cmac77

I recently purchased a Giant XL defy advanced 3. Im 6'2 / '3, and after 4 consecutive days riding a 20-60 minute ride per day, my lower back is killing me. I looked at the giant website, and i feel like i may have gotten a bike that's too big, as the Giant website shows XL good fro those starting at 6'4. I feel like i finally found the perfect bike, but got the wrong size.

https://www.giant-bicycles.com/_uploa...frame_size.pdf

I looked in the manual though and it says you should have a minimum of 2 inches from the frame to your crotch, and i have about 3. it also said to adjust the seatpost so your leg with heal in the pedal is straight, and I can't raise the seatpost high enough for that, keeping it in the 80cm specification for safe riding. So there's a little bit of bend in my knee.

Is it bike size? does anyone have any experience with changing bike sizes or adjustments, that helped with back pain?

Carbonfiberboy 

Well it sure isn't too big if you can't even raise the saddle past the maximum extension mark on the seatpost! Or are you referring to some random 80cm rule or it's in the manual? 80cm from where? Have you seen the max extension mark on the post? That's what I'd go by.

That said, it's unlikely you'd have back pain from too low a saddle. But from your post, it sounds like this might be your first road bike? In which case your core is probably simply not fit enough to put on a lot of weekly hours yet. What's your biking experience?

And of course we need a couple photos of you on your bike, taken from the side, one with pedals up and down, on with them horizontal, hands on hoods, elbows bent.

10 Wheels

Build up your core and Take B-12 everyday.

DrIsotope

The dimensions on the 2017 Defy Advanced are extremely close to those of my KHS CX100-- we have the same reach and stack, and I am also 6'2". Unless your legs are absurdly long, you should be able to get the saddle at the proper height, but with that sloping top tube you will have quite a bit of exposed seatpost, by the sound of it. I have about 7" showing, but my top tube is nearly level.

Regardless, lower back pain can come from any number of sources, but I've gotten it from too long of a reach, as well as having the saddle slightly too high. I set my starting saddle height using the 109% method (pedal to saddle top is 109% of measurement from crotch to floor) and adjust as needed.

You can check the reach without changing anything-- just ride for awhile with your hands on the tops, or at the closest points of the bars, right at the curve; if it's comfortable to have your hands here, the reach to the hoods is likely too long. My bike came with a quite long 120mm stem, which was fine with a very compact bar, but my huge hands didn't fit the bar, so I got a larger one, and had to drop to an 80mm stem to accommodate. I also do not run a setback seatpost.

Short version, the frame should be fine for your height. You may need to change seatpost and stem, like many, many people have to do.

jbucky1

Are you newer to riding?
Could be a combination of fit and newness?

Also
Check out Tom Danielson's Core Advantage Book, it's good, core, flexibility, easy stretches. I'm 6ft 4 and suffer with tall dude bike things. The book helped me a lot.

bucky
https://www.buckyrides.com

superdex

four days of riding, and being new to the sport is a recipe for back soreness.

Throw away anything that judges bike size by standover height. Go ahead, I'll wait.

Did the bike shop do anything to get you fitted when you bought the bike? If they're worth anything, stroll back in there and work with them on saddle height, and perhaps different stem. [edit] just looked at the geometry chart, and the XL has a 59.5 top tube. Makes me wonder if you're too stretched out. Definitely consider stem length. Definitely go back to the bike shop and talk with them about (re)fitting the bike...


Decent 6-min primer: How To Do a Basic Bike Fit - I Love Bicycling

Wilfred Laurier

I am 6'5 or so and I find most stock XL size road bikes feel a tad small for me. Everyone is different, and every bike is different, but in general an XL should work for someone 6'2 or 6'3, but some adjustments tot he fit may be necessary (as may be necessary for any individual to fit any particular bike).

If the bike s comfortable when you first get on, but you get a sore back over time, then the changes necessary will likely be small.

First, as mentioned above, it takes some time for your core strength and/or flexibility to catch up to your desire to ride, so cross-training, stretching, and saddle time will probably be part of the solution equation.
Second, small adjustments to the bike fit, like saddle height, saddle fore/aft, saddle angle, or stem length/rise or height can make a huge difference to comfort. Make one change at a time and only make small changes. Many of these you can fiddle with at home (only a metric allen key set needed for most), and the shop whwere you bought the bike should be more than happy to help, advise, or swap out stems on a new bike to get you dialled in.

This is all 100% normal. Take the time to get your bike to fit you and you will enjoy many happy kilometres.

Nycycle

Some tall guys have a 36 inch in seam, some 30, so height cannot be the main number to use for sizing. Hip rocking will cause back ache. School or hard knocks here.
I had to lower the seat and get a longer stem as I have short legs, and a long back.

cmac77

This is my first bike and I have 0 experience with a bike. I am overall in good shape, so I don't know if strengthening my core will help, but I hope some more time in the saddle and cross training will aleviate my back pain. My inseam is 35 inches, pants don't come in that size, but if they did they would be the perfect length.

The 80cm was what was said in the manual, don't raise the seat post past the 80cm mark.

sumgy

Without seeing you on a bike or knowing anything whatsoever about how you are set up, it is impossible to know what the problem may be.

