Don't forget the Leader TT frame.

Wow, never thought much about this, but you are right. Not even such "high end" aero bikes like the Kuota Kalibur, Guru Crono or Griffen frames have horizontal/adjustable dropouts (I checked). I think you hit the "usual suspects", although I did not know about the Giant frames.

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Fatigue is biochemical, not biomechanical.
- Andrew Coggan, PhD

I don't think the Trek bikes do either. The Giant was definitely a big surprise. Interestingly, I've never seen it listed in their literature or on their website. I saw a Giant frame in person for the first time on Friday at the R&A "Cervelo" night, and that's when I noticed it... I will say that seeing them made me want a Giant frame much more. I think their new Trinity bike will be a big seller. It is a great price for a high-end bike. Comes with nice standard parts on both the high-end spec and low-end spec models.

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

ok, i'll be the dork: why are they desireable?

[reply]I was recently surprised to learn that the Giant TCR TT and new Trinity bikes have rear entry dropouts. This seems to be a generally desireable, but often overlooked feature. So please help me to build this list for everyone's reference. Unfortunately, I think it may be shorter than it should be...

So my list of bikes that have them is:
Litespeed Blade / QR Typhoon
QR Carbon Frames (Lucero/Seduza/Caliente)
Cervelo P2/P3 variations (C. SL, etc.)
Giant TCR Team TT & Trinity[/reply]
Leader TT frame { I own one, great bike, and cheap as hell too}

You're not the dork- the rear-entry dropouts are. Well, I think so at least. They are intended as a means to get the rear wheel/tire closer to the bike's seat tube (assuming it has a rear-wheel cutout). Cervelo and others have a lot of literature on this. The long story short is that it is supposed to be more aerodynamic when the rear tire is very close to the seat tube. There is a more laminar flow and less turbulence when you remove that gap. So what they do is have the wheel enter from the rear, and put some adjuster screws in the dropouts, so you can fine-tune the wheel position; not all tires are the same size. When using vertical dropouts, the wheel has to slide forward a bit so the skewer can clear the rear derailleur mount. This forces a larger gap to be put between tire and seat tube. Well, I suppose you could make the clearance really close, but then you'd have to let air out of the tire to get the wheel out.



The reason I don't like horizontal dropouts is that they're a pain. I find it much more difficult to get the rear wheel out smoothly. I owned a P3 for over a year, and always hated those dropouts. When I'd switch to my race wheels (with different sized tires than my regular wheels), I had to readjust the screws and often the brake pads as well. It is very difficult to remove the wheel without the use of a repair stand or a friend (i.e. at a race or on the side of the road).



When I got my custom bike, one thing I did NOT want was rear-entry dropouts. What the guys at Roark were able to to is get the rear wheel as close as possible to the seat tube without needing to take air out of the tire for wheel removal. This involved a lot of measurement, calculation, and a bit of luck, but it turned out very well. They also use a slightly non-conventional dropout design that places the rear derailleur mount further to the rear of the bike than you typically see. What this means is that the wheel does not have to slide as far forward for removal (so the skewer can clear the derailleur). I don't have a picture of the dropout, but here is one of my seat tube:

Rear entry dropouts are desireable because you can adjust the rear wheel closer to the seat tube cutout (assuming you are sensible enoughto have gotten a Cervelo or imitation) for improved aerodynamics. I also recently learned about the benefit of getting the rear wheel close to the seat tube for better weight distribution and improve handling. A few mm can make a difference.

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TriDork

"Happiness is a myth. All you can hope for is to get laid once in a while, drunk once in a while and to eat chocolate every day"

I've seen plenty of wheel changes on rear entry dropouts that are fast and easy. Cervelo has a video on their website of a guy changing his. 3-5 seconds to do pull it, same as with vertical drops. Like with anything practice makes perfect.

I will not disagree that you may have to change the set screws and the brake pads when changing wheels and tires.

But on a bike like yours, you don't have the option of being close running everything from 20-25mm tires, the way you can on a bike with rear entry dropouts.

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

"But on a bike like yours, you don't have the option of being close running everything from 20-25mm tires, the way you can on a bike with rear entry dropouts."

Very true, but I always use 23mm tires. When designing the bike, we measured the diameter of several different 700x23 clincher tires mounted on a few different rims. The diameters were very close and we ended up going somewhere in the middle (the total variance was ~1mm in diameter from brand to brand; when dealing with the radius measurement from hub to the outside edge of the tire, that is ~.5mm. I experimented ONCE with 20mm tires and wasn't too happy with the results when I flatted out of a 1/2 IM. I'll stick to 23's with standard weight tubes and "heavy" cloth rim tape. On the other hand, some people use 25mm tires in the winter; I've got a cyclocross bike to use for the snowy season.

For 2006 add both the Tequilo and Kilo as well to QR's bikes w/rear entry.

Add the Zipp 2001's. They came with vertical but can be changed to horizonal. Both mine have been changed to horizonal dropouts. I had a really bad habit of pulling the skewers clean out of the vertical dropouts. This would in turn slam the rear wheel sideways and force the bike into a power side. Blew lots of rear tires before I changed over to horizonal dropouts. Zipp makes both horizonal and vertical replaceable dropouts for their frames.

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Paul

Those Zipps were amazing. Definitely seem to be ahead of their time. It is too bad someone doesn't buy the rights (and the molds) and start making them again...

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

J-

You know how I feel about Giant's : )

Did you see the Trinity 1 or 2 ?

I'm surprised to hear that they switched to rear entry DO's. How did the set screws look ?

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Seeing him in deep torment, I said. " You can have my last GU , but its been down my pants for most of the run". - John Hirsch

Take care of your body, its by far the coolest thing you're going to ever own.- Can't remember who told me this, but I love it.

Alas, it was hanging from the ceiling, so I didn't get to see up close.

Your bike does not have rear-entry (it feels so wrong to keep writing that)?

I didn't get to see the new Trinity, but if you look VERY closely on the Giant website, you can see that they are rear entry....

The Team TT bike was stunning, though...

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

I wish, too!! I have to treat mine like babies, since they are no longer available or replaceable. About the only bike I could replace it with would be a Titanflex. I've looked at a few of those and may end up with one after I move out west in January.

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Paul