DH tires on a hardtail?
Hey Lee,
I’d been riding Specialized Chunders and Maxxis Minions on my freeride bike and absolutely love the DH/freeride treads for their cornering and braking/driving strength. However, due to some financial issues, I’ve recently had to switch back to my hardtail with Specialized Resolution tires. Since the switch, I’ve been more shaky in the
corners and more prone to skidding while braking. Would it be feasible to mount some beefier tires on a hardtail? Or should I just learn to ride the Resolutions (and save the $$ for the next big bike)?
Thank you,
Matt
P.S. Congrats on the twins!
Hey Matt,
Thoughts:
– A hardtail will always be sketchier than a freeride bike. But it’ll also be quicker and more nimble. They are different animals. Celebrate your hardtail’s hardtailness!
– Skidding while braking? That sounds like a technique issue that was masked by long-travel suspension and sticky tires. Read: I feel sketchy and want better brakes
– Yes, you can rock some beefier tires. Your hardtail will probably fit 2.3s.
– Burlier tires will make your bike stickier and more forgiving, but: 1) They won’t change the fact it’s a hardtail and 2) They won’t completely mask poor technique.
 After several years of too-serious DH racing (and a major concussion), my GSR Raige reconnected me with the love of riding. GSR downhill bikes were way ahead of their time. www.gsrbikes.com |
– Back in the day, I ran Tioga Factory DH tires on my ultra-light, ultra-sweet 2000 GSR Raige steel hardtail. I was coming off a Foes Weasel (6″ f/r), and the bigger meats helped me ride the hardtail with more confidence. I had no idea back then, but I was a technically awful rider.
– These days, I spend a lot of time on a P.bike, and, while I’ve experimented with every tire you can imagine, I keep coming back to XC trail tires. Their lightness and quickness match the characteristics of the bike. And, as long as I’m smart and smooth, they provide all the traction I need. The Resolution is a darn good all-around tire.
In summary:
– If burlier tires give you confidence, then I say rock ’em. Rather than going full DH, consider more of an all mountain tire like an Eskar. I rock Eskar 2.3 Controls on my Stumpy, and they have a great combo of speed/traction/durability.
– Whichever tires you rock, get in tune with that hardtail. Appreciate, celebrate and Rock it’s sublime hardtailness. When you get your next big bike, you’ll be that much better.
Braaap!
— Lee
PS: Thanks re: the Twins. They are making their mom sick! And not sick as in, “dude, that was siiiiiiick!!!” More like, dude my wife is sick. Hopefully it’ll pass soon.
Know more. Have more fun!
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Matt,
I have a set of spesh chunders on craigs list for 30 bucks.
They have about five miles on them.
Lee
That link to old post was a trip down memory lane! It was the only time your site ever sounded like the real Internet…
Posters’ tempers flaring (over avid brakes no less) some he said she said, and the famous “forum closed” at the end. Classic!
But I love your reply: “got $ to spend? Buy a mtb skill book and ride your bike.”
Razor sharp and dead on.
btw: matt, I run 2.2 front/2.0 rear spesh enduros on my Raleigh htail. 🙂
Thanks for the advice! I think I’ll stick with the resolutions.
I think the skidding is due to me being used to my old setup. I’m using the same hydro brakes as before and I’m trying to stop how I used to. I think the combination of a less sticky tire and less less aggressive tread will take some getting used to. With my previous setup and proper technique (thank you, MMBS), I don’t recall ever locking up my front wheel while braking. I’ll have to get used to the new setup for sure.
$30 chunders sounds tempting! Not sure what I’d do with them for now through.
Use them for your freeride bike.
Lee suggested the eskar which makes a great trail tire it corners well and has big flat edges for braking. Might want to look into that for your hardtail.
Personally, I rocked 2.35 DH tires on my hardtail, cheapest performance boosting switch i made… ran them nice and soft and that thing climbed like a mountain goat(more meat on the ground=more force transmitted.) The DHs also took the edge of the smaller bumps and helped me to float over sandy sections.
So… yes it’s heavier, if you run them you’ll lose some “snap”. Tires aside you have to keep the rubber firmly planted if you want to rail it and i think that is what Lee is sayin about different techniques for different bikes.
This is in response to not only this thread but also the “I feel sketchy and I want better brakes” thread that is linked. So if it looks like my post is out of place, it’s probably addressing the linked thread.
Caveat: my knowledge comes from auto racing, but is just as applicable.
I’m inclined to say that if you can lock up the wheels at will then the problem is with the pilot (assuming consistency/fading is not an issue). At a time, I was 220 and just about any set of V-brakes I rode had more than adequate power, it was just the fading/consistency that made me go hydro discs.
What most people think is that bigger badder brakes = bigger stopping power. True to an extent, but assuming the brakes can lock the wheel, the vehicle’s braking capability is primarily determined by the traction of the tires. You can’t slow down any faster than what the tires are capable of. Even if you threw on your bike brakes that can stop a 1500 lb. vehicle traveling 200mph at the drop of a time, the tires would still be the weakest link.
In auto racing, they call using 100% of your tires traction for braking threshold braking. If you truly are threshold braking, you cannot slow down any faster. Also you can’t turn anymore because all your traction is used up on one axis and any attempt to turn would just cause the vehicle to plow straight.
