Tire chat (nerds only)

For what it's worth, totally scientific. On my old dh bike with an ohlins TTX if I did a top to bottom run of cannonball in thredbo the res would be so hot you couldn't touch it, not quite rotor hot, but hot enough.

Yeah on a 30 degree day at the end of a long run 4:30 plus my shock is hard to touch. 

Rock shox did a lot of temperature data logging. WC riders on WC courses and 160C is not realistic…

160C would be melting rubber parts inside the shock, stickers melting off etc  

I think normal people are getting shocks 50f above ambient on a long run  

60°C on metal is the temperature where things are getting hard to touch. Pulling parts out from my ultrasonic cleaner cleaned at 60°, I throw them away after ~5 seconds. At 80°C you're not touching it.

The 50 f above ambient that Dave mentions is 60-ish °C in a 30°C weather.

Yeah I was going to say the same thing, pulling parts out of the US fare way too hot to handle! It's mostly due to the aluminium bodies of shocks - its a great conductor so will feel much hotter than something which is steel or plastic. 

I also regularly do warm up runs on the dyno to test heating and it typically takes 1.5 minutes at a sustained high speed with zero cooling to reach 60 degrees in a lot of cases. Anything over 40 feels super hot and 60 needs a minute before I can take it out of the dyno. Dampers typically reach a steady state in use where the cooling matches the heating so it would need an insane level of non-stop punishment to exceeed that rate

Or being packaged inside a frame for example... 

for the curious:

https://www.mcmaster.com/product/5951K41

Considering you're here (I meant to ask it in the kinematics thread), how much does the shock heat up from the damping circuit and how much from the spring? Does the spring even warm up during a run?

Edit for clarity: does the spring heat up by itself or is it warmed up by the damper getting warm. Of course it warms up when talking about the shocks, my question is where does the heat come from actually. 

In a 2 min run. My comp adjuster bridge was the hottest part and the rest just warming a bit. So the valving in there gets the oil cooking and not much surface area to spread it out. 

All damper generating the heat. A loooong time ago we made separate air spring and damper and mounted it on a bike (when I worked at trek).  We had a flir camera to verify.  Spring is making almost no heat and has massive aluminum surface area to dissipate thru.

yeah back to tires.  I flatted yesterday and the Stan’s dart tool didn’t work.  Had to shove that thru the hole and use a car plug.  

Too bad to hear about the Stans Dart. Was it a irregular hole/shape? Bacon strips are alright, but I've always had the best luck with Dynaplugs. I also like that after you cut off the metal head you can heat up the plug and deform it into the casing.

I’ve been able to fix a few larger holes with Stan’s darts, and had them hold up for the life of the tire. But are there other plugs that are more reliable? Do yall carry multiple types on the bike?

Are people still running inserts? I have loved Cushcore but understand it can be a big trade off with weight and the need to somehow put in a tube if you’re in the middle of nowhere. @Dave_Camp were you running TWO Cushcores in the back at one time or am I making that up?!

I’ve had good luck with car plugs. But for a permanent fix in the tread area you need to either glue it in with shoe goo or tie a knot in it and install from the inside once you limp it home.  Otherwise they get pulled back out by skidding. 
 

never ran 2 cushcores in one tire haha.  I’ve experimented with some weird DIY inserts from Home Depot.  Also when running an insert- if I flat I’m riding the flat back unless it’s in an enduro race or 5+ miles. 

I have two types of plugs with me, a set of automotive ones (cut down to size, roughly in half) and a set of thin ones (bought mistakenly). Usually the big ones are what's needed anyway.

These appear to be the thin ones off AliExpress (plug only with most orders): https://vi.aliexpress.com/item/1005004687308483.html

And these are the thick, automotive ones (again most orders, plugs only): https://vi.aliexpress.com/item/1005004799685466.html

As for fixing it long term, patch it up. I use Rema Tip Top patches with blue backing (used for tubeless repairs) which work really well - I've rarely had a tyre go through the complete tread without patching it up, mostly it's the front tyres.

As for insert, yes to them. I run them exclusively for puncture and rim protection, it's not about ride feel. Since I've started running inserts the amount of flats in the rear has dropped massively to hardly any.

Has anyone tried dissector 29” 2.4 EXO+ max Terra rear dhr ll 29” 2.4 EXO+ front combo? 

Yes, I quite like that set up for the summer on my enduro bike. The Dissector rolls noticeably faster than the DHR II while still braking quite well. I will say the Dissector side knobs do have a tendency to undercut quicker compared to the DHR, so that is something to consider. 

I'm a big fan of the DHR up front and it's what I run 80% of the time. Dual DHR is my go-to setup for the winter. 

Agree about the dissector. Rolls well, but 3c MaxxTerra in SW CO wears out very quickly in the rear.  
 

Specialized Eliminator T7 Grid Trail on the other hand, lasts really well and seems to roll pretty well in the rear. 

