What kind of handling issues are you having with your TT bike?

No doubt TT bike is faster . . . that's not a question.

Disc on a road bike? Sure, we did that all the time before TT bikes/aero bars were invented.

Now, go learn to ride a TT and get the best of both worlds.

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David
* Ironman for Life! (Blog) * IM Everyday Hero Video * Daggett Shuler Law *
Disclaimer: I have personal and professional relationships with many athletes, vendors, and organizations in the triathlon world.

I just don’t feel stable on it, especially at speeds in excess of 20mph or so which is below my race speed.
It just feels squirrelly. I don’t like feeling like I’m going to fall off / be blown off the road when a car passes or gust catches me by surprise. I feel like I’m going to pop off if I hit a pot hole and death grip the base bars. I’ve been fit by Jim Manton, so it’s not the fit and it’s not the bike. It’s clearly me.

I end up riding at an NP of 0.65 vs a target of 0.8 because I sit up and it coast when I should be flying (false flats, tailwinds, etc). I’m slower over most Strava segments and finish my TT bike rides mentally exhausted from fighting the bike and in poor mental shape to run a marathon.

There is no doubt an effortless joy of gliding along in the aerobars on a straight smooth road windless day with no cars. But that’s like 1% of my riding.

I’m sure I could get better with more experience. But honestly, life’s too short. There are plenty of other ways to challenge myself in sports and life where I enjoy the challenge and process of improving. Riding my TT bike just isn’t one of them.

^^^^This.

The disc will be faster than any other rear wheel, regardless of the bike.

In the early/mid 90s that setup was the go-to.

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ECMGN Therapy Silicon Valley:
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I think you might have two things going on:

First, it sounds like you are getting your fillings knocked out on some bad roads. Which is gonna happen on a TT bike, or on a similarly-equipped road bike.

I solve that by doing the vast majority of my bike training on a gravel bike. Bigger tires are a little bit slower, but the bigger rubber (if inflated properly) can really improve comfort. And my gravel bike is kinda unusual, so it is especially comfy on both gravel and any asphalt, it doesn't matter how bad.

The second thing is the controllability of your TT bike on training rides. But rather than getting rid of it and replacing it with a (slower) road bike, there is another easy and versatile solution, one where you get the ridability of road bike plus the aero speed of a TT bike. Short write up about this here:
https://www.darkspeedworks.com/blog-triathlonbike.htm

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Advanced Aero TopTube Storage for Road, Gravel, & Tri...ZeroSlip & Direct-mount, made in the USA.
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If you can't seem to get more stable and comfortable on your tri bike than I will go against the flow and say use your road bike. If your riding your TT bike at 65% and you can out perform your power and comfort with the road bike and be ready for the marathon (both mentally and physically) then do it. Don't worry about approval from ST, go with what you feel most comfortable with.

You could always do it with the roadie this year and try again next year. Have you done any long or even short but consistent trainer rides with your tri bike?

What are you riding?
Can you post pics of your fit?

On the kind of roads the OP is describing, bigger tires will actually be faster due to reduced suspension losses.

I Think changing pad width, pad stack height, and using u shaped elbow cups can dramatically improve your condition.
Could you show us how’s your fitting?

1. Widen your pads.
This will increase controllability while you are on the bars

2. Use deep U shaped cups wich can hold your elbows tight. This also improves comfort and stability.

3. Raise your base bar & pad stack height.
Extremey low base bar feels really awful while descending. I also had similar experience on I had cannondale slice RS which had the lowest stack height I’ve ever experienced. For its stem was proprietary and had no angle adjustment (only -17) i had no way to adjust the stack. I come to know that P design svet pro base bar can be used up side down(bar ends are 20mm lower than the center. So flipping this means + 20mm to stack)

4. Slightly tilt your aero bars (praying mantis posture) this really helps alot. It also decreases muscular stress to core muscles.

+ do some upper body strength workouts (back and shoulders) and heavy squats, deadlifts and so on. THIS REALLY WORKS. Trust me.

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Stay home, stay healthy.

Good point.

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Advanced Aero TopTube Storage for Road, Gravel, & Tri...ZeroSlip & Direct-mount, made in the USA.
DarkSpeedWorks.com.....Reviews.....Insta.....Facebook
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To answer your question, there's always an advantage to riding with the disc.

