New Aero 2016

[TMjpn]

First of all how long has the Propels current shape been out for and does anyone have any idea if they would be releasing a newly designed Propel next year?

Reason being is that I want to buy one, BUT I don't want to go and spend 9K and then a year later Giant release a brand new Propel

In so far as I'm aware there isn't a new one in the pipeline for next year.. And even if they are, the gains between models are very small, possibly only a few seconds over some distance:

For instance new Foil vs Original Foil:

[Xplora]

Disc brakes are going online in 2017, maybe 2016. If you want long term, don't bother getting this year's Propel, because it will probably have disc brakes on it soon. That said, if you think you're getting a long term bike for 9K, you're doing it wrong. That's a high end race bike, and won't be as high end next year when they bring improvements. 6w is a LOT of watts.

I'm in the market for a new aero bike, but I want some longevity from it (a couple years) so discs rule out anything I would buy.

[vosadrian]

But would disc brakes lose 6W in aero?

[biker jk]

But would disc brakes lose 6W in aero?

1-3 watts at typical yaw angles. Max of 8 watts at -20 deg (crosswind from the right).

[vosadrian]

And for most people under typical circumstances (dry and not huge descents) do they offer much?

[biker jk]

And for most people under typical circumstances (dry and not huge descents) do they offer much?

I wouldn't say most people ride in the dry only, take commuters for example. I don't doubt you could come up with a narrow set of conditions for which disc brakes may not provide much advantage apart from better modulation and no rim wear. But if you want to stop in the wet or use carbon clinchers on steep descents, then disc brakes provide a huge advantage.

[vosadrian]

But in the context of this thread we are talking about performance oriented race bikes. I'm all for disc breaks on a commuter/MTB/anything that does general all purpose duties, but I am not convinced that there will be a general across the board move to discs on race oriented bikes (but I will be quoted as wrong in a few years time!!). Certainly in any racing or fast riding where I like an aero bike, I have never been found wanting for discs. If it is wet on a descent I am more worried about tyre grip than braking performance. Give me the better aero and weight reduction over the braking performance.

[biker jk]

A few pros believe disc brakes would provide better braking on wet descents.

Tom Boonen (Omega Pharma-Quick Step): I’ve never used [discs] before, except on a mountain bike. I’d love to try it in training, and in a race. I think it has its advantages — you see how scary it is to go downhill in a race with no brakes or almost no brakes. The problem now with carbon rims is 50 percent of your brake power is gone when it starts raining so it’s maybe a good thing that they will allow it, or should allow it.

Peter Stetina But I cannot wait for the day when I can go down a wet descent and not have to grab my brakes and then wait four seconds until they actually engage on a carbon rim. I hope someday, and I think it’s the next thing in the sport. But it’ll be awhile.

http://velonews.competitor.com/2014/08/ ... ate_341014

[vosadrian]

It certainly has some benefits. I am just questioning if they outweigh the losses on the very high end of fast bikes where weight and aero are king.

[g-boaf]

biker jk - But compare that with the carbon wheels and rim brakes and the way they behave in the rain. Which would you prefer?

Edit: The quote tag went stupid.

[Xplora]

I don't know about huge descents... but even our lowly Bellbird Hill out west had me getting serious brake fade on my Enve's, with Enve pads, in the dry. A bus was doing 45kmh down the hill... I was riding the brakes quite hard for a couple kilometres (its 8-10% for the most part)... good quality race bike and 73kg rider... brake fade is a serious problem in the wrong circumstances... does this outweigh the risk of rotor injuries? That's a different question... but I would have never thought I could get anywhere near catastrophic failure on my spiffy rims in the dry.

[vosadrian]

Bellbird is a pretty decent descent. Bigger than most people would be likely to do under race conditions (certainly in Sydney). Poor enough road that you are unlikely to be doing it on something you cannot easily repair a puncture with (so clinchers), and there are other solutions short of disk brakes (aluminium brake tracks) for those outlier circumstances. I normally use my DA C24s when I go up there. <1400g and aluminium brake tracks. I prefer light weight over aero for that ride. Also, it is unusual to have to ride the brakes all the way down a big descent which is worst case.

There are certainly conditions I would prefer to have disk brakes. But 99% of my riding (and probably 80% of riders in general) has no issue with rim brake technology on race bikes. I think it will be niche market and we will still be buying rim brake high end road bikes for many years to come. I would certainly choose to have disk brakes on my next commuter though.

