Understanding Downhill Tyres
mbuk is da best
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The more I ride it, the more i get into downhill. I was just wondering what size tires and what pressures do you want for different conditions also is do you always want a tacky compound?
[Mod] The Mod would like to point out that "tires" is spelt 'tyres' Hopefully the posts below should help a lot of people get thier heads round the masses of downhill tyres out there. [/mod]
[Mod] The Mod would like to point out that "tires" is spelt 'tyres' Hopefully the posts below should help a lot of people get thier heads round the masses of downhill tyres out there. [/mod]
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Quick run through of Tyres and there uses:
Dry - Maxxis Minion, Michelin Comp 24, Comp 32
Dry/intermediate - High roller, Comp 16
Intermediate - Maxxis Swampthing
Wet - Wet Scream, Mud 3
Tyre size is dependant on Weight, conditions.
For example: I'm running 2.5 High Roller 42a Front and rear. I'm quite a heavy rider and like to run my tyres at lower pressures than most.
It is suggested that smaller riders run a smaller tyre, and larger riders run bigger tyres.
You always run either same sized tyres front and rear, or a smaller rear tyre. This ensures that the bike is theoretically balanced front to rear, or the rear will break away first, which is easier to control, compared to the front breaking way.
Another one is tread direction, all tyres have a rotational direction. You also get tyres that are Front/Rear specific. The front tyre is designed to corner and brake, and the rear is designed to put down traction, breaking and cornering.
With tyres such as the High roller, IRC Kujo, etc, some people turn the rear tyre around to give more traction when braking.
Yet more confusion, some people mix and match tyres to change the grip balance the bike. For example, a maxxis high roller on the front, minion on the rear, i have used this set up, work very well in dry to intermediate conditions.
A grippier tyre is always used up front, a few combinations:
front/rear
High Roller/Minion R
Swampthing/High roller
Wet Scream/Swampthing
Comp 16/ Comp 24
A pair of Dual Ply, 42a compound, 2.35 or 2.5, Maxxis High rollers will cope in almost all conditions.
Inbred
Tyre type:
Deep thick shitty mud: Wet Scream, Thin tyre with huge spikey knobbles that digs into the poo to give you grip, it's thin to give you mud clearance.
Slime and thick mud: Swampthing, a tyre with high profile, widely spaced knobbles, use the thinnnest that is safe to use given your weight and the course.
Wet conditions, loose stuff over harpack: Highroller, the do everything tyre. It's quicker than the swampy or wet scream and will do the job if the surface is loose or if you've got a wet surface without significant mud.
Bone dry hardpack and rocks: Minions, Much quicker than any of the others because of lower rolling resistance. Only useful if there's no mud though.
Tyre Width
You need to match tyre width to conditions, tyre, tyre compound, rider weight, course type and bike.
A wide tyre will give you more grip if the surface isn't thick mud. A wide tyre also allows you to run lower pressures giving still more grip. A wide tyre also protects your rims from roots and rocks.
A thin tyre is much faster than a thick one due to the much lower rolling resistance and the fact that they're simply lighter. They are much more vulnerable to being overcome by rocks and roots and your weight, so you need to run a higher pressure in them (incidentaly, reducing rolling resistance still further).
If you're after going fast, fit a thin tyre, if you want to survive (for example at Ft bill or in France) then get a thick tyre.
Compound
It's a dark art that only proffesional race mechanics understand. Someday they will reveal thier secrets....
Not really, it's dead simple.
put simply, you've got three compounds with maxxis.
Slow-reezay 40a, which is mega mega soft, and expensive.
Super-tacky 42a, which is still pretty soft, but not quite as steep
Maxxpro which is about 60a Oh yeah, they're dirt cheap and have a red stripe too.
The slow reezays and supertackys being mega soft work miracles on rocks and roots. They grip whee you would have never thought grip was available. Go to a race with slippy roots or rocks in without soft comound tyres on and you can forget finishing, let alone doing well.
The maxxpros are gods gift to the budget racer though, fit some of these and you've got them for a year or so, so long as you keep them off the road. They simply don't wear anything like as fast as the others. They don't grip damp roots or rocks though, so not really a bringewood or caersws tyre. I use a set of maxxpro highrollers myself for practice on the local course.
Soft compound tyres have a high rolling resistance, so if you go for supertacky or slow-reezay, make sure you get a thin tyre to make up for it. Likewise, hard compounds offer a lower rolling resistance, so you can afford to have a bigger one. You'll see lots of big, harder compound tyres at Ft Bill and in france, mostly because people are going to be dragging the brakes a lot, meaning soft compounds would wear too fast.
Pressure
Dead easy. Find a nice healthy balence for yourself on your local track. If you're short on grip, let a little out, if you're hitting the rims, put some more in. Big tyres require less pressure, little tyres require more, and so on.