As for the bike, one interesting datapoint is that I did a tt at the end of last year on the tt bike, and again recently on the road bike. The road bike was 2 min slower, despite putting out 27 more watts average. I was surprised the difference was so great. Obviously you can't make a direct comparison, but its 6% slower overall, so I think you can consider that a meaningful difference.

That being said, life is too short to ride a bike that isn't fun. I say put clip-on bars on the venge and have fun. You're still going to have a super fast bike. I'd say you might want to learn to ride in the "aero hoods" position instead of the drops though, it's faster.

Ride your road bike to train.

Do a couple long rides on your TT before a race.

Race your TT

Hang you TT bike up until next event.


Your road bike is your everyday SUV. Your TT bike is like your specialty car for track days or car shows.

Thanks Littlefoot. I appreciate the encouragement to go against the grain of ST wisdom. Look, I'd love to make a TT bike work. There is no doubt that it would be faster IF I could get comfortable riding it hard and handling it in aero. I've tried, and just can't seem to.

I'm riding a Medium S-Works Shiv Disc. I've attached a photo of my fit (on a fit bike) but coordinates translated to the actual bike.

What's your weight distribution front-to-back?

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Any chance you can slide more forward on your saddle? That may help with your handling. Good luck!

If you got a shiv, and per my post above, I think I have found the perfect road bike for you.
Seriously.

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Advanced Aero TopTube Storage for Road, Gravel, & Tri...ZeroSlip & Direct-mount, made in the USA.
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I have the newer disc brake Shiv with the huge hydration fuel cell wing in the back. There is no way to put standard drop bars on there has it doesn’t have a stem.

I also have a 2019 S-Works Venge disc, which has some pretty deep tubes. Going to experiment with some clips ons and a more low/forward TT-like position on that and just see what happens.

No matter what bike you ride a disc is the faster option on the rear 99.x% of the time.

Sure someone going to chime in but, but N=1. If you went to Vegas and had to bet your life savings on the 99 black squares or the 1 red square what are you betting on? (not the Raiders though that's for sure!)

Someone mentioned being 2 min slower and 27w more power. Over time that 27w is a HUGE physiological ask and that time gap will grow...exponentially. As duration increases holding the same power output becomes a bigger ask aka harder and harder to hold even though power is unchanged.

27w is often > than the bottom to top of some people's threshold training zone. Think about that. At 200w you're riding tempo/bottom of threshold, at 227w you're riding top of threshold/touching vo2. Ouch.

For some it's going to be a smaller gap and others a large gap, but road bikes = almost always more drag (although there are some horrendous TT set ups at LC races where I'm willing to bet they'd be faster on a road bike). Also not the drops. Ride low, hand on the hoods. More aero.

In your case where if you are on the TT bike at .65 or the road bike at .8 you may be faster on the road bike. Just remember that at higher wattages you're also producing more kilojoules (kJ) which means your caloric needs will increase. Now you will also probably get a longer duration to eat them so it could be a wash or you could end up in GI distress.

If you do have to produce more watts on the road bike to cover the race distance that also means your margin of error shrinks. You need to make sure you're making wise decisions on the bike. Otherwise it could be a long walk on the run leg.

Here's a real life example for you. My friend and I went an did a 40k TT 2 seasons ago. I rode 255w for a 56:3x on my TT bike. He rode 275w for a 1:04:xx on his road bike. Over 180k that's probably closer to a 40-45 min gap bc of the physiological costs.

anyway some food for thought. best of luck which ever way you go

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Brian Stover USAT LII
Accelerate3 Coaching
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I think if you put an aero bar on your road bike and maybe run a more forward position it’s fine. I’d suggest a wider saddle too. For Placid in particular there are definitely people that have done very good times on a road bike with clip-ons. If you were trying to win then of course it’d be a terrible idea, but as long as you’re ok getting 11:01 or whatever and knowing you could have gone 10:58 on your Tri bike, then don’t stress it. As to your direct question with the disc wheel, if I’d already decided on the road bike then I’d probably just go with standard deep wheels, but do whatever you want, there’s nothing wrong with riding the disc.

