avole

Took the Brompton up to Paris last week to get visas, vaccinations and all the usual sort of pre-trip things you need to do.

Lovely weather, and I enjoyed re-discovering all my old haunts. Also good to see more bicycles on the road and on the bicycle paths, of which there are quite a few. Nice to be reminded of logic at work, too: several bike lanes run beside parked cars, but separated by a metre of no go zone so theoretically less chance of smashing into an incautiously opened car door. There's even a point on the canal Saint Martin where you can fill up your water bottles with proudly advertised genuine Paris water, although how much of a plus that is I don't know. Hard to very hard water, as I learnt quickly when living there. On la butte in Montmartre, however, while there are still cycle lanes, it's all cobblestones and narrow one way streets, where you are expected to travel in the opposite direction to the other traffic.

I'm used to Paris traffic so even when heading across Bastille and Place d'Italie I wasn't too concerned. A lot of bus lanes are shared with bicycles, and many bus drivers give you a warning toot to let you know they are behind and about to pass; which is a nice thought. In fact, the only problem I had with traffic was on the Saint Martin paths, where, it being Sunday, the boy racers were out and passing people on the left and the right, so it pays to stick as close to the right as possible. Far less pedestrians on the paths these days, which is a definite plus.

Anyway, back to the Brompton with my newly fitted kojaks. The path that runs down from Place de Clichy along the Boulevard dse Batignolles is one of the better ones, although criss crossed by streets the larger of which have bike traffic lights. The smallers ones do not, so normal give way rules apply. The paths are smooth, so you can build up a decent head of steam, which was exactly what I was doing, heading back to my lodgings and to pick up my gear thence to the station. The kojaks had had a fair workout, and, to be honest, running them at 100 psi , felt more lively and faster than the Marathons I've always used. It was while I was crossing a smaller street going at a fair lick that, on jumping up the kerb, I felt that awful flat feeling coming from the rear of a sudden puncture. This has always been a slight worry of mine, and, sure enough, it was vindicated.No question of doing a repair there, and, for once, I'd left the spare inner tubes at home. Not a problem, because in Paris you are never far from a bus or metro, so I folded the bike and headed back on the metro.

The repair is a lot easier with the Kojaks simply because they are so much easier to take off and put back on. The puncture was the classic pinhole, just on the point where the reinforcement stops. Couldn't see anything on the tyre, but it has got me thinking. Those sidewalls look really flimsy, and the kojaks have a reputation for puncturing easily. Because of their performance I was going to replace the tyres on the Neo with Kojaks for the upcoming trip in Cambodia, and have indeed bought a couple for that purpose. If kojaks really puncture that easily, I'll sacrifice performance and go for plan B, which involves my spare Marathon pluses. Hell to fit, but there's no point asking for trouble.

berlinonaut

I'd make the choice dependent from the the roads you are facing. No doubt that Marathon and Marathon+ are far less prone to punctures than the Kojak and you are absolutely right with your observation of the sidewalls being a weak point. But I've done a fair bit of touring on the Kojaks w/o issues. When doing a longer trip with them I usually take two or three spare tubes with me, quickly change them on site in case of a puncture and repair the defective one in the evening. Has not been necessary very often. But sometimes it happens - I had once two punctures with the Kojak on a single trip in less than maybe 30kms.

The more important thing is: The Kojak fun is dependent from smooth roads. The smoother the road the bigger the fun. Bumpy roads a not much fun due to more pressure in the Kojaks than in the Marathons (at least with me) and you have no speed advantage there anyway. Unpaved roads slow them down massively. The lack of profile makes them useless quickly if you manage to leave the pavement and end up in muddy terrain. Also wet rails are something to avoid at any cost. The sidewalls become an issue if you follow "natural paths" where thorns may live. So the livelyness of the Kojak has it's price.

