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Stem Length and Tilt
I was hoping someone may have some knowledge about stem length and tilt and how that affects ride comfort? I've stuffed my back (L5/S1 disc protrusion, herniation and annular tear!) over my soccer years and it's now started to become a problem whilst riding. I'm trying to set-up my bike properly so that I can continue riding and avoid further damage to my spine. Otherwise the wife is going to get really p@#$%d at me for spending days at a time lying on the floor in pain!
Currently I have a 105mm stem (came with the bike) with an 8 degree upswing. Would running a shorter stem and changing the upswing make a difference? If so, how short should I go? I enjoy XC with quick downhills (none of that insane red bull stuff, though). I have accepted that I am unable to compete so I'm riding for pure enjoyment therefore out-and-out speed isn't all that important.
I've also dropped my seat height so that I'm no longer flexing my lower back as much.
Any advice would be awesome!
Cheers 
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Sounds like a vsit to Steve Hogg might be in order:
http://www.stevehoggbikefitting.com/
Thanks! Will check it out
Or Blair Martin, The Body Mechanic.
Incorrect seat height either high or low will be bad for your back. I really recomend going to see blair{ body mechanic} I was having serious troubles earlier this year and with two weeks to go to Capital Punnishment I was about to pull the pin but a friend recommended that I go and see Blair who sorted both my Road and Mountain bikes. My riding position imediatley felt better and I was able to not only do the race but i set a PB for the 100.
I'm not a bike fitting guy but my thoughts are....
I wouldn't drop your seat height as that will just put you in an inefficient riding position and your legs will suffer. There are a few different schools of thought on saddle positioning but they all seem to agree that it's a function of your leg mechanics.
Instead I would raise the front end. Anything more than about a 10deg stem will be reasonably uncommon and also look really odd. Maybe go a little shorter than normal, but my experiment with really short made me feel all hunched over. I reckon the best solution for getting the bars higher is riser bars then use spacers for fine tuning. Wide bars will also bring you forward and down so maybe something a little shorter.
It might be a bit of trial and error before you get it right so it's probably worth getting fitted up by someone with all the different options on hand to experiment with. DIY trial and error can be pretty expensive.
DIY and trial and error can be very expensive. And I wouldn't be ruling out changes to seat height or any other part of the bike until somebody with expertise can actually *see* you in action, under load.
I'd also be very wary of anybody using formulas like inseam multiplied by a certain magic number to set up anything on your bike.
Take a look at this post and scroll down to see comments by anke: http://www.stevehoggbikefitting.com/blog/2011/02... and then you will find out how very expensive getting it wrong can be.
The videos on his blog and the DVD set "Sitting Pretty" are hugely informative. Steve Hogg isn't cheap, but he's a lot cheaper than stuffing yourself up.
I would personally get on ebay & get a shorter stem & like it has been said don't lower your seat it is the worst thing you can do because you will never find that sweet spot again , also see a bike fitter if you have back damage or get off the dirt for a while till you build your back strength up a bit more . My 2 bobs worth .
If your hamstrings are tight rather than rotating from your hips when leaning forward you will curve your lower spine. Working on flexibility has greatly increased the amount of time I can spend on the bike without back pain. Best to discuss this with someone qualified first to work out what stretches would help.
+1 to stretches, but they must be done in such a way, that isolates them without involving your lower back. My physio gets me to do them lying flat on my back on the floor with my legs in the air.
-1 to not changing your seat height - lowering you seat is something you can try. If you read the post I linked to, you can see that having your seat too high can do a lot of damage, including bulging discs. It can do a lot more (and permanent) damage than having your seat too low.
Recording where your seat was before you moved it isn't hard, so no need for apprehension there. You can use the markings on the seatpost, and write it down. Since I swap between a few bikes I use a different method: a spirit level across the top of the seat and then measure from there down to the bottom bracket centre in line with the centre of the seatpost/seat tube. I know that a length of 74cm using that process with 175mm cranks and Shimano pedals will feel right for me on any XC or road bike.
In your case I just wouldn't settle on a permanent seat height or stem length until someone *qualified* has evaluated you medcally for a bike fit. My suspicion is there is a lot more going on than simply seat height and stem length for your dramas to be so acute.
Some of the work that needs to be done will no doubt need to be on you, not just the bike. If this is the case Steve Hogg will make the call very quickly and be able to point you in the right direction and to the right people, people who have a track record. As he says, we too easily give respect to medical professionals when it isn't deserved... it needs to be earned.
The trend at the moment is towards shorter stems. It speeds up the steering and puts you in a more comfortable riding position for technical MTB riding.
When I built up my dually I started with a 90mm stem, and later shortened this to a 70mm.
The difference was very pronounced. The bike came alive, and was much more fun to flick around the singletrack and bomb the downhill sections.
I say go for it. Grab one off ebay, it wont cost too much and it's only a few minutes to swap them around.
Thanks everyone for all the excellent advice and referrals. I've got an appointment with a strength and rehabilitation trainer tomorrow to help with the physical stretching and muscle training. Think I'll definitely make an appointment with a pro bike fitter, sounds like most people have had a good result with this. I will seek their advice before I purchase a new stem.
