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Does this bike fit me?
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TOPIC: Does this bike fit me?

Does this bike fit me? 8 years, 4 months ago #25164

  • jroden
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I ride a road bike with a 58.7 TT and borrowed the pictured bike w/ a 55.7 TT, it seems like the right size to me. I don't seem to get as much speed out of the watts I put out, so perhaps I need to learn to ride with more drop, in the picture it's about 4 inches from saddle top to top of elbow pads.

If I were to shop for my own bike, I'm thinking this would be about the right size, am I correct in that?

Here's the picture, I'm more handsome in real life, really.

http://buffalophotocd.smugmug.com/galle ... uCZtv-A-LB

Re: Does this bike fit me? 8 years, 4 months ago #25167

  • kraig
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jroden wrote:



That's a tough one for us to diagnose over the internets, jroden.

At first blush, though, it looks a bit on the small side in terms of reach at least. That's not to say one couldn't make that size frame get you to where you want to be position-wise, though. I mean, heck, I TT'd for years on a 48cm 1983 Ciocc (and have ridden 58-60 cm road frames over the years with an 81cm +/- saddle height) - though, to be honest, a Look ergostem allowed me to explore lots of different combinations of reach/drop until I found a happier spot on that Ciocc!
-kraig

Re: Does this bike fit me? 8 years, 4 months ago #25197

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does this help

I borrowed this tt frame for a while and I'm trying to figure out oif its the right size. It's pretty small, but notice the knee to elbow thing and my generally high position. There are no spacers left and I'm at about 4 inches of drop. I feel OK but kind of scrunched in this position. I don't have a big belly, just a giant sized flappy jersey





Re: Does this bike fit me? 8 years, 4 months ago #25198

  • kraig
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Is that a powertap on there? If so, how does the power on that bike in that position compare to your road bike over the durations you are interested in?

How long is the stem on that bike right now? Do you have any that are longer?

Can you lengthen those extensions at all, so that you can try to simulate a longer top tube?

How does the saddle setback on that bike compare to your road bike?

It also looks like if you wanted to experiment with getting your elbows lower on that bike you could achieve it by making your forearms flat, and finding a shorter doo-hickey that interacts with the top headset bearing - I'm sure there is a proper name for that, but it looks like there's a couple cm there.
-kraig

Re: Does this bike fit me? 8 years, 3 months ago #25299

  • jroden
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I returned that bike to its rightful owner and bought one formyself in the next size up. I just got it set up today and it feels much, much more comfortable, I think it looks much more aer too:

Re: Does this bike fit me? 8 years, 3 months ago #25306

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jroden wrote:
I returned that bike to its rightful owner and bought one formyself in the next size up.


Congrats on the new bike!

How's the power with how you've got this one set up in comparison to the other one or your road bike?
-kraig

Re: Does this bike fit me? 8 years, 3 months ago #25307

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kraig wrote:
jroden wrote:
I returned that bike to its rightful owner and bought one formyself in the next size up.


Congrats on the new bike!

How's the power with how you've got this one set up in comparison to the other one or your road bike?


Good question. I have only had the power tap for a short while, but I do have some data points, so I looked atthe last month or so, first the TT bike:

couple 40k tt rides at tempo pace, np was 300 and 291, second was on new bike today
40 state championships on old bike hilly 308
12 mi tt on old bike 338
2 x 20's around 300

Now, the road / cross setup:

40k test at 325
2 x 20's at 336

So, I do seem to lose a lot of power when I go to the TT bike, is that a normal sort of drop? My ftp is around 326, so the 308 40K effort seemed kind of lame.

Re: Does this bike fit me? 8 years, 3 months ago #25308

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jroden wrote:
<snip>


GizmoPower doesn't have any meaning when it comes to TT speed. I've found it to be an unscientific and unreliable product (especially for the rides you describe) that doesn't offer any actionable information - however, it does come with a pretty appealing gaurantee: "more watts now"! )

The things you should primarily be looking at from a global perspective are Power and CxA (or axial force coefficient/aerodynamics) when determining which set up has the best chance of being faster. The best ratio there will get you going in the right direction from a big picture perspective, i reckon.

If you are losing 12% +/- on the new TT bike, that seems like quite a bit to overcome. If you search the forum, you can probably find more discussion about adaptation with regards to new TT positions. My experience is that if you don't show progress in your power in a short period of time (i.e, a handful of rides) you aren't likely to make much additional progress.

I'd encourage you to play around with and monitor how your supply side (i.e, average power) changes over time, and then tweak your setup in search of more supply (power) while least affecting CxA. Sometimes this process can take some time, depending on the tools you have at your disposal.

FWIW - when I'm focused on TT events, I reckon I'm only giving up low single digits percent-wise on power relative to my bolt upright climbing position for a 30 minute-ish effort.
-kraig

Re: Does this bike fit me? 8 years, 3 months ago #25310

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what's gizmo power?

