compared to my road bike (2x50-34t with the 11-28 and 2.136m wheel circ in the wahoo app).