Thanks a-million
Hawkeye, I just read the link to comments by Anke... I'll be making an appoinment with Steve 1st thing tomorrow!
You could also try Aaron who runs Fusion Peak Cycle Fitting on the Northern Beaches.
Additionally, he specialises in MTB fitting.
Hi guys, I've just changed my stem to a 90 mm one (threadless headset). How do I know I have the correct tension on the preload bolt? I've watched a few youtube videos but I'm uncertain about the "play" as my forks compress a little when I rock the bike forward with the front brake on. The handle bars do move freely when I lift the front wheel off the ground as it said it should in the videos. I'm just not experienced at this. What is the worst that could happen if the tension is wrong?
Any advice would be great
Cheers
when you rock the bike back and forward, if it's too loose you will see a little lateral movement of the spacer/dust guard on the head-set relative to the frame
If you drop the front wheel from about 200 mm, you will hear a buzz as the headset vibrates if it is too loose.
Ride the bike in a figure eight and retest
Hey andyfev -
I had a bike crash in late April and have a L5S1 disc bulge/ Annular Tear also.
Much to my horror - I have not ridden since, as the pain always strikes up and I wish for a full recovery.
I also plan to see the bodyMechanic when i can ride again.
Out of interest - how long have you had this and have you had any cortisone injections?
Can you still do 100km events etc?
I have had to pull out of geoquest and am planning on XPD in Nov...but the back has me very worried. Any insights from your experience would be much appreciated.
cheers.
Sorry for the late reply.
I first started with lower back problems in my mid twenties caused by Football (talking about the world game here!). I've had multiple episodes of disc bulge all of which have been no fun at all! I had an MRI in 2009 that showed the annular tear and again more recently in April this year. My problems stem further than simple injury as I have a congenitally narrow spinal canal (most should measure >15mm at L5/S1 but mine is <10mm). This congenital anomaly results in huge neuropathy at even the slighst disc bulge. In the most recent event my left foot was numb for a full 5 days!
I have never had any treatment for my back pain. I simply rest and down voltaren! After several years I figured this was not the best solution and sought alternative treatment. Since April I have started to train with a strength rehabilitator to strengthen my pathetic core muscles. Within a month I felt much stronger and had zero lower back pain. My trainer has been away for the past 3 weeks and in honesty I haven't been doing my homework and as such the lower back pain is just starting to show itself again... must do the core exercises!
Basically, with these regular core exercises I am able to ride pain free. It is extremely important to recognise your limits and where you 'fit' in races. This was hard for me as I was just getting into events and suddenly had to 'unfairly' resign myself to shorter distances and holding back. In answer to your question do I do 100 km events... No... but then I never had! My limit is a really quick 15km or a moderately paced 30km. Any more than that and I'm entering into the 'unknown'.
As for the body mechanic... I put my cash into the rehab guy first as without him I wouldn't be riding anymore. Body mechanic last!
An excellent resource is www.backcare4u.com.au
I hope all this helps and best of luck... back pain is a real pain in the... you know!
Cant recommend Blair Martin enough and I have had the same problem as you have Andy as you know.
Also use this website as a Guide of spacers....
http://slamthatstem.com/
Edit: I know its extreme, I had the exact same problem, a bulging disc from my L5S1 and had a microdiscectomy to have it removed as it was causing me sever amounts of pain. My experience of the injury is that no amount of rest or voltaren was going to solve the issue and at the age of 24, I wasnt going to have live the rest of my life with a knackered back impending on the quality of my life, so I had surgery. 2 Years later (almost to the day I went into hospital 2 years ago tomorrow) and I have never looked back.
Imo if your worried about the consequences of what could happen if they get it wrong, talk to the specialist, technology is so advance now that they do the surgery with keyhole surgery, following my surgery I was in more pain from my body rejecting the anesthetic and being sick all the time, instead of the pain from the surgery. Literally I went in and 3 hours later I had no sciatica pain no more. The bottom line for me was at the age of 24 suffer with the rest of my life with a bad back or get the surgery and be free of pain, for me it was a no brainer, I guess it just depends on the price you put on being pain free, for me 20k seemed like a good price to me.
Best $20k the Insurance company ever spent on me as far as I am concerned.
drift have a fan dangled new bike fitting computer at their kotara store.
It sounds as if you already know the right thing to do - sort your core out.
One thing to be mindful of is that just because someone else (rider or not) has LBP, does not mean that what worked for them, will work for you (be it a particular surgery, treatment, stem change etc).
The same can be said for the injury. The same injury for two different people may be caused by two entirely different mechanisms. Best thing is to clearly identify and understand the root cause of the problem. Also consider that where the pain shows up is often different to where the actual problem is.
Anyone serious about back pain (prevention or cure) might want to look into the work by Stuart McGill - http://www.backfitpro.com/
He is generally acknowledged as a leading authority on the lower back and how to treat and train it.
Happy riding!
Thanks guys - I really really appreciate the links, comments and personal info.