Balence all that out and you should know what you want.
I have three sets:
Maxxpro Highrollers in 2.5"
Supertacky Highrollers in 2.35"
Supertacky Swampthings in 2.3"
They pretty much cover all eventualities for my small and spindly body. If you're a bigger chap, get some bigger tyres, unless it's muddy of course.
Don't ask me about what compound you should use for wet screams, no-one knows, should you use hard compound to stop the knobs folding? Or soft so you grip the roots inbetween? It's confusing!
T-Unit
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If you choose Maxxis, get the dual ply's. Also invest in some decent tubes, Maxxis, Hutchinson (my choice), IRC all make some excellent tubes. They'll pretty much remove the chance of punctures.
Rim choice is also a factor in tyre width, if you've got wide rims, say a mavic EX729, D321, Doublewide. You should choose a wider tyre, to keep the tyre profile round, as this will keep the tyre at its optimum shape.
Inbred
As for rims, best just choose a proper 21mm wide world beating rim in the first place [:D]
wet scream is the mud tyre, not swampthing.
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Wet Scream
Sav, Depends what type of mud though.
Inbred
i was led to believe that the wet scream was for that real deep thick sh*tty mud,the sort that'd suck your wellies off![;)]
was just pointin out in chasealexs post that the wet scream would be better for deep thick sludge.
confusing though,if you went by the names you'd think they were meant for each others use...if that makes sense.
My Bicycle
keep \'er lit
The Swampthings are a mud tyre, but will cope with intermediate conditions as well. Wet screams are for when its real deep mud.
Inbred
Both are Mud tyres. You've got to make the judgement on which to run.
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Inbred
360s tyre wisdom:
further general rules
1. Bigger tyre on the front, or same size f&r, quite simply you want more grip on the front wheel, its what you initiate a turn with. If the back end starts to go on a corner you can usually save if it , if the front end goes you've probably had it. Unfortunatley for those big hit owners out there this makes things more awkward but MMA are now doing a wider range of maxxis 24 tyres.
2.Pressure, i run pretty much 30psi everywhere no matter what im doing, sure if you run less pressure you get more grip however at 20psi or so its very inconsistent because theres no longer enough pressure to support the carcass properly, the tyre can start to tuck under and all sorts. Secondly rolling resistance , with soft tyres you might be able to pin a couple of corners tighter and save a few tenths but with harder tyres your gonna roll faster over the whole course.
things to think about:
1. wide tyres are for bad riders, well ok thats abit of a generalisation but hear me out...
take a maxxis tyre in 2.35 and 2.7 both will have almost exactly the same size side knobs and thats what your cornering on, sure your gonna get a slightly larger tyre footprint on the 2.7 but the difference is nothing compared to the masssively lower rolling resistance on a 2.35.
So why bother with big tyres at all? thin tyres deflect easily , if you clip the edge of a rock its gonna send you off line, a big tyre wont do that so much. you also get much better straight line braking with a big tyre.
So if you can hit your lines spot on and you dont need to brake to much then a smaller tyre is for you. But if riding through a 6inch gap at 30mph presents problems then fatter tyres are the one.
2. compound chances are spending lots of money on supertacky or slow reezay tyres wont do much for you. sure stick on on the front where its gonna last but bung a maxxpro on the back and save some cash rather than 0.25secs.
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Inbred
I`ve spent quite a few years riding motorcycles and have allways taken a vested interest on what is keeping me upright . A tyre that gives you confidence in your braking and cornering will allow you to be a lot more happier and enjoy your riding . You`ll know when you have achieved this after a good day out and you realise you were Hammering and were in control without having to think about it . At the end of the day there will be advice that EVERYONE agrees with but there is also a LOT of advice that people will disagree on , take what is said to you on advisement and give it a whirl .... you have nothing to lose but your skin , confidence , kneecaps , teeth , expensive bike bits ....... just kidding ;ª)
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Grip, the lower the pressure the higher the grip.
Sidewall support, if you have too lower pressure you'll find the tyres fold under cornering/jumping.
Rolling resistance, the higher the pressure, the faster the tyre will roll.
Then you have to factor in you.
Your weight, heavier people will need to run higher pressures as they transmit more force into the tyres.
Suspension travel, longer travel bikes will let you run lower pressures, as less forces are transmitted from the rider to the tyres. Opposite with hardtails and short travel bikes.
Your riding style, pinch flatting often and suchlike
Inbred
Whats MMA?
If you die riding, you die happy
Raleigh also distribute Maxxis tyres.
Inbred
What about the medusa tyre?
Or the minion?
Can you get the wet scream in 24?
Has anyone ever put a wet scream on the front and a swamp thing on the back? If so what was it like?
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Read the whole topic again, and all your questions will be answered.
Inbred