Forum menu
tinsy - Member
GW op is talking about loose gravel and stones as his problem surface I dont care what tyre you got, [b]you wont find enough grip to fold the tyre on that surface.[/b] Maybe something Massey Ferguson use!
no matter how many times I read what you typed, you're still talking shite! FFS! of course you can fold a tyre on loose gravel/stones!
If its flat maybe!!
+1 High Roller
GW. I've never folded a tyre over on the rim, or seen anyone do it with tyre pressures I've recommended for them. I realise that it is weight dependent, which is why I mentioned my own weight. Also terrain makes a big difference, but very much more from the point of view of pinch flats than anything else. The first indication that you've gone too low on tyre pressure will almost always be pinch flats, not this mythical "folding over" crash.
In my experience most people who are feeling like they want more grip could do with taking some air out of the front tyre and not looking down. Not all people. But most. Also I have found that tyre pressure makes a bigger difference than tyre brand or model if we're talking about choosing from regular trail tyres. The tyres in the OP question are not bad tyres.
I love Fire XC's as a dirt cheap decent allrounder, but they're complete rubbish in terms of grip compared to a highroller or minion, even in 'hard' 60a compound. But then Fire XC's roll way better 'cos they're harder.
'Folding over', I think its a lot to do with riding style and rim width, as much as pressure. I can fold tyres over left, right and centre if I'm running them at less than 'bike-upright most of the time XC' pressure (35psi plus), and can fold anything that dosn't have damn sturdy sidewalls on any rim if its run at 30spi or less. Kenda for example, I find I have to run in excess of 35-40 psi to prevent them folding and dumping me on the deck if I corner hard. Swap to HRs, drop the pressure to 25 psi, no problems. I only weigh 80kg, so not too much of a biffer, but then I'm not smooth, the bike goes from verticle to horizontal in a flurry of bandyleggedness when I'm pushing on.
I love Fire XC's as a dirt cheap decent allrounder, but they're complete rubbish in terms of grip compared to a highroller or minion, even in 'hard' 60a compound. But then Fire XC's roll way better 'cos they're harder.
Why is it that I find the exact opposite experience to several people on here? I've found the HR to be no better than cheap tioga tat.
Swap to HRs, drop the pressure to 25 psi, no problems. I only weigh 80kg, so not too much of a biffer, but then I'm not smooth, the bike goes from verticle to horizontal in a flurry of bandyleggedness when I'm pushing on.
HRs less than 40psi and I pinch on every last rock, horrific tyre.
coffeeking - on a hardtail or FS?
Minions here at about 30psi, no probs in alps,lakes,spain.
short travel full sus (NRS on 3.5" setting)
DH tubes then you can run 20psi 😛
GW.
Wind your neck in !.
[i]no matter how many times I read what you typed, you're still talking shite! FFS! of course you can fold a tyre on loose gravel/stones!
[/i]
I do believe you're talking twoddle. Weres the grip going to come from on a [b]loose[/b] surface, of a magnitude to cause the tyre to fold, [b]before it slides[/b], eah ?.
Tyres slide for lack of traction, they fold for reasons to do with resultant forces from good traction and meeting anchored obsticles such as roots, etc. If a tyre folds, it does so cos its well [i]anchored[/i]
A tyre may grip an object, but if that object is a loose stone, you're gonna slide, and way before the tyre folds.
Grip, Traction, two different things.
Tinsy knows alot about his chosen subject and is worth listening to, ime.
Keep reading, and calm down
😉
Solo
High Rollers are great tyres (ask half the World Cup DH riders), way grippier in the corners than a Fire XC. However like many squareish, big side knobbed tyres you have to lean them over to get them to grip, and they'll feel a bit vague if only half leant over. If you don't corner hard or lean your bike much the fire XC probably does feel grippier.
Oh and tyres do fold at low pressures, though more likely on the rear than the front, unless you're doing something very odd.
Tyres can be quite personal, and people have normally only had experience on a limited range of the 100s out there. I generally use Minnion up front and High Roller rear in various forms depending on type of riding. I like them, I’m used to them and I’ll stay with them - I'm not going out to buy x number of other tyres just to try them.
But with regards to grip, especially on loose stuff you need to learn to 'feel' for it. Not something you can just pick up overnight, but a good way of practicing is to find a nice big loose surface car park (or equivalent) and go and hoon around like a chav in a Nova! Don't have to go silly fast, just mess around with different body/bike positions, force the bike around, make and expect it to slide. You’ll start to feel when its gripping and what makes it grip more or less.
