I have started (after about 90min of cycling) getting discomfort - a feeling of 'bruising', numbness and irritation-- on the bony bits of my backside.
I wear good quality shorts (Assos), apply chamois cream and have the same irritation on a number of my bikes with different saddles. I have lost about a stone in weight recently. Any idea what the problem may be?
Paul, this is an interesting and not uncommon problem that is not so easy to put your finger on. Where most difficulties regarding that particular contact patch with the bike tend to be in relation to abrasions, saddle sores etc, this is a problem with the sit bones.
Firstly when this, or indeed any other problem suddenly manifests itself in an area where you’ve perceived no previous discomfort, you’re right to try to identify anything that’s changed which might be causing the problem. In this case it’s your weight loss, and you’re clearly thinking that the related lack of ‘padding’ in this area might suddenly be causing you discomfort.
So the obvious thing to try first is simply putting the padding back – not by re-visiting your former, heavier self, but by trying a second pair of shorts. This might sound odd but loads of riders use ‘double bagging’ for all sorts of reasons.
Give it a try and it might provide a simple solution. I’m loathe to say this is definitely the cause (or the solution) however because there are plenty of whippet-thin riders out there on narrow, racing saddles, with little padding who experience no discomfort. And too much padding, either on the saddle or your clothing can lead to their own problems.
So if that doesn’t provide a solution then you might need to get a bit more technical and come at it from a biomechanical angle. The sit bones (actually ischial tuberosities) are the two sticky-out bones that carry your weight when you’re sitting on the saddle, so each saddle you use needs to directly support these two bones.
Too narrow or too wide and you’re likely to experience discomfort. Any number of things can actually change your position slightly on the saddle, often unbeknown to you, so you need to make sure the width of the saddle is correct for the position of your sit bones. This is easily achieved by a good bike-fitting provider who has a machine specifically to measure the width of your sit bones and look at your position on the bike to ensure you’re sitting correctly then recommend a saddle to suit.
While your getting that sorted, there are a few things you can do on each ride to alleviate the discomfort. Simply move around on the saddle more often than you normally would (sitting further back on the climbs for example) and stand in the pedals for 30-60 seconds every 15 minutes or so can offer respite from the normal position by regularly shifting the pressure points.
Huw Williams, BC Level 3 coach