globecanvas

This season I've been messing around with weight distribution on the bike, trying to distribute weight more forward without changing the basic fit triangle between bars, saddle, and BB, by rotating the triangle forward around the BB. A more forward position feels more aerodynamic and control is much better. But as the triangle rotates forward, power and comfort starts to suffer as the saddle setback gets too close to being directly over the BB. I think this is all standard stuff so far.

I'm just under 5'9, fairly normal proportions I think, maybe my legs are a bit shorter than usual. My current frame is a 54 Tarmac with an effective TT length of 54.8 cm according to specialized.com, and a 100 mm stem. The saddle is far enough forward that I could run a zero setback seatpost if I wanted. I can't rotate any more forward on this frame without either changing the basic triangle (that is, changing the fit that works for me) or getting too far over the BB.

So I've been musing about downsizing to a size 52 frame with a longer stem. This would let me keep the same triangle and saddle setback (or even add back some saddle setback), but get more weight out front with a longer stem. With the caveat that I know fit is all relative and personal, I wonder if anyone here rides a frame that is "too small" for what their height would suggest, and what your experiences have been?

thechemist

So, why do you not want to get to far over the BB? Granted you have believers in knee over pedal and various other fit systems but if I recall, most exceptional fit experts debunk the whole knee over pedal/ weight on BB theory.

I am basically going through the same thoughts so really just here to hear others input. I do think you will lose some power climbing by moving further forward but it may also depend on how you climb. I have also dabbled with going to zero setback but it does trouble me that almost nobody in the pro peleton does this( i know...looking to the pros for fit advice is TERRIBLE). Look at nibali's setup, not a small frame at all and setback with modest drop(really just a basic setup) and he is VERY good at handling the bike.

I was going to go zero setback but was worried about too much weight off the back of the bike but I really haven't heard of any stories of people losing the back end because they were to far forward. For now, I went from 100mm stem to 110mm even though my fit was good. With that recent change, i haven't noticed any discomfort but I have noticed better handling.

I have a buddy who is ~6" that rides a 56cm venge and LOVES being on a smaller than normal frame. I want to do the same and may set up a crit bike(specialized allez) with like 130mm stem and serious drop. If I like it, I will transition the fit to road racing as well

mattm

i don't know anything about bike fits, but i think you should do it.

oh and can i have your old frame??

Creatre

We just talked about this a bit in the tech thread. I chose to go with the same size frame on my new setup. Mainly for me I would have had to throw a good bit of spacers underneath a stem that was flipped up so I didn't have too big of a saddle to bar drop. Even though I think it would have been better for handling, I couldn't take the risk of looking fred, haha.

I ended up going with a shorter reach handlebar so I could go with a slightly longer stem. The problem for me is if I get too low or too far forward I roll my shoulders really bad and put weight in bad places. So I can't really run the saddle to bar drop of the smaller frame.

shovelhd

Video is helpful for these internet fitting sessions. If your saddle is slammed forward and your stem is 100mm then you might benefit from a shorter top tube. Do you feel neutral in the drops, with your weight balanced and capable of making good power? If you're looking for the last 10% it's probably not worth swapping a frame for.

rkwaki

First post in a while.
I am just over 5'10".
My first BMC was a 56, my second was a 55.
My current setup is a 53, 135mm stem (sitting on the headset bearings) and my saddle jammed most of the way back.
Bars are Pro Vibe 7S so the drop is a medium drop, not super deep.
The bike was setup as a crit bike and had my ****** actually been racing it would be a great setup.

topflightpro

Saddle position can affect which muscles are engaged to push the pedals. The more forward you are, the more you will rely on you quads, whereas the farther back you are, the more you will engage your glutes.

This could be why you are seeing your power numbers drop as you move forward - the glutes are a much stronger muscle group that the quads.

shovelhd

Muscles can be adapted. This is why I make one change at a time and ride a few times before making another major change.

furiousferret

I'm 5'8 and run a 49 cm frame (100 stem with no spacers) and a zero offset seat post raised about 7 inches higher than the stem. The frame top tube is fairly long, and most brands I am between a 50 or 52. My first frame was a 54 with a 80 stem. Personally, I love the smaller frame with a longer stem . I've been fit twice and the fit is comfortable and aero.