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Dimond Bikes Superfan

I ride the same bike in size S and this is all I ride as I don't owe a road bike. I am only 62kg and never felt uncomfortable or unstable on the bike. I came from a very entry level TT and I was surprised how much more stable that bike is. Part of my long ride is on a road where cars overtake me at 80km/h and my bike doesn't move at all. Not trying to sell the bike but just trying to encourage you I guess. Maybe it would help to see a different bike fitter to see what the feedback is? But then again if you don't enjoy riding in aero position and you don't worry about being faster or saving certain leg muscles for the run why even bother.

So you weight 150 and he weighs 350?

Seriously - I agree TT bike all the time, but your "real life" doesn't have all the data to tell the whole story.

we weigh within 10 pounds of each other

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Brian Stover USAT LII
Accelerate3 Coaching
Insta

If you're not bothered about being a bit slower, (and for many/most of us it fundamentally doesn't matter much since we're competing primarily against ourselves?) then it's perfectly reasonable to stick with the road bike. I find that a much more sensible perspective than the idea sometimes espoused around here, that a road bike is pointless because it's slower and isn't what most of us race on. I have both, but 90% of my outdoor rides are on the road bike. The tri bike spends most of its time on the trainer.

The debatable bit to me is whether it makes sense to try optimising the road bike by tweaking the position, wheels, bars etc... specifically for triathlon, having already decided to skip the biggest potential gains.
The disc will make a road bike quicker, and I don't see anything fundamentally wrong with it. However, it seems a little inconsistent with the philosophy of not worrying about time too much which has justified the road bike over the tri bike. Why not sell the disc wheel too? I'm just playing devil's advocate really ;)

Out of curiosity, what rim width, tyres and approximate pressures do you use on the Shiv?
If you're using high pressures it makes the bike feel far, far less sure footed, especially on poor surfaces in my experience. With stock 23mm Felt TTR tyres on the stock narrow rim (15mm?) wheels and pumped to ~95-110psi my tri bike feels incredibly less composed than it does on wider rims (19.5mm) and 25mm GP5000 tyres at 70-85psi. I think i only ever rode the stock setup twice in the mountains on poor surfaces, but I remember it was a slightly nerve racking experience, and it's not great on much smoother roads either. Whereas, with the latter setup I'm perfectly comfortable on those same mountain roads, including fast descents on the extensions which I'd never risk with the stock setup, and despite the latter setup having deeper rims that are more prone to the inevitable wind.

Before you give up on the tri bike you might want to give it a bit more time and effort. I agree with the suggestion above about tires. For training, run the widest tires you can, you might be able to get 28s on that bike since you have disc brakes, run them at something like 70 psi or so if you're of average weight, adjust depending on weight, light riders can go even lower. If they don't fit, run 25s or 26s at maybe 80-85 psi. This should help a lot with your confidence on rough roads. Ideally you'd run narrower tires for racing but it's worth putting up with the aero penalty if it makes you more confident. Definitely don't run narrow tires at 100 psi for training given what you describe, you might even just be overinflating the tires you have.

Also, you want to make sure the bike is in perfect mechanical running order. If the handling is off, the most likely culprit is a loose or faulty headset, but that's not the only potential cause. For example, I knew the lower headset bearing needed replacement on my Speed Concept but had trouble getting it off. Finally got the bike on the road for the first time since the winter and I realized that the headset was "indexing" in the straight ahead position, and that was making the handling unpredictable. I pulled the thing apart and this time managed to get the bearing replaced and now the bike feels much more stable.

I'd take the bike into a reputable shop that knows what they are doing and have them look carefully to make sure there is no mechanical issue with your bike that could be affecting the handling.

As another poster mentioned, a wider armpad position makes handling easier. Then maybe over time as you get more comfortable revert back to a narrower arm width.

If none of this works then do what you have to do to make yourself happy on the bike.

As your Tri bike is a newer model that will not be updated in the next couple of years, so notionally you won't lose any more money on it, you could "mothball" it and see how you get on this season on the road bike. If you find you are too slow or feel the need for the Tri bike again you will have it there ready to try again.
I got rid of my Giant Trinity last year (trying to de-clutter my life) and will be racing on my road bike for the first season in years. My thinking with the Trinity was that Giant would no doubt be bringing out a disc version soon so it could have lost a chunk more money if I waited. I did put the money aside though, just in case I feel the need for another Tri bike next year ;-)