Although there are many factors that determine where exactly the threshold is (tire, track condition, temp. etc…), a rule of thumb is that the tire is rotating at a ratio of about 0.85:1 relative to the ground (generally it’s right before wheel lockup). Any lower ratio (more braking pressure), would actually cause you to exceed the available traction and overall traction would drop (tires would lock and things not to your liking would happen).
A rule of thumb for the traction decrease when you lock the wheels is about 30% (same goes for travelling at large slip angles aka drifting, which is why it’s so slow).
Of course I’m talking road surfaces here, for dirt, I would intuit that the numbers would be a little more extreme but still follow the same concepts.
My guess as to your problem:
Suspension increases traction for obvious reasons and thus braking power, when you made the switch to the hardtail, all that extra traction from the suspension and beefy tires dissapeared and now you find yourself skidding everywhere.
Solution:
You were probably not using the full braking capabilities of your suspended bike so you never had to worry about modulating. Now that traction is lower, you find yourself at the limit much more often, time to work on your kung fu as Lee stated. Traction is never static it changes with the terrain, the surface texture, temperature and a multitude of other factors.
Threshold braking entails modulating the brakes so you’re using up all the available traction while the traction is constantly changing. Tough I know, but it’s something that all competent race car drivers do, and probably world cup dh racers whether they are conscious of it or not.
On a bike though you keep track of two wheels independently; in a racecar, you got one brake pedal, and a knob for brake bias, so it’s easier in the car (of course in competition it really isn’t easier because since it is inherently easier relative to bikes, everyone will be better at it and it will require much higher levels of precision to beat the guy trying to out brake you).
After tons of practice (and I mean tons), you get a feel for what the threshold is, and you can sense when the wheel is about to lockup and adjust brake pressure accordingly. Since dirt is a lot more varied than the road, this will require you to track all the different surfaces and anticipate large changes in brake pressure.
For mtn biking, I personally threshold brake the rear, but I leave a much larger margin for error in the front for obvious reasons.
Since most braking occurs in the front this necessarily implies that I use more brake pressure in the front, considerably so since I’m generally pointed downhill and the majority of the weight will be on the front (and hence more traction and braking power).
Oh just some quick support for my argument that if you can lock up your wheels at will, than bigger badder brakes would be useless.
Assuming you have sufficent braking power to lock your wheels at will, what are bigger badder brakes going to do? extra lock up your wheels to a greater degree?
See the logic? It’s all in the available traction of your tires.
Might as well dish out some cornering theory since it is semi-related albeit tangential.
Caveat: once again, knowledge is auto racing based, but I fail to see how dirt is that much different since my focus is on tire traction (cars race on dirt too ya know =P)
First a defintion:
Slip Angle: The angle between the direction the tires are pointed vs. the direction actually travelled. So in another words great slip angles = drifting.
Anytime you turn you will develop slip angles, albeit very low ones if you are travelling slowly.
Available traction varies with slip angle. Racing tires generally develop maximum traction around 5-6 degrees, street tires = more around 10 degrees (these are rules of thumb and in reality, it’s all contingent upon many factors, some listed previously)
So as slip angles increase, so does traction, I have a lot of graphs but no scanner, but for those interested a quick internet search should yield results.
Once you hit the slip angle that develops max traction and you exceed it, traction starts tapering off. Different tires have different personalities. On unforgiving tires, the traction plummets after you hit the optimal slip angle; on forgiving tires its a gradual tapering.
Stated earlier once you greatly exceed the optimal slip angle the rule of thumb is that about 30% of the traction dissapears.
So this is why drifting on pavement is so slow. Dirt is another story. On loose gravelly type roads, maximum traction is actually at greater slip angles (don’t take my word for it, youtube some WRC races ).
Actually even on pavement there are some reasons to throw that rear around: extremely tight corners in low traction conditons (i.e. rain soaked track)
So there you have it, now you have an idea of how to rail those flat turns =P
I’ve always wondered why no one bothered applying the wealth of knowledge in auto racing to bikes. Which makes me wonder if I am missing something that makes it completely inapplicable. . . .
Only thing I can think of is that flat turns are only a fraction of the turns out there on any DH track since there are so many ruts/berms to use. So the use of this knowledge is limited.
Plus I bet the top World Cup racers know all this info intuitively through feeling. Afterall, I don’t have to understand how all these pretty pictures/movies/words on my computer screen ultimately boil down to strings of O’s and 1’s to use my computer effectively.
Thanks for the info.
Much of it applies straight across.
That was quite the read there! Very informative!
Almost every bike I’ve owned had a set of soft compound DH tires, a higher end suspension, and hydraulic disc brakes. Since I’ve kept these three constant, I’ve never really had to worry about the different braking threshold of a different setup.
I went out again today for a quick ride and found the tires more than adequate even with some pretty muddy terrain.
I did state something that was a bit inaccurate by itself, so let me clarify it.
I stated that if you can lock up the wheels, then bigger brakes are useless. Not quite, there are some advantages to larger brakes such as heat dissipation for example (more surface area).
8″ rotors would give you more piece of mind (in terms of fading/consistency) than 6″ rotors in races like the mega-avalanche where heat may be an issue.