[Closed] When I ride my flat bar mountain bike - my back leans in?

I've always suspected that if you allow your lower back to kind of slump down and collapse, then it'll end up a bit like bum-shoving in rowing, or lifting a weight badly, where you end up using your legs to mash up your lower spine.

i.e. those discs in your back are fine in compression, but are not well able to cope with torsion.

But I could be wrong. YMMV.

Edit you rest your elbows in the grips?

Sound like you need longer bikes. You don't want to be riding anything more gnar than gravel on Tri bars.

Post a picture of your set up, sounds like the bike is a bit short.

You might want to work on your core strength a bit! Just lift the Moonlander over a few gates and you'll be fit (speaking as an ICT owner)

You've got history of not knowing how to sit on a bike haven't you.

😉

oldnpastit that sounds awful, and that is a horrendous image you've painted there, of mashing up your back. I've seen a lot of long distance riders on things like the Tour Divide use them though, Mike Hall used them I think, and so does Lael Wilcox.

Cynic-al, that is it. The upright bar position is really comfortable for a few miles then my back starts to want to naturally lean in. I think you may be right there. I tried out my Krampus which as well as being much longer, I have a 90mm stem on, and it was a different fit, but still comfortable. It's really confusing though to be honest.

40mpg, I see what you're saying, but it doesn't hurt in my core at all. It's more my back.

Ghostlymachine, I really have, and it's honestly incredibly frustrating! I still haven't managed to sort the AWOL out, just stuck it in a corner and trying to ignore it for now. At least till I finish my exams..

Tri bars on mths are mostly about reducing long term stress on your hands and wrists. Few riders on a bike with mtb geometry can put out effective power in that position so it's mostly for rested cruising, eating while moving etc. Crap position for control though.

Std response if you feel you're tipping fwd- move saddle back, fit layback post. Move your c of g further back towards the bb.

Did you try that on your AWOL?

move your saddle back

Is this right?  I suffer badly from a painful lower back after a few hours, the fix seems to be a reverse stretch on the bike when standing.  My issue is the I hunch over the bars, I attempt to sit up on climbs, or stand to stretch.

I can only think that moving my saddle back would make things worse...?

Std response if you feel you’re tipping fwd- move saddle back, fit layback post. Move your c of g further back towards the bb.

I hatethis bitof advice*. There is a correct place for your saddle and it has nothing** to do with relation to bars.

*Ackonwledging jameso has forgottenmore about bikes than i'll ever know.

** My knees require perfectly placed saddles.

Myknees are fine not injured or anything just hate not being placed well.

Hey all. I tried the above advice, and messed around with a much longer adjustable stem, put it at saddle height (it was higher) and tightened the brooks saddle (I kept feeling like I was falling off) and it feels actually really comfortable now! I'm really happy.

I'm going to get a longer stem, but what I'm really stuck on is, how do you determine the correct stem length to buy? I can't seem to find any decent advice on this anywhere. I'm not sure how long I should go.

Tri bars on mths are mostly about reducing long term stress on your hands and wrists. Few riders on a bike with mtb geometry can put out effective power in that position so it’s mostly for rested cruising, eating while moving etc. Crap position for control though.

It looks so comfortable for long distance though, and so many long distance riders seem to get them, I think I might have to try them! But I'm a bit confused by what oldnpastit said about mashing up your lower spine.

If you can ride with your elbows on the grips, then your frame is far too small surely? For a mountain bike anyway.

But I’m a bit confused by what oldnpastit said about mashing up your lower spine.

Try it and see. If you get back pain after riding for a few hours, then try to get a more upright position (shorter stem, or whatever works). Or core strength exercises.

Bikes are too short for you.

You can compensate a little by moving your saddle back but only if your knees are willing.  As said earlier, there is a correct position for the saddle that is to do with leg length rather than anything else so moving it too much will mess up your knees and pedalling.

A longer stem is the way to go, perhaps lower it with a negative rise or moving spacers around if you have them.  Once again though you'll mess up the handling if you go too long or too low so you can add a little 'perceived' length by switching to wider bars, moving your hands out wider will naturally bring your body forward a bit.