Thanks I’ll give that a look 

Which would have less rolling resistance as a rear tire, DHRII DH MaxxTerra or Dissector DH MaxxGrip?  Ideally I’d run a Dissector DH MaxTerra, but it doesn’t exist. I usually run Assegai DH Maxxgrip front with DHRII DH MaxxTerra rear for Whistler.  I’d like to run a Dissector in the back this year but don’t want much more rolling resistance if the MaxxGrip compound in the Dissector is going to make a big difference. 

Softer compound is always going to roll slower than a harder compound, regardless of tread pattern, unless you're comparing extreme treads like a mudspike vs. a semi-slick. Compound makes more of a difference on grip than tread pattern, too. For instance, for a front tire, I'd rather have any Maxxis tread in a MaxxGrip compound than my favorite in a MaxxTerra. I think tread patterns are kinda overrated compared to the impact of casing, compound, and air pressure. Not that treads don't matter at all, but they're definitely less important than the other three.

MaxxGrip Dissector as a rear tire is going to last for 5 days at best in Whistler.  

I ran one last year- a few days of trail riding, 3 days of lift riding and it was pretty much cooked.

I'd keep running the MaxTerra DHRII rears.  OR I had very good luck with a Specialized T9 Butcher Grid Gravity as a rear tire.  Seems to be in-between MaxxTerra and MaxxGrip in terms of compound and more durable than either.

Make sense. Looks like I’ll stick with old faithful. Appreciate the feedback. 

I had a DHR / Dissector combo for a bit and that was my main issue in SW Colorado (rocky, hard pack).  Last fall I put on a WTB Trail Boss 2.4 fast rolling and been liking it for that type of terrain.  When I get to high country I'll still prefer a DHR maxterra in the rear for my riding. 

Sorry for the newbie question.

Running a 2023 Trek Slash  - im about 230 lbs.  Riding in New Zealand ( Chch so its a bit rutted and not sooth like rotorua )..  Bike new has stock bontrager tyres.  Plan to put in some cush core front and back given the rockiness.

Old slash has Aggesai Evo+ Maxx Grip 29x2.5 , DHR DD 29X2.40WT Maxx Terra on the rear.  Supposedly the bike supports 2.5 wide.

Have been looking at other brands and looking for recommendations, mate has Spesh 2.6x29 T7/T9 Gravity Grid Eliminator + Butcher T9 2.6x29 Trail Grid on their spesh bike.  the 2.6 don't seem to be much larger than the 2.5 maxxis.  anyone run these on a slash?>

Anyways just looking for other suggestions, id like lots of grip in the front tyre.  Still just an intermediate rider this trail is a particular fav 

https://christchurchadventurepark.com/trail-information/trail-previews/…

https://christchurchadventurepark.com/trail-information/trail-previews/…

How did you find the exo+/DD casings of the maxxis tyres? ie squirming, punctures and what kind of pressure did you run?

A 2.5" tyre should be fine - most modern bikes are fine with that and I think the extra volume will be good as well. 

The key things are casing &  width - I feel like Double down is often the minimum for a lot of people, and its proportional to rider weight so I would be looking for tyres that are at least equivalent to that. 

Specialized tyres seem to mostly have awful thin casings - I don't know if that has changed recently but I struggle to think of anyone who rates them highly. Obviously they have options but its not one I see people choosing to buy

I've always like Schwalbe a lot - their casing and rubber is great, the new Continentals seem really good as well and suited to agressive terrain/riding from what I've seen although I've not ridden them personally

Agree with everything the last poster said. I'll add that, if you're curious about whether the 2.6" Specialized tires will fit in the same space that a Maxxis tire fits, the best point of comparison is the ETRTO dimensions on the side of the tire. It should be a number like 622x63 or something. 622 is the bead seat diameter (correlates to wheel size) and 63 is the actual tire width.

These numbers are harder to find on the internet but they're a hundred times more accurate than the nominal sizing that the manufacturer lists (2.3", 2.4", etc) because they're actually inflated and measured on the same rims and at the same pressure by the European Rim and Tire Technical Organization (aka ERTRO). According to my googling, the Eliminator is a 66mm wide tire and the Maxxis 2.4" is 61mm wide according to ERTRO.

heya, i see you are in NZ aswell, the redwoods are a lovely place to ride .. jealous.. 

Would you have any recommendations in the  schwalbe . conti range which are equivalent to the say the DHR2 and Assegai in these ranges?  or i guess the butcher and eliminator.  what im after i guess is traction on the front tire, i was running DHF but found that with less transition knobs id feel a bit uncertain on the concerning, the assegai feel better.  im still learning, so feeling comfortable and safe on the bike, i do run double down on the rear currently with cushcore front and back, as im either on a analogue 29er or ebike .. weight is less the concern given im 105 kg in our scale.  with the spesh tires it was the gravity grid ( which i think are like DD level tires on the rear and trail grid more like exo+ i think).  i was looking at a DH option for the rear but that might be overkill.

also @TEAMROBOT thanks for the measurements information that's super helpful