View Full Version : Gunnotta size dilemma
Dr. Doofus
03-13-2005, 10:12 AM
ok...doofus has ordered a 60 gunnar...richard schwinn talks doofus into the 60...now doofus is second-guessing...which could be typical stupidity....
on the 60:
120 stem
no spacers
zero setback post
16cm of post showing
on the 58
125 stem or 130...could play with the rise)
20mm of spacers
setback post
18cm of post showing
the 58 would be tighter, a better race bike for the next couple of years...schwinn was hesitant about selling the doofus that one because it wouldn't give as much flexibility for bringing the bars up if/as your doofus lost flexibility over the next 4-5 years....
whaddayathink, forumites...doofus is leaning towards callenemup and changing the order to a 58...but you for whom the doofus has much respect for (and you know who you are...no...not you, yeehawfactor)...58 or 60....?
it'll be a gunnotta...the 02 fork is going up front...so technically, doofus can still post here as a serotta owner....
BumbleBeeDave
03-13-2005, 10:32 AM
. . . the fork only makes up about 10% of the total mass of the bike, maybe 15%, so from now on you will only be allowed to respond to 15% of the threads on this forum. Choose carefully! . . . ;) :rolleyes:
BBDave
pbbob
03-13-2005, 11:58 AM
seems to me if your major concern is a race bike for the next couple of years I would go with the 58 and worry about your flexibility and what you may need in 5 years in 2010.
Smiley
03-13-2005, 12:29 PM
Doc Doof , the Captain says you can always make a smaller bike bigger but not the other way around , stick with the 58 and my guess is you won't have the bike more than 4-5 years anyway .
saab2000
03-13-2005, 01:04 PM
Get the 58 and get a Ritchey stem which has 84 degrees of rise instead of 80 of the Italian stems. This is good for a centimeter or so of the spacers.
No doubt in my mind. Get the Fitty8.
You didn't mention the stem angle to go with no spacers. That would make a difference. If it's an 84, then an 80 would drop the height about 1cm and a 90 would raise it about 1cm. If you need an 80 degree with the larger frame, then it's too tall.
What is your saddle height? Got a handlebar height from the ground to the top of the bars (considering the "standard" 7cm bb drop)?
The difference in the seat post setback due to a .5 degree angle change is only about .6cm and the difference between a no offset and offset style is in the range of 1.5-3.5cm.
Looks like you have figured out that the real difference in the TT length (or reach) is only about 5mm.
Dr. Doofus
03-13-2005, 01:55 PM
yep...gonnaget that fiddyate
seat 80.2cm
tip to bars 56.5cm
saddle-bar drop 9.2 cm
setback 7cm
with the 60, straight post and no spacers on a 80 stem
58, setback post (to get the elusive e-ritchie "buisness end in line with seat tube" sweet spot), 84 stem with 20cm spacers
yerrdoof feels non-stupid with his board buddies at his back on this one....dang that feels weird....
Since an 80 degree stem and no spacers would be needed with the 60, I'd say it's too tall, although I have ridden this exact setup on one of my C-40's several years ago. An 84 degree with 1cm of spacer (or an 80 with 2cm of spacer) will provide about the same height on the 58cm.
The 55cm seat tube on the 58cm should be long enough. You'll need about 30mm of the extra 100mm provided by a 350mm post.
Dr. Doofus
03-13-2005, 02:48 PM
yoodaman dave :banana: :banana:
so how do you weigh in on the TT position debate on the other thread?
No opinion on that one. I don't time trial. I used to have aerobars on road bikes a long time ago, when I did a lot of solo rides on moderately rolling terrain, but gave that up quite a few years ago. Now I ride the Clororado mountains, so climbing is my main focus.
Climb01742
03-13-2005, 04:39 PM
i'm exposing my ignorance (which i also do everytime i open my mouth ;) ) but could someone kindly explain how a stem angle is measured? 80 or 84 degrees...the angle is measured from what? forgive the stupidity. thanks. (and if a stem is level, parallel to the ground, what angle is that considered? 90? but wouldn't the HT angle, and thus the steerer angle, impact what the "final" or actual effective angle of the stem? example: let's say an 84 degree stem were put on two frames: one with a 74 HTA and one with 71 HTA, wouldn't the stem's final or effective angle on the frame be different?) i'm just trying to understand. thanks! :beer:
saab2000
03-13-2005, 05:40 PM
I am no expert on stem angle. But I have an idea.
In the stone age, when we used quill stems, they were said to be 73 degree stems, or -17 degrees. My feeling is that most head angles are about 73 - 74 degrees and this gave the stem a more or less parallel look to the ground.
For some reason, most threadless stems are either 80 or 84 degrees. This is probably to give a bit of rise because threadless stems are a bit lower.
A 90 degree stem would be perpendicular to the steerer tube.
I guess the angle is the angle relative to the steerer tube.
Others might express it more eloquently, but I think I have covered it more or less correctly.
vaxn8r
03-13-2005, 06:14 PM
If you can easily fit between two sizes with minor corrections (and it appears you do) the smaller of the two bikes is going to be more fun to race ride. By that I mean it'll be more responsive and quicker, funner, if you will. The larger bike will generally feel tamer, more stable, handle a bit slower, (all things being equal, stock bikes of same builder). Of course some people on this forum apparently like eating tuna fish sandwhiches, hands off bars, while they speed down 50 mph descents. I don't know how that applies but I'm not one of them.
Dr. Doofus
03-13-2005, 06:38 PM
or doof could just bail on it and send the csi back to ny and get 2cm lopped off the tt...looks like the cat who was going to buy it is backing out....
or the frame could get put in the closet with a "I dunno honey...he said he was gonna buy it" shrug...and then doof could still send it back, get 2cm lopped off the tt...and have the dropouts re-done...build it as a fixie...evil...evil...evil..she'd never forgive thst scam....
:cool: :no: :cool: :no: :cool: :no:
Saab200 is basically correct, the angle is measured counterclockwise from the steering tube, so a 90 degree is perpendicular to the steerer and an 84 is six degree less rise. The MTB guys just have to be different, so they measure degrees of rise, where a 90 degree stem is called a 0 degree and an 84 would be -6 degrees. Thus, an 84/96 flippable stem is the same as a +6/-6 stem.
The reason for the angles was originally to make up for the loss of height with a conventional threadless headset. An 80 degree which raises the bars about 1.3cm was one of the first produced. If an 80 is flipped it raises the bars about 5cm (compared to a 73) and many find the extreme angle objectionable.
Later, the 84 degree, which adds about another 1cm (more than the 80)came along and it could be flipped to 96 degree to add another cm.
The 90 degree fits in between the heights provided by the 84/96.
Yes, the HTA does impact the final height a bit, but most riders are looking at frames with a very narrow range of HTA, for a given frame size, so it's usually not much of a consideration.
Climb01742
03-14-2005, 08:50 AM
merci, saab and dave!
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