But you certainly are NOT going to fit on the next size down IMO.

superdex

Let's try this again: How To Do a Basic Bike Fit - I Love Bicycling

Joeyseven

OP
You really need A true bike fit.Talk to bike shop were you bought the bike and even other LBS.

From the info you posted I believe you'll get A better and easier fit on A road bike with less relaxed geometry.

Carbonfiberboy 

Yank the post out and look for a "do not raise beyond this mark." It'll have one. That's what you want to go by. I can't imagine that the seat post is even 80cm long. That's almost a meter. I doubt it. I think you misunderstand something. Since the manual is not online, I can't look at it.

Sojodave

I'm 6'4" and last summer I developed back pain. I have seen every Youtube video on bike fitting and I resisted getting a fitting because I was sure I already had it dialed in. I broke down, paid for a bike fitting, and was blown away that the fitter raised my saddle two inches. That made a huge difference in reducing my back pain, made me more comfortable and helped me ride more often. Yea, it sucks paying someone to adjust your bike, but it may be the best money you will ever spend on your bike.

berner

I've had a bad back since my teens (now 79 y.o.) so I'm careful about anything that involves my back. One sure way to get it sore is to round my back, either lifting, cycling or whatever. I model my position on the bike based on what I've read here on this forum and based on what I see on videos of pro cyclists. Experiences cyclists bend at the hips, not at the waist which would cause a rounded back. The back, when upright, has a shallow S bend. The position on the bike should maintain the same amount of slight bend. It feels as if the back is straight.

Even if the bike is supposedly set up perfectly, this would be perfect only for a fit and experienced rider. The best fit is an evolving process that moves with the rider's experience and miles ridden. The most comfortable fit for you today will be quite different than the most comfortable fit after a few years.

cmac77

What size bike do you have? Please take a look at my initial post to see the size bike I have. It is a giant XL and i'd like to compare it to what you have, if yours is the standard size measured in CM.

I am definately going to get the bike fitted. Even as a beginner, I enjoy the sport so much, I want to do everything in my power to remain riding. I've taken it easy since I posted this initially, but still my back is extremely sore for up to 48 hours after as little as 20 minutes riding. Maybe i could modify the bike with a shorter stem (not sure if that is the proper terminology) to shorten the distance between myself and the handlebar, without raising or lowering the bar. I do enjoy very much the ability to grab the low / racing grips, i accelerate immediately, and don't want to give that up.

Thanks!

sumgy

Honestly I think you are thinking about it back to front.
If your back is sore it is usually because you are too upright.

Bike fit for dummies:

Get pedal in correct position: BEHIND ball of foot. Often this is cleats slammed all the way back.
Get saddle height in correct position: while pedalling in a slightly bigger gear than needed pedal up a hill. The pedal stroke needs to feel circular rather than up and down and there should be no "snapping"/sudden acceleration of the knee. Keep lowering it until it feels awkward then raise again until it starts snapping.
Get saddle setback right: you should not feel like you are using your quads or hamstrings more than the other.
If you feel your hamstrings then move the saddle forward. If you feel your quads then move the saddle back.

When reaching for the bars you should not feel pressure through your back or neck.

sumgy

Refer my previous reply.
A pic of you on your bike would be good.

fietsbob

You wanted a Road Bike and that is what you got..

consider that you need to work on stretches, and all that ,to get your back better
supported , strengthen the core muscles .


or maybe you really didn't want a road bike and want to sit up higher.
I'm just guessing.. ..

cmac77

//goo.gl/photos/teFfAu6cE4hgMRbz7

Im not sure if anyone is still paying attention to this thread anymore, but here is a link to a picture of me on the bike.

I found this, which is an image for I guess for the ideal fit and it's resulting posture / body position:
//goo.gl/images/uMfAhE

i definately look off from this. there's no bend in my arm and the angle is different. I also look more upright. maybe added core strength would help me maintain a better position with a bend in my arm.

sumgy

Refer my earlier post.
You are never going to be in that position while you have your bars twisted up and your stem upside down.
Your left leg also looks too straight suggesting that your saddle is too high.

cmac77

the seat i can easily adjust. I think i understand what you are saying about the handlebars, that I could twist it downward. if you mean the stem is upside down literally, the stem is not upside down judging by the printed words on it. but if i were to switch it upside down, that would lower the handlebars considerably. I may be misunderstanding, I don't know. But based on this picture, do you see anything that could be modified to reduce lower back pain?

Brennan

I am 6'2" and had this problem with a new bike once. I too thought the frame was too big, but the problem was solved by changing stems. You might want to try one of those adjustable stems to experiment with and see if you can get the bars to a comfortable position, then buy the right size fixed stem when you know what works. Can't guarantee this will solve the problem, just that it worked for me.

sumgy

Yes,
Turn your stem over and follow the rest of the instructions up above.

look566 rider

Looked through all the replies... One item I did not see mentioned was stretching after you are done training.

I agree on other suggestions listed are good areas to check.

While not a cure-all for lower back pain, stretching can alleviate the cause for this issue, which are tight leg muscles. Specifically the hamstring and glutes. If you have a self-massage roller, use this after training as well.

Look online for good stretching poses for riders.

Iuse a massage tube similar to this,
Trigger Point GRID Foam Roller | Academy

Using this roller can be a workout on its own, utilizing your upper body to hold yourself up while you move back and forth