Lower back hurting on new bike (Video included)

bagz3

Hi everyone, I'm just wanting your thoughts on this......

I've had my Cannondale Synapse for around 4 years now (my first bike) Whilst it fits generally well, I've always felt a bit stretched out and have considered a shorter stem (currently on a 110mm stem). However, I've never really had any discomfort on it, so never bothered.

Anyway I have now bought a Planet X RT58 (second hand), and went off the geometry charts to ensure a similar sizing. However it came with 90mm stem, which I thought was ok, as I could maybe do with something shorter.

I've been out on 2 rides on the PX and my lower back has been in agony. One leisurely ride and one chain gang. Will my muscles just need time to adjust from the slight different positioning or should I make some changes. ie going back to a longer stem?

I've included a comparison video of the 2 bikes.

https://youtu.be/aqRqHOoIBWA

markhewitt1978

Swap the stems? See what happens?

bagz3

Yes swapping the stems would probably be my first option, but i was just wondering if the lower back pains will be temporary? Before the back pain kicked in, I actually prefered the slightly more compact feel.

simon_masterson

I would definitely suggest trying a longer stem. I also generally wouldn't go for a shorter stem than 100mm on a regular road bike; definitely not 90mm. Sometimes it's appropriate, but because it can make front end handling rather twitchy, it's usually preferable to go for a shorter top tube and a longer stem.

markhewitt1978

Simon Masterson wrote:

I would definitely suggest trying a longer stem. I also generally wouldn't go for a shorter stem than 100mm on a regular road bike; definitely not 90mm. Sometimes it's appropriate, but because it can make front end handling rather twitchy, it's usually preferable to go for a shorter top tube and a longer stem.

I have a 70mm stem on my road bike, no issues.

Guernsey Donkey

Looking at that video there is quite a bit of difference in the height of the front end.

Try flipping the stem the other way up to get the bars back to the original height.

bagz3

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19618400#p19618400]Guernsey Donkey[/url] wrote:

Looking at that video there is quite a bit of difference in the height of the front end.

Try flipping the stem the other way up to get the bars back to the original height.

Thanks Guernsey Donkey, i've flipped the stem over and went out and did a short TT session (low position) and and my back felt ok. Been out today on my first 1st century ride and again no lower back pains. Guess its done the trick, many thanks!!

mfin

The saddle on the Planet-X looks a touch higher than the Cannondale, and looks too high, you can see it in your leg extension. This means your hips will rock ever so slightly and that will be great at causing lower back pain. Lower the saddle by a few mm, maybe 3mm at first and see if that helps, maybe 5mm. (you're not wearing cycling shorts there which when a pad is thicker will effectively put a couple of mm on your saddle height again).

Also, I agree with someone else, your position on the PX looks like it could do with about 20mm longer stem, but it's the saddle height I'd be looking at for the back pain.

lesfirth

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19618396#p19618396]markhewitt1978[/url] wrote:

Simon Masterson wrote:

I would definitely suggest trying a longer stem. I also generally wouldn't go for a shorter stem than 100mm on a regular road bike; definitely not 90mm. Sometimes it's appropriate, but because it can make front end handling rather twitchy, it's usually preferable to go for a shorter top tube and a longer stem.

I have a 70mm stem on my road bike, no issues.

So do I.

bobbymeister

It's hard to say for sure from a static image, but with my bike fitting hat on I would say your saddle is a little high.
That's not intended to be an exhaustive assessment, but I think it's your starting point.

sloppyschleckonds

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19621399#p19621399]lesfirth[/url] wrote:

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19618396#p19618396]markhewitt1978[/url] wrote:

Simon Masterson wrote:

I would definitely suggest trying a longer stem. I also generally wouldn't go for a shorter stem than 100mm on a regular road bike; definitely not 90mm. Sometimes it's appropriate, but because it can make front end handling rather twitchy, it's usually preferable to go for a shorter top tube and a longer stem.

I have a 70mm stem on my road bike, no issues.

So do I.

Can you post a picture?

sloppyschleckonds

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19621470#p19621470]bobbymeister[/url] wrote:

It's hard to say for sure from a static image, but with my bike fitting hat on I would say your saddle is a little high.
That's not intended to be an exhaustive assessment, but I think it's your starting point.

Thank god.

diy

Be careful that going for a more upright position doesn't just give you a temporary fix. if the pain is caused by tight muscles then going upright will just give temporary relief until the muscle retightens against the new position. you have to stretch the back regularly to counter the effects of cycling.