Do 'smaller' frames descend better ?

[tranzformer]

...says the guy named "tranzformer" lol



Giant TCR geometry:
size M (47.0)
size L (52.5)

52.5 - 47.0 = 5.5 sizes bigger
Similarly M/L is 3 sizes bigger than M

Clear?

A smaller and a bigger frame can have almost identical stack and reach. Of course stack and reach is the only thing you have to know on the condition that the frame's angles remain constant across the sizes. That was a concept promoted by Cervelo and others and it was a very bad concept indeed. Manufacturers like Colnago, Pinarello, Look, De Rosa etc. who know much more about geometry and handling always alter the angles as the sizes go up. That is the wise thing to do and in this case stack and reach are secondary parameters.

I can expect a 25 year old rider to have a limited understanding of all these but I am already riding for 25 years, so...

Wait, so you actually were being serious? lol All the more comical. Read some far out there posts from you over the years, but this is towards the top of the top 10 list.

Based on your logic, Giant has 10.5 sizes (from smallest to largest) for the TCR. lol Comical.

[kgt]

Comical for sure.

[jeffy]

@ MoPho. Interesting as I can ride TCR similar (10mm shorter stem on Medium). I would be nervous about the handling of a medium over a small (psychologically more happy on a small bike) ... would be interested to here more about Medium v Small as i am similarly between sizes.

[dkoor]

Hey, you guys actually measured anything with measuring tape or are you just posting manufacturers' manifestoes? I've seen bogus data on oficial pages (regarding geometries) more than once, that's why I'm asking.


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[DMF]

Back onTopic, I believe the main difference between two identical frames but with 15-20mm difference in The length, even matched with 20mm longer or shorter stem or bar reach, is that the proportional placement of the BB in relation to the wheel axles changes quite drastically. I.e a shorter frame has relatively longer seat stays compared to the front-center measurement, possibly altering cornering characteristics.

[Fiery]

Exactly, the M frame has a 9 mm shorter wheelbase than the M/L, while keeping the chainstay length the same, as well as the front end geometry and the seat tube angle. So we have three main things that have changed:
- the obvious one, shorter wheelbase that makes the bike a little more responsive to steering inputs;
- the decrease in front centre measurement while chainstay length stayed the same, which puts more weight on the front wheel and can make the bike feel more stable through corners up to a point;
- the increase in saddle to handlebar drop which also put a little more weight on the front wheel, but also lowered the rider's center of gravity which again can make the bike feel more stable up to a point.

It seems that for this particular rider on this particular bike model, size M/L is a little too big and the described changes when downsizing to M result in an improved handling. I've had a similar experience with a frame that fit fine regarding contact points, but weight distribution over the wheels was not right for me and downsizing helped improve handling noticeably.

[wingguy]

It seems that for this particular rider on this particular bike model, size M/L is a little too big and the described changes when downsizing to M result in an improved handling. I've had a similar experience with a frame that fit fine regarding contact points, but weight distribution over the wheels was not right for me and downsizing helped improve handling noticeably.

That's a terrible conclusion, given that the ML which the OP rides has the potential to drop the bars by what looks like 15 to 20mm anyway, and this was the major positioning difference between the two bikes.

Gven that the OP would have been riding the M with more drop, you cannot make any statement about the differences in handling between the two frames unless the OP tries riding the ML slammed and uses that as the comparison point. Otherwise it's akin to trying to compare two wheelsets while riding one with tyres at 100psi and one with tyres at 60psi.

[Fiery]

It's a perfectly reasonable conclusion, given that the positional difference is just a part of the story, and most likely not a major one either. Did you even read the rest of my post?

And since we aren't writing scientific papers trying to determine the absolute truth on comparative handling characteristics of Giant TCR frames in sizes M and M/L for all of posterity, I actually can make statements on what I believe to be the most probable case based on the provided information and previous experience, even without a double-blind study.

[fromtrektocolnago]

I would say a frame that is slightly too small might be better than one that is slightly too big, but that the important thing is not the overall size but whether the fit is appropriate for the rider.

[wingguy]

It's a perfectly reasonable conclusion, given that the positional difference is just a part of the story, and most likely not a major one either. Did you even read the rest of my post?

Given that the positional difference is part of the story, you have absolutely no idea what is in the story after that. If the position gives the rider a better feeling on the bike every other factor could even be making things worse but the overall result would still be better. Did you not understand that from my post?

