dirk1978

Hi all,

I have what seems to be a fairly common issue with my thighs hitting my chest when I get down low on the bike.

I've taken a video to see if anyone can see any particularly bad bits of my fit on the bike.

https://www.youtube.com/watch?v=EhV1...ature=youtu.be

When I'm on the hoods it's fine but as soon as I get down on the drops my thighs start touching the bottom of my ribs. Only softly so I can stay like that. But then when trying to get lower towards the end of the video, they're properly hitting and means it's quite uncomfortable to pedal like that.

Bit of background info. The bike is a Giant Defy 1 2014 small (46.5cm compact frame, right on the limit for my 5' 8" size but I read that erring on the side of a bit smaller makes it a bit 'racier'). The stem is turned upwards and at the top of the spacers so can't go any higher. I've got about 20mm left on the seat post but the seat is about as far forward as I can get it to make up for the high saddle. I know I'm slightly stocky in the middle and a bit portly but the camera angle makes it look worse than it is (honestly).

If anyone can suggest what's wrong with my fit, or not, or any other comments on my (self done) bike fit I'd be appreciative. Thanks!

10 Wheels

Bad colors on the shorts and shirt.

Not able to see when the legs hit the stomach or chest.

Camera angle is off raise it up.

CharlyAlfaRomeo

I agree with 10 Wheels in that the camera is set far too low to see anything.

Carbonfiberboy 

I see lots of clear space between the left leg and chest. Leg not hitting chest. However back is very rounded. OP should rotate hips forward (clockwise in the video). This will move stomach and bottom rib forward and possibly out of the way of legs if OP sucks it in. Shorter cranks would help.

dirk1978

My usual nice stuff had just been used so was in the wash

I'll try again with the GoPro a bit higher up. Wanted to show the legs and drivetrain enough to see if there's anything wrong there. Looks OK to me though.

They definitely connect. Only lightly when I'm slightly down, but enough to wind me when fully down.

As I understood it, the back should be rounded to take pressure off the manly bits? If I rotate hips forward, won't this cause pain/numbness etc there?

Cranks are 170mm so the smallest they do on that model.

Thanks everyone

Carbonfiberboy 

No, your back should not be rounded. A saddle that fits your anatomy will take the pressure off your perineum. Reaching in there and adjusting your package will take care of the rest. It helps if your shorts fit you, i.e. are tight. If you have a heart rate monitor you can make a little experiment. Holding gear and cadence constant on your rollers, straighten your back. Drop your belly button toward your top tube. I betcha your HR will drop. You can't get a full breath or a full heart stroke with your internals all crammed up in there. And drop your shoulder blades down your back.

Yeah, it's ridiculous that component manufacturers think all cyclists have long legs. Well of course they don't, they just don't care. The Money's the thing.

tedder

Why do you have your bars so low? I mean, unless you are racing, that's pretty aggressive.

dirk1978

That's the highest they go! And this is apparently a relaxed sportive bike with comfortable geometry.

I expect being a bit small for me it means the saddle has to go really high which puts it above the bars.

Although, even on training rides, I need to get aero as I'm mostly averaging 20mph so get a lot of wind resistance being too high up.

10 Wheels

You might do much better with another bike. One that has a longer top tube.

He has the same problem.



Larger bike

tedder

You know you can buy a different stem, right? That is probably a 90x0 degree or 90x6. Try a 30 degree stem:
https://www.westernbikeworks.com/pro...30-degree-stem

McBTC

A different stem and rearranging spacers or go with Ride2 crank shorteners. For < $120 you can try 170mm - 24 = 146mm cranks. According to the seminal research in this area (Jim Martin* at the University of Utah) that is used to justify making fewer options available, going as low as 145mm may actually help put you closer to your peak efficiency. In the above example, you'd raise the seat 24mm and your knees at TDC will be less bent.


