Originally Posted by
MattyLad
It's one of those, "well you would say that, wouldn't you" posts because I've just come off my new Crosstrail Sport Disc, damaged my knee, which is now swollen, grazed fingers and elbow etc. Alright, it was damp, it had been raining, but I was amazed to find myself hitting the tarmac hard and now, as I write this, my bandaged fingers making it a little difficult, I'm wondering about the bike. Fair enough, this might even be a case of 'a bad workman always blames his tools' but I'm wondering whether, had I bought a mountain bike (my usual steed even if it is inappropriate for the riding I do) with nice and thick, bulbous tyres (like my old Kona Scrap) would I have come off? And now I'm thinking, I'll put the Crosstrail on ebay for £425 (a good price for a brand new bike, it's only six weeks old and has been riden about eight times) and buy a new mountain bike instead. I think I will do that, but...then I thought: what about bigger tyres for the Crosstrail. Any thoughts?
I've found bigger tires are more forgiving on both my hybrids than the skinny tires I used on my road bike decades ago. I started with 700x35 and 700x38 tires but went to 700x40 on one bike and just ordered a set of 700x42 for the other, both most-terrain tires (mixed pavement, moderate gravel, no serious offroad riding).
Main advantage comes from using lower tire pressure than the maximum. Experiment to find a compromise between riding comfort and stability, perceived speed (I judge by expended effort, not speed), while avoiding pinch flats.
My 700x40 Michelins recommend 75 psi for my weight, with a range of approx 35-85 psi. At 85 psi the ride was much too harsh, and was still uncomfortable at 75 psi. The tires would also rebound like Superballs off tricky stuff like train tracks at angles (several in my area), ledges between the paved and unpaved trail on the local MUP, potholes and damaged pavement, etc.
A few months ago I fell a couple of times in one week on the local MUP, riding as I always do. Often I'll go around families with toddlers wandering the paved path. Usually no problem. But twice back in the spring I fell at slow speed re-entering the paved path from the adjacent grass or gravel trail. The front tire clipped the pavement ledge and bounced like a Superball. Turned out I'd forgotten to reduce the tire pressure. Once I set the pressure to the sweet spot, no more problems.
I found the sweet spot was 50-55 psi for the front, 60-65 for the rear. I'll go lower when I anticipate rough terrain. The ride is comfortable, secure, and no pinch flats -- I could probably go even lower. My overall average is 12 mph, regardless of bike or terrain. If I ride 20-60 miles, I always average 12 mph. So I judge ride satisfaction by perceived expended effort rather than speed. If I'm not exhausted after a ride, it's good.
Right now my second hybrid (a 1990s era mountain bike that I use only for town riding) wears 700x38 tires rated for 85-100 psi. It's harsh and uncomfortable even at 85 psi, and I'm wary of going any lower with these tires. So I ordered a set of Continental Speed Ride Urban tires, nominally 700x42, which reportedly can safely be ridden at lower pressure. We'll see how that goes.
I could go even wider on both bikes, but I'd need wider rims. I'd hesitate to go wider than 700x45 on my 622-20 rims. Supposedly handling can get squirrelly, especially on cornering, and sidewalls may be compromised by stuffing tires that are too wide for the rims.