 The big one that you'll be super happy about is the uh the stem is now slammed that's Neil's camp mate you got to come back we're going back on the 172.5s can't do it Neil can't do it Neil how are you mate very good very good come on in yeah we're doing house calls now an extra charge for this good to be back with your favorite galah yeah So welcome back to the Friday vlog series where the expert bike fitter Neil Stambry is going to walk us through four major changes I've just made to my BMC team machine following a crank length change I made only a few weeks ago from 172.5 millimeters to 165 and one of those changes is laughable it's become a bit of a running joke on this channel now if you're wondering why I changed crank lengths in the first place I'm going to leave a video for you at the end of this one but in a nutshell the change in crank length is supposed to enable me to roll my pelvis forward and essentially become more aerodynamic and efficient on the bike something that I am far from and what's interesting for me after 11 plus years of road cycling I've had many many bike fits before from different fitters and never before has a bike fitter picked up on my hip impingement and suggested a change in crank length and while this is my story I know there's a lot of people out there that are probably in a similar situation to mine and don't really know about it and Neil even says himself that roughly one out of five people that come to see him for a fit suffer from some type of hip impingement it could be either one sided or on both sides so I'm certainly fascinated with how this is going to change my cycling and whether it will take my cycling performance to a whole new level and I hope it inspires anyone out there that feel like they suffer or could suffer from a similar situation to give this a shot so the four things or the four changes we're going to talk about on the BMC that the shorter cranks have enabled I'm going to let Neil walk you through but the one that is kind of stealing the show is the slammed stem if you're someone that follows the channel you will know that the chimney has been a big part of the plot recently I'll put a video up there if you wanted to check that out first but essentially the chimney is back it's bigger and it's badder than ever and despite people thinking I chopped the original chimney off purely from the influence of the chimney mob led by captain pug wash the decision was mine and let's face it if I did follow the mob I would essentially have to saw my head off change my accent and stop drinking vb so in this case I will be leaving the chimney there despite the heckling that may occur for a long period of time but I am most amazed that for the first time in my 11 year cycling history I have a slam stem it's kind of blown me away so Neil's going to talk to you now about that and the other factors that have changed because of the crank length and how this could potentially take my cycling performance to a whole new level so let's get into it all right Neil you've come over to my house I'm overweight I'm inflexible my dog's humping your leg yeah I noticed that and he dropped a really bad fart it's been a great experience for you hasn't it it has mate yeah it's it's made my Wednesday yeah and and I'm not even getting paid for this you know it's going on here it's supposed to be my day off so first first thing we noticed when I looked at you is that you were dropping your right hip quite badly which is one of the things that you were doing when I first saw you back at cams in Brisbane before we fitted you and in that case the solution was to move your feet further apart and and fit a six millimeter shim and a few other things to the bike you were doing that again which you you weren't doing when you left my my clinic last time so we had to iron that out and why was I doing that you think I did wasn't what I thought it was I thought it was because you're overweight and you've lost condition um and people people as they lose condition they they become tighter and stiffer in some parts of their body and you know so if they put on a fair few kilos they have trouble with knee strike to the to the gut that sort of thing but in your case the solution was actually a bizarre one we actually needed to move your feet closer together again and that's a result of this one of the four sort of main things that we changed today after looking at you with the shorter cranks was moving your feet closer together than they were with the longer cranks now the the logic behind this is actually pretty good but I really wasn't expecting to make this change with you because it's quite rare that this happens as we moved as we moved the crank shorter your knee rises less high at the top of the stroke which allows you to roll your pelvis forward and all sorts of nice things in your case it also unloaded a lot of your your femoroacetabular impingement or hip impingement we call it and as it unloaded it your knees were able to therefore your or your femal was able to to sit in more internal rotation so in other words your knees didn't kick out as far due to the shorter cranks which was great which means that we were able to narrow the cue factor down and you suddenly stopped dropping your right hip or you pretty much completely stopped dropping your right hip when we moved your feet back closer together so that's a nice side effect in your case of the shorter cranks it's obviously unloading your hip impingement to quite a substantial amount which is what I was really hoping it would do in conjunction with that we needed to raise the seat a total of about nine millimeters so you'd already gone up