* https://www.ncbi.nlm.nih.gov/pubmed/11417428

Leisesturm

Maybe on a recumbent, but on a DF road bike a 145mm crank just cannot be something the o.p. should consider. If he should, then we all should. Well certainly all women... I mean... he's 5'8" not 5'2", and there are plenty of 5'2" women using 170mm cranks. Raise the bars. Simple. There are head tube extenders. That is what is needed, not a longer stem.

McBTC

Not necessarily... a second person at 6'3" would probably ride a 61c bike and that frame size ordinarily would come with 175 cranks -- but the taller person is >10% taller than 5'8" so, why not 187.5mm cranks? There is little good science in this area and not much good logic concerning crank sizes and in practice. Many are finding better options through personal experience --e.g., from the Power Crank website:

"Drew Peterson improved his placing in the Everst Challenge (28,000 ft of climbing) from 26th to 9th after changing his crank length from 180 to 110! The proper crank length for you (even if it seems very short compared to what you are used to) actually helps you to race better. Shorter cranks are less fatiguing for the hip flexors and it has been shown in several studies (#1, #2, #3) that hip flexor fatigue can adversely affect performance at the end of a race, usually the most important part of any race. If shorter cranks are less fatiguing and do not affect your power (as will be shown below) what is there to lose by experimenting and seeing what happens? Of course, it is possible to go too short (you can't generate any power at a crank length of zero) but you won't know what too short for you is until you try different lengths."

The OP says he's on a "small (46.5cm compact frame...)." I don't know if that is the correct size frame for the OP but I question whether that size frame should have come with 170mm cranks to begin with. The reality is that cranks less than 165s aren't readily available and that makes it difficult to experiment with what might be the optimum crank length without spending a lot of money.

That said, using the logic of the example above, a 61c frame is >31% larger than a 46.5c frame so... 223mm cranks? We're only getting illogical numbers in these examples because thoughts about what crank lengths have traditionally been considered to be 'standard' are not logical to begin with. In reality, cranks can be too big or too small; and, 145- to 165-mm cranks may actually be a lot better for many riders than 170- to 180-mm cranks.

KLiNCK

What is the offset of your current seat post and how much room do you have to move the saddle back on the rails?
Because the frame is "on the small side" for you, perhaps something like a 20º offset post would stretch you out a little bit more?

Carbonfiberboy 

Yeeesh, that's a good point about the tiny bike. I didn't even notice that at first because I was looking at that back. But yes, his elbows look to be overlapping his knees by about 3" with hands on hoods. A good position for me is with elbows forward of knees when on the hoods - no overlap. That 3" is 75mm of stem length increase - not gonna happen. Raising the stem won't help that. A setback post is only 15mm. Anyway, seems that something like a 5-8 cm longer TT is in order, depending.

dirk1978

I think you guys have nailed it. It simply is that the frame is too small for me. It was an absolute bargain at the time and I read that pro riders go a size smaller anyway. But I'll get measured up properly for the next one.

McBTC

On a Felt Z85, for example -- with its comfort/endurance road bike geometry -- you'd be leaving 51c at 5'8" and landing pretty squarely in size 54c.

Igualmente

I think the bike is probably small, but there is something I don't get. If we take the already mentioned Felt Z85, it has the same seat tube angle as OP's bike. It has only 1 cm more top tube length or frame reach. It does have 15 mm more stack.

So, OP's bike sounds small (especially the "46.5" which mystifies me), but on paper using stack, reach and seat tube angle it is pretty similar to a 54 cm bike (and it's larger than the Z85 51 cm).

So, I don't really get what is going on. OP could probably achieve a similar bike size to a 54cm Z85 with a stem flip and slight lengthening. And given how cramped he looks, I am confused why.

OP, what is your cycling inseam?

Wheever

I don't think his inseam is the only problem, I think he has a long torso and REALLY long arms. Even still, I think this bike could be made to work if the poster wants it to.