Occasional punctures may occur but - as you said - are not much of an issue with the Kojaks plus they occur more rarely than rumors say. On longer tours I even tend to take a spare Kojak with me (folding version) in case that the **** hits the fan but until now never needed it.

avole

That's a good thought, I might take a Kojak as a spare. Last time round took a Marathon as a spare and never needed to use it. The problem isn't Thailand, it's the roads in Cambodia close to Tonle Sap. They should be dry and dusty, unless there's been late rain - I think I'll play it safe and go with the Marathons for Cambodia.

fietsbob

One issue with marathon plus, is they did not reduce the casing width/height
when adding the thick puncture protective band, it displaces the black tread rubber thickness..

so you wear through it .. and because a smaller tire
rolls more often per mile, than a bigger wheel,

the wear life is proportionally shorter..

linberl

Still running my kojaks on my BF that I put on last August, no punctures. But I run them at 85-90 psi. Maybe the higher pressure is less forgiving? I don't run slime tubes in mine, but they do work great on pinhole punctures based on my experience with them on 700c tires. If you can deal with the occasional bit of mess, they might add a little protection for you.

berlinonaut

I am running mine w/o a puncture for more than a year now, roughly about 2000km minimum, maybe more. It is the very same pair that faced two punctures in 30 kms in last June. Im am running them with 7bar minimum and 7,5 Bar normally, so far more than you do.

Punctures that we face individually are typically not statistically relevant but randomly distributed. Over all the years that I've been running Kojaks I'd guess I had 6-10 punctures. Sometimes one a week, sometimes twice a day and then not a single one for a year or more. Just random distribution. Still I'd say more often than with a Marathon or a fresh Brompton Kevelar.

linberl

Personally, I believe in the Flat Fairy. Mine have all come in clumps, within a one or two week period. Same for my son...4 in two weeks and none now for months. The locations I ride I can literally hear the tires fling off glass and metal bits where my Marathons always grabbed them so they worked through the protective layer. Statistically significant or not, I am super happy with them for ride quality as well as lack of flats.

berlinonaut

Maybe it is worth mentioning a best practice with the Kojak: The tire has to mature. Here in Germany when I buy Kojaks in 349 (and often in other sizes as well) the tires seem to come more or less freshly from the factory most of the time. The means it is pretty sticky on it's surface. This is good for grip but unfortunately also good for punctures as the tire collects dirt and stuff. Therefore I put the tire on a cupboard for at least six months before using it to get rid of the chemicals from production. This lowers the risc of puncture massively as after that time it collects far less. I do not know how this is in other countries - Schwalbe is a German brand and though the tires are produced in Indonesia their central warehouse may be in Germany - do not know. So it may be a local German problem only that does not happen in other countries. It is clearly a Kojak problem as well - never faced it with other tires, no matter which brand.

linberl

I can't remember if mine were sticky initially; will have to pay attention when I replace them. I have heard the folding ones are better at flat protection, don't know if that is true, but I will be buying folding ones next due to the lower weight.

berlinonaut

I've had punctures with the folding ones as well. As far as I can judge they seem to be equal in that respect and behaves similar in other aspects as well. Problem is that the folding Kojak in 349 is only available through Brompton at a almost three times the price of the non-folding one. To me not worth the extra money. I am therefor running the non-folding version on my bike and have a folding one with me as a spare tire sometimes as it is easier to pack.

linberl

Oh, well, I guess as long as they are no worse it's good enough for me. I carry my bike A LOT and the folding tire weight will drop the bike weight from 19.25 lbs by almost half a pound. That makes a differerence to me. Can often find them only about twice the price on sale here if one is patient.

berlinonaut

No, they do not seem to be worse. I'd assume the main difference is foldable material (kevelar?) instead of the wires of the non folding version in the ring to keep the tire on the rim. However: The folding Kojak is listed with 185g (sometimes 175g), the non-folding version with 230g per tire. So the difference between the two is 110 - 130g for a pair.

linberl

Ahh, you are right about the weight, I forgot the weight savings included my lighter rear der that I installed. Combined grams work, too =).

berlinonaut

I should stop writing about the Kojak. Literally each time I do it I get a puncture shortly after. So the god of punctures punished me today, on the rear wheel, as usual. This means a 15-16 months since the last puncture with the Kojak. Clearly within tolerance but obviously still annoying.

avole

On the other hand, berlinonaut, i went back to Paris and did the same trip, with extra bits added over cobblestones, and, gess what? The Kojaks were not only great to cycle on over the worst surfaces, if a bit bone-shaking, but also were puncture free. Next and final trip is on the weekend, so will see what happens. At present, I'm a Kojak convert

linberl

Oh, dude, you should NOT have said that, lol. Now the flat fairy is gonna come after you....