Numbness on trainer but not outside

I’ve been using TrainerRoad for a couple months and really see the benefits of structured workouts. Outside and off the trainer I feel really dialed into my position, something that has taken time over the years.

My questions is, “when doing indoor training which requires mostly seated sessions, I am having some numbness issues in my delicate areas. So should I lower my seat to compensate or is there something else I should do (i.e. stand up every 10 minutes)?” I’ve been riding for about 15 years and know too much about numbness and feel great off the trainer my problem is the solely seated for 1-1.5 hours that is causing numbness.

Thanks much.

I’m not a fit expert, but I would say usually these types of issues aren’t indoor only, but riding indoors will tend to magnify fit issues because you move less, as you have described. Outdoors you probably intuitively move around to mitigate them. While standing every 10-20 minutes is probably a good idea, it might be masking a fit issue that may be best to have examined by a good fitter. In watching some fitting content online, it does sound like most people have their seat too high, so might be something you could experiment with if you don’t have access to a fitter right now. Another thing that I and many others have explored are rocker plates designed to simulate the movement outdoors. However, I don’t think that is a silver bullet and won’t fix fit related issues.

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Here is a related guide:

If you are good for comfort outside, I feel that the static nature of the trainer is a common cause. That and the fact that people often stay seated longer while inside. As such (and linked in the thread above), I think adding motion to your rigid trainer is a worthwhile consideration:

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Russell, thank you very much. I raised my seat 6 months ago about 3 mm so I might just start with dropping that down. I have paid lots of money for Retul fits over the years and feel I can tweak my position without putting out $300. I will try lowering a little and see if that helps.

Thank you.

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Awesome. My trainer is a 2017 Kickr. Thank you for the link. dbp

I think you just try all the tricks.

A riser block might help. Indoors, I keep my front tire on the riser block at the highest setting.

Every 10 minutes I stand and do a 1 minute interval. I try to keep power in the correct zone so it may be a standing Z2 interval.

I also find that some bibs work better than others indoors.

I wear my thickest gloves indoors.

I switched from a wheel on Tacx to a Kickr and my new setup, on a cushy trainer mat, has a bit of side to side motion to it. I think it has helped a lot. I’d be tempted by a full on rocker setup if I was doing longer rides but I usually limit it to an hour.


Save your money on Retul. It’s the fitter; not the tool that’s important. My experiences with Retul have been less than good, but an experienced, knowledgeable fitter doesn’t need those toys. As stated by others, indoor training is a bit tougher as the lack of movement out of the saddle as much makes a difference. Good luck finding that sweet spot.


Thank you to everyone. Before trying rocker plates I might just try an extra mat and getting out the saddle a little more. I will probably try this before lowering my seat because my heel is pretty much down where I need it at the bottom of the pedal stroke. Thanks much.


FWIW. I tried 2 things that helped:

Tennis balls on the legs of trainer
Scheduled standing every 10 minutes.


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I echo the suggestion to reduce your saddle height by 3mm. Riding trainers exacerbates pre-existing issues with fit because readily available ‘treatments’ like standing, coasting and shifting just aren’t as accessible indoors. Actually, the cool thing about tweaking fit on a trainer is that when you finally find your sweet spot and then venture outside again, you’ll be as comfortable as you’ve ever been.

I built a cheap and not very pretty rocker plate, but used to get a bit of give from the foam mats I have down on the pain cave floor. You could probably double or triple up?


As others have said (and there’s lots of similar posts on this and other forums about the same problem), I think its just the nature of the bike being static and not moving compared to outdoor rides. I’ve run into this on occasion over the last few years, and its always moderately terrifying when I feel like my junk is going numb – but its 100% never happened outdoors. The old fix was just stand up, move stuff around, maybe put on a pair of fresh and dry shorts.

I’ve found recently that really focusing on my position n the saddle has helped tenfold. Making sure that I’m on my sit-bones, not sliding around or too far forward has fixed it for me.

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I second the riser block.

I used to only be able to do 45 mins on the trainer and/or rollers before experiencing numbess and saddle pain, even with intermittent standing. I got a standard riser block and now I can do an 1:30 no problem if I do some intermittent standing.

I also put the front legs of my rollers on some 1" risers and that fixed the problem too.

I’ve since learned that on any sort of indoor riding, trainer or rollers, I tend to lean forward more for whatever reason, which puts more pressure on the sensitive bits. Raising the front wheels moves the weight back to my sitbones.

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Yes. I did two hours of lento today in the trainer and this was key. I felt I needed to engage my core in a certain way to achieve it. I had no numbness, but let’s see tomorrow. H

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I had this exact issue. I resolved it by going to an ISM saddle. They look a bit weird but definitely removed the pressure on the old fella.

I do something similar, but use foam furniture sliders under the trainer contact points in addition to a mat.

$10 solution with multiple uses and no skill needed.

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The new Kickr Axis Feet have worked very well for me along with frequent standing out of the saddle breaks.

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This is a great thread, and your insight really helps. I get uncomfortable at about 34 minutes on every TR ride. I’ve just been standing up every 10 minutes after that. I measured my axle heights and my front is lower by a few mms. I’m raising it now! I’ll try some foam pads if I need more relief. Hesitant to lower my saddle since I like my peddle stroke, but at least I know that’s an option. Thanks everyone!