five which was pretty safe and we went up about another four millimeters from there the seat went back about four millimeters at the same time and I think I explain this to you when if you've got the crank arms spinning around like this because the crank is effectively shorter your foot sits further back sort of towards the back of the bike due to the shorter crank right which logically all else being equal and this is a bit of an oversimplification but all else being equal your pelvis can sometimes go back in a commensurate manner and in your case yours went back about four millimeters just to keep you nicely balanced if we left the set back where it was you were leaning forward and placing too much weight on your hands and you're just just too quad heavy and moving the seat back that little bit just restored the balance that we had with the longer cranks so the seat went up nine it went back four your feet got closer together and the big one that you'll be super happy about is the the stem is now slammed we've dropped the bars 10 mils in addition to raising the seat nine which is great but you've created a small chimney effect again so yeah look I doubt it what you do about that is your own business Cameron but uh you know I think you should chop at 15 mils personally right we'll take it back to trilogy exactly five at the top apparently for safety because of the in-cap yeah yeah you've got to have the end caps got to be pulling down on the stem to properly preload the bearings that are in the top and the bottom of the the stirrer tube there so as long as you've got some standoff of the bearing cap you're okay it can be two millimeters but um yeah look I would personally leave it like that that's essentially how my bike is and just for resale value you know yeah some some guy buys the bike off here one day he's probably not going to be as flexible as you unless he's running 165 mil cranks so in the end we experimented reducing the height of your shim as part of our efforts to stop you dropping your right hip today and that did nothing so we've left you with a six millimeter shim but the the biggie for me the really interesting thing was was being able to move your feet that much closer together it it was about five or six millimeters closer together than they were in total than what we had with the longer cranks yeah so you'll notice when you look at the footage of yourself from the side and compare it to your old footage when you're doing that ftp test with your longer cranks your spine is it's still rounded to a to a small extent but it's it's a million times better your pelvis is rolled forward about five or ten degrees and your back is much flatter and I would I would guess that your head is sort of five to ten centimeters lower than it used to be and that's one of the primary sort of determinants of of frontal area is how low your head is essentially and your frontal area is is is the biggest the biggest kind of predictor of wind drag and you know this is like we said before it's an efficiency sport and if you if you present less frontal area to the wind if you are less of a windsock you will go faster for the same same wattage you got to remember that that wind drag goes up with the cube of speed so if you sort of graph the drag and and the and the speed of the rider it kind of rises parabolically so it it might take it might take you 500 watts to ride at at 50 kms an hour 400 to ride at 40 but only sort of only sort of 250 to ride at 35 you know so it kind of kind of rises like this so the faster you're going the more effect it has obviously and the slower you go the less it'll worry you yes but hopefully you'll be you'll be going 50 kms an hour everywhere now you know yeah it's it what it usually means is that my judgment wasn't that far off occasionally we get a person in your whack-a-mole shorter cranks because you say oh you know listen John you've got really bad hip impingement and all the things that you've got and they don't change and you think oh you know just made you spend a bunch of money or I've recommended that you spend a bunch of money and it hasn't given you the change that we're expecting but in your case it's done all of the things that I expected it to do and and yeah I think you'll really you think you really like it as long as you don't end up losing too much off your top end and I'll wait wait down the track and see when you do some sprint tests when you're back in shape and you do some tests down the track my guess is that your 20 minute power will go up slightly and your sprint will essentially stay the same but if you look very closely at your data you might find that it takes you a little bit longer to get to the peak power of your sprint as compared to the longer cranks a few more pedal strokes perhaps but you'll notice your overall cadence will go up that's one of the things which you you probably noticed riding on the road already your your average cadence tends to come out five or ten you know cycles higher at the end of a ride and and your efficiency due to wind drag will will mean that this will be worth it in your case as a person who's trying to go fast who's racing and you know trying to train and race at a high level it'll be worth it for you yeah okay good it's the plan anyway yeah yeah we'll see we've just got to get you back in shape now have you have you have you put on that standard the government came out with a three to five kilo range which is what the average person has put on during the COVID outbreak really yes is everyone sitting at home doing nothing i would have been i would be straightforward middle of the bell curve mate middle of the bell curve