puppypilgrim

I just switched 20x1.5 (406mm-40) Schwalbe Marathon Racers to 20x1.35 (406mm-36) Schwalbe Kojaks tonight. Used the same tubes which had 20x1.5/1.75 imprinted on them. They fit fine.

These were mounted on my Dahon Helios modified into a 73 gear inch singlespeed here:
https://www.bikeforums.net/folding-bikes/537715-dahon-helios-short-bullhorns.html

The Kojaks are:

1. Quieter. I noticed this immediately as the Marathon Racers generated a whirring sound from the contact patch. The Kojaks in contrast are almost totally silent! Since the noise floor has been lowered, the chain's sound feels elevated and so does the Dahon's creaks and squeaks.

2. Faster. Much faster. The Kojaks accelerate unbelievably fast from a standstill and what is more surprising, accelerates even faster when stepping on it hard from a cruising speed. I was spinning out at 73 gear inches into a headwind during the test ride tonight. Very surprising as I did not expect this result at all.

3. More stable while cornering. Perhaps it was unique to me but my Marathon Racers felt squirmy when cornering. It felt almost as if the block of tread would move around when leaning into a turn. This also happened in a straightline when the tire went over a pebble. Squirmy is the best way to describe it.

The Kojaks in contrast, felt like a solid piece of rubber glued to the wheel. It was stable and grabbed the asphalt without any concern. Out-of-the-saddle acceleration was also more responsive with the Kojaks.

4. More comfortable. This is counter-intuitive but the Kojaks at 92 psi are more comfortable than the Marathon Racers at 85 psi. I don't understand why. It must have something to do with the bead and carcass construction between the two tires. I don't think I am imagining this as I have a sensitivity to small changes in my physical senses (often a curse not a blessing). The ones on my bike are wire beads (as opposed to folding beads which are lighter and more expensive).


In short, the Kojaks are definitely here to stay and I recommend it to anyone looking to improve the performance of their bike. The rolling resistance of the Kojaks are much lower than the Marathon Racers - how much quantitatively, I cannot say. Except to say it real and the results of switching are spectacular!

Victor in Vancouver, Canada

PS - Here is another review of the Kojaks for ease of reference:
https://www.bikeforums.net/folding-bikes/540899-just-fitted-pair-schwalbe-kojaks-my-brompton.html

longlong14

nice review...i wonder how the kojaks compare to greenspeed scorchers...
are these puncture resistant?

PDR

.... well I ran with Kojaks for a year on my Dahon MU SL, through glass, thorns and other street debris without a single puncture. Really like them so I have also fitted a set to my Brompton.

It is good to see that Len Rubin (UFB ) see the “ Super Brompton” post says that “I have replaced them with the Schwalbe Kojak, which is my favorite tire these days!”

puppypilgrim

Greenspeed Scorchers have also been reviewed very well too. Forum member VIK has them on his Bike Friday NWT. Perhaps someone who has ridden both on the same bicycle can chime in comparing the Scorchers and Kojaks.

The Kojaks have RaceGuard (Schwalbe's puncture resistant technology) built in.
https://www.schwalbetires.com/kojak

Here's a pic:

puppypilgrim

Len's comment was one of the reasons I opted to try the Kojaks as well. I figured someone who is as anal as Len over small-wheeled bikes must know what he is talking about when he endorses a tire.

longlong14

searched around a bit, i found that the max pressure for these tires is 115 psi
they must have super low rolling resistance, how could they be as comfortable as the marathons at such a higher pressure and not to mention they are much skinnier?
i'll get either these or the scorchers for my r20 & brommie, it's nice to know they are comfortable since the scorchers probly won't fit into the rear frame of a brommie.

BruceMetras

Here's my Strida-like running Alex DA16 ERTO 355's shod with Kojaks .. big improvement over ERTO 305 1.95 Maxxis Hookworms that they replaced.. although not quite the footprint of the 1.95s..

feijai

I too am wondering about the Kojak, but for a different reason: I'm looking for a comfier tire than the default Marathon in 349. I'd been eyeing the Scorchers, which are 40-349 vs. Kojak's 32-349 (and Marathon's 37-349), and have a reputation for comfyness (comfitude? comf?) while still being pretty fast -- heavy (280g) but with an unusually low rolling resistance (meaning they're probably thin and will wear out quickly).

So anyway: cushiness plus speed would be a nice combo. How do you think the Kojaks compare to the Scorchers in this regard?

BTW, I am also concerned about possible cornering ability on the Scorchers (I have no data one way or the other there, except that they were designed specifically as trike tires, and trikes don't lean). Any data there? Nothing to worry about?

invisiblehand

The Scorchers have been around a while and have gotten reviews across the spectrum. If my memory is correct, James_Swift tried them on his Xootr Swiftfolder many moons ago. I can't recall whether it is in the monster swift folder thread or if it had its own thread. That is the first one that I recall. In the end, I thought he switched back to Primo Comets ... but it was a long time ago so my memory is pretty fuzzy.

puppypilgrim

Kojak: https://www.schwalbetires.com/kojak

Marathon Racers: https://www.schwalbetires.com/marathon_racer



The max PSI for 20x1.35 is 95 not 115. 115 is for 16" and 18" tires.

If you look at the grey box product summary at the top of each tires model on the schwalbe website, they both present the same with one critical difference. The Kojak in 20x1.35 weighs 285g (wire bead) and the Marathon Racer weighs 330g (wire bead). This is 45 grams per tire. I don't know where the threshold for human perception is, but I can feel a performance difference between the two. I suspect the differences is not only due to the 45 gram weight difference but its a case where the whole is greater than the sum of the parts. On paper, they both look to be equal (according to the grey box summary).

I cannot explain why the Kojaks would feel more comfortable at a higher PSI (I tried mine at 92 PSI) than the Marathon Racer. Perhaps someone more knowledgeable might know. I do however maintain that the switch for me only improved my experience with no compromise thus far. Looking forward to putting more miles on it though. It is MUCH quieter than the Marathon Racers.

The carcass construction of the Kojaks must also be different than the Marathon Racers yielding a different feel under load.

Sammyboy

Oooh, have been planning regular Marathons for my drop-bar Downtube IXFS, but this could tempt me instead.....

feijai

Archived here and here. It looks like pm124 hated them; kept getting glass in 'em. Thing is, I can't find any other negative reviews.

puppypilgrim

Just measured the rolling diameter of the driven wheel with the Kojaks on. The Kojaks are 0.25" smaller in diameter compared to the Marathon Racers.

In my setup, this changes the effective gear inch from 73 to 72 inches.

PDR

Kojaks are grip very well: https://www.thorusa.com/images/dahon/...s/tiretest.jpg
Photo from thorusa’s site.

DLW

I'd have preferred Kojaks for our two Speed Pros, but they're not available. The only compromise was Marathons since the LBS said they couldn't get Kojaks. (Yes, they had MuSL with Kojaks on display.)

Tire and bike feedback is very helpful, especially for those without local access to total parts and dedicated dealers. The LBS has a good selection of bikes, but few parts, and minimal on-bike experience for meaningful support.

Are there any others in China with supportive, well-equipped shops?

jdmitch

um... wow...

invisiblehand

I don't recall purely negative reviews but there were definitely more neutral and "less positive" reviews than Alex and Vik's reviews.

I am not out to "poo-poo" the Scorcher. For instance, I like the Avocet Fastgrip 20x1.75 tire and, simply based on the description, one would think that the Scorchers are similar. But given some of the comments I read lately, I thought that it would be helpful to put them in a better context.

feijai

Since I have different needs than this guy, I'm starting a new thread so as not to pollute this one.