Tire load ratings
 

Is there a "rule of thumb" to use in determining if the load rating on a set of tires is within the requirements for a given weight combination of rider and gear? Is there a percentage that can be assigned to the riders weight being carried by the rear wheel if you don't count any additional gear?

You can figure your weight distribution with a bathroom scale and a book of equal height to the scale. Place the scale under one wheel, the book under the other, mount the bike and have an aid note the reading. Swap book and scale, and repeat. The two readings should equal your combined bike/self weight. Hold the bike while standing on scale to confirm. Divide one of the wheel readings by combo weight, and multiply result by 100 for percentage of total weight.

I wouldn't expect load to be a concern except in extreme circumstances; I've never paid it any mind, anyway, and it's not even a regularly published specification by tire manufacturers.

Hadn't thought of that! Makes sense. Thanks.

Usually the biggest problem with heavier weight is spoke failure, then rim, then hub. I'd think tires would only be a problem if they're under-inflated and you get a pinch flat. This is one reason I don't recommend 'English' style bikes like Breezer or Bobbin, or looks-like-a-Dutch-bikes or looks-like-a-retro-bikes for people looking for a city bike that will be used for carrying groceries and such.

I'm not sure I follow your reasoning. The wheels on those style of bikes usually have 32 to 36 2mm spokes with a wider tire. Or are you saying the frames are suspect?

On a road bike, in the drops, the weight distribution will be about 45% in front, 55% in the rear. As you go more upright from that, the weight shifts to the rear, so that an MTB might be 40/60 and a Dutch-style bike might be 35/65.

There's a big gray area of tire sizes and pressures that will work for a given load. It's hard to know how little you can get away with unless you experiment until you start getting pinch flats. I've been using the "15% drop" method for a couple of years, and it has been working out great for me. :thumb:

Yeah, the 15% drop on pressure is exactly what I use. Maybe even a tad more for the front. Makes for a much nicer ride. If I were carrying heavy loads I would bump that pressure closer to the listed max.

Yea, i'm curious as well.

I had 2 spokes that were damaged in shipping snap at the thread, but since that was sorted i've had no issues, even when accidentally careening full speed into a road hole that wasnt there the day before (construction). 36 spokes is a pretty high count, and its easy enough to swap the stock spokes for thicker/double butted.

- Andy

Based on nothing more than appearance, I would guess that the reason is these bikes put more weight on the back wheel compared to more aggressive hybrids like Marin Muirwoods 29er or Jamis Coda.

But a wheel with 36 straight 14 gage (2mm) will easily handle 350 lbs of weight. And because the frames are usually ridden in a fashion where there is very little undue stress (jumps, wheelies, etc..) They should work fine for groceries and commuter type loads.

No idea, that was just my guess. You'll have to wait for the other guy to explain.

I actually have a breezer, so i am confused by the whole remark. I have found it to be a superior machine to my old steel road bike.

- Andy