I'm going to go out today and really try to hit it for some shorter intervals and compare against the roadster. I'm first going to raise up my position a tad and get more comfy and see if that helps.

Because this is a tri bike, it's well beyond illegal in terms of the saddle-bb relationship. I only do events where it matters once in a blue moon, but I'd have to get a seatpost with a ton of setback, about 2 additional inches. I might do nationals some year if they are close, but otherwise I'll try this steep setup and see how it works out and not worry, it's more comfortable, though the back end seems a little light through the bumps.

I wish the UCI would just man up and ban the aero bars altogether and we'd all just race on road bikes.

Re: Does this bike fit me? 8 years, 3 months ago #25311

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kraig wrote:
jroden wrote:
<snip>



If you are losing 12% +/- on the new TT bike, that seems like quite a bit to overcome. If you search the forum, you can probably find more discussion about adaptation with regards to new TT positions. My experience is that if you don't show progress in your power in a short period of time (i.e, a handful of rides) you aren't likely to make much additional progress.

FWIW - when I'm focused on TT events, I reckon I'm only giving up low single digits percent-wise on power relative to my bolt upright climbing position for a 30 minute-ish effort.


This is interesting. I did some 5 mins intervals today on a rolling course and was quite a bit lower compared to riding 5 mins intervals on the grass on my cross bike. I'm not sure if that's a fair comparison, but wow the wattage is different, like 30 lower on the tt bike.

Looks like I have some work to do...

Re: Does this bike fit me? 8 years, 3 months ago #25314

  • Dalai
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jroden wrote:
I wish the UCI would just man up and ban the aero bars altogether and we'd all just race on road bikes.


Given the way they are going I'm sure you just may get your wish! But over my dead body...

Re: Does this bike fit me? 8 years, 3 months ago #25315

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jroden wrote:
what's gizmo power?


It is a commercial product that is offered for sale by trainingpeaks.com - it looks like you have purchased the product, based on your previous post. There is some discussion of it in the first post/thread here:

http://forum.biketechreview.com/viewforum.php?f=1

It goes by a lot of different names here - there are some creative contributors on BTR!

So, if you'd like to discuss that topic, I'd recommend you contribute to that thread.

Because this is a tri bike, it's well beyond illegal in terms of the saddle-bb relationship.


I'm not sure why bike manufactures pursue this approach:

http://www.biketechreview.com/kdublog/2 ... t-one.html

and the follow up:

http://www.biketechreview.com/kdublog/2 ... t-two.html

and the update:

http://www.biketechreview.com/kdublog/2 ... dated.html



I wish the UCI would just man up and ban the aero bars altogether and we'd all just race on road bikes.


I think they shouldn't even do time trials on the actual road. They should just treat it like a math problem, y'know, do it "virtually" and say whoever has the highest W/CxA # wins! )

Seriously, though, why not do as you propose?! I'm sure the manufacturing community might protest, though!

Don't some early season races (I want to say that some early race in S. Africa doesn't allow TT bikes/wheels) - so, there is precedent for something similar to what you propse!
-kraig

Re: Does this bike fit me? 8 years, 3 months ago #25317

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That's some interesting reading, thanks. I jacked the front end back up with a fairly minimal drop and will do some testing of how that one feels. I seem to lose a bucket of power in the aero position, so maybe I need to push a little air as a short term compromise.

I'm still unsure about the whole steep vs less steep seat tube, I'll just have to head out with an allen wrench and see how it goes.

Do people tend to want to replicate their hip angle from the road bike onto the TT bike?

Re: Does this bike fit me? 8 years, 3 months ago #25318

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jroden wrote:

Do people tend to want to replicate their hip angle from the road bike onto the TT bike?


I think folks naturally gravitate to their own preferred(or maybe trained) lower limb kinematics (i.e - pedal the same way they "normally" do) and pelvis-femur angle when they are giving it full-stick on a bike for a given targetted power level. So, if your bars are too low, or seat is too high, or a host of other issues - well then, you'll probably wind up riding the nose of the saddle and give up on aerodynamics while never quite being able to get things just "so", so to speak...or get your pelvis stable and upper body relaxed. All of these things have an effect on the # you see on your power meter, I reckon.

More reading on my thoughts about low bars:

http://www.biketechreview.com/kdublog/2 ... e-low.html

FWIW, I think hip angle is an obtuse term that doesn't hit the mark quite right - I like Kirk's usage/discussion of "pelvis-femur" angle...I think the caveman way of talking about it would be to say folks, individually, have an amount they can "bend over" before the supply side of things start to go south (i.e - "people bend differently"). Finding that supply side tipping point of "bending over-ness" ) is a great starting point.

Let us know how things progress.
-kraig

Re: Does this bike fit me? 8 years, 3 months ago #25321

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thanks, that gives me a lot to think about. I measure my hip angle yesterday, but it seems like a pretty imprecise kind of thing.

let me ask you this, does the whole relationsip between the plumb line from the knee and the pedal axle remain the same from road >> tt bike?

