so54i88

Hi all, I've been browsing through this great place for some time now but this is my first post. I hope someone here can help me out with the tire on my bike. I bought a used Avanti hybrid for commuting. Great little bike to ride but it has 700cx28 tires on it. The road I used (the best route) is not as smooth as I'd hoped and broken glass can be often found in some places. My commute is 13km and when I was looking around for a bike, I thought 700cx28 would make it easier to ride but The road surface proven me wrong. At 120psi it's not comfortable at all. And I'm averaging 1 puncture every 20kms, and I've just had enough of it! I wonder if I can fit some 32c tires on the current wheels which are Weinmann Sec16, writing of the side wall says 700c 23/28, 622x16. I've read heaps about schwalbe marathon plus as wonderful puncture resistant tire. I'd like to fit some 32 on my bike. Oh, also, since it's a small sized bike, the rear wheel only has 5mm clearance on each side between my 28 tire and the frame at the moment. Would 32 squeeze in?

Any help is very much appreciated!

10 Wheels

What is the cause of each flat tire?
Why don't you try 100 psi in the tires?

I run 28's on my road and touring bike.

so54i88

Broken glass! Once I even found a tiny piece stuck on the tire that hasn't worked itself through the tire yet! I have Specialized All Condition Sport on the bike at the moment. To me, it seems very soft and glass just goes right through it! 100psi? can I do that? Sorry about the dumb question, I'm still learning. The tire says 110-125psi, would 100psi do any harm?

LarDasse74

28c tires can be run softer than that... I weigh 260 lbs and I would feel comfortable running most 28c tires as soft as ~90 PSI. Over 100psi in a 28c tire will rattle the fillings out of your teeth.

I would expect for a sub-200 pound person you could get away with 75 or 80 psi and ride fast and smooth.

However, if you regularily ride on roads and trails where there is broken glass, consider a tire with built in flat protection like Panaracer TourGuard, Continental Gatorskin, or Specialized Armadillo (among many others). Loads of people ride with narrow tires on terrible debris strewn roads with these and do not have regular flats.

jayp410

I agree w/ LarDasse - you could run the tires with less pressure, and furthermore, reducing your tire pressure could actually help reduce the puncture flats. A high pressure tire when it runs over a piece of glass or a rock is not going to be compliant, so it's more susceptible to puncture / shearing forces, whereas a softer tire is going to conform more to the object. Also, you'll have more tire on the road to give additional support so it's not driving the glass into the rubber quite as hard (less pounds per square inch over the obstacle).

At 195 lb, I run my 25c tires at 102 PSI (front) and 110 (rear) although no doubt I could probably run them softer. (I use Continental GP4000S (and just the plain GP4000) and have not had a puncture in 1000-2000 miles at least, although they are lighter construction than some of the others mentioned above that are specifically designed for puncture resistance and I ride on rural roads that are relatively clean. Even so, the GP4000 / GP4000S is a very popular tire around this forum, and I am not alone in having good luck with it.)

Another thing you may have some control over is what part of the road you ride on. If you're riding where car tires go, the cars will clear out most of the glass etc. But areas of small pebbles are really bad to ride over, as there's a high probability that glass and other bad stuff is going to be mixed in with that.

FBinNY 

Unless you're very heavy, there's no reason to inflate your 28mm tires to 120mm, and probably less reason to go to a wider tire. Here's a guide to pressure based on tire section and axle load. I don't offer it as the last word, but as a guide for a starting place.

As a long time commuter through some rough (both the pavement and population) neighborhoods, I've come to the conclusion that tire tread compound makes the biggest difference in flats. Contrary to instinct, often thinner treads do better than thicker ones that are more likely to pick up shards and carry them until they work their way through. I acknowledge there are many who disagree with this, but that's been my experience.

Also it also seems that new tires are more likely to flat, but if they survive a while the UV and weather dry out and toughen the rubber, and if thy can make it a year they then seem to go forever. When buying your next tire roll the tread in your fingers, and press a a fingernail into it looking for the hardest feeling tread.

BTW- you might also want to examine your tires every once in a while looking for and picking out embedded bits of glass.

so54i88

Thanks everyone for chirping in. The part of road I use for commuting is quite old and rough with loose stones, dirt etc. LarDasse, "Over 100psi in a 28c tire will rattle the fillings out of your teeth." this is exactly what I've been experiencing!!! haha... It's not very nice especially my drink bottle is smaller than the cage and it rattles like hell! I guess i didn't need any bell to get people's attention!

It seems that the general consensus is to run 28 with lower psi, but would you say 28 is better than 32 even if i could fit 32 to my bike if i want a more comfortable ride and less vulnerable to puncture? How are those puncture proof tires mentioned here compare to marathon plus? I've hear they are pretty much bomb proof?

10 Wheels

$32 tire.
https://www.ubcbike.com/store/product...X-28---Black)/

FBinNY 

I'm old school cheap (I make Scots look like drunken sailors). Once something is on one of my bikes, it's there until it's dead. I say that so you know my bias.

If they clear, you might see some benefit with 32mm tires which will allow yet lower pressure, but I don't think the difference will be enough to pull off and replace a tire. Consider trying 32mm at replacement time, but not before.

so54i88

sorry, i didn't quite get what you mean by $32 tire?

so54i88

yeah, thanks for the advice. Nothing wrong with being cheap, in fact I'm cheap too！The tires are the original ones that came with the bike. It's a 2007 model. They look ok, just ok. I would say that they will need to be replaced sometime soon. I somehow thought that I would less likely to get a puncture with a wider tire and it would also be more comfortable. I think I maybe able to mount some 32s on my wheels but the clearance between the rear tire and frame would be minimum.. This is the major concern I have.

so54i88

Thanks FBinNY for the great article on tire pressure!