Does Stiffness Matter?

[bpsmith]

Been looking on Veloviewer for comparisons between 2 of my bikes. Managed to show those bikes for every ride in 2017. Stats as above.

Guess which bike is the Aero framed stiffer one and which is the more relaxed, not so stuff one?

Yup. Stiffer one is the Aero bike shown as Bike 1. Weight of both bikes is very similar. Both have equivalent tyres fitted, of the same width and pressure. Haven’t felt any more fatigued on the Aero bike. Rides are over the same range of routes.

Considering I have done 26% more climbing on average, the 0.6mph faster average speed suggests stiffer is better? Or is it the Aero elements of the frame? Or both?

 

[Globalti]

I agree. I have an all-season endurance bike and a summer hooligan bike. The hooligan bike is lighter and stiffer and an absolute blast to ride because it rewards your efforts, but I wouldn't fancy riding it 100 miles.

 

[Smokin Joe]

This video leaves me wondering why we haven't yet adopted full frame suspensions on road bikes...

All the suspension needed on a road bike is in the tyres, it's called air and it is fully adjustable.

 

[derrick]

My S2 Cervelo felt stiffer than my R5, But i think most aero frames are stiffer, but i never suffered from fatigue, and i have done big rides on both of them.

 

[Andrew_P]

View attachment 394648 Been looking on Veloviewer for comparisons between 2 of my bikes. Managed to show those bikes for every ride in 2017. Stats as above.

Guess which bike is the Aero framed stiffer one and which is the more relaxed, not so stuff one?

Yup. Stiffer one is the Aero bike shown as Bike 1. Weight of both bikes is very similar. Both have equivalent tyres fitted, of the same width and pressure. Haven’t felt any more fatigued on the Aero bike. Rides are over the same range of routes.

Considering I have done 26% more climbing on average, the 0.6mph faster average speed suggests stiffer is better? Or is it the Aero elements of the frame? Or both?

You set the wheel size calibration wrong on the Aero bike. Or you rode the Aero bike more in the summer and the other in the winter. Your stats would be similar to mine Winter vs Summer on an identical commute allsorts could be changing the average speed. You clearly prefer the Aero bike as you rode it a lot more. :-)

 

[gbb]

It does matter but not in a speed sense, i found my Bianchi Via Nirone, the one with straight tubes, prior to the C2C version, the frame flexed noticeably when I was hammering along and definitely out of the saddle, the chainset used to rub against the FD. The result of that (i believe) was a broken weld under the BB with the constant flexing...or lack of stiffness if you prefer.
As soon as I got my next bike, a C2C Via Nirone, the frame was noticeably stiffer. My carbon Ribble displays no noticeable flex either.
No way would I want one again that flexed.

 

[Ming the Merciless]

Try riding a full suspension frame then a road bike up a hill and see if it makes a difference.

 

[Moodyman]

Stiffness matters if you're a heavier rider and or carry touring loads. It makes for a stable and confidence-inspiring ride.

 

[bpsmith]

You set the wheel size calibration wrong on the Aero bike. Or you rode the Aero bike more in the summer and the other in the winter. Your stats would be similar to mine Winter vs Summer on an identical commute allsorts could be changing the average speed. You clearly prefer the Aero bike as you rode it a lot more. :-)

Definitely got the sensors set up in the same way, with the calibration figure derived from actually measuring the tyre.

Definitely prefer the Aero bike, I agree there, but do enjoy the other bike too in fairness.

I have gone back and looked at rides between 1st May and 30th September. Bike 1 was 25 rides and Bike 2 was 11 rides. I will export the data and work it out properly tomorrow, but have added up the mph figures and divided that figure by number of rides. I realise that this isn’t ideal, as it doesn’t allow for variance in miles travelled each time, but just as a tough guide for now.

Bike 1 average - 19.5mph
Bike 2 average - 17.4mph

Will post back more accurate data tomorrow, but there does appear to be a clear leader here.

Don’t get me wrong, there are bound to be variances which can’t be controlled, but I find it very hard to believe that of those rides I only experienced a headwinds on Bike 2.

 

[Andrew_P]

Definitely got the sensors set up in the same way, with the calibration figure derived from actually measuring the tyre.

Definitely prefer the Aero bike, I agree there, but do enjoy the other bike too in fairness.

I have gone back and looked at rides between 1st May and 30th September. Bike 1 was 25 rides and Bike 2 was 11 rides. I will export the data and work it out properly tomorrow, but have added up the mph figures and divided that figure by number of rides. I realise that this isn’t ideal, as it doesn’t allow for variance in miles travelled each time, but just as a tough guide for now.

Bike 1 average - 19.5mph
Bike 2 average - 17.4mph

Will post back more accurate data tomorrow, but there does appear to be a clear leader here.

Don’t get me wrong, there are bound to be variances which can’t be controlled, but I find it very hard to believe that of those rides I only experienced a headwinds on Bike 2.

I was pulling your leg, just a bit... Curious now, the choice for bike two in the Summer?

 

[bpsmith]

I was pulling your leg, just a bit... Curious now, the choice for bike two in the Summer?

I read between the lines don’t worry.

I am intrigued by the variance nonetheless. Not trying to force the figures one way or the other tbh. Got no vested interest other than the facts.

Have recently bought a power meter and due to install an Ultegra crank on Bike 2 so I can move it between both bikes. I guess that will allow for some more scientific numbers.

Choice of bikes during the Summer? Who knows? Can’t think of any real reason other than what I fancy on the day. Or maybe if one was dirty and hadn’t had the chance to clean it possibly. Clean bikes are faster, obviously.

 

[ADarkDraconis]

Before I bought my 'new' Trek I asked my brother (who works in our LBS) about this because it has a light suspension fork and I had only ever had rigid. Everything I had read online said that you do not want this as it will make you horribly sluggish and turn an otherwise lovely bike into a doppy sow performance-wise, and to go with a solid frame. He said that at my riding level (definitely not pro-racing) I would not even notice any detriment or performance loss, and in fact it would be more comfortable for my arms. He was right, it still goes much faster than my old bike and I have no complaints.

 

[bpsmith]

Updated stats for 2017:

Bike 1 - 17.54mph for year
Bike 2 - 16.67mph for year

Bike 1 - 17.90mph for May to September
Bike 2 - 17.62mph for May to September

Not hugely different bikes, but Bike 1 is stiffer and more aero than Bike 2, although Bike 2 has aero bars which bike 1 doesn’t have. I plan to swap them over when needing new cables, so will compare again later.

I did climb 3 times the elevation on Bike 1 compared to Bike 2 though. Other than that, the gains appear negligible.

 

[I like Skol]

Not hugely different bikes, but Bike 1 is stiffer and more aero than Bike 2, although Bike 2 has aero bars which bike 1 doesn’t have. I plan to swap them over when needing new cables, so will compare again later.

I did climb 3 times the elevation on Bike 1 compared to Bike 2 though. Other than that, the gains appear negligible.

So not even a remotely valid comparison then?

 

[EatSleepRideRepeat]

A lot of youtube chatter, and attempted technical explanation. No amount of talk will convince me that you can load energy into an object (frame) and get the same amount out. Maths and science says other wise. You will lose power with a flexy frame, part of the loss will be dispersed in heat.