[Xplora]

Dunno about the poor road anymore, they resurfaced the S's and I tickled 83 without pedalling a week back on the lower section. But I tend to agree - mark my words though, I'm definitely not going to stay with cables and rim brakes if a hydraulic option for discs with a 1300-1400g 50mm deep clincher is available (and I suspect this will be a lot easier to reach than we think). Hydraulic FTW. No, my bugger of a Madone can't do them LOL

[vosadrian]

Because brake forces on disc brakes are applied to the hub rather than the rim, the braking torque needs to be transferred via the spokes to the rim. This braking torque is much higher than any torque a rider could provide in positive acceleration force. Does this mean that the spokes will have to be higher counts and stronger and laced differently... particularly on the front (which does most braking but no acceleration) where a light wheel can get away with 16 lighter duty spokes? How would this impact weight/aero of wheels?

[biker jk]

Because brake forces on disc brakes are applied to the hub rather than the rim, the braking torque needs to be transferred via the spokes to the rim. This braking torque is much higher than any torque a rider could provide in positive acceleration force. Does this mean that the spokes will have to be higher counts and stronger and laced differently... particularly on the front (which does most braking but no acceleration) where a light wheel can get away with 16 lighter duty spokes? How would this impact weight/aero of wheels?

Yes more spokes are needed on the front wheel and they can't be laced radially. However, rims can be made lighter given no need for the extra material to reinforce the brake track. They rim can also be made more aero. So the Enve SES 3.4 disc wheelset is actually 20 grams lighter than it's rim brake sister despite more spokes on the front wheel and beefer hubs.

[skydance]

if a hydraulic option for discs with a 1300-1400g 50mm deep clincher is available

Does it even exist? Most wheelsets are above 1400 even in 24 mm depth.

[Xplora]

My Enve's are only using DT240s, and clinchers... around 1450. They aren't light by any stretch... expect that the better braking comes with a weight penalty. Reduce that weight, put some in the hub, I have no doubt that a disc specific rim design can hit the mark easily.

Of course, a tubular at that depth is 1100 to 1200... I'm not sure how much weight is related to the bead surface and rimtape, but it can be done

[TMjpn]

But would disc brakes lose 6W in aero?

1-3 watts at typical yaw angles. Max of 8 watts at -20 deg (crosswind from the right).

To a hardcore racer type (and i'll happily admit I am not) 6 watts may be big, and thus the new model will be well suited to their needs. We've all seen how close stage wins can be at the sprint, with barely an inch between wheels - and the 6W are the difference.

But I often think, how often will a race of any description get 40km of flat, smooth as butter asphalt with the same wind conditions? Even a change in road surface will drain watts if the compliance is awful. And I really only mean this in the sense that many aero road bikes are marketed as your best tool in a solo break away.

Advantage is an advantage, minimal as they come - but for a recreational purchase or trying to find the absolute best, is the extra money worth it?

BTW the new foil at 105 level is still $3.5K, compared to the last model which was around $2.2k and as low as $1.8K when released

[Xplora]

Yes. It's worth it.

End of discussion.

Is it worth it to YOU? I dunno. You like losing? I don't. Always worth noting that those terrible conditions you are discussing make the aero bike more effective, not less effective. Your gains in bad conditions are greater and arguably more important as you can push more evenly, rather than pushing past surging winds.

So yeah, definitely worth it. If you are putting box section wheels on it, and ride it like a lounge chair, sure, might not make sense. But some of us ride REALLY low... some of us are looking for more. 1000 bucks on a frame that gives me better aero, whether my back is sore or not? No question baby.

The question "is it worth it?" posed as a rhetorical only ever says "I can't afford to make the choice between aero and light, and I want someone to justify why I shouldn't have to decide".

[softy]

If we are talking about the pros;

Pros keep braking to a minimum, it is watts wasted.
downhill decents are done at unbelievable speeds, braking means giving an advantage away. So how often does a pro brake over the course of a race? Even it was as much as 10 % how much later can the rider brake to get an advantage. Remember you can only brake as hard as the grip between the tyre and road.

at this level i see little advantage, for the commuter yes! We actually brake alot more than a pro, and will be a big improvement on utility bikes.

racing bikes for racing?? I need to be convinced.....