My recommendation of the Blue Groove usually goes down well because unlike the High Roller, the Blue Groove is very progressive in terms of grip as you lean over. It might not be the outright grippiest tyre in the turns but it's very grippy all over at all angles.
In that respect it's quite a confidence builder because you can keep banking it over a little at a time and gradually build speed and confidence.
High Rollers are great tyres (ask half the World Cup DH riders), way grippier in the corners than a Fire XC. However like many squareish, big side knobbed tyres you have to lean them over to get them to grip, and they'll feel a bit vague if only half leant over. If you don't corner hard or lean your bike much the fire XC probably does feel grippier.
I do lean over quite happily. As I say, they grip to a point and then let go, whereas the XCs seem to be a bit vague initially and then seem to dig in. Maybe it's weight and pressure related.
Swap to HRs, drop the pressure to 25 psi, no problems. I only weigh 80kg, so not too much of a biffer, but then I'm not smooth, the bike goes from verticle to horizontal in a flurry of bandyleggedness when I'm pushing on.
HRs less than 40psi and I pinch on every last rock, horrific tyre.
Run my HR at 25psi or less (LUST) no issues agree with first quote. Works fine Afan Cyb Cmwcarn. 40psi and u pinch flat? Something not right m8.
Gap road final descent take 1 - Kenda BG & Nevegal 2.1, 40psi = 3 pinch flats over 150 yrds.
Gap road final descent take 2 - HR 2.35 F&R, 25 psi = warp speed, no flats.
What are you doing to pinch a HR? My HRs are the single ply too! I've got dings in the rim without pinching the tubes when using HRs!
Too much of this is about riding styles, terrain, preferences and the like for any one answer to be right.
GW - if you are still reading this thread could you e mail me ( in profile) - I'd like to pick your brains about something Ta.
Ok, Glen, tinsy, Solo lets calmly dispell the Myth for you all.
try running about half your usual pressure on your front tyre. then try leaning hard into a flat turn weighting the front wheel for "traction", what happens? the tyre squirms. Why? because the sidewall will deform (ie. the tyre folds) and you lose grip. doesn't really matter how loose the surface is, it's your weight pushing the tyre tread sideways under the rim that causes it. it doesn't need a firm surface to fold, it can still fold even while you are sliding.
Ok, so I've exaggerated the conditions to make my point but you can surely see the effect too low a pressure on too flimsy a sidewall will have under cornering and that the specific pressure/sidewall stiffness required to stop this happening will vary between heavier/lighter or faster/slower and less/more tentative riders.
Tyres slide for lack of traction, they fold for reasons to do with resultant forces from good traction and meeting [B]anchored obsticles such as roots, etc. If a tyre folds, it does so cos its well anchored[/B]
Solo - after you've tried what I suggest above, come back and tell me if you still believe what you wrote?
YGM TJ
You've gotta laugh at weekend warriors and their obsession with tyres, it's riding a bike, not very quickly, on bumpy stuff, rather than F1...
Half my usual pressure would be about 14psi! You're just making an absurd case that has nothing to do with what I suggested.
I don't suggest people run the [i]wrong[/i] tyre pressure, but commonly they can safely and usefully go lower. I can't really see what is so controversial about that! For almost anyone (below 18 stone or more) if the tyre is rock hard and you can't squidge it a bit with your fingers you are missing out on traction. Obviously there is a lower limit, I never said there wasn't.
Seems to me you have either mis-read or failed to read what I said, and then formed an opinion about the thing you haven't even read!
Glen
Not absurd at all. I'm simply trying to explain something to deaf ears!
If I tried to scrub a hip with a 2.35 single ply at 27psi (the pressure you run?) it would fold on the take off. I know this to be FACT from experience.
So why is it that you are full of advice for others but not even vaguely open minded enough to try something that may open your own eyes?
Yet you're happy to dispell the fact that tyres can fold over as a myth.
crikey, it's way more gnar than F1.
GW, I do not dispute what your saying, I have raced & ridden offroad for 30+ years now, MX, BMX, CYCLE SPEEDWAY, MTB, won a hell of a lot of stuff along the way and still doing so.