I've been on this ride for six years now, and shopping for a replacement is a tad bit unnerving because everything fits well. It is refreshing to know that the sales rep can 'fit' me into the whatever frame size happens to be in to the shop.

globecanvas

I admit that part of the reason I'm excited to try a smaller frame size is that it would give me an "excuse" to buy something new.

Saddle is not currently slammed all the way forward, in that I could go to a zero setback post and get a couple more cm. With a smaller frame I expect to need another 20mm of spacers (or zero degree stem or something), so that is a sort of downside.

I'm going to set up a smaller frame with my fit and try it out.


I really have no idea what the blanked-out word is.

jsutkeepspining

I was thinking of going with a 54 for next year's team bike. I don't like a ton of saddle height (especially compared to fudgy), so it's not like i'm going to be running 50 inches of drop. Only issue is my stem. Currently riding a 130, so i would need at least a 140. Damn gorilla arms!

globecanvas

I now see this thread is rehashing some of the conversation in the racer tech thread, so, uh, sorry. I thought that thread was just about tetonrider dremeling out his derailleur bolts.

Anyway, I'm pretty sure I want to get a 52 Venge. But the sponsor LBS is very down on the Venge. They sold like 2 in the past year and both buyers were unhappy with them. In 52 at least, the geometry is identical between the Tarmac and Venge, so ride differences would be down to the different shaped frame bits. Between their bad customer experiences and the fact that it's hilly here, they think I'm an idiot for wanting a Venge.

Creatre

I think the Tarmac is so dang cool I'd pick that. But logically the aero bike makes more sense, especially since it's not a big weight difference.

hack

I'd say don't get too hung up on the nuances of venge vs tarmac. Can the venge really climb that poorly? It's not heavy either; there are some local Cat1 types that crush climbs on their Venges around here. Since you want the Venge, I'd just go Venge.

Creatre

Steve on SC rides more than almost anyone and has a venge I believe and used to have a tarmac, so may ask his opinion too before pulling the trigger.

I'd also just double check what your saddle to bar drop is going to be. I figured I was going to have to run like 20mm of spacers and a +6 120mm stem to get a frame down to work. Which is so not cool haha.

jsutkeepspining

I have a venge. I like it. It lets me win sprints, and crush climbs #cat6

tetonrider

Many thousands of training and racing miles on both venge and Tarmac, with many wheels. Geo is the same but they do ride a bit different. Talk of "the venge is a harsh ride" is overblown. I think it is convenient for people to say that without thinking. I have raced both in a 200-mile race. Any "harsh" characteristic is lost in the noise of tire pressure. Neither one will be mistaken for a roubaix.

Venge has very very slight under steer vs the Tarmac. Very subtle. Tarmac is extremely dialed. Weight diff is on the order of 150g (sworks v sworks) for frame and special parts (eg the venge seat post collar). Venge climbs just fine.

IMO the Tarmac has a bit more pop at low speeds and the venge feels like it comes alive above 25mph.

Love them both but the venue is the bike you'd have to pry out of my cold, dead hands if you broke into my unlocked garage.

globecanvas

Thanks TR. Do you happen to know the frameset weight difference between the venge s-works vs pro?

tetonrider

i can't speak with certainty on this as i don't own a pro and have never stripped one down to the bare frame, but i think it is about 150g difference between the s-works and the pro. not 100% sure.

just looked up some #s and the frame difference between a 56 venge and 56 tarmac is actually 148g, but if you ditch the aero spacer on the venge (i did this as i needed/wanted to get lower) it's 135g. you have a few more options on the tarmac due to the more standard shape (e.g., lighter collar vs the venue's specific aero collar). anyway, that's the ballpark.

globecanvas

I test rode a size 52 Allez yesterday (identical geometry to Tarmac and Venge). I wouldn't call it revelatory. I set up the bars-saddle-BB fit to be identical to my 54 Tarmac, via a 130mm stem and 20mm of spacers, but unfortunately the ride impressions were dominated by the super short reach bars, ridiculous fist-sized Sora shifter hoods, and short cranks, all very distracting and creating a strong feeling of the bike being too small. I realize now I should have moved the saddle further back, because the seat tube angle is steeper on the smaller bike -- in theory I should have gotten the right fit with a 120mm stem. But I don't think I would have been able to see past the other distractions anyway.

So I guess I'll stick with a 54/100mm for my 5'8 1/2, normal leg-and-arm proportioned self.

wsuhoops1000

Go small frame. I'm 6 foot 1 on a 54 with 130 stem.

Ygduf

^^