And since we aren't writing scientific papers trying to determine the absolute truth on comparative handling characteristics of Giant TCR frames in sizes M and M/L for all of posterity, I actually can make statements on what I believe to be the most probable case based on the provided information and previous experience, even without a double-blind study.

And since we are making statements about what is actually happening in this case, I can tell you that your statements are not based on the information provided, you've made massive asumptions above and beyond the information provided.

There is absolutely nothing to suggest that the M is going to be a better descending frame than the ML for a given position for the OP. And since the OP could very, very easily adjust his ML position to be a lot closer to the position on the M he could actually find out if that was the major difference, instead of relying on unwarranted and unsupported hypotheticals.

[Fiery]

I actually have a very good idea what is in the story after the positional differences: I know both the M/L and the M size frame geometries, and I know how the differences between those geometries can affect handling. I also know how much in general a position change affects handling relative to how much a geometry change affects it. All this enables me to come to the conclusion as stated in my original post, along with the "it seems" caveat that you also apparently missed.

If you lack the knowledge or experience to make an informed guess, that doesn't mean everybody else does. Yes, it is possible that the position change alone would be enough to produce the difference in handling as described by the OP; however, I don't think this is very likely. That the OP can easily check this by adjusting the position on the bike he has is a given, but seeing as I didn't make any recommendations one way or the other in my original post, it is also irrelevant. Did you somehow come to the conclusion that I'm recommending the OP to switch frames based only on my thoughts on his experience from the one test ride?

[wingguy]

I actually have a very good idea what is in the story after the positional differences: I know both the M/L and the M size frame geometries, and I know how the differences between those geometries can affect handling.

So do I.

I also know how much in general a position change affects handling relative to how much a geometry change affects it.

It seems you don't.

All this enables me to come to the conclusion as stated in my original post, along with the "it seems" caveat that you also apparently missed.

You can't just say 'it seems' and therefore avoid any criticism of your original conclusion. Otherwise I could say that it seems that you have taken one point of personal experience and tried to extrapolate it onto everyone else despite not actually knowing much of anything about how geometry changes alone affect the handling of a bike, or how several brands are currently changing geometries in the opposite way to what you recommend in order to create more planted and stable bikes at high speed. Then if you had any comeback to that I could say "woah dude, why are you getting offended? I only said 'it seems!'"

Did you somehow come to the conclusion that I'm recommending the OP to switch frames based only on my thoughts on his experience from the one test ride?

Given that it's a thread whose purpose was to help the OP decide which size replacement frame to get, and given that you said the ML was too big for him... um... yeah. That's the obvious concusion. if it's not what you meant, you need to get better at writing.

[spud]

no dog in this race, haven't read all the thread. But come on guys, this is simple - given similarity of geometry features, this is really a two variable equation - bar height and front center/stack. You can't possible know what each independent variable's contribution is until you eliminate one of them. Drop the stem to get the bars in the same place. Run the test.

[Fiery]

Otherwise I could say that it seems that you have taken one point of personal experience and tried to extrapolate it onto everyone else despite not actually knowing much of anything about how geometry changes alone affect the handling of a bike, or how several brands are currently changing geometries in the opposite way to what you recommend in order to create more planted and stable bikes at high speed. Then if you had any comeback to that I could say "woah dude, why are you getting offended? I only said 'it seems!'"

This is the first thing approaching a concrete comment related to my initial post - everything else so far has been just you not agreeing that I have enough data or knowledge to form an opinion. Funny that you think the only comeback to that would be to act offended, but I guess you're used to people doing that when you passionately you try to make them see how terribly wrong their opinions are. I don't really get insulted by a well reasoned counterargument even if it comes with a healthy dose of superiority complex.

If you are interested in actually discussing the issue and sharing the knowledge, I welcome comments such as the one above and I will gladly provide a counterpoint or explain further anything I feel has been misunderstood. If you are going to keep reading into my words and proclaiming that I have nothing to base my opinion on, we'll just have to stay in disagreement then.

[wingguy]

If you are interested in actually discussing the issue and sharing the knowledge, I welcome comments such as the one above and I will gladly provide a counterpoint or explain further anything I feel has been misunderstood. If you are going to keep reading into my words and proclaiming that I have nothing to base my opinion on, we'll just have to stay in disagreement then.

Well, the odd thing is that since you've now said that the one test ride from the OP isn't enough to base a conclusion on then you must agree with my original post anyway.

So I'm really not sure why you were trying to have an argument about it in the first place?