What your saying is bang on, bar 1 thing, the op was on about GRAVEL, & LOOSE STONES, the equivilent of riding on marbles, now I guess that needs defining, and what I am thinking of is pea to larger stone sized bits on top an otherwise hardpack. (nah sod it gravel and stones is enough of a description)
Of course riding this fast is all about technique, I said as much and gave an example on how to weight the bike, I further went on to back glenp in the theory that if it looks slippery you are more likely to slip on it due to how your brain works, this happens, and happens to everyone to an extent. (I have never mentioned pressure, dropping it, upping it etc etc etc)
Bike setup, tyre choice etc will help to an degree, but nothing, and I really mean nothing is going to grip on that surface (did I mention it was gravel and loose stones?) enough to unseat a tyre even at unrealistically low pressures. Their isnt a surface to grip after all, you might grip the stones, you might grip the gravel and yeah you get traction, you might even make the turn, but those stones and that gravel are moving on the ground underneath.
What are you doing to pinch a HR? My HRs are the single ply too! I've got dings in the rim without pinching the tubes when using HRs!
Consistently pinch on the section between The Breech and Full Bore on carron valley (possibly the least rocky trail centre I know of!), it's becoming a joke in fact - I let people go first despite being considerably faster, as I don't want to get in the way when I flat as I know I will. No major impacts either, just mild rockiness. I've swapped out to XCs and had no problems at all, despite running lower pressures. Running an MTB tube. 2.1 120TP ones, running on a D521 rim.
Might as well just run the tyre flat then, and you'll get all the fold you want.
The scenerio you describe would most likely result in a crash, regardless of [i]what tyre[/i]...which I believe was the original Q.
Why ?. Well, we should accept that tyres require a [b]minimum pressure to operate as intended[/b] and if you're folding your tyre on a loose surface (emphaisis on the loose surface), before it loses traction, then it could be argued that you're not running the tyre correctly in the first place.
After all, the intent for a tyre is to grip and provide traction, and not to just fold at the first sign of a direction change for the bike.
Folding a tyre is the result of a force generated by traction at the tread, upon the surface the tyre is in contact with.
On a loose surface, by its very nature, one should not have significant traction on a loose surface, therefore the tyre shouldn't fold.
The tyre will slide though as it will not grip a loose surface, but rather it will grip the moveable elements of that surface (the stones, sometimes described as the "marbles effect").
So, if I do as you suggest, and let my tyre down 5psi (whatever), then lean right over the bars, I'm going to see the tyre "squish" as a consequence of trapping the tyre while it is....under inflated, between my weight and the ground.
Relevance to real world riding ?, Zero.
Run a good tyre that you like, run it at a sensible pressure, enjoy.
For what its worth, I ride MUD X all year round.
[i]You've gotta laugh at weekend warriors and their obsession with tyres, it's riding a bike, not very quickly, on bumpy stuff, rather than F1...
[/i]
I agree, just get out there and ride.
🙂
Cheers.
Its all good fun
🙂
Solo
[Attention seeking cry] back to me. I used to ride an entry level HT and I have never experienced this before.
New bike is a spesh fsr xc, I now feel like I'm riding on marbles.
[s]Lack of[/s] Technique is the same.
Could it be my over active fork/shocks giving me less grip.
If I tried to scrub a hip with a 2.35 single ply at 27psi
GW are you by any chance, sick to the power of rad?
25psi in 2.35 single plies works fine for me. But then, I'm not.
Chuck, lots of variables going from one bike to another. Could just be that you're going faster into corners on the FS than before...?
Stick on the tyres you're comfy with. While some people seem to think tyres have zero effect, I think most of us agree that they do make a fair difference, sometimes night and day, so why not put on the tyres you were used to? But first experiment with different pressures as much as possible.
Sorry i am short of hand bags to join the feast
Maxxis high roller super tacky.
Chuck, when did you swap bike? not about the same time the ground dried up by any chance?
Loads less grip to be had on my local ride since its been hardpack, and its also a lot faster too, wich highlights the less grip quite a bit.
ADH: I have had similar pinch-flat experiences with Kendas. I fixed it by going ghetto tubeless but with pressures of 25/30 psi; I'm 12 stone and a bit of a mincer.
With Maxxis Adv and HRs, I run a bit more pressure e.g. 30/35 with no problems. I pinch flatted the front HR by ramming into a sharp rock at Afan, but that's it.
The edges are very square on the HR and I find it noticeably affects steering, but is inspiring once you get used to it. I think it feels nicer to corner than the Nevs I had. The Adv are a bit more rounded but still have these continuous and strongly supported side knobs which I like.