OP, your seat looks low to me. You have a lot more extension to go before you would have to worry about a straight leg. (Part of that might be the fact that you're peddling very toe-down.) My defy came with a lot of extra seatpost, since Giant is trying to get us all on bikes two sizes small, and you could probably raise it a bunch with the stock seatpost. I'd say 2-3cm to start. That might reduce the chest contact significantly. The defy comes with a 100mm stem, but that stem looks shorter than that. Can you verify that it's 100mm? If it is, I'd say try a 120mm just to see if it helps.

Or you could just get a bigger bike?

McBTC

Added to the marginal differences in in frame angles and tube lengths, the larger frame has the higher stack and a longer reach. The seat tube angles are the same so if the seat needs to be further back relative to the bottom bracket, an even larger frame size may be in order.

rhm

In my opinion, it is something we should all try. I did; I rode almost exclusively on 140 mm cranks for a year or two, and got to like them pretty well (I'm a 6' tall man). Unfortunately the selection of cranks that size --or any size smaller than 165-- is pretty well limited to BMX cranks (not that there's anything wrong with those; they usually take 110 mm bcd rings, so it's pretty easy to set up a "compact double"). Another advantage is, they can be cheap enough that you can experiment all you want.

That said, I've found for most purposes crank arm length doesn't matter much. Short crank arms have advantages for people with knee problems, and for people with OP's problem, but for me, suffering no such problems, it really didn't matter much. I now just get the shortest cranks I can get conveniently, and leave it at that. 160's on a couple bikes, 165's on more, and 170's on a couple.

xlbs

Back to the OP's questions, and a good look at the video, I think that your saddle to bar drop isn't too far off. Us shorter folks, with longer arms and torso, often take some time to get it right, especially when the "standard" stem length is 10 cm. Please don't be messing around with shorter cranks; yours are fine.

Take a series of measurements all 'round so that you have a base point to which you can refer as you make adjustments. Top of saddle to centre of BB spindle. Saddle to bar drop. etc.

As you test each below take measurements and don't try to do everything at once. "Controlling the variables" is vitally important when you are working on a fitting process. Otherwise you simply can't ascertain what works and what doesn't.

I'd suggest four things before getting into a new frame:

1) Set the saddle back further as a couple of others have suggested; you are perched a bit, rather than relaxed and sitting back. Work at setting the angle correctly so that your IT bones are positioned correctly. SMP saddles make a world of difference for a lot of riders, and may be the ticket here too.

2) Raise your saddle a wee bit, and experiment with that as well, based on point # 1.

3) Try a longer stem. Based on your height and arm length from the video, a longer stem will give you some room to stretch out a bit. If this is a new purchase you should be able to experiment with stem lengths. Try 11 or 12 cm, and give yourself some time to see how each one works. And, don't hesitate to try both a longer stem with a slightly higher rise to it as already mentioned.

You may be surprised at just how much a 2-3 cm. adjustment in your reach will change both the way the bike handles and how your riding position improves, including your original complaint about your chest and thigh interaction.

4) Try positioning your cleats so that the ball of your foot isn't perfectly KOPS, but that your foot is slightly further forward on the pedal. Slightly!...maybe 2 or 3 mm, as an experiment. Doing so will give you a tad more forward and therefore downward positioning which may free up your thighs.

Good luck.

noglider 

This is interesting stuff. My thighs hit my stomach but only on my largest bike. I find it strange. I took it as a hint to lose weight, so I've done that.

CliffordK

I only see the knees hitting the chest when the OP really crouches down. He does have pretty good flexibility. But, perhaps it isn't an issue for most ordinary riding.

I agree, I'd try raising the seat a bit. Maybe 1/2", or even 1". I go by the method, heels on the pedals, straighten the leg at bottom of stroke, then adjust from there.

What is the actual crank length on the OP's bike?

ThermionicScott 

I'm kinda late to this party, but 46.5cm is probably the smallest bike I've ever heard of a 5'8" person using! Hopefully that's the actual seat tube measurement, and not what the frame would equal in a classic level-top tube frame.

I think if you exchanged it for a M/50cm or even M/L/53.5cm, you'd have a lot more room to play with.