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Compact frames(18 posts)

Compact frameslakeplacid
Sep 24, 2001 7:46 AM
Looking to purchase a Ti frame either a Serotta Legend or LiteSpeed (Vortex). Does anyone have any experience or preference with compact verse double diamond framing. Why the compact design over the latter?? Weigh 165 to 170 and stand 5 ft 7 in if that is an issue. Currently ride a Serotta CSI. The big difference between the steel and Ti,it appears was the weight difference and the way the Ti climbed. It climbed like a scared cat.
Compact tradeoffKerry Irons
Sep 24, 2001 4:26 PM
Compact frames really offer no advantages other than style. There's nothing wrong with them, but they are not a breakthrough in technology either. Shorter seat tube saves a tiny amount of weight and offers a slightly stiffer frame due to the smaller rear triangle. Longer seat post adds a tiny amount of weight and offers a slightly softer ride due to the longer post. The details of any given frame design (geometry, tube thickness, butting, swaging, ovalizing, etc.) will absolutely swamp out the "effects" of a compact frame design. I sure like my Vortex, but there are many other good bikes out there.
Compact tradeoffScott
Sep 25, 2001 11:32 AM
I have a slopping top tube on my bike. I like it because I no longer hit my shoe cleat on my top tube. With my normal frame I was always doing this. Other then that it just looks cool. I would notgo out of my way to get a compact frame but there is nothing wrong with them.
Compact tradeoffDougal
Sep 26, 2001 4:57 AM
Yeah, there's nothing obvious about having a compact frame that will benifit your riding.

You get more standover clearance, perhaps a slightly stiffer frame, and a lighter frame with extra weight in the longer seatpost.

The Giant TCR Team is the lightest race proven frame in production but I'd imagine that quite a lot of the saving would be put back on by the extra seat post.
Compact tradeofflakeplacid
Oct 20, 2001 4:17 PM
Hi Kerry,

Thank for the input. I have had the opportunity recently to ride for a few days a Vortex with Campy. I really enjoyed the ride, mostly noticing the quality and acceleration of the bike while climbing both in and out of the saddle. I currently have a Serotta CSI which climbs really well, however, it is heavier than the Ti. The CSI weighs in at 19.5 and the Ti in at 17 lbs. The weigh difference and construction of the Ti in sweet. I am looking into Serotta's Legend Ti, however, I think Serotta is pricing themselves out of the market. This comes from someone who has riden Serotta for a long time as the factory is in my backyard.

Ed
my experiencetcr01
Sep 26, 2001 5:14 AM
This has been my first racing season on a compact, a Giant TCR zero. My likes are the light weight, quick handling , very stiff. My dislikes are the fact that there is a lot of drop to deal with here. Giant should have made this bike with an extended headtube. The biggest down side is the sacrifice in descending. With the compacts I do not feel as confident. The bike is a little more twitchy than I would like. Even though I would give the bike a thumbs up overall, I will probably not go with the compact geometry in the future.