I haven't experienced rolling off the rim yet, bit I'm a mincer so maybe I won't.
elliptic - Yes I agree too many variables. I'm not going as fast as I normally would though.
coffeeking - I'm going to try old tioga tyre at the front after I have experimented with pressures.
juan - I'm swaying to the maxxis high roller super tacky if all else fails.
It's been said above that it could be my negative thinking that the tyres aren't gripping enough. If I spend £25 on a new tyre that gives me the placebo effect on grip, then it's money well spent.
Thanks for all your input though.
coffeeking - Member
....A light fairy might be able to deal with 25psi (11-12 stone is fairly light for a chap),
No it isn't, or at least it shouldn't be. Take a look here:
For an average height bloke (5'10") the middle of the green range is about 11st.
If I spend £25 on a new tyre that gives me the placebo effect on grip, then it's money well spent.
There is always that factor 🙂
Also, don't discount what Tinsy said about dry surfaces - always takes me a while to adjust this time of year.
Minions.
One thing that's important is never fit a rear tyre that's more grippy than the front, so if you go for Minions, a 42A front & a 60A rear is good. You can use 2 fronts for ultimate cornering grip or a front/rear for slightly better climbing.
Soz if this has already been said, didn't have time to read everything...
appologies for the thread resurection.
Tinsy - I honestly can't think of anywhere I've ever ridden that has a loose stoney surface as slippy as you're describing! (do you ride actual marbles/ball bearings or are you maybe exaggerating a little?) But even if I could find such a surface, the majority of trail surface wouldn't be quite as freakishly slippy so for me, running the pressures Glen advised (sub 30psi) would be a very bad decision. FWIW I still say that said under pressure tyre would fold* in a loose stoney corner if pushed enough whether it's dust, sand, snow, blaise, driveway chippings, loose rocks, pebbles or garden peas (not frozen :wink:)
*to clarify, by "fold" I mean the carcus folding not the bead ripping clean off the rim
Glen - Bottom line is, recomending sub 30psi to all is way off and the fact you've stated here that you've never witnessed or experienced a tyre folding at all simply highlights your lack of experience.
Ps. 12.5st is the average weight for a UK adult male so I'd conseder 11st to be light.
solo - do you never push your tyres into the ground harder to find more grip as it gets looser/slippier?
now, I'm off to get sideways in some nice loose dry local turns.
Rad! 8)
I have to say one mans pleasure is anothers poison. There are so many variables with the problems discussed here that you're almost in need of finding a short section of trail that you can keep riding over and over again whilst you change variables such as fork/shock pressure, rebound, compression, etc. stem angle, bar height, tyre pressures, etc. until you find the optimum, or else develop a sound enough understanding to tweak these variables for different trails/conditions.
Sometimes though, if you've got it into your mind its the tyres nothing will put you right until you replace them/it.
People warned me that a Nobby-Nic would have weak sidewalls and be puncture prone, but on a 'proper' off trail XC ride around Cannock through bushes, woods, the lot I got nothing at all in 25 miles running 2.25 at 35 psi up front and 2.1 at 40 psi rear. I could have dropped them 5 psi, but I decided to leave them higher to reduce the tendency to pinch flat.
I ran Conti MKs UST on a Five Pro and never had a problem, but just never got a warm feeling. Switched to a HR LUST up front and it I just felt secure and planted regardless. But I was going to be doing some gentler XC so dropped the MK back on the front. After a technical section I was cruising on a linking path and washed out on a gently descending bend. I ended up in A&E with a shoulder injury (not dislocated, but all pulled apart and opened up). I swear it wouldn't have happened with the HR on. I don't know if I washed out because of: a lack of grip, lack of front end weight or because I rolled the tyre on the rim somewhat.
However in the snow I've been using a MK protection (black chilli) on my R8 and it is superb.
I've always been told, and practice, tweaking tyre size/pressure/type to bias grip to the front. From what my LBS was saying Specialized do this now by using the more aggressive tyre up front and (even with same front and rear) using an S-Works 120tpi front (more malleable) and a control 60tpi rear (less malleable and more robust).
Anyway, my penneth worth feel, if you disagree, thats fine I ain't going to change peoples minds as we're all individuals with our own opinions 😉
Cheers Harvey
You want front end grip?
You want one of these with 6psi in it.
[url= http://farm6.static.flickr.com/5161/5223705892_2194e14ed4_z.jp g" target="_blank">
[url= http://www.flickr.com/photos/stu-b/5223705892/ ]2010_1201snowjones0028[/url] by [url= http://www.flickr.com/people/stu-b/ ]singlespeedstu[/url], on Flickr