cyclocross!
Before the barrage of, “there’s no saving you”, “cx bikes are always uncomfy”… “you’re gay” … please let me explain.

I’ve just built up a lovely new Kinesis Crosslight:

I know it’s a funny time of year etc but I just want a good fun bike to get out and blast through some mud on and do some more interesting road rides with.

So, the issue that i’m having is as follows – After 10 minutes riding (so it’s not a fitness/core strength/fatigue issue… I’m quite a fit, young lad if I say so myself!) my whole lower back is aching quite badly and after a slightly longer time I find i’m having issues with my right-hand hip/top of my leg aching too.
It’s not intense pain or anything… just a solid, ache!

In terms of sizing and stuff – I’m just under 6ft and fairly proportional legs/upper body wise.
I got a 54cm frame… normally on a roadie I ride 56cm but as I was going with a X bike I went down a size. I’m also aware that these Kinesis have a fairly short top-tube.
It’s got a 100mm stem, slightly set-back seat post and I’ve slid the saddle back a touch from neutral. Would you suggest a seat post with slightly more layback, coupled with a slightly longer stem? Or am I just convincing myself I need them in a plight to justify new Thomson kit?

Any help appreciated!

drop your saddle 5mm, or 1cm, see if that helps?

Knee offset is already a bit too much… Was thinking of putting it up slightly actually!

anyone?

If you’re talking about tube lengths and knee offset, you obviously have a much better idea of what might be wrong with the geometry than anyone seeing a photo of your bike and reading your description of your physique.

However, I might suggest that if you need a setback saddle and a longer stem, the frame is just too short for you.

Also – raising the saddle too high will make your hips rock (and not in a good way like Shakira).

Up and forward a touch on the saddle. Looking at propotions and how my 56 road bike looks, saddle just looks low. Iam 5-10 with stumpy legs and I would guess from the pic I would run saddle higher.

No science in that. And I would caveat it by saying i like being high up over the bb

I’m 5′ 7″ and that looks about right for me. There is a fashion for small bikes, especially amongst mountain bikers; you’ve been bitten by said fashion.

Cyclocross bikes should be about the same as your road bike; not teeny wee things.

“Knee offset”…meaningless imo

It’s a myth about going down a size for a cross bike.

5’11 here on a 56cm On One dirty disco.

Okay – I do know a fair bit about bike fit but it’s very different when it comes to your own so it’s nice to have some outside eyes on it.

In what way is knee offset meaningless? I’m interested to know.

So no thoughts on stem length etc? I’m a little cautious about extending it too much as I don’t want to affect the handling dramatically…

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1756210/

Adjust saddle angle? I’m banking on this to help with the lower back pain I’ve been having. I can’t vouch for the results myself yet. I adjusted my saddle last night with a view to putting in a decent ride today but it’s been hissing down. It doesn’t feel as awful as I’d expected on a test ride round the block though.

During the 10 mins of riding were your hands on the hoods? If they were how does it feel with your hands on the top of the bars (flat part). If its better then your too stretched out so try a shorter stem, or if its worse try a longer stem.

Very small changes on cross or road bikes often make a big difference so you have lots of options:

Shorter/longer stem
Lower/higher stem
seat foward/back
layback post

Thanks guys – I’ll have a look in to that… I understand that there’s only so many variables for adjustment on a bike!

Yeah hands on the hoods – I tried moving around; pushing myself back on the saddle seems to help slightly. I guess that suggests saddle needs to go further back, however I’m then concerned about knee over crank being wrong?

Hi ttf, if its any consolation, I’m also a fraz under 6ft and ride a Trek Xo2 which is also a 54cm. I race cross on it in the winter but also use it on the road for anything up to 5 hours and love it to bits and have annoyed a few MTBer’s on it at times …. its quite an upright position but I wanted it on the smaller size for cross race … but your sizing matches my theory on the face of it ….

Looking at it, your set up doesn’t look out of kilter, so not really sure why the ache …. nice bike though …..

I guess if your road bike works for you then get the tape measure out and see if you can get near it as a benchmark …

I wouldn’t get too hung up on knee over pedal, which is a bit of an arbitrary, albeit traditional, measure IMO.

When I dropped the nose of my saddle, I also moved it back on its rails – thinking that being a little further behind the pedals might prevent me sliding forward on the saddle. But as I said, I haven’t tested this over any distance yet.

I’d say the frame is too small – 54cm is what I’d expect someone of about 5’7″ to be riding. MTBs you can go down a size, CX you tend to ride the same size as your road bike.

I’m 6’3″ and have a 61cm, same as my road bie and it’s a perfect fit.

Knee offset? Do you mean the knee over pedal axle measurement?
If you can get some pics of you sat on the bike from side on, that’d give us a better idea.

tttf, I have the next size up Crosslight 5T (57 I think) in the Black/blue. I decided that it’s too big for me and that although it’s ok for winter riding and touring, I need the next size down for CX. I’ve used it for about 500 miles between October and February, not been crashed or damaged, might have the odd very minor scuff here and there.

If you decide that yours is too small for you, I’d be more than up for swapping frames with you, just drop me a message.

How is knee offset meaningful?

KNEE PAIN

SEAT SET BACK: for road bikes

ttf – i like that A LOT!