@carfreephilly: where on the tubes are the punctures occurring? Are you positive it's not the rims? The number of flats you're getting with quality tires just sounds ridiculous. Have you run your fingers around the rims to make sure there's no burs?

Are you getting your flats around the same area of your ride? Might want to change your route.

Most of the flats have obviously been from glass shards. I think I had one that was clearly a pinch flat, and a few that resulted from a tear near the valve. I can't help the glass issue, unfortunately--the streets and bikes lanes in particular have a lot of glass in them, and the city does a lousy job of cleaning them. I wish there was a way to avoid it by changing my route, but it doesn't seem to matter where I ride. I just try to check my tires for glass shards every day or two and pick them out.

The thing is, I've gone through phases where I've commuted more on other bikes and have never gotten this many flats! I rode my big city cruiser daily for a while and never got one. With the Brompton, I would say 3 months without a flat is probably the longest I have ever gone. My partner also went through a pair of Kojaks in a couple of months and switched to the Brompton tires--and she's used the same tires on her Steamroller for 5+ years. It's odd to me that it's so specific to one bike.

It's weird that you get so many front punctures. I get them so rarely on the front that I don't use liners on the front on all bikes. I got one of my rare punctures the other day on my Birdy front - Kojak - the second front puncture in some 12,000km of riding.

But punctures are a matter of chance. However perhaps smaller wheels are more prone to disturb glass than big wheels. Also perhaps there is more new glass on your route than when you rode your previous bikes.

Sidewall gashes - your luck is out. There is no tyre that will stand that. No liner that will save you. As I said, perhaps the geometry plus width of the Brompton wheel makes it more prone to getting slashed. I think you have to re-think your strategy. I used to ride with a little brush to brush glass off the bike path where that Big Apple got so badly gashed. I don't ride there that often anymore.

Jeez... watch where you are going, and steer around stuff,
that may puncture your tires.


Schwalbe Marathon Plus are made in the 349 size too..

Gee thanks, I never thought of going around the glass. I was riding through it on purpose, just for fun.

Maybe want to make one of those 'tire scrapers' for your Brompton?
http://velospace.org/forums/discussi...horn-proofing/

(best I could find with Google)

Have you considered maybe not having your tyres inflated to the upper limit? I am currently riding a hired Brompton M3L with Brompton tyres 11 miles/day across the city of London daily. 6 weeks without a flat yet. The Brompton Tyres say (I think) "80-100 PSI" so I inflate mine to 90 PSI. I feel that a bit of give is better than running at breaking point.

Update: Since putting the new Brompton brand tires on in early August, I've gotten 5 flats, 2 in front and 3 in back. All were from glass, and this despite the fact that I check my tires for glass shards every single day and make sure my tires are inflated before every ride. Philly streets are filthy (we call this city Philthy for a reason) and there is absolutely no way to avoid glass. It's in the bike lanes, it's in the streets pretty much everywhere but downtown where the streets are cleaned often. In response to Squiff, I have been inflating to 90psi instead of 100 for a while now, to see if that makes any difference. It hasn't, unfortunately.

In three years I have gone through:

-old generation stock Brompton tires (green stripe)
-Marathon Plus
-Kojaks
-back to Brompton tires

It just doesn't make any difference, I guess. I still don't get it. I have NEVER had this problem on another bike. Ever.

I guess I'll give tire liners a try, finally. I've avoided them because other than the account here, I have heard bad things about putting them on small wheels.

Let us know how you get on with liners. I'm intending to switch to the lightest tyre (probably Primo Comet) plus liner I can find on my rear wheel to save a bit of weight.

How about another route?

maybe Move House so you don't have to go thru that debris field.

I seem to get a lot of flats too, but fortunately (for me) not nearly as many as you do! I use 16" tires on my folder (not a Brompton) and have been running Schwalbe Marathon Racer tires. Since starting to communte in late summer I've had four flats.

1. Unknown but probably glass shard, on the way home from work with no tools (yeah, stupid, I know). Had to call my wife for a ride (oh, the humiliation!).
2. Unknown but probably glass shard, on my way to work . . . slow leak, just pumped it up several times, changed it during break time at work.
3. Installed Mr. Tuffy (brown) tire liners, went a month and half with no flats then . . . Glass shard for sure, sharp little mother, went right through the tire and the Mr. Tuffy! Changed in the dark on the way to work.
4. Nasty metal-working bolt, 1" x 1/16" with sharp pointy end and threads! Went into rear tire between sidewall and tread and I had to actually un-thread it to get it out! Destroyed tube (not patch-able). Changed tube (in the dark, pretty much) on the way to work and got going fairly quickly. When I got home I booted the tire, put it on the front wheel and switched the front (almost new looking) onto the rear.

And yes, I check my tires fairly often and have found numerous glass shards (plus two staples) before they did any lasting damage.

So . . . tire liners, do they help? Probably, but even if so, they can be defeated by evil glass, etc. I haven't had any flats caused by tire liners. I tried to sand down the edges but was unsuccessful . . . Mr.Tuffy's just laughed (metaphorically) at the sand paper. Maybe I need more aggressive sand paper?

Totals: Since 10/01/2011
Flat tires: 4 (all on rear tire)
Patchable tubes: 3
Way to Work flats: 3
Home from Work flats: 1

Streets of Los Angeles county, City of Norwalk/La Mirada/Whitter (mostly).

Rick / OCRR

Old thread, but wanted to reply. I'm pretty sure the reason you get so many flats is overinflation. Maximum pressure does not mean recommended pressure. Think about a basketball. If you pump it so full of air it gets hard and push a needle into it, it goes in quit easily. Imagine if you pumped it to 80% and pushed the needle in. The basketball will give a to more before the needle gets it.

Bicycle Quarterly has published a lot about this over the last few years. I used to get a lot of flats too. Ever since I started going with lower pressure, hardly ever.

I'm using Marathon Racer, seems to work well.

Generally running at 60-65psi unless its for good local roads and I'd pup them up to 80psi

When I first got my used B, I pumped the tires to 100psi and got a flat on the inside of the tube from a spoke or the hard rim strip inside.
I decided to fill in the rim channel with some foam tape over the rim strip add then cloth tape over that.
Problem seems to have gone away now.