MiPeGr

I was visiting a state park about 2 hours away a couple of weeks ago, and I realized that by combining the roads and trails that are inside the park with a return leg along the beach, I could make for an enjoyable loop. My question is whether my 650B x 47 tires (Vittoria Terreno Dry, with tubes) are wide enough to not sink into packed/damp sand. Think sand at the high tide line on an outgoing tide. This beach has firm enough sand that motor vehicles are allowed to drive on it. But being 300 lbs, I'm concerned that the sand might not support the tires sufficiently.

Anybody have any thoughts on whether this would be sufficient? I'd hate to plan another trip out there only to be stymied. Also, what about air pressure? I'll typically ride those around 40 rear/30 front (or maybe a touch higher depending on how smooth/uniform the surface is). The beach doesn't really pose any risk of pinch-flats, so how low could I realistically go, and would it make a difference?

tyrion

Wet sand varies a lot, but my guess is 47mm isn't wide enough. You will be able to move through it, but with much resistance.

Steve B.

Only bikes I know of that work on sand are fat bikes with 5” tires and even then the conditions can vary in a short distance to find you pushing.

tangerineowl

Hard to tell at your weight I think.

I'm under half your weight. Recently with 650b x 48 went through some very long stretches of dry, deep, soft white sand. Stayed in the compressed down tracks which the vehicles had made though.
Got through fine in a low gear. Tyres were probably around 20psi.

MiPeGr

I know the dry sand will probably be a walk. I'm more interested if its worth trying on the hard-packed damp sand.

FYI--it's WA/OR beach sand.

chas58

Point of reference - Scwalbe made a tire for these conditions. Its basically a 60mm G-One speed (designed for beach racing in the Netherlands). Super fast tire, but it sucks in the (non sand) wet (flotation + mud - tread = nightmare).

MiPeGr

That may very well be...but I don't have clearance for anything larger than a 47mm.

chas58

Just a point of reference. When I lived near the (Gulf) coast, sand near the waterline was rather like cement. It would hold a lot. I don't remember your sand being much different. When its saturated, it is hard. As for pressure - i would run about 20psi, but I'm a bit lighter than you. Really, your limits are having the tire fold over on the sidewall during a hard turn, and bottoming out (neither are typically a big concern on sand). You can go as low as you want if those things aren't an issue. (The CX gang goes below 20psi on 33mm tires at race speeds).

MiPeGr

That was my thought, exactly. I mean, if I can drive my Subaru out there, and I've seen plenty of Suburban's and F250's get out there without airing down, I assumed it might work. I was just hoping someone had some practical first-had experience to share.

chas58

If trucks are driving on it without leaving ruts and not airing down, you'll be fine. If you are near the waterline (where it is like cement) you'll be fine. Get away from the water line, at high tide, you'll be walking.

JaccoW

The Koga Beach Racer uses them (Beach slapped - Road.cc) with 60mm wide (2.35") Schwalbe Big One tyres. But those also go over the less packed dry sand.

I've ridden a Continental Urban GP 35-622 (semi-slick) tyre over the damp part of a beach for a bit and it works decently but I was overtaken by people riding MTBs. Cornering was... not so great so I think you should be okay with 47mm. Only one way to find out anyway!

EDIT: This guy rode his loaded touring bike for 15 km on the beach between Brisbane and Sydney on WTB Resolute 700c x 42mm tyres. I think you will be fine.

xroadcharlie

I tried riding my mountain bike with 54mm tires through dry sand Ha...good luck, and I'm only 150 lbs.

Yet beach cruisers often come with 2" (50 mm) tires do fine. But they are usually on damp sand I'm guessing your 47 mm tires will be fine on most damp sand. I would at least try it