jethro00

We are currently riding our Trek T900 (our backup tandem) until we can get our DaVinci Grand Junction going again. We have had 3 flats on the front tire lately. I have turned it inside out to make sure nothing is in the tire. There is nothing in there. So, I'm going to replace the tires. We have always used Continental Town & Country tires on the T900 and we ride on paved roads/paved paths. The LBS put 26 x 2.1 on the front and 26 x 1.9 on the rear when we first got it. I now have 26 x 1.9 on front and rear. What are the pros and cons to putting 26 x 2.1 on the front and 26 x 1.9 on the rear versus 26 x 1.9 on both? Thanks.

headasunder

very little between them so dont over think it, maybe he didnt have 2 the same size? normally I would put the wider tyre in the rear for a marginally more comfortable ride for the stoker.

Leisesturm

It's a wash. Those tires are so close in size that there is no effect on handling or anything else from having one or the other at either end of the bike. Still, unless there is a very good reason, most bikes come with equal size tires f/r. Any bigger difference in tire size than what you have there might mean having to carry two different sizes of inner tube for one thing. When/if I get a flat, I make sure, if at all possible, not to have to find the puncture with the innertube away from the tire. I like to precisely match up the site of the puncture on the innertube with its relationship to the tire. If not then I have to scan the entire inner and outer of the tire by feel and also with a strong lamp relentlessly until I find the culprit. A piece of wire the thickness of a human hair can puncture a tube repeatedly until found. Or it could be a spoke poking through the rim tape. This is rare. A spoke doesn't usually change that much in length without causing a large wobble in the wheel. But if you can site the puncture before you change its orientation in the tire you can quickly determine which direction the puncture came from.

unikid

Larger in front is more of a mountain bike approach to tire sizing. I agree with the above folks that on a standard bicycle or tandem not being used for racing or extreme things its more common and practical to run the same size front and rear.

OneIsAllYouNeed

I like to set my road/gravel bikes up for the same air pressure in each tire. Usually that means a slightly wider tire on the rear. You can plug in your details on this pressure calculator to see how your pressures should be with each setup. https://www.cycleschinook.com/tire-pressure-calculator/

jethro00

Thanks for the replies. We ordered a pair ofContinental Town & Country 26 x 1.9 tires. On the upside, since Covid-19, we see more people outside walking than ever before. But, we also see more broken glass on the road than ever before. That weighs in favor of not running tires as long as we have in the past.

unikid

Reading online reviews it looks like other folks complain about the T&C's getting frequent flats. Here is one guy who wrote an entire about avoiding these tires altogether:https://bicycletouringpro.com/warnin...country-tires/
This would personally make me a bit skittish putting them on a tandem.

jethro00

Unikid, thanks for the link with the extensive review and comments. I read it all. Our usage is different than the reviewer (long tours and outdoor exposure) and our flats have not been caused by the same problem mentioned in the review. That said, I will keep an aye out for the issue mentioned in the review (weakness in the side area where it contacts the rim). I found one or more negative reviews about pretty much every tire I looked at.

rickpaulos

Tire widths printed/molded on tires are usually just suggestions not exact measurements. Each manufacture labels them as they want. The same tire on a wider rim will result in a wider overall width which makes it hard for makers to state exact widths. They don't control what bikes or rims the tires go on. 1.9 & 2.1 is .2"/5mm difference, well within manufacture claims vs actual tire widths. You could get the calipers out and measure them at normal pressure.

I've owned tires that get bigger as I put in more air. I suspect that's due to a lower thread count in the casing. Many wider tires list a pressure range. Try this as an experiment, inflate to the low end, measure the width, inflate to the max rating, measure the width.

Close examination of the hole(s) in the inner tube can reveal the cause of the flats. Punctures from nails, wire, glass, thorns is just one of many possible causes. Snake bites, pinches, poor quality tubes, improper installation, rubber rim strips on double layer rims, leaky valves, over tightened nut on presta valves, abuse from tire pump methods, poorly fitting tire vs rims are all more possibilities. You didn't mention any holes in the tubes....