I must say I love this bike for crits. Very fast acceleration due to very short chain stays. The handling is also very fast. In some ways, I like to think of it as a compact version of a LS Ultimate in terms of geometry, not material.
second thatDuane Gran
Sep 26, 2001 3:36 PM
I own a Giant TCR Team and I also find that it is great for crits, but it feels a tad sketchy in fast descents. It isn't bad by any means, but it doesn't have the same sure feeling that I get descending with my double-diamond Trek. On the plus side, I love how the Giant takes corners. The short wheelbase feels very good with cornering.
ButKerry Irons
Sep 26, 2001 5:38 PM
None of this has to do with whether the bike has a compact frame or not. The designers went for a certain handling characteristic, and could have done the same thing with a horizontal top tube, or even one that sloped to the front.
Buttcr01
Sep 27, 2001 9:11 AM
I think my comments have a lot to due with the compact design. The less stable decending characteristic comes from a shortened wheelbase associated to the smaller rear triangle of compact frames. This is a common to all compact designs. I would argue that traditional frames allow for more design characteristics to be built in such as longer wheelbases, etc.. Compacts definitely have a different feel that is truly inherent to their design. It is easy to make a traditional frame handle like a compact but very very difficult to make a compact ride like a traditional. Comapct design goes beyond simply sloping the top tube.
NopeKerry Irons
Sep 27, 2001 4:33 PM
Actually, I think you have it backwards. It's easy to make a compact like a normal frame. Just give it the same wheelbase, the same angles, the same equivalent tube lengths, same fork rake, same front-center distance, same BB drop, etc. What you can't do is make a normal frame like a compact, if you design the compact poorly and squeeze everything together. Also, the length of the rear triangle is all about how close you will let the tire get to the seat tube, the seat tube angle, or if you indent the seat tube to shorten things up. A compact frame does NOT inherently have shorter chain stays - it's limited by tire diameter and seat tube angle.
Nopecyclequip
Sep 28, 2001 6:02 AM
Have to agree with you. Compact refers to the slooping TT, not the wheelbase. Giant TCR's have always had an iffy descending feel - more a function of the light weight and THAT fork. I used a Time Equipe fork on a TCR Team and it descended as well as anything I've ridden.
questiontcr01
Sep 28, 2001 7:07 AM
OK in retrospect, I more or less agree as well. The weight is a big factor in descending and I have always questioned the stock fork. Whe you replaced with the Time, what rake did you go with? What frame size do you have? I am riding a medium frame and had the stock fork off and the rake measured 43.1mm. I have also had some instabilty in tight corners out of the bike's front end while racing crits.
Compact handlingbike_junkie
Sep 30, 2001 9:52 AM
I own a Serotta Legend Ti Compact. It climbs great and descends like a train. It's not fair to say that compact bikes are nervous descenders, this has to do with frame geometry, fork rake, and how it all fits together. My Serottas wheelbase is the same as a traditional 55cm Legend, but both triangles are "squished", and I still safely run a short roadbike seatpost. There is a little weight savings, but Serotta looks at your weight, riding style/preferences, handling preferences and goes from there. They won't sell a bike that is nervous handling. Serottas have always been known for stable handling and great descending confidence, and they won't ignore all that to make a compact bike just because they look cool. In short, it rides like a Serotta, with a little extra snap, a few grams saved, and a mean look to it.

It's NOT night and day, and traditional frames are not obsolete by any stretch. Personally though, I see more reasons to ride compact than not, and I like the look.
Good observation (nm)Duane Gran
Oct 1, 2001 5:46 AM
my experienceJohnG
Oct 13, 2001 7:42 PM
My TCR feels pretty good up to around 40Mph. Above 40-45MPh the bike is a little twitchy. Not ugly bad but not real confidence inspiring either.

I actually VERY much like the fork on the bike. Nice and comfy and stiff enough for me. The bike is light and quick.

YMMDV
JohnG
my experienceMick Mccutcheon
Oct 19, 2001 9:26 AM
I raced a compact giant frame for a year and the handling of it was great. It does feel very stiff in sprints, especially from slow speeds. i think the main advantage is that you can throw it between your legs more which is a big advantage on climbs i reckon. And as for the handling on descents, its not twitchy, you just keep your weight back a little more and it feels very stable. As well as cornering.
my experienceMD
Nov 18, 2001 6:18 PM
I have had two compact frames along w/ a couple of traditional frames. The one was a Giant frame which was built like rubber. My bb would flex so much that the cranks would hit the side of the chainstay. Plus the fork split on me and I never had a crash. I now have a Santa Cruz and there are no problems w/ the handling on descents or anywhere else. The bike is fantastic. I really like the tight handling of the compact frames over the traditional frames due to the headtube angle. Plus it has a really small rear triangle that is great in sprints and power climbs, no real flexing there. You are going to find that the lighter the bike the more squirrelley it will be for fast descents no matter what the frame material or design.
my experiencesg
Dec 14, 2001 12:23 PM
I recently purchased a custom frame, which I dialed in my measurements to a traditional frame style. Because of the large size of my frame, my builder recommended a sloping top tube to save weight and add more stiffness. Basically he just drops the top tube down a few inches. It had minimal effects on wheelbase, etc. I think some of the handling problems might be due to the fact that many of the frame builders are selling these compact frames in only 3 sizes (s, m, l). I have been told that modifications by way of stem risers, etc. will always effect handling as opposed to having a properly sized frame.