Posted by: D_C_
Is it really possible to have a rubber that doesn’t harden in the cold?
The hardening might not be linear. They allude to this in that blurb when discussing DC tires.
Posted by: D_C_
Is it really possible to have a rubber that doesn’t harden in the cold?
Probably depends on your region and definition of cold. ;)
Schwalbe Addix, Conti Black Chili and Specialized Gripton all work fine in the tempereatures i usually ride in (-5°C to 30°C ). Maybe they harden a little bit, but not enough to notice on the trail.
Posted by: Timer
Posted by: D_C_
Is it really possible to have a rubber that doesn’t harden in the cold?Probably depends on your region and definition of cold. ;)
Schwalbe Addix, Conti Black Chili and Specialized Gripton all work fine in the tempereatures i usually ride in (-5°C to 30°C ). Maybe they harden a little bit, but not enough to notice on the trail.
Yeah I was more asking about the physics. Your observation sent me down the Google rabbit hole.
I am not a materials engineer so my understanding is likely limited, but from what I have read, polymers used in tires have a glass transition temperature, below which they harden substantially to a glass-like state. The glass transition temperature can be altered by additives in the rubber compound. Glass transition temperature is one of the big differences in rubber compound between summer and winter car tires.
This has some good info: https://blobs.continental-tires.com/www8/servlet/blob/1337344/bc8ce984d9236cdc11bf8b288a17c45d/2016-11-11-8-market-place-4-compounding-en-data.pdf
But one question I still have is whether it is possible to have a tire that is both softer and has a higher glass transition temperature, which appears to be the case with Maxxis Maxx Grip vs. Dual Compound.
I also came across a paper looking at mechanical properties of various rubber compounds. An interesting take-away, if I understand correctly, is that harder rubber generally has lower rebound speed. This lines up with some tire brands claiming that their tires, while not the softest, damp out more energy. http://docsdrive.com/pdfs/ansinet/jas/2010/1345-1348.pdf
Posted by: JBV
i asked Schwalbe about their tires. here is their response:
Thanks for the message. I’m actually glad you asked, we didn’t talk about it much but the temperature sensitivity of our old ‘star’ compounds (Pacestar, Trailstar, Vertstar) were highly temperature dependant. Our Addix compounds on the other hand are the most temperature stable compounds on the market, in fact as the temperature gets colder the advantage that Addix holds over other manufacturers rubber starts to widen substantially. There isn’t anything that comes close to an Ultra-Soft compound Magic Mary, Dirty Dan, or Big Betty in the sort of conditions you’re referring to. The Supergravity Ultra-Soft Magic Mary is the ultimate go-to at this time of year in the PNW.
That is great but I can never seem to wrap my head around their nomenclature when I am looking at there website. Is their 2.4 equal to a Maxxis 2.5? What are the casing types and what do the weight? Maxxis web sight is way easier to understand.
I’m back on Contis on my Chromag Rootdown for the winter, this time Der Baron front/Der Kaiser rear, and am thoroughly impressed. The grip on wet roots is in the same realm as the Assegai Maxx Grip I have on my full-suspension.
I was looking at Continental’s DH casing tires and they do a Der Kaiser and a Mud King, but no Der Baron. It looks like a lot of their pros run the Der Kaiser front and rear; it doesn’t seem like a tread pattern I’d choose for a front tire, given the close knob spacing. What’s the deal, do you think it would work well in front?
On my Six Pack, I went from 2.5 Syncros BHTs to 2.5 Kaisers (not Projekt) FR/RR to 2.75 Dirt Wizards
On my Blizzard, I went from 2.35 Kenda Excavators to first-generation 2.4 Barons FR/RR to 2.35 Magic Mary/Nobby Nic
On my Slayer, I'm currently running 2.5 Butcher SXs for pedally days to save a little weight and Kaisers FR/RR for occasional park/shuttle days
On my ETSX, I went from Trail Kings to Excavators to Baron Projekts
Kaiser FR/RR is my favourite tire out of those listed above for every condition I've ridden with them: dusty summer to damp winter. The only reason I don't run them on everything all the time is that the 2.5 steel bead is a little heavier than I'd like for long rides and I can't fit a 2.5 on my "smaller" bikes.
A 2.35 MM only lasted one ride on the Blizzard before it started to buzz the chainstays continuously and I had to step down to the NN. I don't like the NNs, but the 2.4 Baron Projekts are a little smaller a casing than I want on the HT. I'm still thinking of going back to the Baron Projekt on the rear though.
Sounds like quit a stable, how do keep up with all that rubber?
Posted by: FLATCH
Sounds like quit a stable, how do keep up with all that rubber?
The history listed does go back over a dozen years, so it's not like I'm swapping tires all the time.
But...since it's all 26, I do have a huge hoard of rubber bought as each tire I like went to ultra-clearance in case the opportunity didn't present itself again. I think I'm down to my last spare Butcher, so once that's worn out, the Slayer will probably go to Kaisers full time (got at least 4 of them that have never been mounted!)