Re: Does this bike fit me? 8 years, 3 months ago #25322

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jroden wrote:

let me ask you this, does the whole relationsip between the plumb line from the knee and the pedal axle remain the same from road >> tt bike?


I think it is good to try and start from a "known" condition since you are just working into this thing. So, that means I think it would be a good idea to match the important bits from your road position as best you can.
-kraig

Re: Does this bike fit me? 8 years, 3 months ago #25328

  • Ron Ruff
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jroden wrote:
let me ask you this, does the whole relationsip between the plumb line from the knee and the pedal axle remain the same from road >> tt bike?


Most people ride farther forward on the TT bike... so no. On the other hand, what is the reason for why you sit the way you do on the road bike? IMO the important consideration is to be balanced in the saddle and relaxed with your arms while effectively using your leg and butt muscles to propel yourself. If you move the saddle position forward of this, and pedal in the same way, then you will naturally be pushed forward... and this must be counteracted by your arms. Or... you could just pedal differently, using your quads more and your glutes less.

After some experimentation I've discovered that I don't like the forward position and have set up my TT bike only slightly forward of my road bike. That way I am balanced in the saddle and merely rest easily on my arms. This also makes it easier to extend the reach comfortably, since your arms aren't doing much. There is a little tighter angle between the femur and hip (with 14cm drop), but at least in the 24 min TTs that we have here every week, this hasn't effected my power. But the moral of the story for me, is that preserving hip angle doesn't really make sense. When you are trying to get fast on the TT bike there are a bunch of compromises, and changing the hip angle might be more effective than changing your pedal stroke in other ways, or straining with your arms, or sitting up higher.

I'd suggest moving your saddle back as far as possible, and raise the bars to a comfortable level... to where you can produce the same power as on your road bike. Then experiment with lowering your bars and see where the breakpoint is in power. Then do some CdA tests to see if taking a power penalty by going even lower might yield significant improvements in speed. Practice always helps...

Re: Does this bike fit me? 8 years, 2 months ago #25451

  • jroden
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I borrowed a smaller frame that sets the seat back to where it belongs. I took a little video, I think it looks better, I keep having to slide back on the saddle, I'm wondering if the saddle might be set too low--here's my little video

[url:3b5fg1gy]www.vimeo.com/6874280[/url]

Re: Does this bike fit me? 8 years, 2 months ago #25453

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In my experience, sliding forward on the saddle means the saddle is tipped down. Your arms shouldn't be the thing holding you back on the saddle.

I'm also more in the "90 degree" camp regarding your forearm/upper arm angle. As far as your arms are forward, you're putting a lot of stress on your neck muscles and upper arms. Having your pads and bars forward are likely because of concern about hitting your knees on your arms or the pad supports when out of the saddle. My experience is that your knees will always be close to hitting your arms on a TT bike.

Size changes on TT bikes is a bit misleading as you can move the bars/pads around in space far more than on a road bike.

One suggestion about the variation of road bike to tt bike is to get the setups much more similar. Typically, the road bike is the anchor and the TT bike adapts to it's position. This last year, I did the reverse, setting my road bike up as similar to the TT bike as I can. What I noticed before that was not so much the saddle to bar drop aspect but rather the different muscle usage in my legs when switching. Food for thought.

Re: Does this bike fit me? 8 years, 2 months ago #25461

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wasfast wrote:
What I noticed before that was so much the saddle to bar drop aspect but rather the different muscle usage in my legs when switching. Food for thought.


And what was that exactly?

Seems to me that typical tri and TT positions (ie forward) will naturally push you forward *if* you use your glutes effectively, since you end up pushing back pretty hard near the 180 part of the stroke. If the saddle is farther back (close to road position) you can prevent this. Arms and upper body relaxed and saddle level... apply force in a way that does *not* push you forward and see what that is like. It doesn't feel much different on my legs and butt than my road position.

Re: Does this bike fit me? 8 years, 2 months ago #25464

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I had to re-read my sentence to figure out what I said:-) My TT bike has the saddle nose right at the BB centerline. Saddle to bar drop is 17cm. ROad bike had 8cm setback initially, changed to 4cm ish. Saddle to bar drop is much less as well.

The muscles that seemed to complain (anatomy not spoken here) were in the center of my thighs on the front center. My hamstrings also complained and stil do on the TT bike. The latter is likely from the Saddle to bar drop.

I'm not necessarily advocating the idea, just mentioning it as an alternative.

Re: Does this bike fit me? 8 years, 2 months ago #25471

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My road bike is ~7cm back and TT bike is ~5cm. Same saddle height and saddle on both. Drop is ~14cm. The drops on my road bike have me bent over nearly as much. No particular muscle complaints, but I did notice my glutes (actually might have been where the hamstrings insert) were sore after Moriarty, but never were after our weekly TT which lasted half as long. That might have been due to my form starting to fall apart near the end but putting out more power anyway...
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