Just bought an Exo+ casing tire. Impressed! Feels robust and weight was 10g less than advertised. 120tpi label made me nervous, but they've pulled off some successful rubber voodoo. 🧙♂️
Posted by: JBV
Posted by: FLATCH
Sounds like quit a stable, how do keep up with all that rubber?
no doubt! just mounted a WTB Verdict high grip tough with a Tannus tubeless and i can't wait to ride, but feel like i should maybe be thinking about an ark instead.
Please post back with thoughts. I switched to a Verdict judge combo and I am really impressed with the traction in soft soil and wet conditions. I find the Verdict has a bit less grip on rock then my previous combo but a bit more grip in the conditions above.
Posted by: WeTYC...
Kaiser FR/RR is my favourite tire out of those listed above for every condition I've ridden with them: dusty summer to damp winter. The only reason I don't run them on everything all the time is that the 2.5 steel bead is a little heavier than I'd like for long rides and I can't fit a 2.5 on my "smaller" bikes.
Do you think Kaiser f/r rolls better than baron/Kaiser?
I have baron/Kaiser and they are so awesome on greasy roots and such and the casings have a great level of support, but I worry they will be overkill for summer so thinking about a slightly quicker version for summer. Maybe a trail king out back or something.
Posted by: Kenny
Do you think Kaiser f/r rolls better than baron/Kaiser?
I have baron/Kaiser and they are so awesome on greasy roots and such and the casings have a great level of support, but I worry they will be overkill for summer so thinking about a slightly quicker version for summer. Maybe a trail king out back or something.
Unfortunately even with all the combinations and permutations of bikes and Conti's I've ridden, I've never ridden the same size of Barons and/or Kaisers on the same bike. The Barons have only ever been on my more "efficient" bikes. Even though I don't have a direct comparison, I think the 2.5 Kaisers roll easier than the 2.4 Baron Projekts. To further devalue my opinion though, I'm not the most sensitive to rolling resistance. If I could get a 2.35 Smoke, I'd probably run them front and rear!
One thing I do though is try to install new tires in the fall then run them through the summer so the knobs are a little more worn down and easier rolling for the longer summer rides. Although I don't usually use a tire until it's a slick--maybe 50% worn at most?
Posted by: WeTYC...
Unfortunately even with all the combinations and permutations of bikes and Conti's I've ridden, I've never ridden the same size of Barons and/or Kaisers on the same bike. The Barons have only ever been on my more "efficient" bikes. Even though I don't have a direct comparison, I think the 2.5 Kaisers roll easier than the 2.4 Baron Projekts. To further devalue my opinion though, I'm not the most sensitive to rolling resistance. If I could get a 2.35 Smoke, I'd probably run them front and rear!
One thing I do though is try to install new tires in the fall then run them through the summer so the knobs are a little more worn down and easier rolling for the longer summer rides. Although I don't usually use a tire until it's a slick--maybe 50% worn at most?
The 2.4 Kaiser Projekt Protection Apex looks like a very different tyre than the 2.5 Kaiser Apex (26"). Different thread, different casing and probably different rubber. The former is advertised with a fast wearing competition compound, the latter as hard wearing, fast rolling.
Posted by: Timer
The 2.4 Kaiser Projekt Protection Apex looks like a very different tyre than the 2.5 Kaiser Apex (26"). Different thread, different casing and probably different rubber. The former is advertised with a fast wearing competition compound, the latter as hard wearing, fast rolling.
The Projekts are definitely less aggressive than the original DH versions, but I don't think they're night-and-day different. From L-R: 26x2.5 Kaiser, 27.5x2.4 Kaiser Project, 27x2.4 Baron Projekt. I think the narrowest more square knobs every 4th location on the 26 Kaiser will make it much more aggressive and slower rolling. I also think that even though the pictures below make the knob height look the same between the two Kaisers, in reality, the Projekt knobs are shorter.
The Kaiser Projekt's knob spacing is also tighter than the other two which should give lower rolling resistance.
So if the "worst-case" 26 Kaiser has less rolling resistance than the Baron Project, the Kaiser Projekt definitely should.
One question mark though is the compound. I'd always though that black chili was black chili, but it looks like you're right and they do fiddle the compound a little from one tire to the next. Now I'm curious if there's someone out there with durometer measurements for the various tires...
Posted by: WeTYC...
One question mark though is the compound. I'd always though that black chili was black chili, but it looks like you're right and they do fiddle the compound a little from one tire to the next. Now I'm curious if there's someone out there with durometer measurements for the various tires...
Your arguments concerning the different thread patterns make a lot of sense. Rubber is a big issue, though. Judging from Maxxterra and Maxxgrip, compound makes a huge difference in rolling speed. Annoyingly, Black Chili is more of an umbrella term for their rubber technology. Similar to "Addix" for Schwalbe or "Gripton" for Specialized. They make everything from road tires to DH mud spikes in black chili.
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